Community-acquired group B streptococcal meningitis in adults: 33 cases from prospective cohort studies

Objectives: Streptococcus agalactiae (group B streptococcus, GBS) is an uncommon cause of bacterial meningitis in adults. We describe clinical characteristics, serotype distribution and outcome of adult GBS meningitis. Patients and methods: Patients aged 16 years or older with GBS cultured in cerebrospinal fluid included in two prospective nationwide cohort studies performed in the Netherlands between 1998–2002 and 2006–2017 were evaluated. Results: We identified 33 patients with GBS meningitis with a median age of 58 years of whom 22 were male (67%). The mean annual incidence was .16 per 1.000.000 adults. Ten patients (30%) had an immunocompromised state, which was due to alcoholism in 6 (18%) and diabetes mellitus in 4 (12%). Eleven patients (33%) had a distant focus of infection of whom 4 had endocarditis (13%). Seven patients (21%) died and 6 (18%) survivors had sequelae causing disability, including reduced vision and blindness due to endophthalmitis (n = 2). Twenty patients (61%) made a full recovery. Most common bacterial serotypes were serotype III (41%) and Ia (25%). Serotype V was associated with increased mortality (3 of 4 [75%] serotype V died vs. 4 of 28 [14%] other serotypes, P = .025). Conclusion: GBS is a rare cause of meningitis in adults that more frequently occurs in patients with underlying comorbidities. Patients should be carefully evaluated for distant foci of infection. GBS serotype V is associated with poor outcome.