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      Studi epidemiologici (2020 - 2017)

        [ultimo aggiornamento 25/11/2020]  


Nosocomial pneumonia caused by water-born Legionella pneumophila in a pediatric hematopoietic stem cell transplantation recipient for thalassemia major

Erat T, Özdemir H, Yahşi A, Kara TT, İnce EÜ, Memikoğlu KO, Çiftçi E, İnce E.

Departments of Pediatric Infectious Diseases, Ankara University Faculty of Medicine, Ankara, Turkey.

Turk J Pediatr 2020;62(5):868-871.

Abstract: Background: Nosocomial pneumonia caused by Legionella pneumophila serogroup 2-14 occurred in a 7-year-old patient following allogeneic hematopoietic stem cell transplantation for thalassemia major. Case: The patient was diagnosed with nosocomial Legionella pneumophila by polymerase chain reaction (PCR) examination of the bronchoalveolar lavage and culturing Legionella pneumophila serogroup 2-14 from the patient`s room faucet water. Legionella pneumophila was eradicated from our hospital`s water distribution system by superheating and chemical eradication methods (hyper-chlorination and hydrogen peroxide). We did not detect any other case after this event. Conclusion: Early recognition of contamination of the hospital water system with Legionella proves the importance of prevention in new cases.


Healthcare-Associated Legionnaires' Disease, Europe, 2008-2017

Beauté J, Plachouras D, Sandin S, Giesecke J, Sparén P.

European Centre for Disease Prevention and Control, Stockholm, Sweden.

Emerg Infect Dis 2020 Oct;26(10):2309-2318.

Abstract: Healthcare-associated Legionnaires' disease (HCA LD) can cause nosocomial outbreaks with high death rates. We compared community-acquired LD cases with HCA LD cases in Europe during 2008-2017 using data from The European Surveillance System. A total of 29 countries reported 40,411 community-acquired and 4,315 HCA LD cases. Of the HCA LD cases, 2,937 (68.1%) were hospital-acquired and 1,378 (31.9%) were linked to other healthcare facilities. The odds of having HCA LD were higher for women, children and persons <20 years of age, and persons >60 years of age. Out of the cases caused by Legionella pneumophila with a known serotype, community-acquired LD was more likely to be caused by L. pneumophila serogroup 1 (92.3%) than was HCA LD (85.1%). HCA LD patients were more likely to die. HCA LD is associated with specific patient demographics, causative strains, and outcomes. Healthcare facilities should consider these characteristics when designing HCA LD prevention strategies.


The burden of legionnaires' disease in Belgium, 2013 to 2017

Fastl C, Devleesschauwer B, van Cauteren D, Lajot A, Leroy M, Laisnez V, Schirvel C, Mahieu R, Pierard D, Michel C, Jacquinet S.

Department of Epidemiology and Public Health, Sciensano, Brussels, Belgium.

Arch Public Health 2020 Oct 7;78:92.

Abstract: Background: Legionnaires' disease (LD) is a severe bacterial infection causing pneumonia. Surveillance commonly underestimates the true incidence as not all cases are laboratory confirmed and reported to public health authorities. The aim of this study was to present indicators for the impact of LD in Belgium between 2013 and 2017 and to estimate its true burden in the Belgian population in 2017, the most recent year for which the necessary data were available. Methods: Belgian hospital discharge data, data from three infectious disease surveillance systems (mandatory notification, sentinel laboratories and the national reference center), information on reimbursed diagnostic tests from the Belgian National Institute for Health and Disability Insurance and mortality data from the Belgian statistical office were used. To arrive at an estimate of the total number of symptomatic cases in Belgium, we defined a surveillance pyramid and estimated a multiplication factor to account for LD cases not captured by surveillance. The multiplication factor was then applied to the pooled number of LD cases reported by the three surveillance systems. This estimate was the basis for our hazard- and incidence-based Disability-Adjusted Life Years (DALYs) calculation. To account for uncertainty in the estimations of the DALYs and the true incidence, we used Monte Carlo simulations with 10,000 iterations. Results: We found an average of 184 LD cases reported by Belgian hospitals annually (2013-2017), the majority of which were male (72%). The surveillance databases reported 215 LD cases per year on average, 11% of which were fatal within 90 days after diagnosis. The estimation of the true incidence in the community yielded 2674 (95% Uncertainty Interval [UI]: 2425-2965) cases in 2017. LD caused 3.05 DALYs per case (95%UI: 1.67-4.65) and 8147 (95%UI: 4453-12,426) total DALYs in Belgium in 2017, which corresponds to 71.96 (95%UI: 39.33-109.75) DALYs per 100,000 persons. Conclusions: This analysis revealed a considerable burden of LD in Belgium that is vastly underestimated by surveillance data. Comparison with other European DALY estimates underlines the impact of the used data sources and methodological approaches on burden estimates, illustrating that national burden of disease studies remain essential.


Legionnaires' Disease on the Rise in Switzerland: A Denominator-Based Analysis of National Diagnostic Data, 2007-2016

Fischer FB, Schmutz C, Gaia V, Mäusezahl D.

Faculty of Science, University of Basel, Basel, Switzerland.

Int J Environ Res Public Health 2020 Oct 8;17(19):7343.

Abstract: The risk of falling ill with Legionnaires' disease (LD) is suggested to increase, but the global burden of disease is unknown due to a lack of appropriate diagnosis and surveillance systems. In Switzerland, the number of LD cases, captured by the National Notification System for Infectious Diseases, has more than doubled since 2008. This study aims to investigate this increase, contextualizing disease surveillance data with denominator data, which is not routinely available, i.e., the number of tests performed for Legionella spp. We collected the testing data for Legionella spp. of 14 Swiss diagnostic laboratories and calculated the positivity, defined as the proportion of the number of positive tests to the number of tests performed. The number of positive tests increased proportionally to the number of tests performed; hence, the positivity remained stable. However, the cause of the increase in test volume is unclear and has a large impact on the interpretation of the positivity curve. Further, the test outcome was found to be dependent on regional determinants, and the diagnostic method applied. The lack of understanding if and at which stage LD is considered in current case management of pneumonia patients limits the interpretation of observed heterogeneities in incidence or underestimation of LD in Switzerland. The absence of (or non-adherence to) existing guidelines and the heterogeneity in diagnostic testing hampers the comparison of data in the Swiss public health context. Therefore, diagnostic procedures should be harmonised across Switzerland and adherence to national LD management guidelines supported.


Frequency of Mycoplasma pneumoniaeLegionella pneumophila and Chlamydia spp. among patients with atypical pneumonia in Tehran

Noori Goodarzi N, Pourmand MR, Rajabpour M, Arfaatabar M, Mosadegh M, Syed Mohamad SA.

Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

New Microbes New Infect 2020 Aug 14;37:100744.

Abstract: Mycoplasma pneumoniaeLegionella pneumophila and Chlamydia pneumoniae are the most common bacterial agents, which account for 15-40%, 2-15% and 5-10% of atypical community-acquired pneumonia (CAP) respectively. These agents are mostly associated with infection in the outpatient setting. The aim of this study was to evaluate the frequency of these pathogens among patients with CAP attending outpatient clinics in Tehran. A cross-sectional study was carried out of 150 patients attending to educational hospitals in Tehran with CAP. M. pneumoniaeL. pneumophila and Chlamydia spp. were detected by PCR assay, targeting the P1 adhesion gene, macrophage infectivity potentiator (mip) gene and 16S rRNA gene respectively from throat swabs obtained from each patient. A total of 86 (57.3%) of 150 patients were women; median age was 50 years (interquartile range, 35-65 years). M. pneumoniaeL. pneumophila and Chlamydia spp. were detected in 37 (24.7%), 25 (16.7%) and 11 (7.3%) patients respectively; of these, 66 patients (44%) were infected at least by one of these three pathogens. The frequency of L. pneumophila was significantly higher among patients over 60 years old (p 0.03). Coinfection was detected in seven patients (4.7%); six were infected by M. pneumoniae and L. pneumophila, and only one was infected by L. pneumophila and Chlamydia spp. M. pneumoniae was the most prevalent agent of atypical CAP, and L. pneumophila was more likely to infect elderly rather than younger people. Further studies on the prevalence of CAP and its aetiologic agents are needed to improve the diagnosis and treatment of CAP patients.


Epidemiology of Legionnaires' Disease, Hong Kong, China, 2005-2015

Leung YH, Lam CK, Cheung YY, Chan CW, Chuang SK.

Hong Kong Department of Health, Hong Kong, China.

Emerg Infect Dis 2020 Aug;26(8):1695-1702.

Abstract: We reviewed findings of clinical, epidemiologic, and environmental investigations for 288 confirmed case-patients with Legionnaires' disease reported in Hong Kong, China, during January 2005-December 2015. We found that chronic renal failure/impairment (adjusted odds ratio [aOR] 4.09), chronic pulmonary diseases (aOR 3.22), malignancy (aOR 3.04), and heart diseases (aOR 2.15) were independently associated with a higher risk for severe Legionnaires' disease. However, patients with hyperlipidemia had a lower risk for severe outcome (aOR 0.17). Legionella positivity rate was 22% for 1,904 water samples collected. We found a higher positivity rate in summer months (28%-30%), which corroborated with months of highest rainfalls. Our novel finding that Legionnaires' disease patients with hyperlipidemia had a lower risk for severe outcome deserves further study to confirm the observation and ascertain the underlying reason.


Legionella pneumonia: increased risk after COVID-19 lockdown? Italy, May to June 2020

Palazzolo C, Maffongelli G, D'Abramo A, Lepore L, Mariano A, Vulcano A, Bartoli TA, Bevilacqua N, Giancola ML, Di Rosa E, Nicastri E.

National Institute for Infectious Diseases ‘Lazzaro Spallanzani’ IRCCS, Rome, Italy.

Euro Surveill 2020 Jul;25(30):2001372.

Abstract: We report a case of Legionella pneumonia in a dishwasher of a restaurant in Rome, Italy, just after the end of the lockdown that was in place to control the SARS-CoV-2 epidemic. The case highlights the importance of strict monitoring of water and air systems immediately before reopening business or public sector buildings, and the need to consider Legionella infections among the differential diagnosis of respiratory infections after lockdown due to the ongoing COVID-19 pandemic.


Exposure to potting soils and compost material as potential sources of Legionella pneumophilia in Australia

Loh CH, Soni R.

Department of Respiratory Medicine, Gosford Hospital, Gosford, New South Wales, Australia.

Respir Med Case Rep 2020 Jul 27;31:101156.

Abstract: Legionnaires' disease is a form of atypical community-acquired pneumonia usually caused by Legionella pneumophilia, which is typically associated with exposure to tower cooling or water systems. In Australia, Legionnaires' disease is more commonly caused by Legionella longbaechae, which is typically associated with exposure to soil or compost materials, and the presence of Legionella pneumophilia is less recognized. We report a sporadic case of Legionnaires' disease caused by Legionella pneumophilia serogroup 1 that was contracted following exposure to potting mix and topsoil.


Trends in Legionnaires' Disease-Associated Hospitalizations, United States, 2006-2010

Mudali G, Kilgore PE, Salim A, McElmurry SP, Zervos M.

Department of Pharmacy Practice, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan, USA.

Open Forum Infect Dis 2020 Jul 17;7(8):ofaa296.

Abstract: Background: Legionella pneumophila is a waterborne cause of both healthcare-associated and community-acquired pneumonia. Legionella pneumophila serogroup 1 is responsible for 80% of infections. There is currently limited published disease burden data on Legionnaires' disease-associated hospitalization in the United States. Methods: In this study, we estimated the annual incidence of Legionnaires' disease-associated hospitalizations in United States and identified demographic, temporal, and regional characteristics of individuals hospitalized for Legionnaires' disease. A retrospective study was conducted using the National Hospital Discharge Survey (NHDS) data from 2006 to 2010. The NHDS is a nationally representative US survey, which includes estimates of inpatient stays in short-stay hospitals in the United States, excluding federal, military, and Veterans Administration hospitals. All discharges assigned with the Legionnaires' disease International Classification of Diseases 9th Clinical Modification discharge diagnostic code (482.84) were included in this study. Results: We observed the annual incidence and number of Legionnaires' disease-associated hospitalizations (per 100 000 population) in the United States by year, age, sex, race, and region. Over a 5-year period, 14 574 individuals experienced Legionnaires' disease-associated hospitalizations in the United States The annual population-adjusted incidence (per 100 000 population) of Legionnaires' disease-associated hospitalizations was 5.37 (95% confidence interval [CI], 5.12-5.64) in 2006, 7.06 (95% CI, 6.80-7.40) in 2007, 8.77 (95% CI, 8.44-9.11) in 2008, 17.07 (95% CI, 16.62-17.54) in 2009, and 9.66 (95% CI, 9.32-10.01) in 2010. A summer peak of Legionnaires' disease-associated hospitalizations occurred from June through September in 2006, 2007, 2008, and 2010. Conclusions: Legionnaires' disease-associated hospitalizations significantly increased over the 5-year study period. The increasing disease burden of Legionnaires' disease suggests that large segments of the US population are at risk for exposure to this waterborne pathogen.


Transmission of Legionnaires' Disease through Toilet Flushing

Couturier J, Ginevra C, Nesa D, Adam M, Gouot C, Descours G, Campèse C, Battipaglia G, Brissot E, Beraud L, Ranc AG, Jarraud S, Barbut F.

Hôpital Saint-Antoine, Paris, France.

Emerg Infect Dis 2020 Jul;26(7):1526-1528.

Abstract: We describe 2 cases of healthcare-associated Legionnaires' disease in patients in France hospitalized 5 months apart in the same room. Whole-genome sequencing analyses showed that clinical isolates from the patients and isolates from the room's toilet clustered together. Toilet contamination by Legionella pneumophila could lead to a risk for exposure through flushing.


Large community-acquired Legionnaires' disease outbreak caused by Legionella pneumophila serogroup 1, Italy, July to August 2018

Faccini M, Russo AG, Bonini M, Tunesi S, Murtas R, Sandrini M, Senatore S, Lamberti A, Ciconali G, Cammarata S, Barrese E, Ceriotti V, Vitaliti S, Foti M, Gentili G, Graziano E, Panciroli E, Bosio M, Gramegna M, Cereda D, Perno CF, Mazzola E, Campisi D, Aulicino G, Castaldi S, Girolamo A, Caporali MG, Scaturro M, Rota MC, Ricci ML.

Agency for Health Protection of Metropolitan Area of Milan (ATS), Milan, Italy.

Euro Surveill 2020 May;25(20):1900523.

Abstract: In July 2018, a large outbreak of Legionnaires' disease (LD) caused by Legionella pneumophila serogroup 1 (Lp1) occurred in Bresso, Italy. Fifty-two cases were diagnosed, including five deaths. We performed an epidemiological investigation and prepared a map of the places cases visited during the incubation period. All sites identified as potential sources were investigated and sampled. Association between heavy rainfall and LD cases was evaluated in a case-crossover study. We also performed a case-control study and an aerosol dispersion investigation model. Lp1 was isolated from 22 of 598 analysed water samples; four clinical isolates were typed using monoclonal antibodies and sequence-based typing. Four Lp1 human strains were ST23, of which two were Philadelphia and two were France-Allentown subgroup. Lp1 ST23 France-Allentown was isolated only from a public fountain. In the case-crossover study, extreme precipitation 5-6 days before symptom onset was associated with increased LD risk. The aerosol dispersion model showed that the fountain matched the case distribution best. The case-control study demonstrated a significant eightfold increase in risk for cases residing near the public fountain. The three studies and the matching of clinical and environmental Lp1 strains identified the fountain as the source responsible for the epidemic.


A Snapshot of the Prevalence and Molecular Diversity of Legionella pneumophila in the Water Systems of Israeli Hotels

Yakunin E, Kostyal E, Agmon V, Grotto I, Valinsky L, Moran-Gilad J.

Central Laboratories and Public Health Services, Ministry of Health, Jerusalem 9134302, Israel.

Pathogens 2020 May 27;9(6):414.

Abstract: Exposure to Legionella spp. contaminated aerosols in hotel settings confers risk for travel-associated Legionnaire's disease (TALD). In this study, we investigated the prevalence of Legionella contamination and its molecular diversity in hotels and resorts across Israel. The study was comprised of a convenience sample of water systems from 168 hotels and resorts countrywide, routinely inspected between March 2015 and February 2017. Isolation and quantitation of Legionella were performed in a water laboratory using the ISO 11731 method. The distribution of Legionella isolates was analyzed according to geography and source. The genetic diversity of a subset of isolates was analyzed by sequence-based typing (SBT) at the National Reference Laboratory for Legionella and compared to the national database. Out of 2830 samples tested, 470 (17%) obtained from 102 different premises (60% of hotels) were positive for Legionella spp. In 230 samples (49% of all positive, 8% of total samples), accounting for 37% of hotels, Legionella spp. counts exceeded the regulatory threshold of 1000 CFU/L. The most frequently contaminated water sources were cooling towers (38%), followed by faucets, hot tubs, water lines, and storage tanks (14%-17% each). Furthermore, 32% and 17% of samples obtained from cooling towers and hot tubs, respectively, exceeded the regulatory thresholds. SBT was performed on 78 strains and revealed 27 different sequence types (STs), including two novel STs. The most prevalent STs found were ST1 (26%), ST87 (10%), ST93 (6%), and ST461 and ST1516 (5% each). Several L. pneumophila STs were found to be limited to certain geographical regions. This is the first study to investigate the prevalence and diversity of Legionella in hotels and resorts in Israel during non-outbreak environmental inspections. These findings will inform risk assessment, surveillance, and control measures of TALD.


Epidemiologic Survey of Legionella Urine Antigen Testing Within a Large Wisconsin-Based Health Care System

Toberna CP, William HM, Kram JJF, Heslin K, Baumgardner DJ.

Aurora Sinai Medical Center, Milwaukee, WI, USA.

J Patient Cent Res Rev 2020 Apr 27;7(2):165-175.

Abstract: Purpose: Legionella pneumophila pneumonia is a life-threatening, environmentally acquired infection identifiable via Legionella urine antigen tests (LUAT). We aimed to identify cumulative incidence, demographic distribution, and undetected disease outbreaks of Legionella pneumonia via positive LUAT in a single eastern Wisconsin health system, with a focus on urban Milwaukee County. Methods: A multilevel descriptive ecologic study was conducted utilizing electronic medical record data from a large integrated health care system of patients who underwent LUAT from 2013 to 2017. A random sample inclusive of all positive tests was reviewed to investigate geodemographic differences among patients testing positive versus negative. Statistical comparisons used chi-squared or 2-sample t-tests; stepwise regression followed by binary logistic regression was used for multivariable analysis. Positive cases identified by LUAT were mapped to locate hotspots; positive cases versus total tests performed also were mapped by zip code. Results: Of all LUAT performed (n=21,599), 0.68% were positive. Among those in the random sample (n=11,652), positive cases by LUAT were more prevalent in the June-November time period (86.2%) and younger patients (59.4 vs 67.7 years) and were disproportionately male (70.3% vs 29.7%) (P<0.0001 for each). Cumulative incidence was higher among nonwhite race/ethnicity (1.91% vs 1.01%, P<0.0001) but did not remain significant on multivariable analysis. Overall, 5507 tests were performed in Milwaukee County zip codes, yielding 82 positive cases by LUAT (60.7% of all positive cases in the random sample). A potential small 2016 outbreak was identified. Conclusions: Cumulative incidence of a positive LUAT was less than 1%. LUAT testing, if done in real time by cooperative health systems, may complement public health detection of Legionella pneumonia outbreaks.


Review Global seroprevalence of legionellosis - a systematic review and meta-analysis

Graham FF, Hales S, White PS, Baker MG.

Department of Public Health, University of Otago, Wellington, New Zealand.

Sci Rep 2020 Apr 30;10(1):7337.

Abstract: Legionella is a ubiquitous pathogen yet the global occurrence of legionellosis is poorly understood. To address this deficit, this paper summarises the available evidence on the seroprevalence of Legionella antibodies and explores factors that may influence seroprevalence estimates. Through a systematic review, a total of 3979 studies were identified with seroprevalence results published after 1 January 1990. We tabulated findings by World Health Organization (WHO) region, location, study period and design, composition of study population(s) for all ages in terms of exposure, sex, detection methods, IFA titre, Legionella species measured, and present seroprevalence point estimates and 95% confidence intervals. Sampled populations were classified according to income, WHO region, gender, age, occupation and publication date. We conducted a meta-analysis on these subgroups using Comprehensive Meta-Analysis 3.0 software. Heterogeneity across studies was evaluated by the Q test in conjunction with I2 statistics. Publication bias was evaluated via funnel plot and Egger's test. Fifty-seven studies met our inclusion criteria, giving an overall estimate of seroprevalence for Legionella of 13.7% (95% CI 11.3-16.5), but with substantial heterogeneity across studies.


Applying probability-weighted incubation period distributions to traditional wind rose methodology to improve public health investigations of Legionnaires' disease outbreaks

Bays D, Bennett E, Finnie T.

Public Health England, Manor Farm Road, Porton Down, Salisbury, UK.

Epidemiol Infect 2020 Feb 19;148:e33.

Abstract: In the event of a Legionnaires' disease outbreak, rapid location and control of the source of bacteria are crucial for outbreak management and regulation. In this paper, we describe an enhancement of the traditional wind rose for epidemiological use; shifting the focus of measurement from relative frequency of the winds speeds and directions to the relative volume of air carried, whilst also incorporating probability distributions of disease incubation periods to refine identification of the important wind directions during a cases window of exposure, i.e. from which direction contaminated aerosols most likely originated. The probability-weighted wind rose offers a potential improvement over the traditional wind rose by weighting the importance of wind measurements through incorporation of probability of exposure given an individual's time of symptom onset (obtained through knowledge of the incubation period), and by instead focusing on the volume of carrying air which offers better insight into the most probable direction of the source. This then provides a probabilistic distribution of which direction the wind was blowing around the time of infection. We discuss how the probability-weighted wind rose can be implemented during a Legionnaires' disease outbreak, and how outbreak control teams might use it as supportive evidence to identify the most likely direction of the contaminated source from the presumed site of exposure. In addition, this paper discusses how minor adjustments can be made to the method allowing the probability-weighted wind rose to be applied to other non-communicable airborne diseases, providing the disease's probability distribution for the incubation period distribution is well known.


Fatal Case of Legionnaires' Disease After Home Exposure to Legionella pneumophila Serogroup 3 - Wisconsin, 2018

Schumacher A, Kocharian A, Koch A, Marx J.

Bureau of Communicable Diseases, Division of Public Health, Wisconsin Department of Health Services.

MMWR Morb Mortal Wkly Rep 2020 Feb 28;69(8):207-211.

Abstract: In January 2018, the Wisconsin Department of Health Services, Division of Public Health (DPH), received a report of a culture-confirmed case of Legionnaires' disease. The patient, who was immunocompromised, had died at a local hospital 10 days after being admitted. DPH and an infection preventionist from the hospital investigated to determine the source of the infection and prevent additional cases. Because the case was suspected to be nosocomial, health care facility water samples were tested for Legionella. When these samples were negative, water sources in the patient's home were tested. These tested positive for Legionella pneumophila, and the bacteria remained after an attempt to remediate. The patient and home isolates were identified as L. pneumophila serogroup 3, sequence type 93, by whole-genome multilocus sequence typing. A second resident of the home did not become ill. This case highlights the potential for immunocompromised persons and others at risk for Legionnaires' disease to be exposed to Legionella through home water systems containing the bacteria and demonstrates the difficulty of home remediation. This case also illustrates the role of lower respiratory tract specimens in the identification of less common Legionella infections (e.g., L. pneumophila serogroup 3) and confirmation of the infection source.


The relevance of molecular genotyping to allocate cases in a suspected outbreak of Legionella pneumonia in patients with prolonged immunosuppressive therapy

Borella P, Vecchi E, Incerti F, Marchesi I, Meacci M, Frezza G, Fregni Serpini G, Mansi A, Paduano S, Bargellini A.

Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, Modena, Italy.

Int J Infect Dis 2020 Feb;91:174-176.

Abstract: Three cases of pneumonia caused by Legionella pneumophila serogroup 1 (Lp1) in immunosuppressed patients with repeated hospitalization were suspected as a healthcare-associated cluster. The environmental investigation did not reveal the presence of legionellae in the hospital patient rooms. Water samples collected from the homes of two patients were also negative for Legionella spp. In the absence of environmental strains potentially involved in the infections, we proceeded to genotype environmental Lp1 strains isolated in the hospital during routine water sampling during the decade 2009-2019 and recovered after long-term storage at -20°C. These 'historical' strains exhibited a high grade of similarity and stability over time, regardless of the disinfection systems. The different molecular profiles shown among the clinical and environmental strains excluded a nosocomial outbreak. The study suggests that the application of molecular typing may be a useful tool to discriminate hospital vs community-acquired cases, mostly for severely immunosuppressed patients in whom the symptomatology could be insidious and the incubation period could be prolonged. Moreover, the genotyping allowed us to exclude any link between the cases.


Legionnaires' Disease Cases at a Large Community Hospital-Common and Underdiagnosed

Spiegelman J, Pedutem T, Francisco MJ.

Humber River Hospital, Toronto, ON, Canada.

Int J Environ Res Public Health 2020 Jan 3;17(1):332.

