Restaurant outbreak of Legionnaires' disease associated with a decorative fountain: an environmental and case-control study

SUMMARYIn a setting where potable water is contaminated with Legionella pneumophila serogroup 1, we performed two case control studies. The first case control study consisted of 17 cases of nosocomial Legionnaires' disease (LD) and 33 control (the patients who were admitted to the ward where the case was admitted immediately before and after the case) subjects. Cases had a higher mortality rate 65% vs 12% (P < 0.004); were more likely to have received assisted ventilation (P < 0.00001); to have nasogastric tubes (P < 0.0004) and to be receiving corticosteroids or other immunosuppressive therapy (P < 0.0001). Based on the results of this study, sterile water was used to flush nasogastric tubes and to dilute nasogastric feeds. Only 3 cases of nosocomial LD occurred during the next year compared with 12 the previous year (P < 0.0001). Nine cases subsequently occurred and formed the basis for the second case-control study. Eighteen control subjects were those patients admitted to the same unit where the case developed LD, immediately before and after the case. The mortality rate for the cases was 89% vs 6% for controls (P < 0.00003). The only other significant difference was that cases were more likely to be receiving corticosteroids or other immunosuppressive therapy 89% vs 39% ( < 0.01). We hypothesized that microaspiration of contaminated potable water by immunocompromised patients was a risk factor for nosocomial Legionnaires' disease. From 17 March 1989 onwards such patients were given only sterile potable water. Only two cases of nosocomial LD occurred from June 1989 to September 1990 and both occurred on units where the sterile water policy was not in effect. We conclude that aspiration of contaminated potable water is a possible route for acquisition of nosocomial LD in our hospital and that provision of sterile potable water to high risk patients (those who are receiving corticosteroids or other immunosuppressive drugs; organ transplant recipients or hospitalized in an intensive care unit) should be mandatory.

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Legionnaires' disease outbreak associated with a cruise liner, August 2003: epidemiological and microbiological findings

Epidemiology and Infection ◽

10.1017/s0950268806007473 ◽

2006 ◽

Vol 135 (5) ◽

pp. 802-810 ◽

Cited By ~ 29

Author(s):

K. BEYRER ◽

S. LAI ◽

J. DREESMAN ◽

J. V. LEE ◽

C. JOSEPH ◽

...

Keyword(s):

Legionella Pneumophila ◽

Case Control Study ◽

Prolonged Exposure ◽

Interdisciplinary Approach ◽

Case Control ◽

Case Definition ◽

Source Of Infection ◽

Legionnaires Disease ◽

The Mean ◽

Control Study

SUMMARYEight cases of Legionnaires' disease were identified among the 215 German passengers after a cruise to the Nordic Sea in August 2003. An unmatched case-control study was conducted to identify risk factors and the source of infection. In total, eight passengers fulfilled the case definition, one of these died. Forty-two passengers served as controls. The attack rate was 4%. The mean age was 60 years for cases and 62 years for controls. Prolonged exposure to the spa pool seemed to be a risk factor of infection (OR 4·85,P=0·09).Legionella pneumophilaserogroup 1, monoclonal antibody (mAb) subgroup ‘Knoxville’ was isolated from clinical and environmental samples. DNA sequence-based typing revealed that these isolates were indistinguishable from each other. The investigation showed the importance of an interdisciplinary approach of microbiology and epidemiology as not all sites on the ship that tested positive forL. pneumophilaactually posed a relevant risk for the passengers.

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Legionnaires' disease outbreak in Rome, Italy

Epidemiology and Infection ◽

10.1017/s0950268805004115 ◽

2005 ◽

Vol 133 (5) ◽

pp. 853-859 ◽

Cited By ~ 16

Author(s):

M. C. ROTA ◽

G. PONTRELLI ◽

M. SCATURRO ◽

A. BELLA ◽

A. R. BELLOMO ◽

...

