THE MICROBIAL SPECTRUM OF BRAIN-ABSCESS WITH SPECIAL REFERENCE TO ANAEROBIC-BACTERIA

The bacteriological and clinical findings of 18 cases of brain abscess are presented. Identification and antimicrobial susceptibility of ana erobic strains was performed both by conventional methods and the newe r RapID ANA II panel and E-test methods, respectively. Characterizatio n of the anaerobic isolates was done by restriction fragment length po lymorphism (RFLP). Anaerobic or aerobic organisms alone were recovered in three (16.6%), and mixed aerobic and anaerobic in another three (1 6.6%) patients. There were nine anaerobic isolates. The predominant an aerobes were Prevotella melaninogenicus (four isolates), Bacteroides p reacutus (three isolates), Fusobacterium nucleatum and Peptostreptococ cus sp. (one isolate each). A total of six aerobic isolates, all of wh ich were Gram-positive cocci were recovered. All the anaerobic isolate s were susceptible to metronidazole, but two isolates of P. melaninoge nicus were resistant to penicillin. There was complete agreement betwe en the identification based on biochemical profiles and RFLP patterns. These findings indicate the microbial complexity of brain abscess and the need to target antimicrobial therapy against both the aerobic and anaerobic components of infection.