Abstract: Legionnaires' disease (LD) is a severe pneumonia with a mortality rate of about 10%. The illness remains largely underdiagnosed with outbreaks occurring with alarming incidence. In this study, we assessed the frequency of Legionnaires' disease among pneumonia cases treated at a large community hospital over a summer season. We invited all admitted patients diagnosed with pneumonia, able to provide a urine sample for an antigen test, presenting from May to October 2018, to enroll in our study; 35 patients were tested for the presence of Legionella. Out of 33 patients tested, 9 (28%) were positive for Legionella. Three sets of the 9 Legionella cases exhibited spatiotemporal clustering indicative of LD outbreaks. Only one of the 9 Legionella UAT-positive patients presented a sporadic case of LD. The number of pneumonia cases in our community confirmed to be LD was strikingly high (28%), compared to other survey studies that report between 3.7% and 14%. These results are consistent with previous knowledge that LD is underdiagnosed and support that routine testing should be considered for all possible LD cases, particularly in the summer months. Such testing is likely to prevent further cases of community acquired LD.


Residential water heater cleaning and occurrence of Legionella in Flint, MI.

Rhoads WJ, Bradley TN, Mantha A, Buttling L, Keane T, Pruden A, Edwards MA.

Virginia Tech, Civil and Environmental Engineering, Blacksburg, VA, USA.

Water Res 2020 Mar;171:115439.

Abstract: After the Federal emergency in Flint, MI was declared in early 2016 in response to elevated lead-in-water and incidence of Legionnaires' disease, concerns arose that contaminants in residential water heaters could continue to contribute to poor quality tap water. Here, a comprehensive field survey of residential water heaters (n = 30) and associated water quality was conducted and the subsequent effects of an aggressive manual water heater clean-out was determined, including draining the tank and removing sediments via brushing and flushing. Before cleaning, inorganics accumulated in the tank sediments did not serve as a source of metals measured at hot water outlets. After cleaning, hardness- (calcium, magnesium, silica) and corrosion-associated inorganics (lead, iron, copper, aluminum, zinc) decreased by 64% in samples from sediment cleanout drain valves. Culturable L. pneumophila was only detected in 1 home (3.3%) prior to cleaning and 2 homes (6.7%) after cleaning, thus quantitative polymerase chain reaction was used to quantify potential effects on unculturable strains despite the limitation of differentiating live and dead cells. After the cleaning protocol, Legionella spp. and L. pneumophila gene numbers decreased or remained non-detectable in 83% and 98% of samples, respectively. Homes with less than 0.4 mg/L influent free chlorine tended to have quantifiable Legionella spp. gene numbers in water entering the home and had elevated L. pneumophila and Legionella spp. gene numbers throughout the home plumbing. Also, Legionella spp. and L. pneumophila gene numbers were highest for water heaters set at or below 42 °C and significantly decreased >51°C, consistent with Legionella's preferred temperature range. Examination of the only home that had culturable L. pneumophila both before and after the cleaning protocol revealed that the organism was culturable from several sample locations throughout the home, including in water representative of the water main. Notably, the home was located in close proximity to McLaren Hospital, where an outbreak of Legionnaires disease was reported, and the water heater had a setpoint within the Legionella growth range of 44.2 °C. Considering that other factors were more strongly associated with Legionella occurrence and water heater sediment was not detectably mobilizing to tap water, it was concluded that water heater cleaning had some benefits, but was not an overarching factor contributing to possible human health risks.


Clinical Presentation of Community-Acquired Legionella Pneumonia Identified by Universal Testing in an Endemic Area

Puri S, Boudreaux-Kelly M, Walker JD, Clancy CJ, Decker BK.

Statcore, VA Pittsburgh Healthcare System, Pittsburgh, PA 15240, USA; Division of Infectious Diseases, University of Pittsburgh, Pittsburgh, PA 15261, USA.

Int J Environ Res Public Health 2020 Jan;17(2):E533.

Abstract: The rapid identification of Legionella pneumonia is essential to optimize patient treatment and outcomes, and to identify potential public health risks. Previous studies have identified clinical factors which are more common in Legionella than non-Legionella pneumonia, and scores have been developed to assist in diagnosing cases. Since a Legionella pneumonia outbreak at VA Pittsburgh in 2012, nearly all patients with pneumonia have been tested for Legionella. The purpose of this study was to evaluate distinguishing characteristics between Legionella and non-Legionella pneumonia with the application of universal testing for Legionella in all cases of community-acquired pneumonia. We performed a retrospective case-control study matching Legionella and non-Legionella pneumonia cases occurring in the same month. Between January 2013 and February 2016, 17 Legionella and 54 non-Legionella cases were identified and reviewed. No tested characteristics were significantly associated with Legionella cases after Bonferroni correction. Outcomes of Legionella and non-Legionella pneumonia were comparable. Therefore, in veterans who underwent routine Legionella testing in an endemic area, factors typically associated with Legionella pneumonia were non-discriminatory.


Legionnaires' Disease Cases at a Large Community Hospital-Common and Underdiagnosed

Spiegelman J, Pedutem T, Francisco MJ.

Humber River Hospital, Toronto, ON M3M 0B2, Canada.

Int J Environ Res Public Health 2020 Jan;17(1):332.

Abstract: Legionnaires' disease (LD) is a severe pneumonia with a mortality rate of about 10%. The illness remains largely underdiagnosed with outbreaks occurring with alarming incidence. In this study, we assessed the frequency of Legionnaires' disease among pneumonia cases treated at a large community hospital over a summer season. We invited all admitted patients diagnosed with pneumonia, able to provide a urine sample for an antigen test, presenting from May to October 2018, to enroll in our study; 35 patients were tested for the presence of Legionella. Out of 33 patients tested, 9 (28%) were positive for Legionella. Three sets of the 9 Legionella cases exhibited spatiotemporal clustering indicative of LD outbreaks. Only one of the 9 Legionella UAT-positive patients presented a sporadic case of LD. The number of pneumonia cases in our community confirmed to be LD was strikingly high (28%), compared to other survey studies that report between 3.7% and 14%. These results are consistent with previous knowledge that LD is underdiagnosed and support that routine testing should be considered for all possible LD cases, particularly in the summer months. Such testing is likely to prevent further cases of community acquired LD.


Legionella pneumophila Occurrence in Drinking Water Supplied by Private Wells

Mapili K, Pieper KJ, Dai D, Pruden A, Edwards MA, Tang M, Rhoads WJ.

Virginia Tech, Civil and Environmental Engineering, Blacksburg, VA, USA.

Lett Appl Microbiol 2020;70(4):232-240.

Abstract: Unregulated private wells are understudied potential sources of community-acquired Legionnaires' disease. Here we conducted a comprehensive survey of 44 homes supplied by private wells in Wake County, North Carolina, quantifying Legionella spp. DNA, Legionella pneumophila DNA, and total bacterial 16S rRNA genes via real-time polymerase chain reaction in hot and cold drinking water samples, along with culturable L. pneumophila via IDEXX Legiolert in cold drinking water samples. Legionella spp. DNA, L. pneumophila DNA and culturable L. pneumophila were detected in 100, 65.5 and 15.9% of the 44 homes, respectively, and culturable levels were comparable to some municipal surveys applying the same methods. Total coliforms and Escherichia coli were monitored as representative faecal indicators and were found in 20.4 and 0.0% of homes. Within certain sample types, Legionella spp. and L. pneumophila gene copy numbers were positively associated with total bacteria (i.e. total 16S rRNA genes) and water softener use, but were not associated with faecal indicator bacteria, inorganic water parameters or other well characteristics. These findings confirm that occurrence of Legionella and L. pneumophila is highly variable in private wells. SIGNIFICANCE AND IMPACT OF THE STUDY: Legionella is the leading identified cause of waterborne disease outbreaks associated with US municipal water systems. While Legionella is known to occur naturally in groundwater, prior efforts to characterize its occurrence in unregulated private wells are limited to sampling at the wellhead and not in the home plumbing where Legionella can thrive. This work documents much higher levels of Legionella in home plumbing versus water directly from private wells and examines factors associated with higher Legionella occurrence.


Legionella pneumophila as Cause of Severe Community-Acquired Pneumonia, China

Yi H, Fang J, Huang J, Liu B, Qu JZhou M.

Ruijin Hospital, Shanghai, China.

Emerg Infect Dis Jan 2020;26(1):160-162.

Abstract: We report a case of community-acquired pneumonia in a patient in China. We verified Legionella pneumophila infection through next-generation sequencing of blood, sputum, and pleural effusion samples. Our results show the usefulness of next-generation sequencing and of testing different samples early in the course of illness to identify this bacterium.


A Cluster of Legionnaires' Disease in Belgium Linked to a Cooling Tower, August-September 2016: Practical Approach and Challenges

Hammami N, Laisnez V, Wybo I, Uvijn D, Broucke C, Van Damme A, Van Zandweghe L, Bultynck W, Temmerman WVan De Ginste L, Moens TRobesyn E.

European Centre for Disease Prevention and Control, Surveillance and Response Support Unit, Stockholm, Sweden; Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden.

Epidemiol Infect 2019 Dec;147:e326.

Abstract: A cluster of Legionnaires' disease (LD) with 10 confirmed, three probable and four possible cases occurred in August and September 2016 in Dendermonde, Belgium. The incidence in the district was 7 cases/100 000 population, exceeding the maximum annual incidence in the previous 5 years of 1.5/100 000. Epidemiological, environmental and geographical investigations identified a cooling tower (CT) as the most likely source. The case risk around the tower decreased with increasing distance and was highest within 5 km. Legionella pneumophila serogroup 1, ST48, was identified in a human respiratory sample but could not be matched with the environmental results. Public health authorities imposed measures to control the contamination of the CT and organised follow-up sampling. We identified obstacles encountered during the cluster investigation and formulated recommendations for improved LD cluster management, including faster coordination of teams through the outbreak control team, improved communication about clinical and environmental sample analysis, more detailed documentation of potential exposures obtained through the case questionnaire and earlier use of a geographical information tool to compare potential sources and for hypothesis generation.


Multiple Sources of the Outbreak of Legionnaires' Disease in Genesee County, Michigan, in 2014 and 2015

Smith AF, Huss A, Dorevitch S, Heijnen LArntzen VH Davies MRobert-Du Ry van Beest Holle M, Fujita YVerschoor AM, Raterman B, Oesterholt F, Heederik DMedema G.

KWR Water Research Institute, Nieuwegein, Netherlands.

Environ Health Perspect 2019 Dec;127(12):127001.

Abstract: Background: A community-wide outbreak of Legionnaires' disease (LD) occurred in Genesee County, Michigan, in 2014 and 2015. Previous reports about the outbreak are conflicting and have associated the outbreak with a change of water source in the city of Flint and, alternatively, to a Flint hospital. Objective: The objective of this investigation was to independently identify relevant sources of Legionella pneumophila that likely resulted in the outbreak. Methods: An independent, retrospective investigation of the outbreak was conducted, making use of public health, health care, and environmental data and whole-genome multilocus sequence typing (wgMLST) of clinical and environmental isolates. Results: Strong evidence was found for a hospital-associated outbreak in both 2014 and 2015: a) 49% of cases had prior exposure to Flint hospital A, significantly higher than expected from Medicare admissions; b) hospital plumbing contained high levels of L. pneumophilacLegionella control measures in hospital plumbing aligned with subsidence of hospital A-associated cases; and d) wgMLST showed Legionella isolates from cases exposed to hospital A and from hospital plumbing to be highly similar. Multivariate analysis showed an increased risk of LD in 2014 for people residing in a home that received Flint water or was located in proximity to several Flint cooling towers. Discussion: This is the first LD outbreak in the United States with evidence for three sources (in 2014): a) exposure to hospital A, b) receiving Flint water at home, and c) residential proximity to cooling towers; however, for 2015, evidence points to hospital A only. Each source could be associated with only a proportion of cases. A focus on a single source may have delayed recognition and remediation of other significant sources of L. pneumophila.


Evaluation of the National Surveillance of Legionnaires' Disease in Norway, 2008-2017

Wolff C, Lange H, Feruglio SVold LMacDonald E.

Division for Environmental Health and Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway.

BMC Public Health 2019 Dec;19(1):1624.

Abstract: Background: In Norway, Legionnaires' disease is reportable upon clinical suspicion to public health authorities and mandatorily notifiable through the Norwegian surveillance system for communicable diseases (MSIS) for both clinicians and laboratories. In the summer of 2017, several European countries reported high notification rates for Legionnaires' disease, which was not observed in Norway. We evaluated MSIS to assess if it meets its objectives of detecting cases and trends in incidence of Legionnaires' disease. Methods: We retrieved MSIS data from 2008 to 2017 and calculated timeliness as days from sampling to notification, and internal completeness for key variables as the proportion of observations with a value. Where possible, we assessed internal validity on the presence of a plausible value. To estimate external completeness and validity we linked MSIS with hospital reimbursement claims in the Norwegian Patient Registry. To assess acceptability and representativeness, we surveyed doctors in 39 hospitals on their units' diagnostic and notification procedures, and their use of MSIS. Results: There were 438 notified cases. Internal completeness and internal validity were high for key variables (≥95%). The median delay from sampling to notification was 4 days. There were 73 patients in MSIS only, 70 in the Norwegian Patient Registry only, and 351 in both registers. The external completeness of MSIS was 83% (95% CI 80-86%). For external validity, the positive predictive value of MSIS was 83% (95% CI 79-86%). Forty-seven respondents from 28 hospitals described testing procedures. These were inconsistent: 29 (62%) reported no systematic application of criteria for requesting legionella testing. Eighteen (38%) reported testing all patients with suspected pneumonia and a travel history. Thirty-one (66%) found the notification criteria clear. Conclusions: Our results suggest that the surveillance in MSIS can detect incidence changes for Legionnaires' disease over time, by place and person, but likely does not detect every case diagnosed in Norway. We recommend wider investigation of diagnostic procedures in order to improve representativeness and awareness of MSIS notification criteria among clinicians in order to improve acceptability of the surveillance. We also recommend a more comprehensive assessment of whether patients only registered in the Norwegian Patient Registry were true Legionnaires' disease cases.


Legionella and Legionellosis in Touristic-Recreational Facilities: Influence of Climate Factors and Geostatistical Analysis in Southern Italy (2001-2017)

De Giglio O, Fasano F, Diella G, Lopuzzo M, Napoli C, Apollonio F, Brigida S, Calia C, Campanale C, Marzella A, Pousis C, Rutigliano S, Triggiano F, Caggiano G, Montagna MT.

Department of Biomedical Science and Human Oncology, University of Bari "Aldo Moro", Piazza G. Cesare 11, 70124, Bari, Italy.

Environ Res 2019 Nov;178:108721.

Abstract: Legionella is the causative agent of Legionnaires' disease, a flu-like illness normally acquired following inhalation or aspiration of contaminated water aerosols. Our recent studies revealed that climatic parameters can increase the number of reported cases of community-acquired Legionnaires' disease. Here, we evaluated the presence of Legionella in water networks and the distribution of Legionnaires' disease cases associated with touristic-recreational facilities in the Apulia region (southern Italy) during the period 2001-2017 using geostatistical and climatic analyses. Geostatistical analysis data revealed that the area with the highest concentration of Legionella in water systems also had the greatest number of cases of Legionnaires' disease associated with touristic-recreational facilities. Climatic analysis showed that higher daily temperature excursion (difference between maximum and minimum temperature) on the day of sampling was more often associated with Legionella-positive samples than Legionella-negative samples. In addition, our data highlighted an increased risk of Legionnaires' disease with increases in precipitation and average temperature and with decreases in daily temperature excursion (difference between maximum and minimum temperature over the course of 24 h in the days of incubation period of disease) and minimum temperature. Healthcare professionals should be aware of this phenomenon and be particularly vigilant for cases of community-acquired pneumonia during such climatic conditions and among the tourist population. The innovative geo-statistical approach used in this study could be applied in other contexts when evaluating the effects of climatic conditions on the incidence of Legionella infections.


Solar and Climate Effects Explain the Wide Variation in Legionellosis Incidence Rates in the United States

Han XY.

Department of Laboratory Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA.

Appl Environ Microbiol 2019 Oct;85(22):e01776-19.

Abstract: Legionellosis, an infection caused by the environmental bacteria Legionella spp., has become a significant public health problem in the United States in recent years; however, among the states, the incidence rates vary widely without a clear explanation. This study examined environmental effects on the 2014-to-2016 average annual legionellosis incidence rates in the U.S. states through correlative analyses with long-term precipitation, temperature, solar UV radiation, and sunshine hours. The continental states west of 95°W showed low incidence rates of 0.51 to 1.20 cases per 100,000 population, which corresponded to low precipitation, below 750 mm annually. For the eastern states, where precipitation was higher, solar effects were prominent and mixed, leading to wide incidence variation. Robust regressions suggested a dividing line at 40°N: north of this line, rising temperature, mainly from solar heat, raised legionellosis incidence to a peak of 4.25/100,000 in Ohio; south of the line, intensifying sunlight in terms of high UV indices and long sunshine hours prevailed to limit incidence gradually to 0.99/100,000 in Louisiana. On or near the 40°N line were 15 eastern states that had leading legionellosis incidence rates of >2.0/100,000. These states all showed modest environmental parameters. In contrast, the frigid climate in Alaska and the strong year-round solar UV in Hawaii explained the lowest U.S. incidences, 0.14/100,000 and 0.47/100,000, respectively, in these states. The findings of solar and climate effects explain the wide variation of legionellosis incidence rates in the United States and may offer insights into the potential exposure to and prevention of infection. IMPORTANCE: Legionellosis, caused by the environmental bacteria Legionella spp., has become a significant public health problem in the United States in recent years, with 6,000 cases annually. The present study showed, through a series of correlative analyses with long-term precipitation, temperature, solar UV radiation, and sunshine hours, that these environmental conditions strongly influence the legionellosis incidence rates across the United States in mixed and dynamic fashions. The incidence rates varied remarkably by region, with the highest in Ohio and New York and the lowest in Alaska. A precipitation threshold above 750 mm was required for elevated legionellosis activity. Regression models and dividing lines between regions were established to show the promotive effect of temperature, as well as the inhibitive effects of solar UV and sunshine hours. These findings explain the wide variation of legionellosis incidence rates in the United States. They may also offer insights into potential exposure to and prevention of infection.


Investigation of Atmospheric Conditions Fostering the Spreading of Legionnaires' Disease in Outbreaks Related to Cooling Towers

Villanueva D, Schepanski K.

Leibniz Institute for Tropospheric Research, Leipzig, Germany.

Int J Biometeorol 2019 Oct;63(10):1347-1356.

Abstract: Legionnaires' disease (LD) is a severe lung infection caused by the bacteria Legionella pneumophila which is usually associated with water managing installations like cooling towers. Several outbreaks of LD have been linked to individual sources of bioaerosol in the past. However, the transmission pathways as well as the influence of meteorological factors in the spreading of such bioaerosols remain unclear. Using the meteorological data near 12 LD outbreaks in Europe for the period 2000-2016, the correlation between key meteorological factors and the occurrence of LD was assessed. Temperature, humidity, atmospheric pressure, wind speed, precipitation, cloud cover and, for the first time, fog occurrence were included as potential risk factors. It was found that the occurrence of fog was related to four of the LD outbreaks, suggesting that the presence of fog droplets and/or the thermal inversions associated with fog may play a role in the disease spreading. This finding can contribute to outbreak investigations and to the prevention of future outbreaks.


Legionella Pneumonia Following the Heavy Rain Event of July 2018 in Japan

Oda N, Hirahara T, Fujioka Y, Mitani R, Takata I.

Department of Internal Medicine, Fukuyama City Hospital, Japan.

Intern Med 2019 Oct;58(19):2831-2834.

Abstract: We herein report the case of a 62-year-old man diagnosed with Legionella pneumonia while engaged in recovery work in a flooded area after the Heavy Rain Event of July 2018 in Japan. The patient was intubated and maintained on mechanical ventilation and continuous hemodiafiltration. He was also administered antimicrobial therapy with ciprofloxacin and azithromycin. After 53 days in the hospital, he was discharged. It is important to recognize the risk of Legionella infection and to take measures to prevent it during recovery work that involves exposure to water and soil after a flood disaster.


Epidemiological Surveillance and Wild-Type MIC Distribution of Legionella pneumophila in North-Western Spain. 2003-2016

March GA, Gutiérrez MP, López I, Muñoz MFOrtiz de Lejarazu RSimarro M, Orduña ABratos MÁ.

Service of Microbiology and Immunology, Hospital Clínico Universitario, Valladolid, Spain.

Enferm Infecc Microbiol Clin 2019 Oct;37(8):514-520.

Abstract: Purpose: To perform epidemiological surveillance of Legionella pneumophila in recreational swimming pools in the city of Valladolid (Spain), an area with a continental climate and low incidence of legionella-associated infections. Additionally, wild-type minimum inhibitory concentration (MIC) distributions for eight antibiotics commonly used for the treatment of legionellosis were calculated from the isolates obtained. Methods: Twelve recreational pools were enrolled between June 2003 and December 2016 and 7221 water samples were taken from three different points of the water network (tank, tap and shower). Legionella culture was performed according to ISO 11731 and 11731-2 standards. MICs of antibiotics were obtained by a gradient test. Results: 1.44% of the water samples were positive for L. pneumophila. 60 strains (57.69%) were isolated from showers, 26 (25.00%) from tanks and 18 (17.31%) from taps. L. pneumophila counts were <100CFU/L in 75 samples (72.12%), 100-1000CFU/L in 17 (16.35%) and >1000CFU/L in 12 (11.54%). The MIC90 values obtained were for Rifampicin 0.125mg/L; Trimethoprim-Sulfamethoxazole 0.25mg/L; Azithromycin and Levofloxacin 0.5mg/L; Clarithromycin and Ciprofloxacin 1.0mg/L; Doxycycline and Tigecycline 4.0mg/L.

Conclusions: The use of showers in recreational pools can become a potential pathway for exposure to L. pneumophila, even in cold climates. The wild-type MIC distributions presented in this article may be useful for a better detection of antibiotic resistance and can contribute to improvements in the choice of the antibiotic treatment of legionellosis.


Estimating the True Burden of Legionnaires' Disease

Cassell KGacek PRabatsky-Her T, Petit SCartter M, Weinberger DM.

Department of Epidemiology of Microbial Diseases, School of Public Health, Yale University, New Haven, Connecticut.

Am J Epidemiol 2019 Sep;188(9):1686-1694.

Abstract: Over the past decade, the reported incidence of Legionnaires' disease (LD) in the northeastern United States has increased, reaching 1-3 cases per 100,000 population. There is reason to suspect that this is an underestimate of the true burden, since LD cases may be underdiagnosed. In this analysis of pneumonia and influenza (P&I) hospitalizations, we estimated the percentages of cases due to Legionella, influenza, and respiratory syncytial virus (RSV) by age group. We fitted mixed-effects models to estimate attributable percents using weekly time series data on P&I hospitalizations in Connecticut from 2000 to 2014. Model-fitted values were used to calculate estimates of numbers of P&I hospitalizations attributable to Legionella (and influenza and RSV) by age group, season, and year. Our models estimated that 1.9%, 8.8%, and 5.1% of total (all-ages) inpatient P&I hospitalizations could be attributed to Legionella, influenza, and RSV, respectively. Only 10.6% of total predicted LD cases had been clinically diagnosed as LD during the study period. The observed incidence rate of 1.2 cases per 100,000 population was substantially lower than our estimated rate of 11.6 cases per 100,000 population. Our estimates of numbers of P&I hospitalizations attributable to Legionella are comparable to those provided by etiological studies of community-acquired pneumonia and emphasize the potential for underdiagnosis of LD in clinical settings.


Environmental Surveillance and Spatio-Temporal Analysis of Legionella Spp. In a Region of Northeastern Italy (2002-2017)

Felice A, Franchi M, De Martin S, Vitacolonna N, Iacumin L, Civilini M.

Department of Agriculture, Food, Environmental and Animal Sciences, University of Udine, Udine, Italy.

PLoS One 2019 Jul;14(7):e0218687.

Abstract: Legionella spp. are considered an important cause of potentially preventable morbidity and mortality, making environmental surveillance a crucial component of risk assessment plans. In this work, 20,319 water samples were collected in 3,983 environmental surveys during a 16-year period by ARPA, the Regional Agency for Environmental Protection, Friuli Venezia Giulia, and the results were studied to better understand the diffusion mechanisms of Legionella. The data showed a strong seasonal signal, a prevalence of L. pneumophila serogroup 2-15 in most environments (63% of positive samples), a prevalence of L. pneumophila serogroup 1 in swimming pool-associated environments (82% of positive samples), a persistent presence of Legionella in hospitals and a recurrent presence of Legionella in other facilities such as hotels, possibly years after interventions, highlighting the difficulty of eradicating the bacteria. Retrospective spatio-temporal analyses on geocoded historical data were carried out with SaTScan using an ordinal model with risk as a covariate to identify potential clusters with an excess of cases in the higher-risk categories. Although no outbreaks occurred during the period of study, such analyses identified spatially restricted zones with unusual contamination, which sometimes were also areas in which several surveys triggered by notifications of clinical cases were performed. Simulations of periodic prospective analyses permitted the assessment of the efficacy of the method in early detection of such clusters. The proposed method may be a useful tool in environmental surveillance, prevention and control of Legionella.


Cluster of Legionnaires' Disease in an Italian Prison

Fasciana T, Mascarella C, Distefano SA, Calà C, Capra G, Rampulla A, Di Carlo P, Palermo M, Giammanco A.

Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, University of Palermo, 90133 Palermo, Italy.

Int J Environ Res Public Health 2019 Jun;16(11): 2062.

