Antibacterial activity of the cephamycin cefotetan: an in-vitro comparison with other beta-lactam antibiotics

The cephamycin, cefotetan, was compared with other beta-lactam antibiotics including the monocyclic beta-lactam, azthreonam, against a total of 277 recent clinical isolates. Cefotetan had activity comparable to moxalactam against Staphylococcus aureus and against the Enterobacteriaceae, inhibiting all isolates except for Serratia marcescens and Enterobacter spp. at less than or equal to 0.5 mg/l. Cefotetan was active against beta-lactamase producing and non-beta-lactamase producing Haemophilus influenzae (MIC90 1 mg/l); was inactive against Pseudomonas aeruginosa (MIC90 greater than 128 mg/l); and was eightfold less active than cefoxitin against the Bacteroides fragilis group. Azthreonam was as active as moxalactam against the Enterobacteriaceae and was more active than moxalactam against Ps. aeruginosa, inhibiting 90% of isolates at less than or equal to 8 mg/l, but was inactive against the Bact. fragilis group (MIC90 greater than 128 mg/l) and against Staphylococcus aureus (MIC90 greater than 128 mg/l).