Adaptation of Amoeba Plate Test To Recover Legionella Strains from Clinical Samples.

The isolation of Legionella from respiratory samples is the gold standard for diagnosis of Legionnaires' disease (LD) and enables epidemiological studies and outbreak investigations. The purpose of this work was to adapt and to evaluate the performance of an amoebic coculture procedure (the amoeba plate test [APT]) for the recovery of Legionella strains from respiratory samples, in comparison with axenic culture and liquid-based amoebic coculture (LAC). Axenic culture, LAC, and APT were prospectively performed with 133 respiratory samples from patients with LD. The sensitivities and times to results for the three techniques were compared. Using the three techniques, Legionella strains were isolated in 46.6% (n = 62) of the 133 respiratory samples. The sensitivity of axenic culture was 42.9% (n = 57), that of LAC was 30.1% (n = 40), and that of APT was 36.1% (n = 48). Seven samples were positive by axenic culture only; for those samples, there were <10 colonies in total. Five samples, all sputum samples, were positive by an amoebic procedure only (5/5 samples by APT and 2/5 samples by LAC); all had overgrowth by oropharyngeal flora with axenic culture. The combination of axenic culture with APT yielded a maximal isolation rate (i.e., 46.6%). Overall, the APT significantly reduced the median time for Legionella identification to 4 days, compared with 7 days for LAC (P < 0.0001). The results of this study support the substitution of LAC by APT, which could be implemented as a second-line technique for culture-negative samples and samples with microbial overgrowth, especially sputum samples. The findings provide a logical basis for further studies in both clinical and environmental settings.

Epidemiologic characteristics associated with ST23 clones compared to ST1 and ST47 clones of Legionnaires disease cases in France.

In France, approximately 1200 cases of Legionnaires disease (LD) are reported annually, and isolates are available for approximately 20% of cases identified since 2000. All Legionella pneumophila serogroup 1 (sg1) isolates are characterized by sequence-based typing at the National Reference Centre. LD cases caused by L. pneumophila sg1 reported from 2008 through 2012 were considered for the study. Our study objective was to describe cases according to their sequence type (ST). We also constructed multivariable modified Poisson regression models to estimate the incidence rate ratio (IRR) and to identify characteristics potentially associated with ST23 clones compared to ST1 and ST47 clones. We studied 1192 patients infected by ST1 (n = 109), ST23 (n = 236), ST47 (n = 123) or other STs (n = 724). The geographic distribution of the ST23 cases across the country was significantly different compared to other ST groups. This genotype was significantly associated with the absence of corticosteroid therapy compared to ST1 (IRR = 0.56; p 0.016). Concerning exposure, the ST23 genotype was significantly less associated with hospital-acquired infections compared to ST1 (IRR = 0.32; p 0.001), but it was more associated with infections acquired in hospitals and elderly settings compared with ST47. Finally, the ST23 genotype was less frequently associated with travel than other STs. Despite the large number of cases of ST23 infection, we did not identify any characteristics specific to this ST. However, we identified independent associations between ST1 and nosocomial transmission and steroid therapy. These findings should encourage further exploration, especially in terms of environmental diffusion, strain virulence and host factors.

Legionnaires' disease in France.

The aim of this review was to describe the current knowledge of Legionnaires' disease (LD) illustrated by the epidemiological situation in France in 2013. LD is a severe pneumonia commonly caused by Legionella pneumophila serogroup 1. The diagnosis is usually based on the urinary antigen test. This rapid method reduces the delay between clinical suspicion and initiation of an appropriate treatment. However, the availability of a clinical strain is important to improve knowledge of circulating bacteria, to document case clusters, and to identify the sources of contamination. The source of contamination is unknown in most cases. The main contamination sources generating aerosols are water network systems and cooling towers. Thanks to the strengthening of clinical and environmental monitoring and to several guidelines, no epidemic has been reported in France since 2006. Despite these efforts, the number of LD cases has not decreased in recent years. It is essential that applied research continue to better understand the spatial and temporal dynamics of the disease and its characteristics (impact of environmental factors, sources of exposure, strains, host, etc.). Fundamental knowledge has been greatly improved (pathogenesis, immune mechanisms, etc.). The results of this research should help define new strategies for the diagnosis, prevention, and control to decrease the number of LD cases diagnosed every year.

First cases of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infections in France, investigations and implications for the prevention of human-to-human transmission, France, May 2013.

In May 2013, Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection was diagnosed in an adult male in France with severe respiratory illness, who had travelled to the United Arab Emirates before symptom onset. Contact tracing identified a secondary case in a patient hospitalised in the same hospital room. No other cases of MERS-CoV infection were identified among the index case's 123 contacts, nor among 39 contacts of the secondary case, during the 10-day follow-up period.

