The epidemiology of community-acquired bacterial meningitis (CABM) in adults has changed significantly in the past several years. Despite substantial improvement in patient care, CABM remains a major cause of morbidity and mortality. Thus, new prognostic factors could help improve patient stratification. We conducted a multicenter retrospective study to determine the clinical pattern of CABM in an urban area of Western Europe and to identify potential predictors of unfavorable prognosis and complicated course. Over a period of 6-8 years, 79 adult CABM cases were treated at three tertiary hospitals. A Glasgow Outcome Scale (GOS) score of ≤4 was defined as unfavorable outcome. Predictors of unfavorable prognosis or complicated course were identified through logistic-regression analysis. S. pneumoniae was the most frequent pathogen (34%). 82% of patients exhibited at least two of five signs, including fever, neck stiffness, altered mental status, headache and nausea. Almost 50% presented focal neurological deficits; the overall mortality rate was 15%. In the multivariate analysis, risk factors for an unfavorable outcome included a GCS score of ≤13, female sex, and etiology by L. monocytogenes and gram-negative bacilli. However, risk factors for systemic complications were a GCS score of ≤13 and reduced platelet count, whereas C-Reactive Protein (CRP) increase was associated with a higher rate of neurological complications. Patients with non-pneumococcal CABM were more prone to an unfavorable outcome, probably because of underutilization of empiric ampicillin in patients at risk of listeriosis and because the suspicion of pneumococcal infection was facilitated by the existence of otitis and the higher yield of Gram's stain. Patients presenting a GCS of ≤13, thrombocytopenia and/or increased CRP, may benefit from more aggressive care to avoid in-hospital complications and neurological sequelae.
Keywords: Community-acquired bacterial meningitis; complications; epidemiology; prognosis.