Microbiologic features of adult community-acquired bacterial meningitis in Taiwan

Community-acquired bacterial meningitis (CABM) is a life-threatening disease that requires prompt initiation of appropriate antibiotic therapy. The purpose of this study was to determine the causative microorganisms of CABM and their antimicrobial susceptibility patterns at a major teaching hospital in Taipei from 1993 to 1998.

A review of medical records and microbiologic data was used to identify cases of CABM and causative pathogens. Antimicrobial susceptibility testing for bacterial isolates was performed by the disk diffusion method.

Among the 48 adult patients with a diagnosis of CABM during the study period, the causative pathogens were identified in 36 cases. Unlike reports from other countries, Klebsiella pneumoniae was the leading causative pathogen (33%), followed by Streptococcus pneumoniae (28%), Listeria monocytogenes (11%), Neisseria meningitidis (6%), Staphylococcus aureus (6%), streptococci (6%), and Pseudomonas aeruginosa (6%). The incidence of CABM due to K. pneumoniae increased during the study period (p = 0.012, Poisson regression), while the incidence of CABM due to other pathogens remained stable. All of the CABM-associated K. pneumoniae isolates were susceptible to cefotaxime but 25% of the CABM-associated S. pneumoniae strains were not susceptible to penicillin G.

Penicillin G alone was not an appropriate empiric therapy for adult CABM because a high percentage of cases were due to K. pneumoniae or penicillin nonsusceptible S. pneumoniae. While the recommendations for the initial empiric regimen for CABM due to S. pneumoniae in Taiwan remain to be developed, third-generation cephalosporins appear to be an appropriate initial empiric regimen for the treatment of CABM due to K. pneumoniae.