Major changes in the epidemiological characteristics of bacterial meningitis have been observed as a result of changes in behaviour, human interventions (use of antibiotics, prophylactic vaccinations), as well as poorly elucidated mechanisms responsible for epidemic outbreaks.

The objective of this study is to identify the determinants of in-hospital mortality of bacterial meningitis in adults.

Hypothesis : the standardized data collection concerning cases of bacterial meningitis in adults with telephone follow-up would allow analysis of the determinants of mortality and neurosensory sequelae, description of the psychosocial impact and proposal of new treatment strategies.

Introduction: Bacterial meningitis is a rare (about 1,200 cases per year in France, 50% occurring in adults) and serious disease (20% mortality during the acute phase; neurosensory sequelae in 30% of survivors). Major changes in the epidemiological characteristics of bacterial meningitis have been observed as a result of changes in behaviour, human interventions (use of antibiotics, prophylactic vaccinations), as well as poorly elucidated mechanisms responsible for epidemic outbreaks. No standardized clinical, microbiological and prognostic data collection concerning bacterial meningitis in adults is available in France.

Hypothesis: Standardized data collection concerning cases of bacterial meningitis in adults with telephone follow-up would allow analysis of the determinants of mortality and neurosensory sequelae, description of the psychosocial impact and proposal of new treatment strategies.

Primary objective: To identify the determinants of in-hospital mortality of bacterial meningitis in adults.

Secondary objectives: To describe the epidemiological characteristics of community-acquired bacterial meningitis in adults, changes in these characteristics and their relations with the vaccine status of the affected adult and his/her family; to characterize clinical and microbiological failures and their determinants (pharmacological, microbiological, immunological, etc.); to analyse the determinants of neurosensory sequelae and failure to return to work after 1 month, 6 months and 12 months.

Primary endpoint: In-hospital mortality (D30). Secondary endpoints: History including vaccination of the case and the family, clinical, microbiological (species, susceptibility, virulence factors, cerebrospinal fluid CSF) culture on D0 and H48), imaging characteristics; treatments, CSF antibiotic concentrations, neurological sequelae (modified Rankin, Glasgow Outcome Scale, IQCODE) at M1, M6 an M12, quality of life test SF12, WHO QoL, CESD) at M1, M6, M12, hearing loss (audiometric tests, hereditary hearing impairment (HHI), telephone speech test in noise) at M1, M6, M12.

Methodology, study design: National observational cohort study with comprehensive recruitment in participating centres.

Legal classification of the project: Epidemiological study. Number of subjects required: The inclusion of 150 cases of meningitis per year would allow the collection of about 450 cases over a period of 3 years. For a mortality rate of 20%, we would be able to estimate this percentage with a confidence interval of ± 3.7% (95% confidence interval: 16.3-23.7). With 90 deaths, a power of 80% and a level of significance of 5% (two-tailed), this sample size would demonstrate relative risks of 1.8 for a prevalence of the risk factor of 25% and 2.6 for a prevalence of the risk factor of 10%.

Inclusion criteria: Adult with community-acquired bacterial meningitis defined by the presence of at least one of the following criteria: 1/ Positive CSF culture and/or positive soluble antigen in CSF with or without cell reaction; 2/ Positive PCR in CSF; 3/ Purpura fulminant (with or without positive CSF culture); Positive polymerase chain reaction (PCR) in blood and/or positive blood culture AND CSF cell reaction.

Non inclusion criteria: Age less than 18 years old or refusal to participate. Inclusion period: 3 years. Duration of participation for one patient: 12 months. Number of participating centers: Constitution in participating centers of a dual investigator team comprising a clinician (infectious diseases physician, intensive care physician, or neurologist) and a microbiologist (participating in the national network of "OBSERVATOIRES REGIONAUX DU PNEUMOCOQUE" [Regional Pneumococcal Observatories]). Declaration by the microbiologist to the data management centre. On-site validation of cases by the dual investigator team and then by a national multidisciplinary validation unit.

Mean number of inclusions per month and per centre: 0.5

Inclusion Criteria:

• Positive CSF culture and/or positive soluble antigens in CSF with or without a cell reaction
• Positive PCR in CSF
• Purpura fulminant (with or without positive CSF culture)
• Positive PCR in blood and/or positive blood culture AND CSF cell reaction.

Exclusion Criteria:

• Age less than 18 years old
• Refusal to participate

patients with bacterial meningitis adults