Keyword(s):

Legionella Pneumophila ◽

Cooling Tower ◽

Case Control Study ◽

Hospital Admissions ◽

Case Control ◽

Phenotypic Analysis ◽

Single Strain ◽

Increased Risk ◽

Legionnaires Disease ◽

Control Study

Between August and October 2003, 15 cases of Legionnaires' disease were detected in the 9th district of Rome. To identify possible sources of Legionella exposure, a matched case-control study was conducted and environmental samples were collected. Hospital discharge records were also retrospectively analysed for the period July–November 2003, and results were compared with the same period during the previous 3 years. The case-control study revealed a significantly increased risk of disease among those frequenting a specific department store in the district (OR 9·8, 95% CI 2·1–46·0), and Legionella pneumophila was isolated from the store's cooling tower. Genotypic and phenotypic analysis of human and environmental isolates demonstrated that the cluster was caused by a single strain of L. pneumophila serogroup 1, and that the cooling tower of the store was the source of infection. The increased number of hospital admissions for microbiologically undiagnosed pneumonia during the study period may indicate that some legionellosis cases were not identified.

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An outbreak investigation of Legionella non-pneumophila Legionnaires’ disease in Sweden, April to August 2018: Gardening and use of commercial bagged soil associated with infections

Eurosurveillance ◽

10.2807/1560-7917.es.2021.26.7.1900702 ◽

2021 ◽

Vol 26 (7) ◽

Author(s):

Emma Löf ◽

Fanny Chereau ◽

Pontus Jureen ◽

Sabina Andersson ◽

Kristina Rizzardi ◽

...

Keyword(s):

Case Control Study ◽

Case Control ◽

Soil Samples ◽

Outbreak Investigation ◽

Joint Analysis ◽

Whole Genome ◽

Legionnaires Disease ◽

Dry Soil ◽

Control Study ◽

Different Soils

In early June 2018, an increase in non-travel-related cases of Legionella non-pneumophila Legionnaires’ disease (LD) was observed in Sweden and a national outbreak investigation was started. Outbreak cases were defined as notified confirmed or probable cases of L. non-pneumophila LD, with symptom onset after 1 April 2018. From April to August 2018, 41 cases were reported, 30 of whom were identified as L. longbeachae. We conducted a case–control study with 27 cases and 182 matched controls. Results from the case–control study indicated that gardening and handling commercial bagged soil, especially dusty dry soil, were associated with disease. L. longbeachae was isolated in soils from cases’ homes or gardens, but joint analysis of soil and human specimens did not identify any genetic clonality. Substantial polyclonality was noted between and within soil samples, which made finding a genetic match between soil and human specimens unlikely. Therefore, whole genome sequencing may be of limited use to confirm a specific soil as a vehicle of transmission for L. longbeachae. Handling soil for residential gardening was associated with disease and the isolation of L. longbeachae in different soils provided further evidence for Legionella non-pneumophila infection from soil.

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Sporadic community-acquired Legionnaires' disease in France: a 2-year national matched case-control study

Epidemiology and Infection ◽

10.1017/s0950268807000283 ◽

2008 ◽

Vol 136 (12) ◽

pp. 1684-1690 ◽

Cited By ~ 17

Author(s):

D. CHE ◽

C. CAMPESE ◽

P. SANTA-OLALLA ◽

G. JACQUIER ◽

D. BITAR ◽

...

Keyword(s):

Risk Factors ◽

Case Control Study ◽

Conditional Logistic Regression ◽

Case Control ◽

Dose Effect ◽

Personal Hygiene ◽

Legionnaires Disease ◽

Matched Case ◽

Matched Case Control Study ◽

Control Study

SUMMARYLegionnaires' disease (LD) is an aetiology of community-acquired bacterial pneumonia in adults, with a high case-fatality ratio (CFR). We conducted a matched case-control study to identify risk factors for sporadic, community-acquired LD. Cases of sporadic, community-acquired and biologically confirmed LD, in metropolitan France from 1 September 2002 to 31 September 2004, were matched with a control subject according to age, sex, underlying illness and location of residence within 5 km. We performed a conditional logistic regression on various host-related factors and exposures. Analysis was done on 546 matched pairs. The CFR was 3·5%. Age ranged from 18–93 years (mean 57 years), with a 3·6 male:female sex ratio. Cases were more likely to have smoked with the documentation of a dose-effect relation, to have travelled with a stay in a hotel (OR 6·1, 95% CI 2·6–14·2), or to have used a wash-hand basin for personal hygiene (OR 3·5, 95% CI 1·6–7·7) than controls. Tobacco and travel have been previously described as risk factors for LD, but this is the first time that such a dose-effect for tobacco has been documented among sporadic cases. These findings will provide helpful knowledge about LD and help practitioners in identifying patients at high risk.

