BACTERICIDAL ACTIVITY OF DU-6859A COMPARED TO ACTIVITIES OF 3 QUINOLONES, 3 BETA-LACTAMS, CLINDAMYCIN, AND METRONIDAZOLE AGAINST ANAEROBES AS DETERMINED BY TIME-KILL METHODOLOGY

The activities of DU-6859a, ciprofloxacin, levofloxacin, sparfloxacin, piperacillin, piperacillin-tazohactam, imipenem, clindamycin, and met ronidazole against 11 anaerobes were tested by the broth microdilution and time-kill methods, DU-6859a was the most active drug tested (brot h microdilution MICs, 0.06 to 0.5 mu g/ml), followed by imipenem (MICs , 0.002 to 4.0 mu g/ml). Broth macrodilution MICs were within 3 (but u sually 1) dilutions of the broth microdilution MICs. All compounds wer e bactericidal at the MIC after 48 h; after 21 h, 90% killing was show n for all strains when the compounds were used at four times the MIC. DU-6859a at less than or equal to 0.5 mu g/ml was bactericidal after 3 8 h.