In vitro antianaerobic activity of ertapenem (MK-0826) compared to seven other compounds

Ertapenem, imipenem, meropenem, ceftriaxone, piperacillin, piperacillin-tazobactam, clindamycin, and metronidazole were agar dilution MIC tested against 431 anaerobes. Imipenem, meropenem, and ertapenem were the most active beta -lactams (MICs at which 50% of the strains are inhibited [MIC(50)s], 0.125 to 0.25 mug/ml; MIC(90)s, 1.0 to 2.0 mug/ml). Time-kill studies revealed that ertapenem, at two times the MIC was bactericidal for 9 of 10 strains after 48 h. The kinetics for other beta -lactams were similar to those of ertapenem.