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

Bacterial meningitis, a world-wide disease, has to be reviewed periodically because the specific microorganisms responsible for the infection vary wit h time, geography and patient age. To determine its incidence and clinical features in Taiwan, we reviewed the microbiological records for cerebrospin al fluid (CSF) and blood cultures, and the medical records of patients with bacterial meningitis admitted between 1981 and mid-1998. Bacterial microor ganisms were demonstrated in the CSF and/or blood in 395 patients with 418 episodes of bacterial meningitis. Streptococcus species were the most commo n 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 th e last 10.5 years (19.2%). However, Klebsiella meningitis and Staphylococca l meningitis were more frequently noted after 1987. More than 70% of patien ts had at least one underlying disease or condition. Poor prognostic factor s 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 >5000 x 10(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 antibioti cs has not reduced the mortality rate in our patients with bacterial mening itis.