Abstract: Background: Legionella pneumophila (Lp) is the most common etiologic agent causing Legionnaires' Disease (LD). Water systems offer the best growth conditions for Lp and support its spread by producing aerosols. From 2015 to 2017, the Regional Reference Laboratory of Clinical and Environmental Surveillance of Legionellosis of Palermo monitored the presence of Lp in nine prisons in Western Sicily. During this investigation, we compared Lp isolates from environmental samples in a prison located in Palermo with isolates from two prisoners in the same prison. Methods: We collected 93 water samples from nine Sicilian prisons and the bronchoalveolar lavages (BALs) of two prisoners considered cases of LD. These samples were processed following the procedures described in the Italian Guidelines for the Prevention and Control of Legionellosis of 2015. Then, genotyping was performed on 19 Lp colonies (17 from water samples and 2 from clinical samples) using the Sequence-Based Typing (SBT) method, according to European Study Group for Legionella Infections (ESGLI) protocols. Results: Lp serogroup (sg) 6 was the most prevalent serogroup isolated from the prisons analyzed (40%), followed by Lp sg 1 (16%). Most of all, in four penitentiary institutions, we detected a high concentration of Lp >104 Colony Forming Unit/Liter (CFU/L). The environmental molecular investigation found the following Sequence Types (STs) in Lp sg 6: ST 93, ST 292, ST 461, ST 728, ST 1317 and ST 1362, while most of the isolates in sg 1 belonged to ST 1. We also found a new ST that has since been assigned the number 2451 in the ESGLI-SBT database. From the several Lp sg 1 colonies isolated from the two BALs, we identified ST 2451. Conclusions: In this article, we described the results obtained from environmental and epidemiological investigations of Lp isolated from prisons in Western Sicily. Furthermore, we reported the first cluster of Legionnaires' in an Italian prison and the molecular typing of Lp sg 1 from one prison's water system and two BALs, identified the source of the contamination, and discovered a new ST.


Community-acquired Legionnaires' Disease at a Medical Center in Northern Taiwan

Kao W, Wang J, Sheng W, Chen Y.

Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan; Center for Infection Control, National Taiwan University Hospital, Taipei, Taiwan.

J Microbiol Immunol Infect 2019 Jun;52(3):465-470.

Abstract: Background/purpose: Legionella pneumophila had been recognized as an important pathogen for community-acquired pneumonia. We aimed to investigate clinical features and outcomes of patients with Legionnaires' disease at a tertiary medical center in northern Taiwan. Methods: From June 2012 to February 2017, a retrospective review of adult community acquired. Legionnaires' disease at a medical center was conducted. All Legionella infections were confirmed by positive urinary Legionella antigen assay, sera indirect immunofluorescence assay, or sputum culture for Legionella. Literature review of Legionnaires' disease from Medline and PubMed websites was performed. Results: A total of 32 cases of Legionnaires' disease were identified. Their mean age was 64.3 years, with male predominance (27 cases, 84.3%). The underlying diseases were varied and most were attributed to chronic disorders, such as diabetes mellitus (31%) and cigarette smoking (40.6%). The most common symptoms were cough (68%) and fever (59.3%). More than half of patients (18, 56.2%) with Legionnaires' disease could initially present with extrapulmonary manifestations. Sixteen (50%) patients had delay in initiation of appropriate antibiotic therapy. Patients without adequately initiation of appropriate antibiotic therapy had higher proportion (11 of 16, 68.7%) of intensive care unit admission than patients with adequate initiation (5 of 16, 31.2%). Our results inferred that a delay in treatment might result in worsening of disease severity and the need for more intensive management. Overall mortality rate was 21.8%. Development of vasopressor requirement is an independent risk factor associated with mortality. Conclusion: Legionnaires' disease in Taiwan frequently present with extrapulmonary manifestations. Patients with hemodynamic instability that need vasopressor therapy associated with mortality.


Slowly or Non-Resolving Legionnaires' Disease: Case Series and Literature Review

Pouderoux C, Ginevra C, Descours G, Ranc AG, Beraud L, Boisset S, Magand N, Conrad A, Bergeron-Lafaurie A, Jarraud S, Ader F.

Département des Maladies infectieuses et tropicales, Hospices Civils de Lyon, Lyon, France.

Clin Infect Dis 2019 Jun:ciz538.

Abstract: Background: Rarely, Legionnaires' disease (LD) can progress into a slowly or non-resolving form. Methods: A nation-wide retrospective study was conducted by the French National Reference Center for Legionella (2013-2017) including cases of slowly or non-resolving LD defined as persistent clinical symptoms, CT-scan abnormalities, and Legionella detection in lower respiratory tract (LRT) specimens by culture and/or real-time (RT) PCR beyond 30 days after the onset of symptoms. Results: Twelve cases of community-acquired slowly or non-resolving LD were identified among 1686 cases of culture-positive LD. Median age was 63 years (interquartile range, IQR [29-82]). Ten (83.3%) patients had ≥1 immunosuppressive factor. Clinically, nine patients transiently recovered before further deterioration (median symptom-free interval of 30 days, IQR [18-55]), three patients had uniformly persistent symptoms (median time of 48 days, IQR [41.5-54]). Two patients had >2 recurrences. CT-scan imagery found lung abscess in five (41.6%) cases. Slowly or non-resolving LD were diagnosed on positive LRT Legionella cultures (n=10, 83.3%) at 49.5 days (IQR [33.7-79]). Two cases were documented through positive Legionella RT PCR at 52 and 53 days (cycle threshold detection of 21.5 and 33.7, respectively). No genomic microevolution and no Legionella resistance to antibiotics were detected. The median duration of treatment of slowly or non-resolving LD was 46.5 days (IQR [21-92.5]). Two empyema cases required thoracic surgery. At a median follow-up of 26 months (IQR [14-41.5]), LD-attributable mortality was 16.6% (n=2). Conclusions: Slowly or non-resolving LD may occur in immunocompromised patients, possibly leading to lung abscess and empyema.


Multistate Analysis of Prospective Legionnaires' Disease Cluster Detection Using SaTScan, 2011-2015

Edens C, Alden NB, Danila RN, Fill MA, Gacek P, Muse A, Parker E, Poissant T, Ryan PA, Smelser C, Tobin-D'Angelo M, Schrag SJ.

CDC, Atlanta, Georgia, USA.

PLoS One 2019 May;14(5):e0217632.

Abstract: Detection of clusters of Legionnaires' disease, a leading waterborne cause of pneumonia, is challenging. Clusters vary in size and scope, are associated with a diverse range of aerosol-producing devices, including exposures such as whirlpool spas and hotel water systems typically associated with travel, and can occur without an easily identified exposure source. Recently, jurisdictions have begun to use SaTScan spatio-temporal analysis software prospectively as part of routine cluster surveillance. We used data collected by the Active Bacterial Core surveillance platform to assess the ability of SaTScan to detect Legionnaires' disease clusters. We found that SaTScan analysis using traditional surveillance data and geocoded residential addresses was unable to detect many common Legionnaires' disease cluster types, such as those associated with travel or a prolonged time between cases. Additionally, signals from an analysis designed to simulate a real-time search for clusters did not align with clusters identified by traditional surveillance methods or a retrospective SaTScan analysis. A geospatial analysis platform better tailored to the unique characteristics of Legionnaires' disease epidemiology would improve cluster detection and decrease time to public health action.


Emerging Respiratory Infections: The Infectious Disease Pathology of SARS, MERS, Pandemic Influenza, and Legionella

Bradley BT, Bryan A.

University of Washington, Department of Laboratory Medicine, Box 357110, 1959 NE Pacific Street, NW120, Seattle, WA 98195-7110, USA.

Semin Diagn Pathol 2019 May;36(3):152-159.

Abstract: Lower respiratory infections remain one of the top global causes of death and the emergence of new diseases continues to be a concern. In the first two decades of the 21st century, we have born witness to the emergence of newly recognized coronaviruses that have rapidly spread around the globe, including severe acute respiratory syndrome virus (SARS) and Middle Eastern respiratory syndrome virus (MERS). We have also experienced the emergence of a novel H1N1 pandemic influenza strain in 2009 that caused substantial morbidity and mortality around the world and has transitioned into a seasonal strain. Although we perhaps most frequently think of viruses when discussing emerging respiratory infections, bacteria have not been left out of the mix, as we have witnessed an increase in the number of infections from Legionella spp. since the organisms' initial discovery in 1976. Here, we explore the basic epidemiology, clinical presentation, histopathology, and clinical laboratory diagnosis of these four pathogens and emphasize themes in humans' evolving relationship with our natural environment that have contributed to the infectious burden. Histology alone is rarely diagnostic for these infections but has been crucial to bettering our understanding of these diseases. Together, we rely on the diagnostic acumen of pathologists to identify the clinicopathologic features that raise the suspicion of these diseases and lead to the early control of the spread in our populations.


Factors Associated with Legionnaires' Disease Recurrence in Hotel and Holiday Rental Accommodation Sites

Beauté JSandin Sde Jong B, Payne Hallström L, Robesyn E, Giesecke J, Sparén POn Behalf of The European Legionnaires' Disease Surveillance Network.

Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden; ECDC, Stockholm, Sweden.

Euro Surveill  2019 May;24(20):pii=1800295.

Abstract: Background: The detection of a cluster of travel-associated Legionnaires' disease (TALD) cases in any European Union/European Economic Area (EU/EEA) country prompts action at the accommodation, follow-up by health authorities and reporting of measures taken. Some accommodations incur further cases despite presumed implementation of adequate control measures. Aim: To identify factors associated with the occurrence of a further TALD case after the implementation of control measures. Methods: We conducted a retrospective cohort study of hotel and holiday rental accommodations in the EU/EEA associated with two or more TALD cases with onset dates less than 2 years apart (a 'cluster') and notification between 1 June 2011-31 December 2016. We fitted Cox regression models to estimate the association between accommodation characteristics and the occurrence of a further case, defined as any case with onset date after the report on measures taken. Results: Of the 357 accommodations in the analysis, 90 (25%) were associated with at least one further case after the report on measures taken (12.4/100 accommodation-years). Accommodations associated with two or more cases before the cluster notification were more likely to be associated with a further case, compared with those not previously associated with any case (adjusted hazard ratio 1.85; 95% confidence interval: 1.14-3.02). Neither the detection of Legionella in the water system nor the type of disinfection were found to be associated with the risk of a further case. Conclusion: Accommodation size and previous TALD cases were predictive of further Legionnaires' disease cases after implementation of control measures.


Pneumococcal and Legionella Urinary Antigen Tests in Community-acquired Pneumonia: Prospective Evaluation of Indications for Testing

Bellew S, Grijalva CG, Williams DJ, Anderson EJ, Wunderink RG, Zhu Y, Waterer GW, Bramley AM, Jain S, Edwards KM, Self WH.

Vanderbilt University Medical Center, Nashville, Tennessee.

Clin Infect Dis 2019 May;68(12):2026-2033.

Abstract: Background: Adult, community-acquired pneumonia (CAP) guidelines from the Infectious Diseases Society of America (IDSA) and American Thoracic Society (ATS) include indications for urinary antigen tests (UATs) for Streptococcus pneumoniae (SP) and Legionella pneumophila (LP). These recommendations were based on expert opinions and have not been rigorously evaluated. Methods: We used data from a multicenter, prospective, surveillance study of adults hospitalized with CAP to evaluate the sensitivity and specificity of the IDSA/ATS UAT indications for identifying patients who test positive. SP and LP UATs were completed on all included patients. Separate analyses were completed for SP and LP, using 2-by-2 contingency tables, comparing the IDSA/ATS indications (UAT recommended vs not recommended) and UAT results (positive vs negative). Additionally, logistic regression was used to evaluate the association of each individual criterion in the IDSA/ATS indications with positive UAT results. Results: Among 1941 patients, UATs were positive for SP in 81 (4.2%) and for LP in 32 (1.6%). IDSA/ATS indications had 61% sensitivity (95% confidence interval [CI] 49-71%) and 39% specificity (95% CI 37-41%) for SP, and 63% sensitivity (95% CI 44-79%) and 35% specificity (95% CI 33-37%) for LP. No clinical characteristics were strongly associated with positive SP UATs, while features associated with positive LP UATs were hyponatremia, fever, diarrhea, and recent travel. Conclusions: Recommended indications for SP and LP urinary antigen testing in the IDSA/ATS CAP guidelines have poor sensitivity and specificity for identifying patients with positive tests; future CAP guidelines should consider other strategies for determining which patients should undergo urinary antigen testing.


Probable Reinfection with Legionella pneumophila - A Case Report

Buchholz U, Reber F, Lehfeld A, Brodhun BHaas W, Schaefer B, Stemmler F, Otto CGagell C, Lück C, Gamradt R, Heinig M, Meisel C, Kölsch U, Eisenblätter MJahn HJ.

Robert Koch Institute, Berlin, Germany.

German Environment Agency, Bad Elster, Germany.

Int J Hyg Environ Health 2019 Mar;222 (2):315-318.

Abstract: In Germany community-acquired Legionnaires' disease is usually caused by the species Legionella pneumophila. Recurrent cases of Legionnaires' disease are rarely reported and are due either to a second infection (reinfection) or a relapse of a previous case. We report a case of recurrent Legionnaires' disease in an 86-year-old female patient infected with Legionella pneumophila serogroup 1, monoclonal antibody-subtype Knoxville, sequence type unknown. Between the two disease incidents the patient had completely recovered. Legionella pneumophila was detected with the monoclonal antibody-subtype Knoxville, sequence type 182, in the drinking water of the patient's apartment. Exposure to contaminated drinking water was interrupted after the first incident exposure through the application of point-of-use water filters. The filters were later removed due to low water pressure, and the second illness occurred thereafter. It is unclear if immunological predisposition has contributed to this case of probable reinfection of Legionnaires' disease. Clinical, microbiological and epidemiological information combined suggest this is a case of reinfection of Legionnaires' disease. In cases of recurrent Legionnaires' disease complete collection of patient and water samples is necessary to differentiate relapse from reinfection cases, to implicate the source of infection and to gain more evidence for the role of immunological predisposition.


Community-acquired Pneumonia Secondary to Legionella pneumophila and Streptococcus pneumoniae: A Rare Co-infection

Beg M, Arif H, Walsh. T

Internal Medicine, University of Texas Health Science Center San Antonio, San Antonio, USA.

Cureus 2019 Feb;11(2):e4080.

Abstract: Community-acquired pneumonia (CAP) is a frequent cause of hospitalization in adults. Streptococcus pneumoniae is the most commonly identified pathogen in CAP whereas Legionella pneumophilia is infrequently identified in CAP. Although co-infections have been previously described, the presence of both pneumococcus and legionella together is rare. We present a patient with positive urinary antigens for both Streptococcus pneumoniae and Legionella pneumophilia serogroup 1, indicating an unusual co-infection.


Fatal Legionella pneumophila Serogroup 1 Pleural Empyema: A Case Report

Maillet F, Bonnet N, Billard-Pomares T, El Alaoui Magdoud F, Tandjaoui-Lambiotte Y.

Intensive Care Unit, Avicenne Hospital, Assistance Publique - Hôpitaux de Paris, Bobigny, France.

World J Crit Care Med 2019;8(6):99-105.

Abstract: Background: Legionella pneumophila (L. pneumophila) is a gram-negative intracellular bacillus composed of sixteen different serogroups. It is mostly known to cause pneumonia in individuals with known risk factors as immunocompromised status, tobacco use, chronic organ failure or age older than 50 years. Although parapneumonic pleural effusion is frequent in legionellosis, pleural empyema is very uncommon. In this study, we report a case of fatal pleural empyema caused by L. pneumophila serogroup 1 in an 81-year-old man with multiple risk factors. Case summary: An 81-year-old man presented to the emergency with a 3 wk dyspnea, fever and left chest pain. His previous medical conditions were chronic lymphocytic leukemia, diabetes mellitus, chronic kidney failure, hypertension and hyperlipidemia, without tobacco use. Chest X-ray and comouted tomography-scan confirmed a large left pleural effusion, which puncture showed a citrine exudate with negative standard bacterial cultures. Despite intravenous cefotaxime antibiotherapy, patient's worsening condition after 10 d led to thoracocentesis and evacuation of 2 liters of pus. The patient progressively developed severe hypoxemia and multiorgan failure occurred. The patient was treated by antibiotherapy with cefepime and amikacin and with adequate symptomatic shock treatment but died of uncontrolled sepsis. The next day, cultures of the surgical pleural liquid samples yielded L. pneumophila serogroup 1, consistent with the diagnosis of pleural legionellosis. Conclusion: L. pneumophila should be considered in patients with multiple risk factors and undiagnosed pleural empyema unresponsive to conventional antibiotherapy.


Evaluation and Treatment of Severe Rhabdomyolysis in a Patient with Legionnaires' Disease

Buzzard JW, Zuzek Z, Alencherry BP, Packer CD.

Case Western Reserve University School of Medicine, Cleveland, USA.

Cureus, 2019;11(9):e5773.

Abstract: A 53-year-old man with alcoholism and a three-day history of diarrhea and abdominal pain was hospitalized with mild acute kidney injury (AKI) and rhabdomyolysis after a fall where he was down for a short duration. Subsequent testing revealed patchy right lower lobe infiltrates on chest X-ray and a positive urinary Legionella antigen test. Creatinine phosphokinase (CPK) peaked at 85,780 U/L (normal 0-250) on hospital day two and remained markedly elevated for five days despite aggressive intravenous (IV) hydration and appropriate antibiotic treatment. When the patient defervesced and showed clinical signs of resolution of pneumonia, the CPK level declined rapidly, and renal function returned to baseline. Rhabdomyolysis with AKI is a rare but serious complication of Legionella pneumonia, with most patients requiring dialysis. Our patient's complete recovery without renal replacement therapy can probably be attributed to his normal baseline renal function, timely diagnosis of his Legionella-associated rhabdomyolysis, and prompt treatment with aggressive IV hydration and appropriate antibiotics. Legionella infection should be considered in acutely ill patients with rhabdomyolysis of unclear etiology.


Fatal Case of Nosocomial Legionella pneumophila Pneumonia, Spain, 2018

Vicente D, Marimón JM, Lanzeta I, Martin T, Cilla G.

Hospital Donostia-Instituto Biodonostia, Microbiology, Paseo Dr Begiristain S/N, San Sebastian 20014, Spain.

Emerg Infect Dis 2019;25(11):2097-2099.

Abstract: A nosocomial case of Legionella pneumophila pneumonia likely caused by a serogroup 3 strain was detected by a urinary antigen test in Spain in 2018. Although Legionella bacteria could not be isolated from respiratory samples, molecular methods implicated the sink faucet of the patient's room as the probable infection source.


Evaluation of the Prevalence of Legionella pneumophila in Iranian Clinical Samples: A Systematic Review and Meta-Analysis

Khaledi AEsmaeili SA, Vazini H, Karami P, Bahrami A, Sahebkar A.

University of Medical of Sciences, Mashhad, Iran.

Microb Pathog 2019;129:93-98.

Abstract: Background: Legionella pneumophila is the main cause for community-acquired pneumonia especially in hospital environments. In this systematic review and meta-analysis, we evaluated the prevalence of L. pneumophila in clinical samples obtained from Iranian patients. Methods: The studies reporting L. pneumophila prevalence in Iranian clinical samples that were published between January 2000 and July 2016 were recruited. Comprehensive Meta-Analysis Software (version 3.3.070) was used for quantitative data analysis. Because of high heterogeneity between the studies according to the Cochrane Q and I2 statistics, a random-effects model was used for meta-analysis. Results: Sixteen studies encompassing 1956 subjects were included in the meta-analysis. The overall prevalence of L. pneumophila was 9.6% in clinical samples obtained from the Iranian patients. The age spectrum ranged from 6 months to 80 years old. Dyspnea and cough comprised the most common clinical manifestations. In the subgroup analysis, the prevalence of L. pneumophila was higher in studies with sample size ≤100 (12.9%) in comparison with studies with sample size >100 (8.4%). In addition, the prevalence of L. pneumophila was higher in the years 2009-2016 (9.2%) compared with 2000-2008 (0.7%). Conclusion: L. pneumophila is a major cause of community- and hospital-acquired pneumonia. It is of pivotal importance to implement sensitive and reliable molecular and culture-based techniques to detect and control this infection in healthcare environments.


Legionellosis in Poland in 2017

Stypulkowska-Misiurewicz H, Czerwiński M.

Department of Epidemiology of Infectious Diseases and Surveillance, National Institute of Public Health – National Institute of Hygiene in Warsaw.

Przegl Epidemiol 2019;73(2):151-155.

Abstract: Objective: The aim of this study is to assess the epidemiological situation of legionellosis in Poland in 2017 in comparison with previous years. Material and methods: The analysis is based on national surveillance data published in the annual bulletin: “Infectious diseases and poisonings in Poland in 2017” and bulletins from previous years along with data from legionellosis case reports collected and sent to the Department of Epidemiology of Infectious Diseases and Surveillance NIPH – NIH by Sanitary and Epidemiological Stations. Results: In Poland, both cases of Legionnaires’ disease (an acute form of infection with pneumonia) and Pontiac fever (a mild, influenza-like form of infection) are routinely reported to the surveillance system. In 2017, a total of 39 cases of legionellosis were registered, including 38 cases of Legionnaires’ disease and 1 case of Pontiac fever; the annual incidence rate 0.102 (per 100,000 population) has increased by almost 50 percent since previous year (0.070) and is almost three times higher than the median incidence (0.036) for 2011-2015. The infections were reported in fourteen voivodeships; only one voivodeship (Świętokrzyskie) did not register any case in last years. The incidence in men (0.129 per 100,000) was higher compared to women (0.076); the highest incidence (0.323) was noted in men aged 50-59. All reported cases were sporadic and were hospitalised. The Sanitary Inspection reported nine fatal cases – 6 women and 3 men. Thirty-three cases were autochthonous including four cases linked with contaminated water systems in health-care settings. Six cases were associated with travels abroad (to Egypt, Albania, Italy and Crete). Summary and conclusions: Although in recent years number of reported cases continues to rise, the incidence of legionellosis in Poland remains one of the lowest in the entire EU. Also draws attention variation of incidence between provinces and a high mortality among reported cases. Our data suggest significant under-diagnosis of legionellosis. A priority remains to improve early diagnosis of Legionnaires’ disease in health care settings.


Travel-associated Legionnaires' Disease: Would Changing Cluster Definition Lead to the Prevention of a Larger Number of Cases?

Rota MC, Bella A, Caporali MG, Nicolau A, Drasar V, Ricci ML, Scaturro M, Gumá M, Crespi S.

Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy.

Epidemiol Infect 2018 Dec;147:1-6.

Abstract: According to European Guidelines for Legionnaires' Disease prevention and control, travel-associated Legionnaires' disease (TALD) cases are managed differently if classified as sporadic or as part of a cluster and more stringent control measures are deployed after clusters are identified. In this study, we propose to modify the current cluster definition: 'two or more cases of Legionnaires' disease (LD) who stayed at, or visited, the same commercial accommodation site 2-10 days before onset of illness and whose onset is within the same 2-year period' with a new cluster definition, i.e. accommodation sites associated with multiple cases regardless of the time elapsed between them. TALD cases occurred in Italy and in the Balearic Islands between 2005 and 2015 were analysed applying the current European Legionnaires' Disease Surveillance Network (ELDSNet) cluster definition. In a sample of selected accommodation sites with multiple cases, a microbiological study was also conducted. Using the new definition, 63 additional sites (16.4% increase) and 225 additional linked cases (19.5% increase) were identified. Legionella pneumophila sg1 was isolated from 90.7% of the selected accommodation sites. The use of the here proposed TALD cluster definition would warrant a full investigation for each new identified case. This approach should therefore increase the number of sites that will require a risk assessment and, in the presence of an increased risk, the adoption of LD control measures to hopefully prevent additional cases.


Atypical Pathogens in Hospitalized Patients with Community-Acquired Pneumonia: A Worldwide Perspective

Gramegna A, Sotgiu G, Di Pasquale M, Radovanovic D, Terraneo SReyes LF, Vendrell E, Neves JMenzella FBlasi F, Aliberti SRestrepo MIGLIMP Study Group.

Department of Pathophysiology and Transplantation, University of Milan, Internal Medicine Department, Respiratory unit and Adult Cystic Fibrosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.

BMC Infect Dis 2018 Dec;18(1):677.

Abstract: Background: Empirical antibiotic coverage for atypical pathogens in community-acquired pneumonia (CAP) has long been debated, mainly because of a lack of epidemiological data. We aimed to assess both testing for atypical pathogens and their prevalence in hospitalized patients with CAP worldwide, especially in relation with disease severity. Methods: A secondary analysis of the GLIMP database, an international, multicenter, point-prevalence study of adult patients admitted for CAP in 222 hospitals across 6 continents in 2015, was performed. The study evaluated frequency of testing for atypical pathogens, including L. pneumophila, M. pneumoniae, C. pneumoniae, and their prevalence. Risk factors for testing and prevalence for atypical pathogens were assessed through univariate analysis. Results: Among 3702 CAP patients 1250 (33.8%) underwent at least one test for atypical pathogens. Testing varies greatly among countries and its frequency was higher in Europe than elsewhere (46.0% vs. 12.7%, respectively, p<0.0001). Detection of L. pneumophila urinary antigen was the most common test performed worldwide (32.0%). Patients with severe CAP were less likely to be tested for both atypical pathogens considered together (30.5% vs. 35.0%, p=0.009) and specifically for legionellosis (28.3% vs. 33.5%, p=0.003) than the rest of the population. Similarly, L. pneumophila testing was lower in ICU patients. At least one atypical pathogen was isolated in 62 patients (4.7%), including M. pneumoniae (26/251 patients, 10.3%), L. pneumophila (30/1186 patients, 2.5%), and C. pneumoniae (8/228 patients, 3.5%). Patients with CAP due to atypical pathogens were significantly younger, showed less cardiovascular, renal, and metabolic comorbidities in comparison to adult patients hospitalized due to non-atypical pathogen CAP. Conclusions: Testing for atypical pathogens in patients admitted for CAP in poorly standardized in real life and does not mirror atypical prevalence in different settings. Further evidence on the impact of atypical pathogens, especially in the low-income countries, is needed to guidelines implementation.