Legionnaires' disease in France: sensitivity of the mandatory notification has improved over the last decade.

The notification rate of Legionnaires' disease (LD) in France was 2.4/100 000 population in 2010, varying across regions with an increasing rate from west to east. Two sources [mandatory notifications (MN) and a survey of hospital laboratories] were used in a capture-recapture study to estimate the number of LD cases and the sensitivity of the MN system at national and regional levels in 2010. The number of missed cases was estimated using Chapman's method. The estimated sensitivity of MN was 88.5% (95% CI 88.0-89.0) and ranged from 70% to 100% by region. The estimated incidence was 2.7/100 000 population. Sensitivity of the MN system improved since the previous capture-recapture estimates (10% in 1995, 33% in 1998). This study confirmed that the observed west-east gradient is not related to regional notification disparities. Ecological studies should be conducted to better understand the observed spatial variations in LD incidence.

Contribution of amoebic coculture to recovery of Legionella isolates from respiratory samples: prospective analysis over a period of 32 months.

We evaluated the contribution of amoebic coculture to the recovery of Legionella spp. from 379 respiratory samples. The sensitivity of axenic culture was 42.1%. The combination of axenic culture with amoebic coculture increased the Legionella isolation rate to 47.1%. Amoebic coculture was particularly efficient in isolating Legionella spp. from respiratory samples contaminated with oropharyngeal flora.

Factors associated with hospital mortality in community-acquired legionellosis in France.

The aims of this study were to describe the clinical, biological and radiological features of community-acquired (CA) Legionnaires' disease (LD) and identify the predictors of mortality in hospitalised patients. Demographic data, risk factors, clinical and biological features, medical management, complications, and outcome from 540 hospitalised patients with confirmed CA LD were prospectively recorded. 8.1% of patients (44 out of 540) died. The predictors of survival after Kaplan-Meier analysis were male sex (p = 0.01), age <60 yrs (p = 0.02), general symptoms (p = 0.006), intensive care unit (ICU) stay (p<0.001), and class II-III Pneumonia Severity Index score (p = 0.004). Six predictors of death were identified by multivariate analysis: age (per 10-yr increment) (relative hazard (RH) 1.50, 95% CI 1.21-1.87), female sex (RH 2.00, 95% CI 1.08-3.69), ICU admission (RH 3.31, 95% CI 1.67-6.56), renal failure (RH 2.73, 95% CI 1.42-5.27), corticosteroid therapy (RH 2.54, 95% CI 1.04-6.20) and C-reactive protein (CRP) >500 mg · L(-1) (RH 2.14, 95% CI 1.02-4.48). Appropriate antibiotic therapy was prescribed for 70.8% (292 out of 412) of patients after admission and for 99.8% (537 out of 538) of patients after diagnosis confirmation. In conclusion, female sex, age, ICU stay, renal failure, corticosteroid treatment and increased level of CRP are significant risk factors for mortality in CA LD.

Cluster of Legionnaires' disease associated with a public whirlpool spa, France, April-May 2010.

In May 2010, a cluster of three cases of Legionnaires' disease was identified in France. The results of the epidemiological, environmental and microbiological investigations allowed the rapid identification of a public whirlpool spa as the most probable source of contamination and the implementation of appropriate control measures. This investigation has stressed the need for good cooperation between partners and the importance of the molecular analysis of Legionella strains.

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

Legionnaires' 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.

Clusters of travel-associated Legionnaires disease in Italy, Spain and France, July 2002 - June 2006.

For several years, over 50% of the cases of travel-associated Legionnaires' disease (TALD) reported to the European Working Group for Legionella Infections (EWGLINET) have been among travellers to France, Italy, and Spain. We describe clusters of TALD cases reported in these countries during a four-year period. We analysed data from EWGLINET and from the individual countries. In all three countries, upon notification of a cluster, local health authorities are alerted by the national collaborator and immediately begin an environmental investigation at the accommodation site, which includes risk assessments and analysis of water samples. From July 1, 2002 to June 30, 2006, 2,101 accommodation sites were associated with TALD cases and reported by EWGLINET to Italian, Spanish and French collaborators. Of these, 252 sites (12%) were associated with clusters: 13.8% (96/697) in Italy, 13.2% (81/615) in Spain and 9.5% (75/789) in France. Overall, 641 cases were reported. Hotels, camping sites and ships and other sites represented respectively 83%, 10% and 7% of the total accommodation sites, with similar proportions in the three countries. In 99% of the sites, samples were collected; 62% of them were found to be positive for Legionella. The findings of this study highlight that disinfection and long-term preventive measures were correctly implemented by the large majority of sites. However, additional efforts must be made to further reduce the percentage of re-offending sites so as to reduce the number of accommodations that are contaminated by Legionella.

