Severe Legionellosis Cases Admitted to Grenoble University Hospital, 2006-2011.

Study Overview
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Brief Summary
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The study aimed at further describing the epidemiological, clinical, diagnostic and prognostic features in legionellosis cases admitted to Grenoble University Hospital during the 2006-2011period. The investigators also tested lower respiratory samples collected from these patients during their routine medical care, using a number of molecular tools allowing determination of the involved Legionella species, the bacterial load, and the presence of antibiotic resistant mutants. Our primary goal was to define biological markers that could predict severity and outcome of infection in legionellosis cases requiring hospitalization.

Detailed Description
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Patients admitted to Grenoble University Hospital between 2006 and 2011 for severe legionellosis were retrospectively included in the study. Clinical, epidemiological, diagnostic and prognostic data of these patients were recorded retrospectively. Lower respiratory samples collected from these patients on a routine basis for microbiological analysis, especially Legionella culture, were tested using traditional microbiological methods. The remaining part of these samples was stored at -80°C fur further molecular analyses. The molecular tools developed by our bacteriology laboratory included the following: a real-time polymerase chain reaction (qPCR) test allowing detection and differentiation of L. pneumophila and other Legionella species; a qPCR test allowing determination of the Legionella DNA load in lower respiratory samples; a qPCR allowing detection of gyrA (the gene encoding subunit A of DNA gyrase) mutations that the investigators previously determined to be correlated with fluoroquinolones resistance in L. pneumophila; a high-throughput sequencing approach allowing confirmation of gyrA mutations and determination of the percentage of mutated alleles. The microbiological data, especially those obtained with the developped molecular tools, were tentatively correlated with the severity and outcome of infection in our patients' cohort.

Official Title
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Molecular Epidemiology of Legionellosis in Grenoble Region

Conditions
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Legionnaires' Disease

Intervention / Treatment
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* Biological: Real-time PCR testing of lower respiratory tract samples


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age higher than 18 years proven legionellosis case (positive culture and/or PCR and/or urinary antigen test) severe case requiring hospitalization Exclusion Criteria: age under 18 years pregnant women

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 99 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Severe legionellosis cases<br>Patients admitted to Grenoble University Hospital for severe legionellosis between 2006 and 2011. | Biological: Real-time PCR testing of lower respiratory tract samples<br>* qPCR and high-throughput DNA sequencing testing of lower respiratory tract samples collected routinely in patients with severe legionellosis<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Legionella DNA load in lower respiratory tract samples | Real-time polymerase chain reaction (qPCR) dosages in lower respiratory tract samples collected on a routine basis all over the hospitalization duration | through study completion, an average of 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fluoroquinolones resistant gyrA mutants in lower respiratory tract samples | Real-time polymerase chain reaction (qPCR) and high-throughput DNA sequencing testing of lower respiratory tract samples collected on a routine basis all over the hospitalization duration | through study completion, an average of 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Legionella, Legionnaires' disease, Diagnosis, Prognosis