A Community Outbreak of Legionnaires' Disease in Geneva, Switzerland, June to September 2017

Zanella MC, Yerly S, Cherkaoui A, Renzi G, Mamin ALourenço Cordes L, Delaporte E, Baranczuk-Turska ZKeiser O, Schrenzel J, Harbarth SGaia V, Kaiser L.

Laboratory of Virology, Division of Laboratory Medicine and Division of Infectious Diseases, University of Geneva Hospitals, Switzerland; University of Geneva Medical School, Switzerland.

Swiss Med Wkly 2018 Dec;148:w14687.

Abstract: Purpose: Eight confirmed cases of Legionnaires’ disease were identified at the Geneva University Hospitals between 28 July 2017 and 02 August 2017, leading to a detailed outbreak investigation. Methods: Legionnaires’ disease cases were defined according to Swiss and European (ELDSNet) consensus guidelines. An outbreak investigation task force was put in place. Patients were interviewed, when feasible, with a standard questionnaire. A Legionella pneumophila urinary antigen test was performed in all cases. Lower respiratory tract (LRT) specimens were collected for culture, polymerase chain-reaction (PCR) assay, monoclonal antibody subtyping and sequenced-based typing (SBT). Multiple environmental samples were collected. Case geographical mapping was performed, and local meteorological data were obtained. Results: Thirty-four confirmed cases of Legionnaires’ disease were identified between 20 June 2017 and 16 September 2017, including 28 patients living in the Canton of Geneva and 6 cases in neighbouring cantons and France. The case fatality rate was 8.8%. The urinary antigen test was positive in 32/34 (94.1%) cases. Among the 17/34 (50%) cases with available LRT specimens, 8 (47.1%) were culture/PCR positive, 5 (29.4%) were PCR positive only, and 4 (23.5%) were culture/PCR negative. Monoclonal antibody subtyping and SBT on 12 samples allowed subtype identification of 8 samples, with a predominance of L. pneumophila serogroup-1 subtype-France/Allentown ST23 among clinical isolates. A specific city area was identified as a possible outbreak epicentre in 25/34 (73.5%) cases, although molecular analysis of clinical and environmental specimens revealed heterogeneous subtypes of L. pneumophila.


Prevalence of Legionella in Retirement Homes and Group Homes Water Distribution Systems

De Filippis P, Mozzetti C, Messina A, Loreto D'Alò G.

Section of Hygiene, Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Rome, Italy.

Sci Total Environ 2018 Dec;643:715-724.

Abstract: Background: Although historically the focus has been placed above all on hospital infections and travel-associated outbreaks, most of the cases of Legionella infection are sporadic and occur in community-dwellers. Objectives: To evaluate the presence and load of Legionella in hot water systems of non-healthcare facilities that host closed communities. Furthermore, we tried to verify the association between Heterotrophic Plate Counts (HPCs) and presence of Legionella. Methods: We collected hot water and biofilm samples from the showerheads of retirement homes and group homes. Samples were tested by culture method for the presence of Legionella. Confirmation and identification were carried out through Latex test and PCR. We determined the HPCs at 22 and 37 °C by the pour plate method. Statistics performed through STATA. Results: We collected 140 hot water and biofilm samples, 95 from 26 retirement homes and 35 from 9 group homes. Legionella was found in 36.8% samples collected from retirement homes and only in 10.3% group homes' samples (p=0.01). Legionella was identified more frequently in water than in biofilm (29.8% vs 16.9%); just in one case the pathogen was found in the biofilm only. L. pneumophila sg 1 was the pathogen more frequently isolated (65.8%), with an average load of 2720 CFU/L (SD=8393 CFU/L). We have often noticed a high microbial contamination (67% of HPCs >200 CFU/mL) and identified a higher prevalence of Legionella for intermediate values of HPC 22 °C (p=0.011). 32% of people hosted in retirement homes were exposed to Legionella. Conclusions: Colonization of water-systems of retirement homes and group homes is anything but occasional, and in our survey it mainly affects the former, moreover often due to L. pneumophila sg 1. The search for the pathogen in the biofilm has proved to be of little use. The relationship between HPC and Legionella deserves further studies.


Diagnostic Performance of Multiplex PCR on Pulmonary Samples Versus Nasopharyngeal Aspirates in Community-Acquired Severe Lower Respiratory Tract Infections

Robert S, Lhommet C, Le Brun C, Garot D, Legras A, Mankikian J, Goudeau A.

Service de Bactériologie et Virologie, CHRU de Tours, Tours, France; Faculté de Médecine, Université de Tours, France.

J Clin Virol 2018 Nov;108:1-5.

Abstract: Background: PCR-based techniques for the diagnosis of community- acquired severe lower respiratory tract infections are becoming the standard of care. However, their relative ability to identify either atypical bacteria or viruses that cause LRTI from clinical samples from various sources is yet to be determined. Objectives and study designThe aim of our study was to compare the diagnostic yield of nasopharyngeal aspirates with that of pulmonary samples for the etiological diagnosis of severe acute lower respiratory tract infections by multiplex PCR. Patients were adults with community-acquired pneumonia or acute exacerbation of chronic obstructive pulmonary disease. Results: We obtained concordant results for 81 (79%) of the 103 pairs of samples. In 14 of the 22 discordant results, more pathogens were evidenced in the lower respiratory tract samples. Conclusions: Pulmonary samples had a similar diagnostic sensitivity for virus detection by multiplex PCR as nasopharyngeal aspirates. In contrast, in our study, the diagnostic efficacy of pulmonary samples for Legionella pneumophila over simple aspirates was clearly superior.


A Case Report of Legionella and Mycoplasma pneumonia: Co-incidence or Co-Infection?

Saladi L, Zaidi B, Toolsie O, Vakde T, Adrish M.

Division of Pulmonary and Critical Care Medicine, Department of Medicine, BronxCare Health System, Bronx, NY, USA.

Medicine (Baltimore) 2018 Oct;97(40):e12650.

Abstract: Rationale: Concurrent or sequential coinfections of Legionella pneumophila and Mycoplasma pneumoniae have been reported in the past though infrequently. Distinguishing a true co-infection from cross reactivity is often challenging as the diagnosis is mostly dependent on serological testing. Patient concerns: A 77-year-old male presented with worsening dyspnea, cough with yellow sputum, diarrhea and fever of 2-days duration. Patient had history of chronic obstructive pulmonary disease (COPD) on home oxygen, bronchiectasis, rheumatoid arthritis (on methotrexate and leflunomide), treated pulmonary tuberculosis and 30-pack-year smoking. Chest X-ray showed bilateral interstitial changes with left lower lobe infiltrate. On day 5, his urine antigen for L pneumophila serogroup 1 was reported positive. The following day his serum M pneumoniae IgM antibody titers were reported elevated at 6647 U/mL. Patient was started on antibiotics and placed on non-invasive positive pressure ventilation. Diagnosis: The patient was diagnosed with possible Legionella and Mycoplasma co-infection. Outcomes: Sputum Mycoplasma polymerase chain reaction (PCR) and serum cold agglutinins were obtained on day 6 and later reported negative. He was treated with azithromycin for 10 days with clinical improvement. Lessons: Serological testing alone is an indirect measure with poor sensitivity and specificity and has its own limitations. Urine antigen detection confirms L pneumophila serogroup 1 infection in a patient with suggestive symptoms. However, diagnosis of M pneumonia should be based on combination of tests including serology and PCR to confirm true co-infection.


Two Community Clusters of Legionnaires' Disease Directly Linked to a Biologic Wastewater Treatment Plant, the Netherlands

Loenenbach AD, Beulens C, Euser SM, van Leuken JPG, Bom B, van der Hoek W, Husman AMR, Ruijs WLM, Bartels AA, Rietveld A, den Boer JW, Brandsema PS.

ECDC, Stockholm, Sweden.

Emerg Infect Dis 2018 Oct;24(10):1914-1918.

Abstract: A biologic wastewater treatment plant was identified as a common source for 2 consecutive Legionnaires' disease clusters in the Netherlands in 2016 and 2017. Sequence typing and transmission modeling indicated direct and long-distance transmission of Legionella, indicating this source type should also be investigated in sporadic Legionnaires' disease cases.


Community Acquired Pneumonia by Legionella pneumophila: Study of 136 Cases

Romay-Lema E, Corredoira-Sánchez J, Ventura-Valcárcel P, Iñiguez-Vázquez I, García Pais M, García-Garrote F, Rabuñal Rey R.

Servicio de Medicina Interna, Hospital Universitario Lucus Augusti, Lugo, España.

Med Clin (Barc) 2018 Oct;151(7):265-269.

Abstract: Objective: Most of the data on Legionella pneumonia in our country come from the Mediterranean area, and there are few studies from the Northwest area. This study tries to assess the situation of this infection in this area. Method: Retrospective study of all patients with positive Legionella antigenuria treated at the University Hospital Lucus Augusti in Lugo (Spain) from 2001, the year in which this test was introduced in our centre, until 2015. We analysed epidemiological data, risk factors, clinical, radiological and biochemical findings, and clinical outcome. Results: The sampled included 136 patients. When comparing the first five years of the study with the last five, the incidence increased from 10.9 to 64.5 cases/1,000,000; the number of antigenuria requests increased 3.4 times and compared to other pneumonia aetiologies Legionella increased from 0.9% to 15%. The mean age was 64.1years and 84.6% were males; 74.3% had comorbidities. Males were significantly younger (62.7±16.6 vs 71.9±17.3) and consumed more alcohol (26.1% vs 0%) and tobacco (67.8% vs 14.3%). Diagnosis was established within the first 72 hours in 88.9% of cases and most received levofloxacin (95.6%). Hospitalisation was needed in 85% of cases, 11.7% in ICU and 4.4% died. Conclusions: After the introduction of antigenuria there was an increase in the incidence of Legionella pneumonia recorded in our health area. Its rate in recent years has been one of the highest in our country. Despite the fact that the patients had advanced age and comorbidities, mortality was low.


Microbiological Testing of Adults Hospitalised With Community-Acquired Pneumonia: An International Study

Carugati M, Aliberti S, Reyes LF, Sadud RF, Irfan M, Prat C, Soni NJ, Faverio P, Gori A, Blasi FRestrepo MI.

Dept of Pathophysiology and Transplantation, Università degli Studi di Milano, Milan, Italy; Internal Medicine Dept, Respiratory Unit and Adult Cystic Fibrosis Center, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico Milano, Milan, Italy.

ERJ Open Res 2018 0ct;4(4):00096.

Abstract: This study aimed to describe real-life microbiological testing of adults hospitalised with community-acquired pneumonia (CAP) and to assess concordance with the 2007 Infectious Diseases Society of America (IDSA)/American Thoracic Society (ATS) and 2011 European Respiratory Society (ERS) CAP guidelines. This was a cohort study based on the Global Initiative for Methicillin-resistant Staphylococcus aureus Pneumonia (GLIMP) database, which contains point-prevalence data on adults hospitalised with CAP across 54 countries during 2015. In total, 3702 patients were included. Testing was performed in 3217 patients, and included blood culture (71.1%), sputum culture (61.8%), Legionella urinary antigen test (30.1%), pneumococcal urinary antigen test (30.0%), viral testing (14.9%), acute-phase serology (8.8%), bronchoalveolar lavage culture (8.4%) and pleural fluid culture (3.2%). A pathogen was detected in 1173 (36.5%) patients. Testing attitudes varied significantly according to geography and disease severity. Testing was concordant with IDSA/ATS and ERS guidelines in 16.7% and 23.9% of patients, respectively. IDSA/ATS concordance was higher in Europe than in North America (21.5% versus 9.8%; p<0.01), while ERS concordance was higher in North America than in Europe (33.5% versus 19.5%; p<0.01). Testing practices of adults hospitalised with CAP varied significantly by geography and disease severity. There was a wide discordance between real-life testing practices and IDSA/ATS/ERS guideline recommendations.


Sensitivity and Positive Predictive Value of Death Certificate Data Among Deaths Caused by Legionnaires' Disease in New York City, 2008-2013

Tran OCLucero DE, Balter S, Fitzhenry RHuynh MVarma JK, Vora NM.

Division of Disease Control, New York City Department of Health and Mental Hygiene, Queens, NY, USA.

Public Health Rep 2018 Sep/Oct;133(5):578-583.

Abstract: Objectives: Death certificates are an important source of information for understanding life expectancy and mortality trends; however, misclassification and incompleteness are common. Although deaths caused by Legionnaires' disease might be identified through routine surveillance, it is unclear whether Legionnaires' disease is accurately recorded on death certificates. We evaluated the sensitivity and positive predictive value of death certificates for identifying deaths from confirmed or suspected Legionnaires' disease among adults in New York City. Methods: We deterministically matched death certificate data from January 1, 2008, through December 31, 2013, on New York City residents aged ≥18 years to surveillance data on confirmed and suspected cases of Legionnaires' disease from January 1, 2008, through October 31, 2013. We estimated sensitivity and positive predictive value by using surveillance data as the reference standard. Results: Of 294 755 deaths, 27 (<0.01%) had an underlying cause of death of Legionnaires' disease and 33 (0.01%) had any mention of Legionnaires' disease on the death certificate. Of 1211 confirmed or suspected cases of Legionnaires' disease, 267 (22.0%) matched to a record in the death certificate data set. The sensitivity of death certificates that listed Legionnaires' disease as the underlying cause of death was 17.3% and of death certificates with any mention of Legionnaires' disease was 20.9%. The positive predictive value of death certificates that listed Legionnaires' disease as the underlying cause of death was 70.4% and of death certificates with any mention of Legionnaires' disease was 69.7%. Conclusions: Death certificates had limited ability to identify confirmed or suspected deaths with Legionnaires' disease. Provider trainings on the diagnosis of Legionnaires' disease, particularly hospital settings, and proper completion of death certificates might improve the sensitivity of death certificates for people who die of Legionnaires' disease.


The Influence of Climate Change on Waterborne Disease and Legionella: A Review

Walker JT.

Public Health England, Porton, Salisbury SP1 3DX, UK.

Perspect Public Health 2018 Sep;138(5):282-286.

Abstract: Climate change is predicted to have a major impact on people's lives with the recent extreme weather events and varying abnormal temperature profiles across the world raising concerns. The impacts of global warming are already being observed, from rising sea levels and melting snow and ice to changing weather patterns. Scientists state unequivocally that these trends cannot be explained by natural variability in climate alone. Human activities, especially the burning of fossil fuels, have warmed the earth by dramatically increasing concentrations of heat-trapping gases in the atmosphere; as these concentrations increase, the more the earth will warm. Climate change and related extreme weather events are being exacerbated sooner than has previously been considered and are already adversely affecting ecosystems and human health by increasing the burden and type of disease at a local level. Changes to the marine environment and freshwater supplies already affect significant parts of the world's population and warmer temperatures, especially in more temperate regions, may see an increased spread and transmission of diseases usually associated with warmer climes including, for example, cholera and malaria; these impacts are likely to become more severe in a greater number of countries. This review discusses the impacts of climate change including changes in infectious disease transmission, patterns of waterborne diseases and the likely consequences of climate change due to warmer water, drought, higher rainfall, rising sea levels and flooding.


Legionella pneumophila and Other Legionella Species Isolated from Legionellosis Patients in Japan Between 2008 and 2016

Amemura-Maekawa J, Kura F, Chida K, Ohya H, Kanatani J, Isobe J, Tanaka S, Nakajima H, Hiratsuka T, Yoshino S, Sakata M, Murai M, Ohnishi MWorking Group for Legionella in Japan.

Department of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan.

Appl Environ Microbiol 2018 Aug;84(18):e00721-18.

Abstract: The Legionella Reference Center in Japan collected 427 Legionella clinical isolates between 2008 and 2016, including 7 representative isolates from corresponding outbreaks. The collection included 419 Legionella pneumophila isolates, of which 372 belonged to serogroup 1 (SG1) (87%) and the others belonged to SG2 to SG15 except for SG7 and SG11, and 8 isolates of other Legionella species (Legionella bozemanaeLegionella dumoffiiLegionella feeleiiLegionella longbeachaeLegionella londiniensis, and Legionella rubrilucens).

L. pneumophila isolates were genotyped by sequence-based typing (SBT) and represented 187 sequence types (STs), of which 126 occurred in a single isolate (index of discrimination of 0.984). These STs were analyzed using minimum spanning tree analysis, resulting in the formation of 18 groups. The pattern of overall ST distribution among L. pneumophila isolates was diverse. In particular, some STs were frequently isolated and were suggested to be related to the infection sources. The major STs were ST23 (35 isolates), ST120 (20 isolates), and ST138 (16 isolates). ST23 was the most prevalent and most causative ST for outbreaks in Japan and Europe. ST138 has been observed only in Japan, where it has caused small-scale outbreaks; 81% of those strains (13 isolates) were suspected or confirmed to infect humans through bath water sources. On the other hand, 11 ST23 strains (31%) and 5 ST120 strains (25%) were suspected or confirmed to infect humans through bath water. These findings suggest that some ST strains frequently cause legionellosis in Japan and are found under different environmental conditions. IMPORTANCE: Legionella pneumophila serogroup 1 (SG1) is the most frequent cause of legionellosis. Our previous genetic analysis indicated that SG1 environmental isolates represented 8 major clonal complexes, consisting of 3 B groups, 2 C groups, and 3 S groups, which included major environmental isolates derived from bath water, cooling towers, and soil and puddles, respectively. Here, we surveyed clinical isolates collected from patients with legionellosis in Japan between 2008 and 2016. Most strains belonging to the B group were isolated from patients for whom bath water was the suspected or confirmed source of infection. Among the isolates derived from patients whose suspected infection source was soil or dust, most belonged to the S1 group and none belonged to the B or C groups. Additionally, the U group was discovered as a new group, which mainly included clinical isolates with unknown infection sources.


Community-Acquired Legionella Pneumonia in Human Immunodeficiency Virus-Infected Adult Patients: A Matched Case-Control Study

Cillóniz C, Miguel-Escuder L, Pedro-Bonet ML, Falcó V, Lopez Y, García-Vidal C, Gabarrús A, Moreno A, Torres AMiró JMLegionella-HIV Researchers.

Department of Pulmonary Medicine, Institut Clinic del Tórax, Hospital Clinic of Barcelona-IDIBAPS, University of Barcelona.

Clin Infect Dis 2018 Aug;67(6):958-961.

Abstract: We investigate whether the clinical presentations and outcomes of Legionella pneumonia in human immunodeficiency virus (HIV)-infected patients were comparable to those seen in non-HIV-infected patients (case-control design). HIV-infected individuals presented neither a more severe disease nor a worse clinical outcome than matched HIV-negative control patients.


Lessons Learned from Implementing an Incident Command System During a Local Multiagency Response to a Legionnaires' Disease Cluster in Sydney, NSW

Quinn E, Johnstone TNajjar Z, Cains T, Tan G, Huhtinen E, Nilsson S, Burgess S, Dunn M, Gupta L.

Sydney Local Health District, Public Health Unit, Royal Prince Alfred Hospital, Camperdown, Sydney, New South Wales, Australia.

Disaster Med Public Health Prep 2018 Aug;12(4):539-542.

Abstract: The incident command system (ICS) provides a common structure to control and coordinate an emergency response, regardless of scale or predicted impact. The lessons learned from the application of an ICS for large infectious disease outbreaks are documented. However, there is scant evidence on the application of an ICS to manage a local multiagency response to a disease cluster with environmental health risks. The Sydney Local Health District Public Health Unit (PHU) in New South Wales, Australia, was notified of 5 cases of Legionnaires' disease during 2 weeks in May 2016. This unusual incident triggered a multiagency investigation involving an ICS with staff from the PHU, 3 local councils, and the state health department to help prevent any further public health risk. The early and judicious use of ICS enabled a timely and effective response by supporting clear communication lines between the incident controller and field staff. The field team was key in preventing any ongoing public health risk through inspection, sampling, testing, and management of water systems identified to be at-risk for transmission of legionella. Good working relationships between partner agencies and trust in the technical proficiency of environmental health staff aided in the effective management of the response.


Legionella: A Reemerging Pathogen

Herwaldt LA, Marra AR.

Division of Infectious Diseases, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa, USA.

Curr Opin Infect Dis 2018 Aug;31(4):325-333.

Abstract: Purpose of review: The present review summarizes new knowledge about Legionella epidemiology, clinical characteristics, community-associated and hospital-based outbreaks, molecular typing and molecular epidemiology, prevention, and detection in environmental and clinical specimens. Recent findings: The incidence of Legionnaire's disease is rising, and the mortality rate remains high, particularly for immunocompromised patients. Extracorporeal membrane oxygenation may help support patients with severe respiratory failure. Fluoroquinolones and macrolides appear to be equally efficacious for treating Legionnaires' disease. Whole genome sequencing is an important tool for determining the source for Legionella infections and for understanding routes of transmission and mechanisms by which new pathogenic clones emerge. Real-time quantitative polymerase chain reaction testing of respiratory specimens may improve our ability to diagnose Legionnaire's disease. The frequency of viable but nonculturable organisms is quite high in some water systems but their role in causing clinical disease has not been defined. Summary: Legionellosis remains an important public health threat. To prevent these infections, staff of municipalities and large buildings must implement effective water system management programs that reduce Legionella growth and transmission and all Medicare-certified healthcare facilities must have water management policies. In addition, we need better methods for detecting Legionella in water systems and in clinical specimens to improve prevention strategies and clinical diagnosis.


Legionellosis Associated with Recreational Waters: A Systematic Review of Cases and Outbreaks in Swimming Pools, Spa Pools, and Similar Environments

Leoni E, Catalani F, Marini S, Dallolio L.

Unit of Hygiene, Public Health and Medical Statistics, Department of Biomedical and Neuromotor Sciences, University of Bologna, via S. Giacomo 12, 40126 Bologna, Italy.

Int J Environ Res Public Health 2018 Jul;15(8):pii:E1612.

Abstract: Legionella spp. is widespread in many natural and artificial water systems, such as hot water distribution networks, cooling towers, and spas. A particular risk factor has been identified in the use of whirlpools and hot tubs in spa facilities and public baths. However, there has been no systematic synthesis of the published literature reporting legionellosis cases or outbreaks related to swimming/spa pools or similar environments used for recreational purposes (hot springs, hot tubs, whirlpools, natural spas). This study presents the results of a systematic review of the literature on cases and outbreaks associated with these environments. Data were extracted from 47 articles, including 42 events (17 sporadic cases and 25 outbreaks) and 1079 cases, 57.5% of which were diagnosed as Pontiac fever, without any deaths, and 42.5% were of Legionnaires' disease, with a fatality rate of 6.3%. The results are presented in relation to the distribution of Legionella species involved in the events, clinical manifestations and diagnosis, predisposing conditions in the patients, favourable environmental factors, and quality of the epidemiological investigation, as well as in relation to the different types of recreational water sources involved. Based on the epidemiological and microbiological criteria, the strength of evidence linking a case/outbreak of legionellosis with a recreational water system was classified as strong, probable, and possible; in more than half of the events the resulting association was strong.


Legionnaires' Disease Outbreak on a Merchant Vessel, Indian Ocean, Australia, 2015

Inglis TJJ, Spittle C, Carmichael H, Downes J, Chiari M, McQueen-Mason A, Merritt AJ, Hodge M, Murray RJ, Dowse GK.

PathWest Laboratory Medicine WA, Nedlands, Western Australia; University of Western Australia, Crawley, Western Australia, Australia.

Emerg Infect Dis 2018 Jul;24(7):1345-1348.

Abstract: Two cases of Legionnaires' disease and 1 of Pontiac fever occurred among the crew of a merchant ship operating off the shores of Australia. PCR assays identified potential sources in the ship's cabins. Modification of maritime regulations for Legionnaires' disease prevention in commercial vessels is needed for nonpassenger merchant ships.


Environmental Surveillance and in Vitro Activity of Antimicrobial Agents Against Legionella pneumophila Isolated from Hospital Water Systems in Campania, South Italy: A 5-year Study

Torre I, Alfano R, Borriello T, De Giglio OIervolino C, Montagna MT, Scamardo MS, Pennino F.

Department of Public Health, University of Napoli "Federico II", Via S. Pansini 5, 80131 Naples, Italy.

Environ Res 2018 Jul;164:574-579.

Abstract: Background: Legionellosis' treatment failures have been recently reported showing the possibility of resistance development to traditional therapy, especially in healthcare related disease cases. Environmental impact of antibiotic residues, especially in hospital waters, may act on the resistome of Legionella resulting in developing resistance mechanisms. Objectives: In this study we investigate the antibiotic susceptibility of environmental Legionella pneumophila (Lpn) strains isolated from hospital water systems in Campania, a region located in Southwest Italy. Methods: 5321 hospital water samples were investigated for the presence of Lpn. Among positive samples, antibiotic susceptibility was tested for a random subset of 125 Lpn strains (25 Lpn isolates from each of the following serogroups: 1, 3, 5, 6, 8). Susceptibility testing was performed, using the E-test on buffered charcoal yeast extract agar supplemented with α-ketoglutarate, for 10 antimicrobial drugs: azithromycin, cefotaxime, clarithromycin, doxycycline, erythromycin, rifampicin, tigecycline, ciprofloxacin, levofloxacin and moxifloxacin. Non parametric tests were used to determine and assess the significant differences in susceptibility to the different antimicrobics between the serogroups. Results: Among the isolated strains, none showed resistance to the antibiotics tested. Rifampicin was the most active antibiotic against overall Legionella strains, followed by levofloxacin. Between the macrolides the clarithromycin was overall the most active drug, instead the azithromycin was the less active. Analyzing the different serogroups, a significant difference was found between serogroup 1 and non-1 serogroup isolates for doxycycline and tigecycline. Conclusions: Antibiotic susceptibility of environmental isolates of Legionella spp. might be useful for the early detection of resistance to antibiotics that directly impacts on mortality and length of hospital stay.


