Susceptibility of anaerobic bacteria to FCE 22101

The activity of FCE 22101 against 675 strains of anaerobic bacteria was determined by an agar dilution method. Its activity was compared with those of benzylpenicillin, piperacillin, cefoxitin, imipenem, clindamycin, metronidazole, chloramphenicol, vancomycin, fusidic acid, and bacitracin. FCE 22101 and imipenem (MIC, less than or equal to 0.5 mg/liter) were the most active agents against the anaerobic strains tested, except against Clostridium difficile strains. On the basis of these results, FCE 22101 appears to be a promising antimicrobial agent for treatment of anaerobic infections, and further clinical investigations are indicated.