Cefotetan: profile of in-vitro activity

Cefotetan, a novel 7 alpha-methoxy cephalosporin, was shown to be comparable to other third-generation cephalosporins when tested in vitro against 1063 Gram-negative clinical isolates of 11 species. Ninety per cent of all isolates of Escherichia coli, Klebsiella, Proteus mirabilis, Proteus vulgaris, Proteus rettgeri, Providencia stuartii, Serratia marcescens and Citrobacter freundii were inhibited by concentrations of cefotetan between 0.07 and 3.2 mg/l. Activity against Gram-positive cocci was about equal to that of moxalactam. Pseudomonas aeruginosa and Acinetobacter were resistant. Cefotetan inhibited about two-thirds of Enterobacter strains at 16 mg/l. beta-Lactamases of Enterobacter cloacae highly resistant to cefotetan inactivated this cephamycin. These strains were resistant to most other beta-lactams as well. Synergism between cefotetan and aminoglycosides was found in 8 out of 16 Gram-negatives.