In vitro activity of imipenem against gram-positive anaerobic bacteria.

ABSTRACT

The in vitro activity of imipenem, a new penem antibiotic, was determined against 210 clinical Gram-positive anaerobic isolates and compared with the activities of metronidazole, clindamycin, cefoxitin, moxalactam, ceftizoxime, ceftriaxone and cefotiam. All investigated strains were inhibited by a 4-mg/l concentration of imipenem. Cefoxitin demonstrated good activity against most strains with exception of some Clostridium difficile and Clostridium ramosum strains. Cephalosporins were classed in decreasing activity order as follows cefoxitin moxalactam ceftriaxone ceftizoxime cefotiam. Metronidazole had better activity against Clostridium spp. than against non-sporulated bacilli. Clindamycin resistance rates were superior to 10% for most groups, with the exception of Clostridium perfringens. Actinomyces and Bifidobacterium. Imipenem was the most potent inhibitor, as 81% and 95% of tested strains were inhibited at concentrations of 0.25 and 0.5 mg/l respectively.