The Unprecedented 2014 Legionnaires' Disease Outbreak in Portugal: Atmospheric Driving Mechanisms

Russo A, Gouveia CM, Soares PM, Cardoso RM, Mendes MT, Trigo RM.

Instituto Dom Luiz, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal.

Int J Biometeorol 2018 Jul,62(7):1167-1179.

Abstract: A large outbreak of Legionnaires' disease occurred in November 2014 nearby Lisbon, Portugal. This epidemic infected 377 individuals by the Legionella pneumophila bacteria, resulting in 14 deaths. The primary source of transmission was contaminated aerosolized water which, when inhaled, lead to atypical pneumonia. The unseasonably warm temperatures during October 2014 may have played a role in the proliferation of Legionella species in cooling tower systems. The episode was further exacerbated by high relative humidity and a thermal inversion which limited the bacterial dispersion. Here, we analyze if the Legionella outbreak event occurred during a situation of extreme potential recirculation and/or stagnation characteristics. In order to achieve this goal, the Allwine and Whiteman approach was applied for a hindcast simulation covering the affected area during a near 20-year long period (1989-2007) and then for an independent period covering the 2014 event (15 October to 13 November 2014). The results regarding the average daily critical transport indices for the 1989-2007 period clearly indicate that the airshed is prone to stagnation as these events have a dominant presence through most of the study period (42%), relatively to the occurrence of recirculation (18%) and ventilation (17%) events. However, the year of 2014 represents an exceptional year when compared to the 1989-2007 period, with 53 and 33% of the days being classified as under stagnation and recirculation conditions, respectively.


Outbreaks of Legionnaires' Disease and Pontiac Fever 2006-2017

Hamilton KA, Prussin AJ 2nd, Ahmed W, Haas CN.

Drexel University, 3141 Chestnut Street, Philadelphia, PA, 19104, USA.

Curr Environ Health Rep 2018 Jun;5(2):263-271.

Abstract: Purpose of review: The global importance of Legionnaires' disease (LD) and Pontiac fever (PF) has grown in recent years. While sporadic cases of LD and PF do not always provide contextual information for evaluating causes and drivers of Legionella risks, analysis of outbreaks provides an opportunity to assess these factors. Recent findings: A review was performed and provides a summary of LD and PF outbreaks between 2006 and 2017. Of the 136 outbreaks, 115 were LD outbreaks, 4 were PF outbreaks, and 17 were mixed outbreaks of LD and PF. Cooling towers were implicated or suspected in the a large portion of LD or PF outbreaks (30% total outbreaks, 50% confirmed outbreak-associated cases, and 60% outbreak-associated deaths) over this period of time, while building water systems and pools/spas were also important contributors. Potable water/building water system outbreaks seldom identify specific building water system or fixture deficiencies. The outbreak data summarized here provides information for prioritizing and targeting risk analysis and mitigation strategies.


Environmental Sources of Community-Acquired Legionnaires' Disease: A Review

Orkis LT, Harrison LH, Mertz KJ, Brooks MM, Bibby KJ, Stout JE.

Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, 130 DeSoto Street, Pittsburgh, PA, 15261, USA; Bureau of Assessment, Statistics, and Epidemiology, Allegheny County Health Department, 542 Fourth Ave. Pittsburgh, PA, 15219, USA.

Int J Hyg Environ Health 2018 Jun;221(5):764-774.

Abstract: Background: Most Legionnaires' disease in the US and abroad is community-acquired and believed to be sporadic, or non-outbreak associated. Most patients are exposed to numerous water sources, thus making it difficult to focus environmental investigations. Identifying known sources of sporadic community-acquired Legionnaires' disease will inform future sporadic Legionnaires' disease investigations as well as highlight directions for research. The objective is to summarize and rank sporadic Legionnaires' disease sources based on the level of linkage between the environmental source and cases. Methods: A PubMed search was conducted using the search terms legion* and (origins or source or transmission) and (sporadic or community-acquired). Studies of nosocomial and/or outbreak-associated disease were excluded from this review. Definite, probable, possible and suspect ranks were assigned to sources based on evidence of linkage to sporadic Legionnaires' disease. Results: The search yielded 196 articles and 47 articles were included in the final review after application of exclusion criteria. A total of 28 sources were identified. Of these, eight were assigned definite rank including residential potable water and car air-conditioner water leakage. Probable rank was assigned to five sources including solar-heated potable water and soil. Possible rank was assigned to nine sources including residential potable water and cooling towers. Suspect rank was assigned to 20 sources including large building water systems and cooling towers. Conclusion: Residential potable water, large building water systems and car travel appear to contribute to a substantial proportion of sporadic Legionnaires' disease. Cooling towers are also a potentially significant source; however, definitive linkage to sporadic cases proves difficult. The sources of sporadic Legionnaires' disease cannot be definitively identified for most cases


Legionnaires Disease Surveillance in US Department of Veterans Affairs Medical Facilities and Assessment of Health Care Facility Association

Gamage SD, Ambrose M, Kralovic SM, Simbartl LA, Roselle GA.

National Infectious Diseases Service, Specialty Care Services, Veterans Health Administration, Department of Veterans Affairs, Washington, DC.

JAMA Netw Open 2018 Jun;1(2):e180230.

Abstract. Importance: Legionnaires disease (LD) incidence is increasing in the United States. Health care facilities are a high-risk setting for transmission of Legionella bacteria from building water systems to occupants. However, the contribution of LD in health care facilities to national LD rates is not well characterized. Objectives: To determine the burden of LD in US Department of Veterans Affairs (VA) patients and to assess the amount of LD with VA exposure.  Design, setting, and participants: Retrospective cohort study of reported LD data in VA medical facilities in a national VA LD surveillance system from January 1, 2014, to December 31, 2016. The study population included total veteran enrollees and enrollees who used the VA health care system. Main outcomes and measures: The primary outcome was assessment of annual LD rates, categorized by VA and non-VA exposure. Legionnaires disease rates for cases with VA exposure were determined on both population and exposure potential levels. Rates by VA exposure potential were calculated using inpatient bed days of care, long-term care resident days, or outpatient encounters. In addition, types and amounts of LD diagnostic testing were calculated. Case and testing data were analyzed nationally and regionally. Results: There were 491 LD cases in the case report surveillance system from January 1, 2014, to December 31, 2016. Most cases (447 [91%]) had no VA exposure or only outpatient VA exposure. The remaining 44 cases had VA exposure from overnight stays. Total LD rates from January 1, 2014, to December 31, 2016, increased for all VA enrollees (from 1.5 to 2.0 per 100 000 enrollees; P = .04) and for users of VA health care (2.3 to 3.0 per 100 000 enrollees; P = .04). The LD rate for the subset who had no VA exposure also increased (0.90 to 1.47 per 100 000 enrollees; P < .001). In contrast, the LD rate for patients with VA overnight stay decreased on a population level (5.0 to 2.3 per 100 000 enrollees; P < .001) and an exposure level (0.31 to 0.15 per 100 000 enrollees; P < .001). Regionally, the eastern United States had the highest LD rates. The urine antigen test was the most used LD diagnostic method; 49 805 tests were performed in 2015-2016 with 335 positive results (0.67%). Conclusions and relevance: Data in the VA LD databases showed an increase in overall LD rates over the 3 years, driven by increases in rates of non-VA LD. Inpatient VA-associated LD rates decreased, suggesting that the VA's LD prevention efforts have contributed to improved patient safety.


Re-evaluation of the Etiology and Clinical and Radiological Features of Community-Acquired Lobar Pneumonia in Adults

Ishiguro T, Yoshii Y, Kanauchi T, Hoshi T, Takaku Y, Kagiyama N, Kurashima K, Takayanagi N.

Department of Respiratory Medicine, Saitama Cardiovascular and Respiratory Center, Japan.

J Infect Chemother 2018 Jun:24(6):463-469.

Abstract: Objective: The aims of this study were to elucidate the frequency and etiology of community-acquired lobar pneumonia (CALP) and the clinical and radiological differences between CALP and tuberculous lobar pneumonia (TLP). Patients and methods: We retrospectively reviewed medical records of patients with community-acquired pneumonia (CAP) (n = 1032) and tuberculosis (n = 1101) admitted to our hospital. Results: Sixty-nine (6.7%) patients with CAP and 23 (2.1%) with pulmonary tuberculosis developed CALP. Legionella species were the most common pathogen (27 patients, 39.1%), followed by Streptococcus pneumoniae (19 patients, 27.5%) and Mycoplasma pneumoniae (18 patients, 26.1%). Symptom duration was longer in the patients with TLP than in those with CALP. On chest radiographs, cavitation in the area of lobar pneumonia and nodular shadows were radiological findings predictive of TLP. High-resolution computed tomography showed cavitation in the area of lobar pneumonia, well-defined centrilobular nodules, and tree-in-bud sign to be the radiological findings predictive of TLP by multivariate logistic regression models. Conclusion: Common causes of CALP are Legionella species, S. pneumoniae, and M. pneumoniae. TLP should be considered in patients with lobar pneumonia, particularly in patients with long symptom duration, cavitation, and nodular shadows on chest radiographs, and cavitation, well-defined centrilobular nodules, and tree-in-bud sign on CT.


Outbreaks Associated with Treated Recreational Water - United States, 2000-2014

Hlavsa MC, Cikesh BL, Roberts VA, Kahler AM, Vigar M, Hilborn ED, Wade TJ, Roellig DM, Murphy JL, Xiao L, Yates KM, Kunz JM, Arduino MJ, Reddy SC, Fullerton KE, Cooley LA, Beach MJ, Hill VR, Yoder JS.

Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC.

MMWR Morb Mortal Wkly Rep 2018 May;67(19):547-551.

Abstract: Outbreaks associated with exposure to treated recreational water can be caused by pathogens or chemicals in venues such as pools, hot tubs/spas, and interactive water play venues (i.e., water playgrounds). During 2000-2014, public health officials from 46 states and Puerto Rico reported 493 outbreaks associated with treated recreational water. These outbreaks resulted in at least 27,219 cases and eight deaths. Among the 363 outbreaks with a confirmed infectious etiology, 212 (58%) were caused by Cryptosporidium (which causes predominantly gastrointestinal illness), 57 (16%) by Legionella (which causes Legionnaires' disease, a severe pneumonia, and Pontiac fever, a milder illness with flu-like symptoms), and 47 (13%) by Pseudomonas (which causes folliculitis ["hot tub rash"] and otitis externa ["swimmers' ear"]). Investigations of the 363 outbreaks identified 24,453 cases; 21,766 (89%) were caused by Cryptosporidium, 920 (4%) by Pseudomonas, and 624 (3%) by Legionella. At least six of the eight reported deaths occurred in persons affected by outbreaks caused by Legionella. Hotels were the leading setting, associated with 157 (32%) of the 493 outbreaks. Overall, the outbreaks had a bimodal temporal distribution: 275 (56%) outbreaks started during June-August and 46 (9%) in March. Assessment of trends in the annual counts of outbreaks caused by Cryptosporidium, Legionella, or Pseudomonas indicate mixed progress in preventing transmission. Pathogens able to evade chlorine inactivation have become leading outbreak etiologies. The consequent outbreak and case count and mortality underscore the utility of CDC's Model Aquatic Health Code ( to prevent outbreaks associated with treated recreational water.


Legionnaires' Disease as an Occupational Risk Related to Decontamination Work After the Fukushima Nuclear Disaster: A Case Report

Sawano T, Tsubokura M, Ozaki A, Leppold C, Kato S, Kambe T.

Department of Surgery, Minamisoma Municipal General Hospital.

J Occup Health 2018 May;60(3):271-274.

Abstract: Objectives: Legionnaires' disease (LD), which is atypical pneumonia with a broad variety of clinical symptoms, can lead to death despite its low incidence. There are multiple risk factors for LD, yet little information is available concerning what kind of environmental factors are linked to higher risk of LD development. We have experienced a fatal case of LD, which occurred in a decontamination worker after the Fukushima nuclear disaster. Case: A 53-year-old Japanese male visited our hospital with symptoms of fever, vomiting, diarrhea, and altered mental status, but not with respiratory manifestations. He was engaged in decontamination work, which generally includes operations such as the removal of topsoil in mountainous areas and cleaning roads and roofs of residential buildings with high-pressure water. He was required to wear specific equipment to prevent radiation exposure, and lived in a workers' dormitory or shared house, thereby sharing spaces with other workers. Normal antibiotic therapy did not improve his symptoms following his diagnosis with pneumonia. A urinary antigen detection test was then conducted, leading to a diagnosis of LD. Despite the change of antibiotic to levofloxacin, multiple organ failure led to his death. Conclusion: Decontamination workers may be at a high risk for developing LD and living and working conditions among them are possible contributors.


Legionella indianapolisensis Sp. Nov., Isolated from a Patient with Pulmonary Abscess

Relich RF, Schmitt BH, Raposo H, Barker L, Blosser SJ, May M.

Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA.

Int J Infect Dis 2018 Apr;69:26-28.

Abstract: Background: To date, at least 50 species of Legionella have been described. These organisms are ubiquitous in nature and have been isolated from diverse ecological environments, including man-made structures such as cooling towers and spas. Legionellae have also been isolated from human and veterinary clinical specimens, and their roles in disease are well-established. This report describes the isolation of a novel Legionella species from a respiratory specimen from a patient with influenza and suspected pulmonary embolus. Case: A 68-year-old male presented to an Indianapolis-area hospital with pulmonary disease; upon workup, he was found to have influenza A. Bronchoalveolar lavage fluid was also submitted for conventional bacterial culture and Legionella culture. The patient was prescribed a broad-spectrum antibiotic and recovered. Results: A Legionella-like bacterium was isolated on buffered charcoal yeast extract agar, and mass spectrometry and comparative 16S rRNA gene sequencing inconclusively identified the isolate as a Legionella sp. Further analysis of the 16S rRNA gene confirmed the strain to be a new species, related to Legionella hackeliae. Physiochemical and morphological testing were used to confirm the discovery of a novel species, Legionella indianapolisensis sp. nov., type strain SMNF-IS.


Case of Infantile Legionella Pneumonia After Bathing in Reheated and Reused Water

Tomari K, Morino S, Horikoshi Y.

Department of General Pediatrics, and Division of Infectious Diseases, Department of Pediatrics, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan.

Pediatr Infect Dis J 2018 Apr;37(4):370-372.

Abstract: A 1-month-old girl developed respiratory failure due to bilateral interstitial pneumonia after bathing in reheated and reused water. A molecular test for sputum and an environmental culture detected Legionella pneumophila serotype 1. This is the first report of infantile legionellosis contracted from a bathtub at home.


Population Structure of Environmental and Clinical Legionella pneumophila Isolates in Catalonia

Quero S, Párraga-Niño N, Barrabeig I, Sala MR, Pedro-Botet ML, Monsó E, Jané M, Sabrià M, Garcia-Núñez M.

Hospital Universitari Germans Trias i Pujol, Badalona, Spain. e

Sci Rep 2018 Apr;8(1):6241.

Abstract: Legionella is the causative agent of Legionnaires' disease (LD). In Spain, Catalonia is the region with the highest incidence of LD cases. The characterisation of clinical and environmental isolates using molecular epidemiology techniques provides epidemiological data for a specific geographic region and makes it possible to carry out phylogenetic and population-based analyses. The aim of this study was to describe and compare environmental and clinical isolates of Legionella pneumophila in Catalonia using sequence-based typing and monoclonal antibody subgrouping. A total of 528 isolates were characterised. For data analysis, the isolates were filtered to reduce redundancies, and 266 isolates (109 clinical and 157 environmental) were finally included. Thirty-two per cent of the clinical isolates were ST23, ST37 and ST1 while 40% of the environmental isolates were ST284 and ST1. Although the index of diversity was higher in clinical than in environmental ST isolates, we observed that clinical STs were similar to those recorded in other regions but that environmental STs were more confined to particular study areas. This observation supports the idea that only certain STs trigger cases or outbreaks in humans. Therefore, comparison of the genomes of clinical and environmental isolates could provide important information about the traits that favour infection or environmental persistence.


Microbial Etiology in Hospitalized North Indian Adults with Community-Acquired Pneumonia

Para RA, Fomda BA, Jan RA, Shah S, Koul PA.

Department of Internal and Pulmonary Medicine, Sher-i-Kashmir Institute of Medical Sciences, Srinagar, Jammu and Kashmir, India.

Lung India 2018 Mar-Apr;35(2):108-115.

Abstract: Background: There is a paucity of literature regarding the microbial etiology of community-acquired pneumonia (CAP) in India. The current study was aimed to study the microbial etiology of hospitalized adults with CAP. Methods: The study was conducted in a 700-bedded North Indian hospital. Consecutive adults admitted with CAP over a period of 2 years from 2013 to 2015 were recruited for the study, and apart from clinical evaluation underwent various microbiological studies in the form of blood culture, sputum culture, urinary antigen for pneumococcus and Legionella, serology for Mycoplasma and Chlamydia and real-time reverse transcriptase polymerase chain reaction for influenza viruses. Radiographic studies were performed in all patients and repeated as required. The patients were treated with standard antibiotic/antiviral therapy and outcomes were recorded. Results: A total of 225 patients (median age: 59 years) were enrolled. Streptococcus pneumoniae was the most common organism found (30.5%), followed by Legionella pneumophila (17.5%), influenza viruses (15.4%), Mycoplasma pneumoniae (7.2%), Chlamydia pneumoniae (5.5%), Mycobacterium tuberculosis (4.8%), Klebsiella pneumoniae (4.8%), methicillin-resistant Staphylococcus aureus (3.5%), Pseudomonas aeruginosa (3.1%), methicillin-sensitive S. aureus (1.7%), and Acinetobacter sp. (0.8%) with 4% of patients having multiple pathogens etiologies. High Pneumonia Severity Index score correlated with the severity and outcome of the CAP but was not predictive of any definite etiological pathogen. In-hospital mortality was 8%. Conclusion: Streptococcus pneumoniae, Legionella, and influenza constitute the most common etiological agents for north Indian adults with CAP requiring hospitalization. Appropriate antibiotic therapy and preventive strategies such as influenza and pneumococcal vaccination need to be considered in appropriate groups.


Rolling Epidemic of Legionnaires' Disease Outbreaks in Small Geographic Areas

MacIntyre CR, Dyda A, Bui CM, Chughtai AA.

School of Public Health and Community Medicine, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.

Emerg Microbes Infect 2018 Mar;7(1):36.

Abstract: Legionnaires' disease (LD) is reported from many parts of the world, mostly linked to drinking water sources or cooling towers. We reviewed two unusual rolling outbreaks in Sydney and New York, each clustered in time and space. Data on these outbreaks were collected from public sources and compared to previous outbreaks in Australia and the US. While recurrent outbreaks of LD over time linked to an identified single source have been described, multiple unrelated outbreaks clustered in time and geography have not been previously described. We describe unusual geographic and temporal clustering of Legionella outbreaks in two cities, each of which experienced multiple different outbreaks within a small geographic area and within a short timeframe. The explanation for this temporal and spatial clustering of LD outbreaks in two cities is not clear, but climate variation and deteriorating water sanitation are two possible explanations. There is a need to critically analyse LD outbreaks and better understand changing trends to effectively prevent disease.


Combining Environmental Investigation and a Dual-Analytical Strategy to Isolate the Legionella longbeachae Strain Linked to Two Occupational Cases of Legionellosis

Marchand G, Lord J, Pépin C, Lacombe N.

Department of Chemical and Biological Hazard Prevention, Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), Montréal, Quebec, Canada.

Ann Work Expo Health 2018 Mar;62(3):321-327.

Abstract: Legionella has a global distribution, mainly in aquatic and man-made environments. Under the right conditions, this bacterium is a notorious human pathogen responsible for severe pulmonary illnesses. Legionellosis outbreaks are reported around the world, and exposure to water droplet aerosols containing Legionella pneumophila is usually the mechanism of its transmission. Even if L. pneumophila causes most outbreaks, Legionella longbeachae also accounts for some cases. Unlike most other Legionella strains, L. longbeachae is typically found in soil. Given the wide diversity and high concentration of microorganisms found in soil, isolating L. longbeachae by culture can be challenging. Because the chances of successfully isolating the strain are low, it is often not even attempted. This study reports the strategies used to successfully isolate L. longbeachae strain that was responsible of the two occupational legionellosis in Quebec. Fifteen random samples were collected from the soil of the metal recycling plant where the diagnosed workers were employed, covering 1.5% of the accessible surface of the plant. All samples were analyzed with both the quantitative polymerase chain reaction (qPCR) and culture methods. Four qPCR detection systems targeting Legionella spp, L. pneumophila, L. pneumophila serogroup 1, and L. longbeachae were used. Acid, heat, and acid/heat treatments were used for the culture method. For the qPCR method, all samples were positives for Legionella spp but only four were positives for L. longbeachae. For the culture method, only one isolate could be confirmed to be L. longbeachae. However, that strain proves to be the same one that caused the occupational legionellosis. Detecting the presence of L. longbeachae using the qPCR method made it possible to target the right samples to enable the cultivable strain of L. longbeachae to be isolated from the soil of the metal recycling plant. The complementarity of the two methods was established. This paper demonstrated the advantages of selecting the proper sampling and analytical strategies to achieve the isolation of the strain responsible for the infections. It also highlights for the first time in Quebec the potential occupational risks associated with L. longbeachae from soil and should motivate questioning soil exposures when all sources of water contamination have been eliminated from the causal analysis of legionellosis.


Assessment of the Legionnaires' Disease Outbreak in Flint, Michigan

Zahran S, McElmurry SP, Kilgore PE, Mushinski D, Press J, Love NG, Sadler RC, Swanson MS.

Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI USA.

Proc Natl Acad Sci USA 2018 Feb;115(8):E1730-E1739.

Abstract: The 2014-2015 Legionnaires' disease (LD) outbreak in Genesee County, MI, and the outbreak resolution in 2016 coincided with changes in the source of drinking water to Flint's municipal water system. Following the switch in water supply from Detroit to Flint River water, the odds of a Flint resident presenting with LD increased 6.3-fold (95% CI: 2.5, 14.0). This risk subsided following boil water advisories, likely due to residents avoiding water, and returned to historically normal levels with the switch back in water supply. During the crisis, as the concentration of free chlorine in water delivered to Flint residents decreased, their risk of acquiring LD increased. When the average weekly chlorine level in a census tract was <0.5 mg/L or <0.2 mg/L, the odds of an LD case presenting from a Flint neighborhood increased by a factor of 2.9 (95% CI: 1.4, 6.3) or 3.9 (95% CI: 1.8, 8.7), respectively. During the switch, the risk of a Flint neighborhood having a case of LD increased by 80% per 1 mg/L decrease in free chlorine, as calculated from the extensive variation in chlorine observed. In communities adjacent to Flint, the probability of LD occurring increased with the flow of commuters into Flint. Together, the results support the hypothesis that a system-wide proliferation of legionellae was responsible for the LD outbreak in Genesee County, MI.


Outbreak of Legionnaires' Disease Associated with Cooling Towers at a California State Prison, 2015

Lucas KD, Wheeler C, McLendon P, Leistikow BN, Mohle-Boetani JC.

California Correctional Health Care Services, Public Health Branch, Elk Grove, CA, USA.

Epidemiol Infect 2018 Feb;146(3):297-302.

Abstract: A large outbreak of Legionnaires' disease occurred at a California state prison in August 2015. We conducted environmental and epidemiological investigations to identify the most likely source of exposure and characterise morbidity. Sixty-four inmates had probable Legionnaires' disease; 14 had laboratory-confirmed legionellosis. Thirteen (17%) inmates were hospitalised; there were no deaths. Ill inmates were more likely to be 65 years old (P<0.01), have the chronic obstructive pulmonary disease (P<0.01), diabetes mellitus (P=0.02), hepatitis C infection (P<0.01), or end-stage liver disease (P<0.01). The case-patients were in ten housing units throughout the prison grounds. All either resided in or were near the central clinical building (for appointments or yard time) during their incubation periods. Legionella pneumophila serogroup 1 was cultured from three cooling towers on top of the central medical clinic (range, 880-1200 cfu/ml). An inadequate water management program, dense biofilm within the cooling towers, and high ambient temperatures preceding the outbreak created an ideal environment for Legionella sp. proliferation. All state prisons were directed to develop local operating procedures for maintaining their cooling towers and the state health department added a review of the maintenance plans to their environmental inspection protocol.


Genome Sequencing Links Persistent Outbreak of Legionellosis in Sydney (New South Wales, Australia) to an Emerging Clone of Legionella pneumophila Sequence Type 211

Timms VJ, Rockett R, Bachmann NL, Martinez EWang QChen SC, Jeoffreys N, Howard PJ, Smith AAdamson S, Gilmour R, Sheppeard V, Sintchenko V.

Centre for Infectious Diseases and Microbiology-Public Health, Westmead Hospital, Sydney, New South Wales, Australia.

Appl Environ Microbiol 2018 Feb;84(5):e02020-17.

