Listeria monocytogenes meningitis:: serotype distribution and patient characteristics in The Netherlands, 1976-95

Two hundred and seven cases of listeria meningitis that occurred in The Netherlands over 20 years were reviewed to study associations between Listeria monocytogenes serotype, age, underlying disease, and outcome. The mean annual incidence per 100000 population was 0.12 in 1981-90, decreasing to 0.07 in 1991-5. Underlying disease was present in 50% of non-neonatal patients, most often haematological malignancy (15%) and the use of immunosuppressive therapy (14%). The meningitis-related case fatality rate was 16%; a significantly higher rate was associated with the presence of underlying disease (30%) or age greater than or equal to 70 years (29%). Serotype 4b was most frequent (65 %) and L. monocytogenes types 1/2a, 1/2b, or 1/2c (30% of cases) were significantly more often isolated from non-neonatal patients with underlying disease, suggesting a higher virulence of listerial serotype 4b.