Cefoperazone and cefotiam--two new cephalosporins: an in-vitro comparison.

The in vitro activity of cefoperazone (CPZ) and cefotiam (CTM) was compared to other available cephalosporins. Using an agar dilution procedure both CTM and CPZ were more active against the Enterobacteriaceae tested than cefoxitin, cefuroxime and cefazolin; CTM being slightly more active than CPZ, in particular against Klebsiella spp Haemophilus influenzae were more susceptible to CPZ. CTM had no activity against Pseudomonas aeruginosa but CPZ exhibited considerable activity (mode MIC 4 mg/l). Against Bacteroides fragilis CPZ had a similar activity to cefuroxime, but CTM was less active. CTM was about twice as active as CPZ against Staphylococcus aureus, cefazolin being the most active agent tested. The MBC was about twice the MIC for each compound and the presence of 75% serum had only a modest effect on the MIC and MBC. The protein binding of CPZ was 94% and CTM 62%.