Abstract: The city of Sydney, Australia, experienced a persistent outbreak of Legionella pneumophila serogroup 1 (Lp1) pneumonia in 2016. To elucidate the source and guide public health actions, the genomes of clinical and environmental Lp1 isolates recovered over 7 weeks were examined. A total of 48 isolates from human cases and cooling towers were sequenced and compared using single-nucleotide polymorphism (SNP)-based core-genome multilocus sequencing typing (MLST) and pangenome approaches. All three methods confirmed phylogenetic relatedness between isolates associated with outbreaks in the Central Business District (CBD) in March and May and those in suburb 1. These isolates were designated the "main cluster" and consisted of isolates from two patients from the CBD March outbreak, one patient and one tower isolate from suburb 1, and isolates from two cooling towers and three patients from the CBD May outbreak. All main cluster isolates were sequence type 211 (ST211), which previously has only been reported in Canada. Significantly, pangenome analysis identified mobile genetic elements containing a unique type IV A F-type secretion system (T4ASS), which was specific to the main cluster, and cocirculating clinical strains, suggesting a potential mechanism for increased fitness and persistence of the outbreak clone. Genome sequencing enabled linking of the geographically dispersed environmental sources of infection among the spatially and temporally coinciding cases of legionellosis in a highly populated urban setting. The discovery of a unique T4ASS emphasizes the role of genome recombination in the emergence of successful Lp1 clones. IMPORTANCE: A new emerging clone has been responsible for a prolonged legionellosis outbreak in Sydney, Australia. The use of whole-genome sequencing linked two outbreaks thought to be unrelated and confirmed the outliers. These findings led to the resampling and subsequent identification of the source, guiding public health actions and bringing the outbreak to a close. Significantly, the outbreak clone was identified as sequence type 211 (ST211). Our study reports this ST in the Southern Hemisphere and presents a description of ST211 genomes from both clinical and environmental isolates. A unique mobile genetic element containing a type IV secretion system was identified in Lp1 ST211 isolates linked to the main cluster and Lp1 ST42 isolates that were cocirculating at the time of the outbreak.


May Car Washing Represent a Risk for Legionella Infection?

Baldovin TPierobon A, Bertoncello C, Destefani E, Gennari M, Stano ABaldo V.

Department of Cardiac, Thoracic and Vascular Sciences, Hygiene and Public Health Unit, University of Padua, Padua, Italy.

Ann Ig 2018 Jan-Feb:30(1):57-65. 

Abstract: Background: Legionella is a ubiquitous Gram-negative bacterium naturally found in aquatic environments. It can pose a health problem when it grows and spreads in man-made water systems. Legionella pneumophila is the most common cause of Legionnaires' disease nowadays, a community-acquired pneumonia with pulmonary symptoms and chest radiography no different from any other form of infectious pneumonia. Legionella monitoring is important for public health reasons, including the identification of unusual environmental sources of Legionella. Methods: We report two cases of Legionnaires' disease associated with two different car wash installations in the province of Vicenza, in the Veneto region, northeastern Italy. Patients were not employees of the car wash installations, but users of the service. In both cases, Legionella antigen was detected in urine using the Alere BinaxNOW® Legionella Urinary Antigen, and Legionella antibodies were detected in serum using SERION ELISA classic Legionella pneumophila 1-7 IgG and IgM. Water samples were also analyzed as part of the surveillance program for Legionella prevention and control in compliance with the Italian guidelines. Results: Both patients had clinical symptoms and chest radiography compatible with pneumonia, and only one of them had diabetes as a risk factor. Legionella urinary antigen and serological test on serum samples were positive for Legionella in both patients, even if much slighter in the case A due to the retrospective serological investigation performed a year later the episode and after the second clinical case occurred in the same district. The environmental investigations highlighted two different car wash plants as potential source of infection. A certified company using shock hyperchlorination was asked to disinfect the two plants and, subsequently, control samples resulted negative for Legionella pneumophila. Conclusion: Any water source producing aerosols should be considered at risk for the transmission of Legionella bacteria, including car wash installations frequently used by a large number of customers and where poor maintenance probably creates favorable conditions for Legionella overgrowth and spreading. Additional research is needed to ascertain optimal strategies for Legionella monitoring and control, but environmental surveillance, paying careful attention to possible unconventional sources, should remain an important component of any Legionnaires' disease prevention program. Additionally, all available diagnostic methods would be recommended for the confirmation of all cases even in the event of non-serogroup 1 Legionella pneumophila infection, probably underestimated at this time.


Association Between Sporadic Legionellosis and River Systems in Connecticut

Cassell K, Gacek P, Warren JL, Raymond PA, Cartter M, Weinberger DM.

Departments of Epidemiology of Microbial Diseases, New Haven, Connecticut.

J Infect Dis 2018 Jan;217(2):179-187.

Abstract: Background: There has been a dramatic increase in the incidence of sporadic legionnaires' disease in Connecticut since 1999, but the exact reasons for this are unknown. Therefore, there is a growing need to understand the drivers of legionnaires' disease in the community. In this study, we explored the relationship between the natural environment and the spatial and temporal distribution of legionellosis cases in Connecticut. Methods: We used spatial models and time series methods to evaluate factors associated with the increase and clustering of legionellosis in Connecticut. Stream flow, proximity to rivers, and residence in regional watersheds were explored as novel predictors of disease, while controlling for testing intensity and correlates of urbanization. Results: In Connecticut, legionellosis incidence exhibited a strong pattern of spatial clustering. Proximity to several rivers and residence in the corresponding watersheds were associated with increased incidence of the disease. Elevated rainfall and stream flow rate were associated with increases in incidence 2 weeks later. Conclusions: We identified a novel relationship between the natural aquatic environment and the spatial distribution of sporadic cases of legionellosis. These results suggest that natural environmental reservoirs may have a greater influence on the spatial distribution of sporadic legionellosis cases than previously thought.


Clusters of Healthcare-Associated Legionnaires' Disease in Two Hospitals of Central Greece

Kyritsi MA, Mouchtouri VA, Katsiafliaka A, Kolokythopoulou F, Plakokefalos E, Nakoulas V, Rachiotis G, Hadjichristodoulou C.

Department of Hygiene and Epidemiology, Faculty of Medicine, University of Thessaly, Larissa, Greece.

Case Rep Infect Dis 2018:2570758.

Abstract: Healthcare-associated Legionnaires' disease often leads to fatal respiratory tract infection among hospitalized patients. In this report, three cases of Legionnaires' disease among patients in two different hospitals (Hospital A and Hospital B) were investigated. After conducting an epidemiologic and environmental investigation, the water distribution systems (WDSs) were identified as the possible source of infection, as Legionella pneumophila serogroup 1 (Lp1) was isolated from both clinical and environmental samples. Patients received aerosol therapy with nebulizers during their hospitalization. Based on the results of the investigation, the hospitals' infection control committees reviewed their policies for Legionnaires' disease prevention and implemented control measures focusing on using sterile fluids for aerosol treatments.


Legionella Pneumonia Appeared During Hospitalization in a Patient with Hematological Malignancy Confirmed by Sputum Culture After Negative Urine Antigen Test

Hase R, Miyoshi K, Matsuura Y, Endo Y, Nakamura M, Otsuka Y.

Department of Infectious Diseases, Japanese Red Cross Narita Hospital, 90-1 Iidacho, Narita, Chiba, Japan.

J Infect Chemother 2018;24(7):579-582.

Abstract: Legionella pneumophila is recognized as a common causative organism for community-acquired pneumonia, but it is rarely a causative organism for hospital-acquired pneumonia, except in cases of hospital outbreak. Recently, most of the Legionella cases have been diagnosed using the urine antigen test. However, this test can reliably detect only L. pneumophila serogroup 1. Here we report a 63-year-old male patient who was recently diagnosed with acute leukemia and treated with chemotherapy and who developed pneumonia on hospital day 8 during the nadir phase. He was later diagnosed with Legionella pneumonia by culture despite a negative urine antigen test. This case suggests that Legionella pneumonia is an important differential diagnosis for pneumonia in inpatients in the early phase of hospitalization and that when Legionella infection is clinically suspected, culture using selective media or molecular tests should be performed even if the urine antigen test is negative.


Legionellosis in Poland in 2016

Stypułkowska-Misiurewicz H, Czerwiński M.

National Institute of Public Health – National Institute of Hygiene in Warsaw, Department of Bacteriology.

Przegl Epidemiol 2018;72(2):143-147.

Abstract: Objective: The aim of the study was to assess the epidemiological situation of legionellosis in Poland in 2016 in comparison to the preceding years. Material and methods: The assessment was based on national surveillance data published in the annual bulletin: “Infectious diseases and poisonings in Poland in 2016” and its prior versions along with data from legionellosis case reports sent from Sanitary-Epidemiological Stations to the Department of Epidemiology of NIPH - NIH. Results: In Poland, both two main forms of legionellosis - Legionnaires’ disease and Pontiac fever are routinely reported to the surveillance system. In 2016, a total of 27 cases of legionellosis were registered, including 25 cases of Legionnaires’ disease and 2 cases of Pontiac fever; in 2016, a total of 27 cases of legionellosis have been reported, including 25 cases of Legionnaires’ disease and 2 cases of Pontiac fever; the annual incidence rate 0.070 (per 100,000 population) was comparable to previous year (0.060) but almost twice as high as the median (incidence) for 2010-2014. The infections were reported in 11 provinces, including two, which in previous years usually did not register any cases; only two provinces (out of 16 in the country) have reported no cases in recent years. The incidence in men (0.080 per 100,000) was higher compared to women (0.055). All reported cases were sporadic and, except for one mild case of Legionnaires’ disease, required hospitalization. The Sanitary Inspection reported two fatal cases – both women aged 59 and 69. Twenty cases were autochthonous including four cases linked with contaminated water systems in hospitals. Seven cases were associated with travel abroad (to Germany, Russia, Greece, Australia, USA and Thailand). Summary and conclusions: Despite the increase in the number of cases in recent years as well as number of provinces, which detected cases, the annual incidence of legionellosis in Poland remains one of the lowest in the EU, which suggests that this infection is likely under-recognized and underdiagnosed in all provinces of the country.


A Case of Legionella Pneumonia Caused by Home Use of Continuous Positive Airway Pressure

Schnirman R, Nur N, Bonitati A, Carino G.

Pulmonary and Critical Care Medicine, The Warren Alpert Medical School, Brown University, Providence, RI, USA.

SAGE Open Med Case Rep 2017 Dec;5:2050313X17744981.

Abstract: A 67-year-old woman with morbid obesity and severe obstructive sleep apnea presented to the emergency department with 2 days of productive cough, fever, shortness of breath and loose stools. A chest x-ray showed extensive bilateral infiltrates, and she was quickly intubated for acute hypoxic respiratory failure. A urine legionella antigen test was positive, and she was admitted to the intensive care unit with a diagnosis of severe legionella pneumonia. She improved over the next week with a course of levofloxacin. Once improved, the state health department visited her home and interviewed her husband and determined that she had not been cleaning her continuous positive pressure mask, tubing and humidifier appropriately. They concluded that the legionella likely came from her continuous positive airway pressure equipment. Cases of legionella pneumonia have frequently been reported through infected water supplies and even respiratory equipment. It is crucial that the mask and tubing used with these devices are cleaned appropriately to minimize the risk of infection.


Male Neonate with Legionellosis

Szewc AM, Taylor S, Cage GD, de Mello D.

Department of Pathology and Laboratory Medicine, Phoenix Children's Hospital, Phoenix, AZ.

Lab Med. 2017 Dec;49(1):e9-e13.

Abstract: Legionellaceae are composed of a single genus, Legionella, which is currently comprised of over 52 species. L. pneumophila, L. micdadei, L. longbeachae, and L. dumoffi are clinically considered the most important, with L. pneumophila causing >90% 1,7 of cases of legionnaires disease (LD). Since LD's recognition in 1976 following an outbreak of pneumonia involving delegates of an American Legion convention in Philadelphia, there has been increased awareness and importance of the isolation, detection, and reporting of these cases. Herein we describe the unfortunate case of a 7 month old boy with undiagnosed LD that lead to respiratory insufficiency, sepsis, multisystem organ failure and death. Laboratory investigation methods, and clinical and pathological findings are discussed.


Legionellosis in Poland in 2015

Stypułkowska-Misiurewicz H, Czerwiński M.

National Institute of Public Health – National Institute of Hygiene in Warsaw, Department of Bacteriology.

Przegl Epidemiol 2017;71(3):333-337.

Abstract: Objective: The aim of the study was to assess the epidemiological situation of legionellosis in Poland in 2015 in comparison to the preceding years. Material and methods: We reviewed data published in the annual bulletin: “Infectious diseases and poisonings in Poland in 2015” and its prior versions along with the legionellosis case reports sent from Sanitary- Epidemiological Stations to the Department of Epidemiology of NIPH - NIH. Results: In Poland, both two forms of legionellosis - Legionnaires’ disease (a severe form of disease accompanied by pneumonia) and Pontiac fever (mild, influenza-like form of infection) - are notifiable. In 2015, a total of 23 cases of Legionnaires’ disease have been reported (there were no reports of Pontiac fever). The annual incidence rate 0.060 (per 100,000 population) slightly increased when compared to previous year as well as to the median (incidence) for 2009-2013. The infections were reported in 10 provinces, including five, which in previous years usually did not register any cases; however, there is a number of provinces that did not identify any LD cases in recent years. The incidence in males (0.097 per 100,000) was almost 4-times higher compared to females (0.025). Except for one cluster of two, all cases were sporadic; All patients required hospitalization. The Sanitary Inspection reported four fatal cases – all men 43- 67 years/old. Eighteen cases were likely acquired in the country, including a cluster of two cases linked with contaminated building water system. Four cases were associated with travels abroad (to Russia, Croatia, United Arab Emirates and USA) and in one case the exposure occurred during the transport of goods (lorry driver). Summary and conclusions: This study suggests that legionellosis is likely under recognized and under diagnosed in all provinces of the country. Geographical variations in incidence may reflect local differences in availability of laboratory tests for LD. Number of detected cases - without information on the number of laboratory tests performed - do not appear to be sufficient to fully assess the epidemiological situation.


Risk Assessment of Legionellosis in Cardiology Units

Laganà P, Delia S, Avventuroso E, Casale M, Dattilo G.

Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University Hospital of Messina, Italy.

J Prev Med Hyg 2017;58 (2):E173-E176.

Abstract: Infective Endocarditis (IE) is a disease with high morbidity and mortality. Nowadays, in addition to classic pathogens were isolated exigent Gram-negative bacteria as A. baumannii, A. lwoffii, C. burnetii, Bartonella, Chlamydia and Legionella. We present our experience of Legionella isolations in environmental sample (water and air) collected from the Cardiology units belonging to two hospitals in Messina (Italy). A total of 80 samples were carried out, 30 and 50, respectively in the first and in the second structure: 55 of water and 25 of aerosol. The positivity of 30% of the water samples analyzed and 15% of those aerosol strengthens the conviction of the need for greater environmental monitoring, especially in the wards at high risk.


Whole-genome Sequencing for Identification of the Source in Hospital-Acquired Legionnaires' Disease

Rosendahl Madsen AM, Holm A, Jensen TG, Knudsen E, Lundgaard H, Skov MN, Uldum SA, Kemp M.

Department of Clinical Microbiology, Odense University Hospital, Odense, Denmark.

J Hosp Infect 2017;96(4):392-395.

Abstract: Acquisition of Legionnaires' disease is a serious complication of hospitalization. Rapid determination of whether or not the infection is caused by strains of Legionella pneumophila in the hospital environment is crucial to avoid further cases. This study investigated the use of whole-genome sequencing to identify the source of infection in hospital-acquired Legionnaires' disease. Phylogenetic analyses showed close relatedness between one patient isolate and a strain found in hospital water, confirming suspicion of nosocomial infection. It was found that whole-genome sequencing can be a useful tool in the investigation of hospital-acquired Legionnaires' disease.


Detection of Mycoplasma pneumoniae and Legionella pneumophila in Patients Having Community-Acquired Pneumonia: A Multicentric Study from New Delhi, India

Chaudhry R, Valavane A, Sreenath K, Choudhary M, Sagar T, Shende T, Varma-Basil M, Mohanty S, Kabra SK, Dey AB, Thakur B.

Department of Microbiology, All India Institute of Medical Sciences, New Delhi, India.

Am J Trop Med Hyg 2017 Dec;97(6):1710-1716.

Abstract: Atypical pathogens including Mycoplasma pneumoniae and Legionella pneumophila are increasingly recognized as important causes of community-acquired pneumonia (CAP). Mycoplasma pneumoniae accounts for 20-40% of all CAP and L. pneumophila is responsible for 3-15% of cases. The paucity of data from India in this regard prompted us to conduct this prospective multicentric analysis to detect the prevalence of M. pneumoniae and L. pneumophila in our geographical region. A total of 453 patients with symptoms of pneumonia and 90 controls with no history of lower respiratory tract infections were included in the study. A duplex polymerase chain reaction (PCR) targeting 543 bp region of P1 adhesin gene of M. pneumoniae and 375 bp region of macrophage infectivity potentiator (mip) gene of L. pneumophila was standardized for simultaneous detection of these atypical pathogens. Respiratory secretions, blood, and urine samples were collected from each patient and control and were subjected to duplex PCR, culture and serology for M. pneumoniae and L. pneumophila. Urine samples were subjected for detecting L. pneumophila antigen. Among the 453 patients investigated for M. pneumoniae, 52 (11.4%) were positive for IgM antibodies, 17 were positive by culture, and seven tested positive by PCR (P1 gene). Similarly for L. pneumophila, 50 cases (11%) were serologically positive for IgM antibodies, one was positive by PCR (mip gene) and urine antigen detection. A total of eight samples were positive by duplex PCR for M. pneumoniae P1 gene (N=7) and L. pneumophila mip gene (N=1). Of the 90 controls, two samples (2.2%) showed IgM positivity, and 15 (16.7%) showed IgG positivity for M. pneumoniae. For L. pneumophila, three samples (3.3%) tested positive for IgM, and 12 (13.3%) tested positive for IgG antibodies. The study findings indicate the presence of M. pneumoniae and L. pneumophila in our geographical region, and a combination of laboratory approaches including PCR, culture, and serology is required for effective detection of these agents.


Epidemiological Information Is Key When Interpreting Whole Genome Sequence Data - Lessons Learned from a Large Legionella pneumophila Outbreak in Warstein, Germany, 2013

Petzold M, Prior K, Moran-Gilad J, Harmsen D, Lück C.

Institute of Medical Microbiology and Hygiene, Dresden University of Technology, Dresden, Germany.

Euro Surveill 2017 Nov;22(45):pii=17-00137.

Abstract: Introduction Whole genome sequencing (WGS) is increasingly used in Legionnaires' disease (LD) outbreak investigations, owing to its higher resolution than sequence-based typing, the gold standard typing method for Legionella pneumophila, in the analysis of endemic strains. Recently, a gene-by-gene typing approach based on 1,521 core genes called core genome multilocus sequence typing (cgMLST) was described that enables a robust and standardised typing of L. pneumophila. Methods: We applied this cgMLST scheme to isolates obtained during the largest outbreak of LD reported so far in Germany. In this outbreak, the epidemic clone ST345 had been isolated from patients and four different environmental sources. In total 42 clinical and environmental isolates were retrospectively typed. Results: Epidemiologically unrelated ST345 isolates were clearly distinguishable from the epidemic clone. Remarkably, epidemic isolates split up into two distinct clusters, ST345-A and ST345-B, each respectively containing a mix of clinical and epidemiologically related environmental samples. 

Discussion/conclusion: The outbreak was therefore likely caused by both variants of the single sequence type, which pre-existed in the environmental reservoirs. The two clusters differed by 40 alleles located in two neighbouring genomic regions of ca 42 and 26 kb. Additional analysis supported horizontal gene transfer of the two regions as responsible for the difference between the variants. Both regions comprise virulence genes and have previously been reported to be involved in recombination events. This corroborates the notion that genomic outbreak investigations should always take epidemiological information into consideration when making inferences. Overall, cgMLST proved helpful in disentangling the complex genomic epidemiology of the outbreak.


Waterborne Disease Outbreaks Associated with Environmental and Undetermined Exposures to Water - United States, 2013-2014

McClung RP, Roth DMVigar M, Roberts VA, Kahler AM, Cooley LA, Hilborn ED, Wade TJ, Fullerton KE, Yoder JS, Hill VR.

Epidemic Intelligence Service, CDC.

MMWR Morb Mortal Wkly Rep 2017 Nov;66(44):1222-1225.

Abstract: Waterborne disease outbreaks in the United States are associated with a wide variety of water exposures and are reported annually to CDC on a voluntary basis by state and territorial health departments through the National Outbreak Reporting System (NORS). A majority of outbreaks arise from exposure to drinking water (1) or recreational water (2), whereas others are caused by an environmental exposure to water or an undetermined exposure to water. During 2013-2014, 15 outbreaks associated with an environmental exposure to water and 12 outbreaks with an undetermined exposure to water were reported, resulting in at least 289 cases of illness, 108 hospitalizations, and 17 deaths. Legionella was responsible for 63% of the outbreaks, 94% of hospitalizations, and all deaths. Outbreaks were also caused by Cryptosporidium, Pseudomonas, and Giardia, including six outbreaks of giardiasis caused by ingestion of water from a river, stream, or spring. Water management programs can effectively prevent outbreaks caused by environmental exposure to water from human-made water systems, while proper point-of-use treatment of water can prevent outbreaks caused by ingestion of water from natural water systems.


Legionnaires' Disease Outbreak Caused by Endemic Strain of Legionella pneumophila, New York, New York, USA, 2015

Lapierre P, Nazarian E, Zhu Y, Wroblewski D, Saylors A, Passaretti T, Hughes S, Tran A, Lin Y, Kornblum J, Morrison SS, Mercante JW, Fitzhenry R, Weiss D, Raphael BH, Varma JK, Zucker HA, Rakeman JL, Musser KA.

Center for Medical Science, New York State Department of Health, Wadsworth Center, Albany, NY 12208, USA.

Emerg Infect Dis 2017 Nov;23(11):1784-1791.

Abstract: During the summer of 2015, New York, New York, USA, had one of the largest and deadliest outbreaks of Legionnaires' disease in the history of the United States. A total of 138 cases and 16 deaths were linked to a single cooling tower in the South Bronx. Analysis of environmental samples and clinical isolates showed that sporadic cases of legionellosis before, during, and after the outbreak could be traced to a slowly evolving, single-ancestor strain. Detection of an ostensibly virulent Legionella strain endemic to the Bronx community suggests potential risk for future cases of legionellosis in the area. The genetic homogeneity of the Legionella population in this area might complicate investigations and interpretations of future outbreaks of Legionnaires' disease.


A Case of Community-Acquired Pneumonia Due to Legionella pneumophila Serogroup 9 Wherein Initial Treatment with Single-Dose Oral Azithromycin Appeared Useful

Ito A, Ishida T, Tachibana H, Ito Y, Takaiwa TFujii H, Hashimoto TNakajima HAmemura-Maekawa J.

Department of Respiratory Medicine, Kurashiki Central Hospital.

Jpn J Infect Dis 2017 Nov;70(6):660-662.

Abstract: Legionella species are important causative pathogens for severe community-acquired pneumonia (CAP). Most cases of Legionella pneumonia are due to Legionella pneumophila serogroup 1, and CAP due to L. pneumophila serogroup 9 is rare. A fourth case of CAP due to L. pneumophila serogroup 9 has been reported, and initial treatment using single-dose oral azithromycin appeared useful. Azithromycin or fluoroquinolone injection is usually recommended for the treatment of Legionella pneumonia, and no previous reports have shown the effectiveness of single-dose oral azithromycin. This case report is therefore valuable from the perspective of possible treatment for mild to moderate Legionella pneumonia using single-dose oral azithromycin.


Legionnaires' Disease Outbreaks and Cooling Towers, New York City, New York, USA

Fitzhenry R, Weiss D, Cimini D, Balter S, Boyd C, Alleyne L, Stewart R, McIntosh N, Econome A, Lin Y, Rubinstein I, Passaretti T, Kidney A, Lapierre P, Kass D, Varma JK.

Department of Health and Mental Hygiene, Bureau of Communicable Disease, New York, USA.

Emerg Infect Dis 2017 Nov;23(11):1769-1776.

Abstract: The incidence of Legionnaires' disease in the United States has been increasing since 2000. Outbreaks and clusters are associated with decorative, recreational, domestic, and industrial water systems, with the largest outbreaks being caused by cooling towers. Since 2006, 6 community-associated Legionnaires' disease outbreaks have occurred in New York City, resulting in 213 cases and 18 deaths. Three outbreaks occurred in 2015, including the largest on record (138 cases). Three outbreaks were linked to cooling towers by molecular comparison of human and environmental Legionella isolates, and the sources for the other 3 outbreaks were undetermined. The evolution of investigation methods and lessons learned from these outbreaks prompted enactment of a new comprehensive law governing the operation and maintenance of New York City cooling towers. Ongoing surveillance and program evaluation will determine if enforcement of the new cooling tower law reduces Legionnaires' disease incidence in New York City.


Weather-Dependent Risk for Legionnaires' Disease, United States

Simmering JE, Polgreen LA, Hornick DB, Sewell DK, Polgreen PM.

Division of Infectious Diseases, Carver College of Medicine, University of Iowa, Iowa City, USA.

Emerg Infect Dis 2017 Nov;23(11):1843-1851.

Abstract: Using the Nationwide Inpatient Sample and US weather data, we estimated the probability of community-acquired pneumonia (CAP) being diagnosed as Legionnaires' disease (LD). LD risk increases when weather is warm and humid. With warm weather, we found a dose-response relationship between relative humidity and the odds for LD. When the mean temperature was 60°-80°F with high humidity (>80.0%), the odds for CAP being diagnosed with LD were 3.1 times higher than with lower levels of humidity (<50.0%). Thus, in some regions (e.g., the Southwest), LD is rarely the cause of hospitalizations. In other regions and seasons (e.g., the mid-Atlantic in summer), LD is much more common. Thus, suspicion for LD should increase when weather is warm and humid. However, when weather is cold, dry, or extremely hot, empirically treating all CAP patients for LD might contribute to excessive antimicrobial drug use at a population level.


