The activity of cefbuperazone, a 7 alpha-methoxy 7 beta acyl ureido cephalosporin

The activity of cefbuperazone, a 7 alpha-methoxy ureido cephalosporin, was determined against 726 clinical isolates. Ninety percent of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Citrobacter diversus, Proteus mirabilis, Enterobacter aerogenes, Proteus vulgaris, Morganella morganii, Salmonella, and Shigella species were inhibited by less than or equal to 6.3 micrograms/ml. Cefbuperazone was more active than cefamandole, cefoxitin and piperacillin against these species. Concentrations of 25 micrograms/ml of cefbuperazone were needed to inhibit Serratia marcescens and Providencia species, and 50% of Enterobacter cloacae had MICs greater than 25 micrograms/ml. Cefbuperazone was less active by 8 to 32-fold than cefotaxime or moxalactam against most Enterobacteriaceae. Cefbuperazone did not inhibit Acinetobacter or Pseudomonas species. Hemolytic streptococci were inhibited by 12.5 micrograms/ml and staphylococci by 25 micrograms/ml. Cefbuperazone had activity comparable to cefoxitin and moxalactam against Bacteroides fragilis with MIC90s of 6.3 micrograms/ml. Cefbuperazone was not hydrolyzed by plasmid or chromosomal beta-lactamases and was an inhibitor of the P99 E. cloacae beta-lactamase with an I50 of 1 microgram/ml. It was a less effective inhibitor of the K. oxytoca K1 and E. coli TEM-1 beta-lactamases than was clavulanic acid. Cefbuperazone induced beta-lactamases in P. aeruginosa and resistant E. cloacae. A permeability barrier in E. cloacae, C. freundii and P. aeruginosa is suggested by the potentiation of cefbuperazone's activity by EDTA.