Streptococcal meningitis in adult patients: Current epidemiology and clinical spectrum

Streptococci other than Streptococcus pneumoniae are a rare cause of bacter ial meningitis in adults. We report 29 cases of streptococcal meningitis (1 977-1997). The patients comprised 19 men and 10 women, with a mean age +/- standard deviation of 47 +/- 18 years. Nine cases were secondary to neurosu rgical procedures, seven to brain abscess, five to cerebrospinal fluid peri cranial fistula, and three to endocarditis. Causative microorganisms includ ed the following: viridans group streptococci, 20 cases; anaerobic streptoc occi, 3; Streptococcus agalactiae, 3; Streptococcus bovis, 2; and Streptoco ccus pyogenes, 1. Four Streptococcus mitis strains showed decreased suscept ibility to penicillin (MIC, 0.5-2 mu g/mL). Five patients (17%) died. The i nfection is increasing in the hospital setting. Streptococci resistant to p enicillin should be considered in the empirical treatment of nosocomial men ingitis. In cases of community-acquired infection, anaerobic streptococci o r streptococci of the Streptococcus milleri group should alert the clinicia n to the presence of an undiagnosed brain abscess, whereas oral streptococc i of the viridans group suggest the diagnosis of bacterial endocarditis.