Comparative in-vitro activity of ceftazidime (GR-20263) and other -lactamase stable cephalosporins against anaerobic bacteria

The in-vitro activity of ceftazidime was determined against 586 clinical isolates of anaerobic bacteria by an agar-dilution technique and compared with that of cefuroxime, moxalactam and cefoxitin. At 16 mg/l, only 60% of all isolates were inhibited by ceftazidime, compared to 79% by cefuroxime, 81% by moxalactam and 80% by cefoxitin. Ceftazidime was relatively inactive against Bacteroides fragilis group, Lactobacillus and Clostridium species other than Cl. perfringens. Peptococcus, Peptostreptococcus, Cl. perfringens, microaerophilic streptococci and Propionibacterium were readily inhibited. Moxalactam was the most active agent against Bact. fragilis group, while cefuroxime was the most active agent against Streptococcus and Lactobacillus.