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

Eurosurveillance ◽

10.2807/1560-7917.es.2020.25.20.1900523 ◽

2020 ◽

Vol 25 (20) ◽

Cited By ~ 1

Author(s):

Marino Faccini ◽

Antonio Giampiero Russo ◽

Maira Bonini ◽

Sara Tunesi ◽

Rossella Murtas ◽

...

Keyword(s):

Crossover Study ◽

Legionella Pneumophila ◽

Case Control Study ◽

Dispersion Model ◽

Case Control ◽

Case Crossover ◽

Large Outbreak ◽

Legionnaires Disease ◽

Aerosol Dispersion ◽

Control Study

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.

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Epidemiological investigation and case–control study: a Legionnaires’ disease outbreak associated with cooling towers in Warstein, Germany, August–September 2013

Eurosurveillance ◽

10.2807/1560-7917.es.2015.20.46.30064 ◽

2015 ◽

Vol 20 (46) ◽

Cited By ~ 15

Author(s):

Anna Maisa ◽

Ansgar Brockmann ◽

Frank Renken ◽

Christian Lück ◽

Stefan Pleischl ◽

...

Keyword(s):

Legionella Pneumophila ◽

Case Control Study ◽

Case Fatality ◽

Case Control ◽

Cooling Towers ◽

Multiple Sources ◽

Source Tracing ◽

Infection Source ◽

Legionnaires Disease ◽

Control Study

Between 1 August and 6 September 2013, an outbreak of Legionnaires’ disease (LD) with 159 suspected cases occurred in Warstein, North Rhine-Westphalia, Germany. The outbreak consisted of 78 laboratory-confirmed cases of LD, including one fatality, with a case fatality rate of 1%. Legionella pneumophila, serogroup 1, subtype Knoxville, sequence type 345, was identified as the epidemic strain. A case–control study was conducted to identify possible sources of infection. In univariable analysis, cases were almost five times more likely to smoke than controls (odds ratio (OR): 4.81; 95% confidence interval (CI): 2.33–9.93; p < 0.0001). Furthermore, cases were twice as likely to live within a 3 km distance from one identified infection source as controls (OR: 2.14; 95% CI: 1.09–4.20; p < 0.027). This is the largest outbreak of LD in Germany to date. Due to a series of uncommon events, this outbreak was most likely caused by multiple sources involving industrial cooling towers. Quick epidemiological assessment, source tracing and shutting down of potential sources as well as rapid laboratory testing and early treatment are necessary to reduce morbidity and mortality. Maintenance of cooling towers must be carried out according to specification to prevent similar LD outbreaks in the future.

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An outbreak of legionnaires’ disease in a municipality in northern Portugal

Eurosurveillance ◽

10.2807/esm.06.07.00228-en ◽

2001 ◽

Vol 6 (7) ◽

pp. 121-124 ◽

Cited By ~ 14

Author(s):

A M Correia ◽

G Gonçalves ◽

J Reis ◽

J M Cruz ◽

J A Castro e Freitas

Keyword(s):

Legionella Pneumophila ◽

Case Control Study ◽

District Hospital ◽

Case Control ◽

Northern Portugal ◽

Legionnaires Disease ◽

Control Study

Eleven cases of legionnaires´ disease, all patients living in the same municipality, were admitted to a district hospital in northern Portugal. Preliminary investigations suggested an association with the events of the annual festivities in that municipality. Legionella pneumophila was not isolated from any of the suspected sources, but evidence from a case control study suggested that an aerosol produced by a decorative fountain in the main square during the night of a rock concert was the likely vehicle of infection. The prevalence of smoking was higher among cases than controls.

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