In vitro activity of cefbuperazone, a new cephamycin, against anaerobic bacteria.

The 90% MIC of cefbuperazone (BMY 25182) was 32 micrograms/ml for Bacteroides fragilis and Bacteroides spp., 128 micrograms/ml for Fusobacterium and Clostridium spp., 64 micrograms/ml for Eubacterium and Peptococcus spp., 8 micrograms/ml for Actinomyces spp., and 32 micrograms/ml for Peptostreptococcus spp. The level of activity of cefbuperazone was higher against B. fragilis and lower against anaerobic cocci than those of related cephalosporins, i.e., cefoxitin, cefoperazone, cefotaxime, ceftizoxime, and cefmenoxime. However, the activity of cefbuperazone was comparable to that of moxalactam against all groups tested. Size of inoculum and type of media used did not alter the MICs of cefbuperazone for B. fragilis. Cefbuperazone showed synergistic activity when combined with cefoxitin against resistant strains of B. fragilis.