[Legionnaire's disease: surveillance in France in 2005]. / Epidémiologie de la légionellose en France en 2005.

Legionnaire's disease is a recently described infection and surveillance in France was implemented in 1987. In 2005, 1,527 cases were notified corresponding to a population incidence rate of 2.5 per 100,000. The median age of cases was 61 years [5-100] and the male to female sex ratio was 3.0. The case fatality rate was 11%. One or more risk factors were identified for 1,084 (71%) cases. The majority of cases (91%) was diagnosed by urinary antigen detection and a strain was identified in 276 cases (18%). Legionella pneumophila serogroup 1 infection was confirmed in 95% of cases. A specific exposure during the incubation period was reported for 39% of cases. Travel exposure was reported for 17% and hospital exposure for 7%. Multiple clusters and outbreaks were investigated. The largest one reported was identified in the north Lyon with 34 cases. Since 1997 the incidence of LD has steadily increased. This probably suggests a better detection of cases and an improvement in the surveillance system. In recent years, several new measures concerning prevention and control were implemented. However these efforts must continue particularly in the research domain to improve knowledge of the disease, in order to limit its impact on exposed populations.

[Factors associated with mortality in Legionnaires' disease, France, 2002-2004]. / Les facteurs associés à la mortalité de la légionellose en France, 2002-2004.

UNLABELLED: Risk factors for Legionnaires' disease are well known (older age, smoking, or immunosuppression), however, the factors associated with mortality are less documented. A retrospective analysis based on cases notified between 2002 and 2004 was conducted in France to identify these factors. METHOD: Cases were identified through mandatory notifications sent to the Institut de veille sanitaire, France. Factors associated with mortality were identified using a logistic regression analysis. RESULTS: Three thousand two hundred sixty-seven cases of Legionnaire's disease were notified during the study period and the evolution was documented for 85% of the cases (2.791). Three hundred seventy-seven deaths (13.5%) were notified. 72.5% of the patients were men and the median age was 61. The multivariate analysis applied to patients under 60 years revealed that cancer or hemopathy (OR=6.4 CI95% 3.6-11.2), underlying renal disease (OR=3.2 CI95% 1.0-9.9), or alcohol abuse (OR=2.2 CI95% 1.1-4.4) were associated with mortality. For older patients (>60 years) factors linked to mortality were: cancer/hemopathy (OR=1.8 CI95% 1.2-2.6), underlying renal disease (OR=3 CI95% 1.4-6.4), underlying cardiac disease (OR=2.4 CI95% 1.4-4), alcohol abuse (OR=2.4 CI95% 1.2-5.2), immunosuppression (OR=1.7 CI95% 1.1-2.6), nosocomial acquisition of the disease (OR=2.0 CI95% 1.3-3), or infection acquired in nursing home residents (OR=2.4 IC 95% 1.6-3.6). CONCLUSION: These preliminary results further describe Legionnaires' disease and its mortality. However, they should be confirmed by carefully conducted prospective analysis. The description of LD patients at high risk of death will contribute to better prevention measures.

[Principles of an outbreak investigation in public health practice]. / Les principes de l'investigation d'une épidémie dans une finalité de santé publique.

An outbreak (or epidemic) is a higher number of cases of a given disease in a given population and time interval. A timely investigation has for aim to identify the source and vehicle of the outbreak and provides unique opportunities to better understand its occurrence and the role of contributing risk factors to implement the most appropriate measures to control it and prevent further recurrences. The investigation of an outbreak is based on a multidisciplinary approach (clinical, epidemiological, environmental, and microbiological) with a descriptive and analytical (hypothesis testing) phase. In this article, we describe the methodological approach of a field outbreak investigation illustrated by examples taken from our experience. The investigation includes the following steps: establishing the existence of the outbreak; defining the disease; finding cases; describing cases by time, place, and person characteristics; establishing a hypothesis related to the mode of occurrence; testing the hypotheses; conducting an environmental investigation; conducting a microbiological investigation; controlling the outbreak, preventing further occurrences, and writing an investigation report to share experience with the public health and scientific community. The investigation of an outbreak is an evolving process: information gathered or conclusions made at a given stage must be fully used for following steps. The social, institutional, and political background associated with outbreaks usually makes their investigation complex and should be taken into account. The earlier the outbreak is detected and investigated in close relation with public health authorities, the greater will be the potential preventive impact of control measures.

[Epidemiology of tuberculosis in Ile-de-France in 2001]. / Situation épidémiologique de la tuberculose en Ile-de-France en 2001.

