Community-acquired meningitis caused by beta-haemolytic streptococci in adults: a nationwide population-based cohort study.

The objective of this study was to examine the clinical presentation of community-acquired beta-haemolytic streptococcal (BHS) meningitis in adults. This is a nationwide population-based cohort study of adults (≥ 16 years) with BHS meningitis verified by culture or polymerase chain reaction of the cerebrospinal fluid (CSF) from 1993 to 2005. We retrospectively evaluated clinical and laboratory features and assessed outcome by Glasgow Outcome Scale (GOS). We identified 54 adults (58% female) with a median age of 65 years (IQR 55-73). Mean incidence rate was 0.7 cases per 1,000,000 person-years. Alcohol abuse was noted among 11 (20%) patients. Group A streptococci (GAS) were found in 17 (32%) patients, group B (GBS) in 18 (34%), group C (GCS) in four (8%) and group G (GGS) in 14 (26%). Patients with GAS meningitis often had concomitant otitis media (47%) and mastoiditis (30%). Among patients with GBS, GCS or GGS meningitis, the most frequent concomitant focal infections were bone and soft tissue infections (19%) and endocarditis (16%). In-hospital mortality was 31% (95% CI 19-45), and 63% (95% CI 49-76) had an unfavourable outcome at discharge (GOS < 5). BHS meningitis in adults is primarily observed among the elderly and has a poor prognosis. GAS meningitis is primarily associated with concomitant ear-nose-throat infection.