Presence of Legionella Spp. In Hot Water Networks of Different Italian Residential Buildings: A Three-Year Survey

Totaro M, Valentini P, Costa AL, Frendo L, Cappello A, Casini B, Miccoli M, Privitera GBaggiani A.

Department of Translational Research N.T.M.S., University of Pisa, 56126 Pisa, Italy.

Int J Environ Res Public Health 2017 Oct;14(11):1296.

Abstract: Although the European reports highlight an increase in community-acquired Legionnaires' disease cases, the risk of Legionella spp. in private houses is underestimated. In Pisa (Italy) we performed a three-year survey on Legionella presence in 121 buildings with an independent hot water production (IB); 64 buildings with a central hot water production (CB); and 35 buildings with a solar thermal system for hot water production (TB). From all the 220 buildings Legionella spp. was researched in two hot water samples collected either at the recirculation point or on the first floor and on the last floor, while the potable water quality was analysed in three cold water samples collected at the inlet from the aqueduct network, at the exit from the autoclave, and at the most remote tap. Legionella pneumophila sg1, Legionella pneumophila sg2-16, and non-pneumophila Legionella species were detected in 26% of the hot water networks, mostly in CB and TB. In these buildings we detected correlations between the presence of Legionella and the total chlorine concentration decrease and/or the increase of the temperature. Cold water resulted free from microbiological hazards, with the exception of Serratia liquefaciens and Enterobacter cloacae isolated at the exit from two different autoclaves. We observed an increase in total microbial counts at 22 °C and 37 °C between the samples collected at the most remote taps compared to the ones collected at the inlet from the aqueduct. The study highlights a condition of potential risk for susceptible categories of population and supports the need for measures of risk assessment and control.


Legionnaires' Disease in Transplant Recipients: A 15-year Retrospective Study in a Tertiary Referral Center

Sivagnanam S, Podczervinski S, Butler-Wu SM, Hawkins V, Stednick Z, Helbert LA, Glover WA, Whimbey E, Duchin J, Cheng GS, Pergam SA.

Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.

Transpl Infect Dis 2017 Oct;19(5).

Abstract: Legionnaires' disease (LD) can be fatal among high-risk transplant recipients. To understand the epidemiology of LD, we reviewed 15-year longitudinal data from a center in Seattle, Washington that cares for both solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients. We identified all laboratory-confirmed LD and extracted data on species, diagnostic modalities, clinical presentation, management, and outcomes from medical records. Among 32 patients with LD, transplant recipients made up the majority of diagnoses (22, 69%; SOT 10, HCT 12). Approximately 0.8% of transplant recipients who underwent Legionella-specific testing were positive. Non-pneumophila Legionella species (LNLP), which are not detected by urinary antigen test, accounted for half the cases, led by Legionella micdadei (32%). The severity and outcome between Legionella pneumophila and LNLP infections were similar (attributed mortality, 36% vs 27%); all LNLP deaths occurred in transplant recipients with L. micdadei. The clinical and radiological features mimicked other opportunistic pathogens; 32% (n=7) were not on empiric treatment at the time of diagnosis. These data add to the emerging literature describing the importance of LD and highlight the need for both routine Legionella testing on transplant recipients with pulmonary findings and empiric Legionella-active antibiotic therapy.


Distribution System Operational Deficiencies Coincide with Reported Legionnaires' Disease Clusters in Flint, Michigan

Rhoads WJ, Garner E, P Ji, Zhu N, Parks J, Schwake DO, Pruden A, Edwards MA.

Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia, USA.

Environ Sci Technol 2017 Oct;51(20):11986-11995.

Abstract: We hypothesize that the increase in reported Legionnaires' disease from June 2014 to November 2015 in Genesee County, MI (where Flint is located) was directly linked to the switch to corrosive Flint River water from noncorrosive Detroit water from April 2014 to October 2015. To address the lack of epidemiological data linking the drinking water supplies to disease incidence, we gathered physiochemical and biological water quality data from 2010 to 2016 to evaluate characteristics of the Flint River water that were potentially conducive to Legionella growth. The treated Flint River water was 8.6 times more corrosive than Detroit water in short-term testing, releasing more iron, which is a key Legionella nutrient, while also directly causing disinfectant to decay more rapidly. The Flint River water source was also 0.8-6.7°C warmer in summer months than Detroit water and exceeded the minimum Legionella growth temperature of 20°C more frequently (average number of days per year for Detroit was 63 versus that for the Flint River, which was 157). The corrosive water also led to 1.3-2.2 times more water main breaks in 2014-2015 compared to 2010-2013; such disruptions have been associated with outbreaks in other locales. Importantly, Legionella spp. and Legionella pneumophila decreased after switching back to Detroit water, in terms of both gene markers and culturability, when August and October 2015 were compared to November 2016.


Increase in Legionnaires' Disease Cases Associated with Travel to Dubai Among Travellers From the United Kingdom, Sweden and the Netherlands, October 2016 to End August 2017

Dabrera G, Brandsema P, Lofdahl M, Naik F, Cameron R, McMenamin J, Pebody R, Phin N.

Centre for Infectious Disease Surveillance and Control, National Infection Service, Public Health England, London, United Kingdom.

Euro Surveill 2017 Sep;22(38):30618.

Abstract: Between 1 October 2016 and 31 August 2017, 51 Legionnaires' disease (LD) cases from the United Kingdom, Sweden and the Netherlands were identified with associated travel to Dubai. Cases did not all stay in the same accommodation, indicating that no single accommodation could be the source for all these infections. While local investigations continue into other potential sources, clinicians should remain alert to the possibility of LD among travellers returning from Dubai with respiratory illness.

Legionellosis: A Walk-through to Identification of the Source of Infection

Chochlakis D, Sandalakis V, Keramarou M, Tselentis Y, Psaroulaki A.

Regional Laboratory of Public Health of Crete, Heraklion, Crete, Greece.

Cent Eur J Public Health 2017 Sep;25(3):235-239.

Abstract: Objectives: Although a number of human Legionnaires' disease in tourists are recorded annually in Europe, there are few cases where a direct link can be made between the infected person and the source of infection (hotel or other accommodation). We present a scheme followed in order to track down and identify the source of infection in a tourist suffering from L. pneumophila sg 5 infection, who was accommodated in seven different hotels during his holidays in the island of Crete, and we comment on various difficulties and draw-backs of the process. Method: Water samples were collected from the seven hotels where the patient had resided and analyzed at the regional public health laboratory using cultivation and molecular tests. Results: Of 103 water samples analyzed, 19 (18.4%) were positive for Legionella non-pneumophila and 8 (7.8%) were positive for L. pneumophila. A successful L. pneumophila sg 5 match was found between the clinical and environmental sample, which led us to the final identification of the liable hotel. Conclusion: Timely notification of the case, within the European Legionnaires' Disease Surveillance Network (ELDSNet) of the partners involved, is crucial during a course of travel associated with Legionella case investigation. Moreover, the urinary antigen test alone cannot provide sufficient information for the source identification. However, acquiring clinical as well as environmental isolates for serogroup and SBT identification is highly important for the successful matching.


Vital Signs: Health Care-Associated Legionnaires' Disease Surveillance Data From 20 States and a Large Metropolitan Area-United States, 2015

Soda EA, Barskey AE, Shah PP, Schrag S, Whitney CG, Arduino MJ, Reddy SC, Kunz JM, Hunter CM, Raphael BH, Cooley LA.

Epidemic Intelligence Service, CDC, Atlanta, GA.

Am J Transplant 2017 Aug;17(8):2215-2220.

Abstract: Background: Legionnaires' disease, a severe pneumonia, is typically acquired through inhalation of aerosolized water containing Legionella bacteria. Legionella can grow in the complex water systems of buildings, including health care facilities. Effective water management programs could prevent the growth of Legionella in building water systems. Methods: Using national surveillance data, Legionnaires' disease cases were characterized from the 21 jurisdictions (20 U.S. states and one large metropolitan area) that reported exposure information for ≥90% of 2015 Legionella infections. An assessment of whether cases were health care-associated was completed; definite health care association was defined as hospitalization or long-term care facility residence for the entire 10 days preceding symptom onset, and possible association was defined as any exposure to a health care facility for a portion of the 10 days preceding symptom onset. All other Legionnaires' disease cases were considered unrelated to health care. Results: A total of 2,809 confirmed Legionnaires' disease cases were reported from the 21 jurisdictions, including 85 (3%) definite and 468 (17%) possible health care-associated cases. Among the 21 jurisdictions, 16 (76%) reported 1-21 definite health care-associated cases per jurisdiction. Among definite health care-associated cases, the majority (75, 88%) occurred in persons aged ≥60 years, and exposures occurred at 72 facilities (15 hospitals and 57 long-term care facilities). The case fatality rate was 25% for definite and 10% for possible health care-associated Legionnaires' disease. Conclusions and implications for public health practice: Exposure to Legionella from health care facility water systems can result in Legionnaires' disease. The high case fatality rate of health care-associated Legionnaires' disease highlights the importance of case prevention and response activities, including implementation of effective water management programs and timely case identification.


Legionella longbeachae Detected in an Industrial Cooling Tower Linked to a Legionellosis Outbreak, New Zealand, 2015; Possible Waterborne Transmission?

Thornley CN, Harte DJ, Weir RP, Allen LJ, Knightbridge KJ, Wood PRT.

MidCentral Public Health Services, MidCentral District Health Board, Palmerston North, New Zealand.

Epidemiol Infect 2017 Aug;145(11):2382-2389.

Abstract: A legionellosis outbreak at an industrial site was investigated to identify and control the source. Cases were identified from disease notifications, workplace illness records, and from clinicians. Cases were interviewed for symptoms and risk factors and tested for legionellosis. Implicated environmental sources were sampled and tested for legionella. We identified six cases with Legionnaires' disease and seven with Pontiac fever; all had been exposed to aerosols from the cooling towers on the site. Nine cases had evidence of infection with either Legionella pneumophila serogroup (sg) 1 or Legionella longbeachae sg1; these organisms were also isolated from the cooling towers. There was 100% DNA sequence homology between cooling tower and clinical isolates of L. pneumophila sg1 using sequence-based typing analysis; no clinical L. longbeachae isolates were available to compare with environmental isolates. Routine monitoring of the towers prior to the outbreak failed to detect any legionella. Data from this outbreak indicate that L. pneumophila sg1 transmission occurred from the cooling towers; in addition, L. longbeachae transmission was suggested but remains unproven. L. longbeachae detection in cooling towers has not been previously reported in association with legionellosis outbreaks. Waterborne transmission should not be discounted in investigations for the source of L. longbeachae infection.


Early Radiographic and Tomographic Manifestations of Legionnaires' Disease

Poirier R, Rodrigue J, Villeneuve J, Lacasse Y.

Centre de recherche, Centre de pneumologie, Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec City, Québec, Canada.

Can Assoc Radiol J  2017 Aug;68(3):328-333.

Abstract: Legionnaires' disease (LD) may occur sporadically or in the course of outbreaks, where the typical radiological manifestations of the disease may better be delineated. We took advantage of a rare community-based epidemic of LD (181 patients) that occurred in 2012 in Quebec City, Canada, to describe the radiographic features of LD and compare the its tomographic presentation with that of community-acquired pneumonia caused by common bacteria other than Legionella pneumophila. From the 181 individuals affected in the outbreak, we obtained the chest radiographs of 159 individuals (mean 63 ± 15 years of age) for detailed analysis; 33 patients had a computed tomography (CT) scan performed during the course of their illness. In a case-control study, we compared the CT scans of patients with LD with those of patients who had received a diagnosis of community-acquired pneumonia caused by a pathogen other than Legionella and confirmed by chest CT scan. Results: Overall, LD most often presented as an airspace consolidation involving 1 of the lower lobes. Pleural effusion and mediastinal adenopathies were apparent only in a minority, whereas no pneumothorax or cavitation was noted. We did not find any significant difference in chest CT scan findings in patients with LD vs those with community-acquired pneumonia from other bacterial origin. No radiological finding was clearly associated with an increased risk of intensive care unit admission or mortality. Conclusions: The early radiographic and tomographic manifestations of LD are nonspecific and similar to those found in community-acquired pneumonia from other bacterial origin.


Risk Factors for Legionella longbeachae Legionnaires' Disease, New Zealand

Kenagy E, Priest PC, Cameron CM, Smith D, Scott P, Cho V, Mitchell P, Murdoch DR.

Department of Preventive and Social Medicine, University of Otago, Dunedin, New Zealand.

Emerg Infect Dis 2017 Jul;23(7):1148-1154.

Abstract: Legionella longbeachae, found in soil and compost-derived products, is a globally underdiagnosed cause of Legionnaires' disease. We conducted a case-control study of L. longbeachae Legionnaires' disease in Canterbury, New Zealand. Case-patients were persons hospitalized with L. longbeachae pneumonia, and controls were persons randomly sampled from the electoral roll for the area served by the participating hospital. Among 31 cases and 172 controls, risk factors for Legionnaires' disease were chronic obstructive pulmonary disease, history of smoking >10 years, and exposure to compost or potting mix. Gardening behaviors associated with L. longbeachae disease included having unwashed hands near the face after exposure to or tipping and troweling compost or potting mix. Mask or glove use was not protective among persons exposed to compost-derived products. Precautions against inhaling compost and attention to hand hygiene might effectively prevent L. longbeachae disease. Long-term smokers and those with chronic obstructive pulmonary disease should be particularly careful.


Occupational Risk for Legionella Infection Among Dental Healthcare Workers: Meta-Analysis in Occupational Epidemiology

Petti S, Vitali M.

Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.

BMJ Open 2017 Jul;7(7):e015374.

Abstract: Objective: The occupational risk for Legionella infection among dental healthcare workers (DHCWs) is conjectured because of the risk of routine inhalation of potentially contaminated aerosols produced by the dental instruments. Nevertheless, occupational epidemiology studies are contrasting. This meta-analysis assessed the level of scientific evidence regarding the relative occupational risk for Legionella infection among DHCWs. Methods: Literature search was performed without time and language restrictions, using broad data banks (PubMed, Scopus, Web of Science, GOOGLE Scholar) and generic keywords ('legionella' AND 'dent*'). Analytical cross-sectional studies comparing prevalence of high serum Legionella antibody levels in DHCWs and occupationally unexposed individuals were considered. The relative occupational risk was assessed through prevalence ratio (PR) with 95% CI. Between-study heterogeneity was assessed (Cochran's Q test) and was used to choose the meta-analytic method. Study quality (modified Newcastle-Ottawa Scale) and publication bias (Begg and Mazumdar's test, Egger and colleagues' test, trim and fill R0 method) were assessed formally and considered for the sensitivity analysis. Sensitivity analysis to study inclusion, subgroup analyses (dental staff categories; publication year, before vs after 1998, ie, 5 years after the release by the Centers for Disease Control and Prevention of the infection control guidelines in dental healthcare setting) were performed. Results: Seven studies were included (2232 DHCWs, 1172 occupationally unexposed individuals). No evidence of publication bias was detected. The pooled PR estimate was statistically non-significant at 95% level (1.7; 95% CI 0.8 to 3.2), study-quality adjustment did not change the PR considerably (PR, 1.5; 95% CI 0.5 to 4.1). PR was statistically significant before 1998 and no longer significant after 1998. Subgroup analysis according to DHCW categories was inconclusive. Conclusions: There is no scientific evidence that DHCWs are at high occupational risk. The differences between former and recent studies could be due to different characteristics of municipal water systems and the infection control guideline dissemination.


Legionnaires' Disease in Europe, 2011 to 2015

Beauté J, on behalf of The European Legionnaires' Disease Surveillance Network.

European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden; Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.

Euro Surveill 2017 Jul;22(27):pii=30566.

Abstract: Under the coordination of the European Centre for Disease Prevention and Control (ECDC), the European Legionnaires' disease Surveillance Network (ELDSNet) conducts surveillance of Legionnaires' disease (LD) in Europe. Between 2011 and 2015, 29 countries reported 30,532 LD cases to ECDC (28,188 (92.3%) confirmed and 2,344 (7.7%) probable). Four countries (France, Germany, Italy and Spain) accounted for 70.3% of all reported cases, although their combined populations represented only 49.9% of the study population. The age-standardised rate of all cases increased from 0.97 cases/100,000 population in 2011 to 1.30 cases/100,000 population in 2015, corresponding to an annual average increase of 0.09 cases/100,000 population (95%CI 0.02-0.14; p = 0.02). Demographics and infection setting remained unchanged with ca 70% of cases being community-acquired and 80% occurring in people aged 50 years and older. Clinical outcome was known for 23,164 cases, of whom 2,161 (9.3%) died. The overall case fatality ratio decreased steadily from 10.5% in 2011 to 8.1% in 2015, probably reflecting improved reporting completeness. Five countries (Austria, Czech Republic, Germany, Italy, and Norway) had increasing age-standardised LD notification rates over the 2011-15 period, but there was no increase in notification rates in countries where the 2011 rate was below 0.5/100,000 population.


Legionella Risk Assessment in Cruise Ships and Ferries

Laganà P, Gambuzza ME, Delia S.

Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Italy.

Ann Agric Environ Med 2017 Jun;24(2):276-282.

Abstract: Introduction: The increasing development of marine traffic has led to a rise in the incidence of legionellosis among travellers. It occurs in similar environments, especially closed and crowded, and aboard ships Legionella survives and multiplies easily in water pipes, spreading into the environment through air conditioning systems and water distribution points. Although in recent years in the construction of cruise ships preventive measures aimed at curbing the proliferation of Legionella (design, materials, focus on the operation and maintenance of the water system), have been taken account, little or no attention has been paid to small ships which, in many cases, are old and not well maintained. Objective: The aim of the study was to evaluate the frequency and severity of Legionella contamination in ferries and cruise ships in order to adopt more specific control measures. Materials and method: A prevalence study was carried out on 10 ferries and 6 cruise ships docking or in transit across the port of Messina (Sicily, Italy). Water and air samples collected from many critical points were tested for qualitative and quantitative identification of Legionella. Results and conclusions: Legionella pneumophila sg 1 was isolated from the samples of shower and tap water in 7 (70%) of the 10 ferries examined, and in 3 (33%) of the 6 cruise ships examined, and L. pneumophila sg 2-14 in 8 (80%) and 1 (16.7%) of these ships, respectively. No Legionella contamination was found in whirlpool baths, air and ice samples. In conclusion, the data obtained confirm higher levels of Legionella contamination in local ferries and cruise ships, underlining the need to adopt corrective actions more specific for these smaller vessels.


Genomic Investigation of a Suspected Outbreak of Legionella pneumophila ST82 Reveals Undetected Heterogeneity by the Present Gold-Standard Methods, Denmark, July to November 2014

Schjørring S, Stegger M, Kjelsø C, Lilje B, Bangsborg JM, Petersen RF, David S, Uldum SA, ESCMID Study Group for Legionella Infections (ESGLI)

Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Copenhagen, Denmark; European Programme for Public Health Microbiology Training (EUPHEM), ECDC, Stockholm, Sweden.

Euro Surveill 2017 Jun;22(25):pii=30558.

Abstract: Between July and November 2014, 15 community-acquired cases of Legionnaires´ disease (LD), including four with Legionella pneumophila serogroup 1 sequence type (ST) 82, were diagnosed in Northern Zealand, Denmark. An outbreak was suspected. No ST82 isolates were found in environmental samples and no external source was established. Four putative-outbreak ST82 isolates were retrospectively subjected to whole genome sequencing (WGS) followed by phylogenetic analyses with epidemiologically unrelated ST82 sequences. The four putative-outbreak ST82 sequences fell into two clades, the two clades were separated by ca 1,700 single nt polymorphisms (SNP)s when recombination regions were included but only by 12 to 21 SNPs when these were removed. A single putative-outbreak ST82 isolate sequence segregated in the first clade. The other three clustered in the second clade, where all included sequences had <5 SNP differences between them. Intriguingly, this clade also comprised epidemiologically unrelated isolate sequences from the UK and Denmark dating back as early as 2011. The study confirms that recombination plays a major role in L. pneumophila evolution. On the other hand, strains belonging to the same ST can have only few SNP differences despite being sampled over both large timespans and geographic distances. These are two important factors to consider in outbreak investigations.


Legionnaires' Disease: Clinicoradiological Comparison of Sporadic Versus Outbreak Cases

Hashmi HRT, Saladi L, Petersen F, Khaja M, Diaz-Fuentes G.

Division of Pulmonary and Critical Care Medicine, Bronx-Lebanon Hospital Center, Bronx, NY, USA; Icahn School of Medicine at Mount Sinai, New York, NY, USA.

Clin Med Insights Circ Respir Pulm Med 2017 Jun;11:1179548417711941.

Abstract: Background: In 2015, New York City experienced the worst outbreak of Legionnaires' disease in the history of the city. We compare patients seen during the 2015 outbreak with sporadic cases of Legionella during the past 5 years. Methods: We conducted a retrospective chart review of 90 patients with Legionnaires' disease, including sporadic cases of Legionella infection admitted from 2010 to 2015 (n=55) and cases admitted during the 2015 outbreak (n=35). Results: We saw no significant differences between the 2 groups regarding demographics, smoking habits, alcohol intake, underlying medical disease, or residence type. Univariate and multivariate analyses showed that patients with sporadic case of Legionella had a longer stay in the hospital and intensive care unit as well as an increased stay in mechanical ventilation. Short-term mortality, discharge disposition, and most clinical parameters did not differ significantly between the 2 groups. Conclusions: We found no specific clinicoradiological characteristics that could differentiate sporadic from epidemic cases of Legionella. Early recognition and high suspicion for Legionnaires' disease are critical to provide appropriate treatment. Cluster of cases should increase suspicion for an outbreak.


Community-acquired Legionnaires' Disease in a Newly Constructed Apartment Building

Ryu S, Yang K, Chun BC.

Division of Infectious Disease Control, Gyeonggi Provincial Government, Suwon, Korea.

J Prev Med Public Health 2017 Jun;50(4):274-277.

Abstract: Objectives: Legionnaires' disease (LD) is a severe type of pneumonia caused by inhalation of aerosols contaminated with Legionella. On September 22, 2016, a single case of LD was reported from a newly built apartment building in Gyeonggi province. This article describes an epidemiologic investigation of LD and identification of the possible source of infection. Methods: To identify the source of LD, we interviewed the patient's husband using a questionnaire based on the Legionella management guidelines from the Korea Centers for Disease Control and Prevention. Water samples from the site were collected and analyzed. An epidemiological investigation of the residents and visitors in the apartment building was conducted for 14 days before the index patient's symptoms first appeared to 14 days after the implementation of environmental control measures. Results: Legionella pneumophila serogroup 1 was isolated from the heated-water samples from the patient's residence and the basement of the apartment complex. Thirty-two suspected cases were reported from the apartment building during the surveillance period, yet all were confirmed negative based on urinary antigen tests. Conclusions: The likely source of infection was the building's potable water, particularly heated water. Further study of effective monitoring systems in heated potable water should be considered.


Vital Signs: Health Care-Associated Legionnaires' Disease Surveillance Data From 20 States and a Large Metropolitan Area - United States, 2015

Soda EA, Barskey AE, Shah PP, Schrag S, Whitney CG, Arduino MJ, Reddy SC, Kunz JM, Hunter CM, Raphael BH, Cooley LA.

Epidemic Intelligence Service, CDC; Divison of Bacterial Diseases, National Center of Immunization and Respiratory Diseases, CDC.

MMWR Morb Mortal Wkly Rep 2017 Jun;66(22):584-589.

Abstract: Background: Legionnaires' disease, a severe pneumonia, is typically acquired through inhalation of aerosolized water containing Legionella bacteria. Legionella can grow in the complex water systems of buildings, including health care facilities. Effective water management programs could prevent the growth of Legionella in building water systems. Methods: Using national surveillance data, Legionnaires' disease cases were characterized from the 21 jurisdictions (20 U.S. states and one large metropolitan area) that reported exposure information for ≥90% of 2015 Legionella infections. An assessment of whether cases were health care-associated was completed; definite health care association was defined as hospitalization or long-term care facility residence for the entire 10 days preceding symptom onset, and possible association was defined as any exposure to a health care facility for a portion of the 10 days preceding symptom onset. All other Legionnaires' disease cases were considered unrelated to health care. Results: A total of 2,809 confirmed Legionnaires' disease cases were reported from the 21 jurisdictions, including 85 (3%) definite and 468 (17%) possible health care-associated cases. Among the 21 jurisdictions, 16 (76%) reported 1-21 definite health care-associated cases per jurisdiction. Among definite health care-associated cases, the majority (75, 88%) occurred in persons aged ≥60 years, and exposures occurred at 72 facilities (15 hospitals and 57 long-term care facilities). The case fatality rate was 25% for definite and 10% for possible health care-associated Legionnaires' disease. Conclusions and implications for public health practice: Exposure to Legionella from health care facility water systems can result in Legionnaires' disease. The high case fatality rate of health care-associated Legionnaires' disease highlights the importance of case prevention and response activities, including implementation of effective water management programs and timely case identification.


The Typical Presentation of an Atypical Pathogen During an Outbreak of Legionnaires' Disease in Vila Franca De Xira, Portugal, 2014

Dias A, Cysneiros A, Lopes FT, von Amann B, Costa C, Dionísio P, Carvalho J, Durão V, Carvalho GPaula F, Serrado M, Nunes B, Marques T, Froes F, Bárbara C.

