Bacteria isolated from perforation peritonitis and their antimicrobial susceptibilities

Bacteria isolated from 25 cases of perforation peritonitis and its antimicrobial susceptibilities were studied. One hundred and forty-six strains including 36 strains of aerobic bacteria, 107 strains of anaerobic bacteria and 3 strains of yeast were isolated from intra-peritoneal fluid obtained at operation. Among aerobic bacteria, Enterobacteriaceae was isolated from 13 cases (52%) out of all, and followed by those of Enterococcus spp. (24%), Pseudomonas aeruginosa (20%), in this order. Among non-spore forming anaerobic Gram-negative bacteria, the isolation rate of Bacteroides fragilis group (64%) was highest, followed by Fusobacterium spp. (40%), Prevotella spp./Porphyromonas spp. (32%) and Bilophila wadsworthia (28%), in this order. The isolation rate of non-spore forming anaerobic Gram-positive bacteria was 60%, and that of Clostridium spp. was 24%. Even by the recent advanced methods, there were 17 strains of anaerobic bacteria, which were not identified by phenotypic-identification levels. Carbapenems and beta-lactams plus beta-lactamase inhibitors have strong antimicrobial activities against both aerobic and anaerobic bacteria. Although metronidazole and minocycline have strong activities against anaerobic bacteria, there were many strains highly resistant to clindamycin.