INTRODUCTION: The incidence of tuberculosis in France is stable at around 10 per 100,000 per year since 1997. However in the Ile-de-France (which includes Paris and its suburbs) high population density, social deprivation and large numbers of immigrants result in the region providing more than half of the total number of cases notified in France. METHODS: Retrospective analysis using data from the mandatory notification forms of patients diagnosed in 2001. RESULTS: The incidence of tuberculosis in 2001 was 27.2 cases per 100,000 in the Ile-de-France region and 48.4 per 100,000 in the Paris area. The incidence was particularly high amongst young immigrants, especially those from Sub-Saharian countries. Pulmonary tuberculosis was the most commonly observed disease form (72% of cases). HIV infection was documented in 7.5% of subjects. Local tuberculosis control services were asked to intervene in only 30% of overall cases, and in only 50% of pulmonary cases living in crowded housing. CONCLUSION: More resource is needed for the surveillance of tuberculosis and the implementation of public health initiatives in the Ile-de-France to strengthen the fight against tuberculosis.

Clusters of travel associated legionnaires' disease in France, September 2001- August 2003.

Clusters of travel associated legionnaires' disease warrant urgent attention, and are detected by the French national surveillance system and the European network EWGLINET. Between September 2001 and August 2003, 37 clusters were identified in French tourist accommodation: 27 hotels and 10 campsites. The number of clinical cases per cluster was as follows: 30 clusters of 2 cases (81%), 6 clusters of 3 cases (16%) and one cluster of 4 cases (3%), a total of 82 cases. The local health authorities performed environmental investigations for 36 of the 37 clusters. Among the 36 clusters investigated, water samples were collected for 35. At 16 (46%) sites, Legionella pneumophila was found at a level of more than 103 cfu/litre. In all of the accommodation where risk assessment was found to be inadequate- control measures were implemented immediately. Six hotels were closed immediately following cluster alerts. Comparison of clinical and environmental isolates by pulsed field gel electrophoresis (PFGE) was possible in 3 clusters and identical genomic profiles of the isolates were found in all. During this two year period of surveillance, we found that on many sites there has been a risk of exposure to Legionella. This reinforces the importance of the European surveillance network and the timely notifications of all the cases to EWGLINET.

Sporadic cases of community acquired legionnaires' disease: an ecological study to identify new sources of contamination.

STUDY OBJECTIVE: To explore the relation between incidence of sporadic and community acquired legionnaires' disease and exposure to potentially contaminated industrial aerosols. DESIGN: Geographical ecological approach using the postcode as the statistical unit. A multivariate Poisson regression model was used to model the relation between exposure to industrial aerosols and legionnaires' disease. SETTING: Metropolitan France. MAIN RESULTS: More than 1000 sources of industrial exposure (aerosol and plume of smoke) were identified in 42 French departments. After adjusting for confounding factors, there was a statistically increased incidence of legionnaires' disease in postcodes with plume of smoke in comparison with postcodes without (RR=1.45, 95% CI=1.12 to 1.87), and in postcodes with more than one aerosol in comparison with postcodes without (RR=1.37, 95% CI=1.04 to 1.79). CONCLUSION: These findings highlight that any industrial systems generating water aerosols should be regarded as potential sources of contamination for legionnaires' disease.

Notified cases of legionnaires disease in France in 2001.

In 2001, 807 cases of Legionnaires' disease were reported to the Institut de veille sanitaire (French national public health centre). The incidence of the disease was 1.35 cases per 100,000 inhabitants, compared to a mean European incidence of 0,6 per 100,000. The median age was 59 years [16-97], the group aged more than 80 being the most affected. The sex ratio M/W was 3.1. The outcome of the disease was known in 69% of all cases, the case fatality ratio rating 19.9%. Among the contributing factors found in 558 cases, 11% had a cancer or blood disease, 12% received an immunosuppressant treatment, 10% were diabetic and 40% were smokers. In 2001, 13% (105/807) cases stayed in a hospital or a clinic during the incubation period, compared to 20% in 2000, and 11% were travel-associated.

Preparation, experience, and aftermath of hurricane Floyd.

In September 1999, Hurricane Floyd threatened the southeastern coast of the United States, causing the largest peacetime evacuation in history. The hurricane moved onto land when it curved northward and slammed into southeastern North Carolina near Wilmington and Cape Fear. This region already had experienced three hurricanes in recent years and had been brushed by Hurricane Dennis one month earlier. This article describes actions taken by the New Hanover Regional Medical Center surgical services department in Wilmington, NC, to prepare for and weather the storm. The aftermath and cleanup also are discussed.