Acute bacterial meningitis in adults: a hospital-based epidemiological study

Bacterial meningitis, a world-wide disease, has to be reviewed periodically because the specific micro-organisms responsible for the infection vary with time, geography and patient age. To determine its incidence and clinical features in Taiwan, we reviewed the microbiological records for cerebrospinal fluid (CSF) and blood cultures, and the medical records of patients with bacterial meningitis admitted between 1981 and mid-1998. Bacterial micro-organisms were demonstrated in the CSF and/or blood in 395 patients with 418 episodes of bacterial meningitis. Streptococcus species were the most common causative micro-organism group, at 23. 21% of all episodes. Its prevalence rate significantly decreased from the first 7 years of study (41.9%) to the last 10.5 years (19. 2%). However, Klebsiella meningitis and Staphylococcal meningitis were more frequently noted after 1987. More than 70% of patients had at least one underlying disease or condition. Poor prognostic factors indicated by univariable analysis were: age >60 years; diabetes mellitus; severe neurological deficits on the first day of treatment; infection with Gram-negative bacilli; CSF WBC count >5000x10(6)/l; malignancy; seizure; and bacteraemia. The overall mortality rate was 29.4%, 29.7% in the first 7 years of study and 29. 4% in the last 10.5 years. The use of new antibiotics has not reduced the mortality rate in our patients with bacterial meningitis.