Chest Department, Centro Hospitalar Lisboa Norte, Lisboa, Portugal.


Rev Port Pneumol 2017 May-Jun;23(3):117-123. 

Abstract: Background: An outbreak of Legionella pneumophila serogroup 1, with 403 cases was identified on the 7th November 2014 in Vila Franca de Xira, Portugal. Outbreak source was the wet cooling system of a local factory. Hospital Pulido Valente was one of the hospitals receiving patients with Legionnaires' disease (LD). Methods: We describe the clinical findings and diagnostic methods used among the 43 confirmed or probable cases admitted to our department. Results: 60.5% were male, mean age was 56.1±13.5 years and tobacco smoking was the most frequent risk factor (76.7%). All patients had fever, 62.8% ≥39.5°C, 72.1% had chills and myalgia/arthralgia and 62.8% had dry cough. Extra pulmonary symptoms were frequent: confusion and headache occurred in 34.9% and gastrointestinal symptoms in 20.9%. High C-Reactive Protein (55.8%≥30mg/dL) and hyponatremia (62.8%) were the laboratorial abnormalities most commonly found. Hypoxemia occurred in 55.8% and hypocapnia in 93%. Urinary Antigen Test (UAT) was positive in 83.7% of the cases. Conclusions: Although not specific, a combination of risk factors, symptoms and laboratory findings can be highly suggestive of LD, even in an outbreak. This should prompt diagnosis confirmation. Routine use of UAT in less severe cases of community acquired pneumonia might contribute to earlier diagnosis.


Legionellosis Acquired Through a Dental Unit: A Case Study

Schönning C, Jernberg C, Klingenberg D, Andersson S, Pääjärvi A, Alm E, Tano E, Lytsy B.

Department of Surveillance and Coordination, Public Health Agency of Sweden, Sweden.

J Hosp Infect  2017 May;96(1):89-92.

Abstract: In 2012, an elderly immunocompromised man died from legionellosis at a hospital in Uppsala, Sweden. The patient had visited a dental ward at the hospital during the incubation period. Legionella spp. at a concentration of 2.000 colony-forming units/L were isolated from the cupfiller outlet providing water for oral rinsing. Isolates from the patient and the dental unit were Legionella pneumophila serogroup 1, subgroup Knoxville and ST9. Pulsed-field gel electrophoresis and whole-genome sequencing strongly suggested that the isolates were of common origin. This report presents one of few documented cases of legionellosis acquired through a dental unit.


Exploring the Legionella pneumophila Positivity Rate in Hotel Water Samples from Antalya, Turkey

Sepin Özen N, Tuğlu Ataman SEmek M.

Clinical Microbiology, Public Health Laboratory, Antalya, Turkey.

Environ Sci Pollut Res Int 2017 May;24(13):12238-12242.

Abstract: The genus Legionella is a fastidious Gram-negative bacteria widely distributed in natural waters and man-made water supply systems. Legionella pneumophila is the aetiological agent of approximately 90% of reported Legionellosis cases, and serogroup 1 is the most frequent cause of infections. Legionnaires' disease is often associated with travel and continues to be a public health concern at present. The correct water management quality practices and rapid methods for analyzing Legionella species in environmental water is a key point for the prevention of Legionnaires' disease outbreaks. This study aimed to evaluate the positivity rates and serotyping of Legionella species from water samples in the region of Antalya, Turkey, which is an important tourism center. During January-December 2010, a total of 1403 samples of water that were collected from various hotels (n=56) located in Antalya were investigated for Legionella pneumophila. All samples were screened for L. pneumophila by culture method according to "ISO 11731-2" criteria. The culture positive Legionella strains were serologically identified by latex agglutination test. A total of 142 Legionella pneumophila isolates were recovered from 21 (37.5%) of 56 hotels. The total frequency of L. pneumophila isolation from water samples was found as 10.1%. Serological typing of 142 Legionella isolates by latex agglutination test revealed that strains belonging to L. pneumophila serogroups 2-14 predominated in the examined samples (85%), while strains of L. pneumophila serogroup 1 were less numerous (15%). According to our knowledge, our study with the greatest number of water samples from Turkey demonstrates that L. pneumophila serogroups 2-14 is the most common isolate. Rapid isolation of L. pneumophila from environmental water samples is essential for the investigation of travel related outbreaks and the possible resources. Further studies are needed to have epidemiological data and to determine the types of L. pneumophila isolates from Turkey.


Legionella Prevalence and Risk of Legionellosis in Japanese Households

Kuroki T, Watanabe Y, Teranishi H, Izumiyama S, Amemura-Maekawa J, Kura F.

Department of Microbiology, Kanagawa Prefectural Institute of Public Health, Chigasaki, Kanagawa, Japan.

Epidemiol Infect 2017 May;145(7):1398-1408. 

Abstract: This study determined the occurrence of legionellae in private houses for which there were no available data on aquatic environments other than the water supply system. From June 2013 to November 2014, we collected 138 water and 90 swab samples from aquatic environments in 19 houses. Legionella DNA was detected via a loop-mediated isothermal amplification assay in 66 (47·8%) water and 17 (18·9%) swab samples. High Legionella DNA detection rates were observed in water samples from washing machines and aquariums. Legionella spp. was isolated from 9 (6·5%) water and 3 (3·3%) swab samples. Legionella pneumophila SG 1 was detected from the outlet water of a bathtub spout and a bath sponge. Use of amoebic co-culture effectively increased legionellae and Legionella DNA detection rates from all sample types. A logistic regression analysis revealed that the heterotrophic plate count was significantly related to Legionella contamination. Our findings indicate that there is a risk of legionellosis from exposure to Legionella spp. in a variety of aquatic environments in residential houses. Control measures for legionellae in houses should include frequent cleaning and disinfecting to reduce heterotrophic bacteria in water and, where possible, preventing aerosolization from aquatic environments.


Is Legionellosis Present and Important in Colombia? An Analyses of Cases From 2009 to 2013

Patiño-Barbosa AM, Gil-Restrepo AF, Restrepo-Montoya V, Villamil-Gomez WE, Cardona-Ospina JA, Rodriguez-Morales AJ.

Public Health and Infection Research Group, Faculty of Health Sciences, Universidad Tecnológica De Pereira.

Cureus 2017 Mar;9(3):e1123.

Abstract: Infection due to Legionella pneumophila has been not studied in Colombia, although it is present. The observational, retrospective study in which the incidence of legionellosis in Colombia, 2009-2013, was estimated based on data extracted from the personal health records system (Registro Individual de Prestación de Servicios, RIPS) using the ICD-10 codes A48.1 (Legionnaires' disease) and A48.2 (Pontiac Fever). Using official population estimates of the National Administrative Department of Statistics (DANE), crude and adjusted incidence rates were estimated (cases/100,000 pop). During the period, 206 cases were reported (mean of 41.2 per year) for the cumulated national rate of 0.45 cases/100,000 pop. The clinical form of legionellosis with the highest incidence rates was the non-pneumonic Legionnaires' disease (0.39 cases/100,000 pop) with women being the main affected (0.42 cases/100,000 pop). The territory with the highest incidence rate was Bolivar department (1.94 cases/100,000 pop), followed by La Guajira (1.7 cases/100,000 pop). Finally, age groups with the highest morbidity were 0-9.999 years old (1.16 cases/100,000 pop) and system of identification for social subsidies beneficiaries (SISBEN) category with the highest number of total cases was level one (88 cases). According to these results, we can show that legionellosis in Colombia is more common than it could be thought. Nevertheless, cross-sectional and prospective studies should be conducted in our country in order to improve the knowledge of incidence, prevalence, and burden of disease.


Diagnosing Viral and Atypical Pathogens in the Setting of Community-Acquired Pneumonia

Waterer GW.

University of Western Australia, Level 4 MRF Building, Royal Perth Hospital, Wellington Street, Perth 6000, Australia; Northwestern University, 420 East Superior Street, Chicago, IL 60611, USA.

Clin Chest Med 2017 Mar;38(1):21-28.

Abstract: The 'atypical' pathogens causing pneumonia have long been problematic for physicians because we have had to rely on serologic tests to make a diagnosis. The introduction of polymerase chain reaction techniques revolutionized the diagnosis of respiratory infections and now a new wave of technologies promising faster, cheaper, and more comprehensive testing are becoming available. This review focuses principally on the diagnosis of Legionella, Mycoplasma, and influenza infections, but also covers recent publications on the cutting edge of diagnostic tools likely to transform the field of infectious diseases over the coming decade.


Microbiology and Epidemiology of Legionnaire's Disease

Burillo A, Pedro-Botet ML, Bouza E.

Division of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.

Infect Dis Clin North Am 2017 Mar;31(1):7-27. 

Abstract: Legionnaire's disease (LD) is the pneumonic form of legionellosis caused by aerobic gram-negative bacilli of the genus Legionella. Individuals become infected when they inhale aerosolized water droplets contaminated with Legionella species. Forty years after the identification of Legionella pneumophila as the cause of the 1976 pneumonia outbreak in a hotel in Philadelphia, we have non-culture-based diagnostic tests, effective antibiotics, and preventive measures to handle LD. With a mortality rate still around 10%, underreporting, and sporadic outbreaks, there is still much work to be done. In this article, the authors review the microbiology, laboratory diagnosis, and epidemiology of LD.


Rates and Predictors of Exposure to Legionella pneumophila in the United States Among Dental Practitioners: 2002 Through 2012

Estrich CG, Gruninger SE, Lipman RD.

Center for Scientific Information, American Dental Association, Chicago, USA.

J Am Dent Assoc 2017 Mar;148(3):164-171. 

Abstract: Background: In this study, the authors compared the odds of exposure to Legionella pneumophila among currently active dental practitioners with that of nonpractitioners and evaluated demographic and clinical practice predictors of exposure. Methods: The authors obtained demographic characteristics and dental practice behaviors from participants in the annual American Dental Association Health Screening Program survey administered from 2002 through 2012. The authors assayed serum samples obtained from participants for L. pneumophila antibodies. The authors used an adjusted logit model to evaluate predictors of positive results. Results: Among 5,431 participants, approximately 10% were positive for L. pneumophila, with no significant differences between dental practitioners and nonpractitioners. Geographic location was the only significant predictor of seropositivity, with no increased risk of being exposed to L. pneumophila associated with age, race, sex, years in practice, hours of practice per week, use of barrier protection, or infection control practices. Conclusions: Prevalence of L. pneumophila antibodies was 10.4% among dental and nondental personnel. US Census division was the only significant predictor of seropositivity. The authors conclude that provision of dental care did not increase the risk of being exposed to Legionella. Practical implications: Dentists should be aware of the prevalence of Legionella species in their practice areas to understand their personal risk of developing an infection.


Nosocomial (Health Care-Associated) Legionnaire's Disease

Agarwal S, Abell V, File TM Jr. 

Infectious Disease Division, Summa Health, 1077 Forge Boulevard, Akron, OH 44310, USA; Internal Medicine, Infectious Disease Section, Northeast Ohio Medical University, 4029 Street Rt 44, Rootstown, OH 44272, USA.

Infect Dis Clin North Am 2017 Mar;31(1):155-165. 

Abstract: Nosocomial Legionnaire's disease is most frequently associated with presence of the organism in hospital water systems. Patients are often susceptible as a result of age, underlying comorbidities, or immunosuppression. Prevention focuses on reducing the reservoir within water systems and includes super heating, ultraviolent light, chlorination, silver-copper ionization, and distal filtration. This article reviews the epidemiology of health care-associated Legionnaire's disease, reviews characteristics of several health care-associated outbreaks, and discusses strategies to prevent health care-associated infection.


Lessons from an Outbreak of Legionnaires' Disease on a Hematology-Oncology Unit

Francois Watkins LK, Toews KEHarris AM, Davidson S, Ayers-Millsap S, Lucas CE, Hubbard BC, Kozak-Muiznieks NA, Khan E, Kutty PK.

Epidemic Intelligence Service Program, Atlanta, Georgia.

Infect Control Hosp Epidemiol 2017 Mar;38(3):306-313. 

Abstract: OBJECTIVES To define the scope of an outbreak of Legionnaires' disease (LD), to identify the source, and to stop transmission. DESIGN AND SETTING Epidemiologic investigation of an LD outbreak among patients and a visitor exposed to a newly constructed hematology-oncology unit. METHODS An LD case was defined as radiographically confirmed pneumonia in a person with positive urinary antigen testing and/or respiratory culture for Legionella and exposure to the hematology-oncology unit after February 20, 2014. Cases were classified as definitely or probably healthcare-associated based on whether they were exposed to the unit for all or part of the incubation period (2-10 days). We conducted an environmental assessment and collected water samples for culture. Clinical and environmental isolates were compared by monoclonal antibody (MAb) and sequence-based typing. RESULTS Over a 12-week period, 10 cases were identified, including 6 definite and 4 probable cases. Environmental sampling revealed Legionella pneumophila serogroup 1 (Lp1) in the potable water at 9 of 10 unit sites (90%), including all patient rooms tested. The 3 clinical isolates were identical to environmental isolates from the unit (MAb2-positive, sequence type ST36). No cases occurred with exposure after the implementation of water restrictions followed by point-of-use filters. CONCLUSIONS Contamination of the unit's potable water system with Lp1 strain ST36 was the likely source of this outbreak. Healthcare providers should routinely test patients who develop pneumonia at least 2 days after hospital admission for LD. A single case of LD that is definitely healthcare associated should prompt a full investigation.


Legionnaire's Disease Since Philadelphia: Lessons Learned and Continued Progress

Cunha CB, Cunha BA.

Division of Infectious Disease, Rhode Island Hospital, Miriam Hospital, Brown University Alpert School of Medicine, Providence, USA.

Infect Dis Clin North Am 2017 Mar;31(1):1-5. 

Abstract: Legionnaire's disease has been recognized as a cause of severe community-acquired pneumonia (CAP). Legionnaire's disease has characteristic extrapulmonary findings that are the basis for a presumptive clinical diagnosis. The widespread use of Legionella culture, sputum DFA, serology, urinary antigen testing, and polymerase chain reaction have allowed earlier diagnosis of Legionnaire's disease. Excluding common source outbreaks, CAP caused by Legionnaire's disease is manifested as sporadic cases. In contrast, nosocomial Legionnaire's disease occurs in clusters or outbreaks from common Legionella species-contaminated water sources. Improved diagnostic tests have permitted accurate diagnosis. Bacterial coinfections with Legionnaire's disease are uncommon, but when present, are most often associated with bacteremia pneumococcal pneumonia.


High Prevalence of Legionella in Non-Passenger Merchant Vessels

Collins SL, Stevenson D, Mentasti M, Shaw A, Johnson A, Crossley L, Willis C.

Biosafety, Air and Water Microbiology Group, National Infection Service, Public Health England, Porton, UK.

Epidemiol Infect 2017 Mar;145(4):647-655. 

Abstract: There is a paucity of information on the risk from potable water in non-passenger merchant vessels (NPMVs) particularly with regard to Legionella and other bacteria. This retrospective study examined water samples from 550 NPMVs docked in eight UK ports. A total of 1027 samples from 412 NPMVs were examined for total aerobic colony counts (ACC), coliforms, Escherichia coli and enterococci; 41% of samples yielded ACC above the action level (>1×103 c.f.u./ml) and 4.5% contained actionable levels (>1 c.f.u./100 ml) of faecal indicator bacteria. Eight hundred and three samples from 360 NPMVs were cultured specifically for Legionella and 58% of vessels proved positive for these organisms with 27% of samples showing levels greater than the UK upper action limit of 1×103 c.f.u./l. Cabin showers (49%) and hospital shower (45%) were frequently positive. A subset of 106 samples was analysed by quantitative polymerase chain reaction for Legionella and identified a further 11 Legionella-positive NPMVs, returning a negative predictive value of 100%. There was no correlation between NPMV age or size and any microbial parameters (P>0.05). Legionella pneumophila serogroup 1 was isolated from 46% of NPMVs and sequence-based typing of 17 isolates revealed four sequence types (STs) previously associated with human disease. These data raise significant concerns regarding the management of microbial and Legionella risks on board NPMVs and suggest that better guidance and compliance are required to improve control.


A Supervised Statistical Learning Approach for Accurate Legionella pneumophila Source Attribution During Outbreaks

Buultjens AH, Chua KYL, Baines SL, Kwong J, Gao W, Cutcher Z, Adcock S, Ballard S, Schultz MB, Tomita T, Subasinghe N, Carter GP, Pidot SJ, Franklin L, Seemann T, Gonçalves Da Silva A, Howden BP, Stinear TP.

Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, Victoria, Australia.

Appl Environ Microbiol 2017 Oct:83(21): e01482-17.

Abstract: Public health agencies are increasingly relying on genomics during Legionnaires' disease investigations. However, the causative bacterium (Legionella pneumophila) has an unusual population structure, with extreme temporal and spatial genome sequence conservation. Furthermore, Legionnaires' disease outbreaks can be caused by multiple L. pneumophila genotypes in a single source. These factors can confound cluster identification using standard phylogenomic methods. Here, we show that a statistical learning approach based on L. pneumophila core genome single nucleotide polymorphism (SNP) comparisons eliminates ambiguity for defining outbreak clusters and accurately predicts exposure sources for clinical cases. We illustrate the performance of our method by genome comparisons of 234 L. pneumophila isolates obtained from patients and cooling towers in Melbourne, Australia, between 1994 and 2014. This collection included one of the largest reported Legionnaires' disease outbreaks, which involved 125 cases at an aquarium. Using only sequence data from L. pneumophila cooling tower isolates and including all core genome variation, we built a multivariate model using discriminant analysis of principal components (DAPC) to find cooling tower-specific genomic signatures and then used it to predict the origin of clinical isolates. Model assignments were 93% congruent with epidemiological data, including the aquarium Legionnaires' disease outbreak and three other unrelated outbreak investigations. We applied the same approach to a recently described investigation of Legionnaires' disease within a UK hospital and observed a model predictive ability of 86%. We have developed a promising means to breach L. pneumophila genetic diversity extremes and provide objective source attribution data for outbreak investigations. IMPORTANCE: Microbial outbreak investigations are moving to a paradigm where whole-genome sequencing and phylogenetic trees are used to support epidemiological investigations. It is critical that outbreak source predictions are accurate, particularly for pathogens, like Legionella pneumophila, which can spread widely and rapidly via cooling system aerosols, causing Legionnaires' disease. Here, by studying hundreds of Legionella pneumophila genomes collected over 21 years around a major Australian city, we uncovered limitations with the phylogenetic approach that could lead to a misidentification of outbreak sources. We implement instead a statistical learning technique that eliminates the ambiguity of inferring disease transmission from phylogenies. Our approach takes geolocation information and core genome variation from environmental L. pneumophila isolates to build statistical models that predict with high confidence the environmental source of clinical L. pneumophila during disease outbreaks. We show the versatility of the technique by applying it to unrelated Legionnaires' disease outbreaks in Australia and the UK.


Outbreak of Legionnaire's Disease Caused by Legionella pneumophila Serogroups 1 and 13

Kuroki T, Amemura-Maekawa J, Ohya H, Furukawa I, Suzuki M, Masaoka T, Aikawa K, Hibi K, Morita MLee KI, Ohnishi M, Kura F.

Department of Microbiology, Kanagawa Prefectural Institute of Public Health, Chigasaki, Kanagawa, Japan.

Emerg Infect Dis 2017 Feb;23(2):349-351. 

Abstract: In Japan, hot springs and public baths are the major sources of legionellosis. In 2015, an outbreak of Legionnaires' disease occurred among 7 patients who had visited a spa house. Laboratory investigation indicated that L. pneumophila serogroup 1 and 13 strains caused the outbreak and that these strains were genetically related.


Influence of Antibiotics on the Detection of Bacteria by Culture-Based and Culture-Independent Diagnostic Tests in Patients Hospitalized with Community-Acquired Pneumonia

Harris AM, Bramley AM, Jain S, Arnold SRAmpofo K, Self WH, Williams DJ, Anderson EJ, Grijalva CG, McCullers JA, Pavia AT, Wunderink RG, Edwards KM, Winchell JM, Hicks LA.

Centers for Disease Control and Prevention, Atlanta, Georgia.

Open Forum Infect Dis 2017 Feb;4(1):1-7.

Abstract: Background: Specimens collected after antibiotic exposure may reduce culture-based bacterial detections. The impact on culture-independent diagnostic tests is unclear. We assessed the effect of antibiotic exposure on both of these test results among patients hospitalized with community-acquired pneumonia (CAP). Methods: Culture-based bacterial testing included blood cultures and high-quality sputum or endotracheal tube (ET) aspirates; culture-independent testing included urinary antigen testing (adults) for Streptococcus pneumoniae and Legionella pneumophila and polymerase chain reaction (PCR) on nasopharyngeal and oropharyngeal (NP/OP) swabs for Mycoplasma pneumoniae and Chlamydia pneumoniae. The proportion of bacterial detections was compared between specimens collected before and after either any antibiotic exposure (prehospital and/or inpatient) or only prehospital antibiotics and increasing time after initiation of inpatient antibiotics. Results: Of 4678 CAP patients, 4383 (94%) received antibiotics: 3712 (85%) only inpatient, 642 (15%) both inpatient and prehospital, and 29 (<1%) only prehospital. There were more bacterial detections in specimens collected before antibiotics for blood cultures (5.2% vs 2.6%; P < .01) and sputum/ET cultures (50.0% vs 26.8%; P < .01) but not urine antigen (7.0% vs 5.7%; P = .53) or NP/OP PCR (6.7% vs 5.4%; P = .31). For all diagnostic testing, bacterial detections declined with increasing time between inpatient antibiotic administration and specimen collection. Conclusions: Bacteria were less frequently detected in culture-based tests collected after antibiotics and in culture-independent tests that had longer intervals between antibiotic exposure and specimen collection. Bacterial yield could improve if specimens were collected promptly, preferably before antibiotics, providing data for improved antibiotic selection.


Unusual Legionnaires' Outbreak in Cool, Dry Western Canada: An Investigation Using Genomic Epidemiology

Knox NC, Weedmark KA, Conly J, Ensminger AW, Hosein FS, Drews SJLegionella Outbreak Investigative Team.

Alberta Health Services, Calgary, Alberta, Canada.

Epidemiol Infect 2017 Jan;145(2):254-265.

Abstract: An outbreak of Legionnaires' disease occurred in an inner city district in Calgary, Canada. This outbreak spanned a 3-week period in November-December 2012, and a total of eight cases were identified. Four of these cases were critically ill requiring intensive care admission but there was no associated mortality. All cases tested positive for Legionella pneumophila serogroup 1 (LP1) by urinary antigen testing. Five of the eight patients were culture positive for LP1 from respiratory specimens. These isolates were further identified as Knoxville monoclonal subtype and sequence subtype ST222. Whole-genome sequencing revealed that the isolates differed by no more than a single vertically acquired single nucleotide variant, supporting a single point-source outbreak. Hypothesis-based environmental investigation and sampling was conducted; however, a definitive source was not identified. Geomapping of case movements within the affected urban sector revealed a 1.0 km common area of potential exposure, which coincided with multiple active construction sites that used water spray to minimize transient dust. This community point-source Legionnaires' disease outbreak is unique due to its ST222 subtype and occurrence in a relatively dry and cold weather setting in Western Canada. This report suggests community outbreaks of Legionella should not be overlooked as a possibility during late autumn and winter months in the Northern Hemisphere.


Prevalence of Atypical Pathogens in Patients with Cough and Community-Acquired Pneumonia: A Meta-Analysis

Marchello C, Dale APThai TNHan DS, Ebell MH.

Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, Athens, Georgia.

Ann Fam Med 2016 Nov;14(6):552-566.

Abstract: Purpose: Community-acquired pneumonia (CAP), acute cough, bronchitis, and lower respiratory tract infections (LRTI) are often caused by infections with viruses or Streptococcus pneumoniae. The prevalence of atypical pathogens Mycoplasma pneumoniaeChlamydophila pneumoniaeLegionella pneumophila, and Bordetella pertussis among patients with these illnesses in the ambulatory setting has not been previously summarized. We set out to derive prevalence information from the existing literature. Methods: We performed a systematic review of MEDLINE for prospective, consecutive-series studies reporting the prevalence of M pneumoniae, C pneumoniae, L pneumophila and/or B pertussis in outpatients with cough, acute bronchitis, LRTI, or CAP. Articles were independently reviewed by 2 authors for inclusion and abstraction of data; discrepancies were resolved by consensus discussion. A meta-analysis was performed on each pathogen to calculate the pooled prevalence estimates using a random effects model of raw proportions. Results: Fifty studies met our inclusion criteria. While calculated heterogeneity was high, most studies reported prevalence for each pathogen within a fairly narrow range. In patients with CAP, the overall prevalence of M pneumoniae and C pneumoniae were 10.1% (95% CI, 7.1%-13.1%) and 3.5% (95% CI, 2.2%-4.9%), respectively. Consistent with previous reports, M pneumoniae prevalence peaked in roughly 6-year intervals. Overall prevalence of L pneumophila was 2.7% (95% CI, 2.0%-3.4%), but the organism was rare in children, with only 1 case in 1,765. In patients with prolonged cough in primary care, the prevalence of B pertussis was 12.4% (95% CI, 4.9%-19.8%), although it was higher in studies that included only children (17.6%; 95% CI, 3.4%-31.8%). Conclusions: Atypical bacterial pathogens are relatively common causes of lower respiratory diseases, including cough, bronchitis, and CAP. Where surveillance data were available, we found higher prevalence in studies where all patients are tested for these pathogens. It is likely that these conditions are underreported, underdiagnosed, and undertreated in current clinical practice.