The antimicrobial activity of cefpirome, a new cephalosporin.

The activity of the extended spectrum cephalosporin cefpirome (HR 810) was compared with that of other beta-lactams and gentamicin. A total of 524 clinical isolates and strains known to be resistant to certain agents were studied. Against the Enterobacteriaceae, Haemophilus influenzae and Neisseria spp. cefpirome was highly active (MIC90 less than or equal to 0.5 mg/l), generally being as active or slightly more active than ceftazidime and cefotaxime, and 8 to 32 times more active than cefuroxime. Against Pseudomonas aeruginosa cefpirome (MIC90 8 mg/l) was four-fold less active than ceftazidime. Staphylococcus aureus was susceptible to cefpirome (MIC90 2 mg/l) and cefpirome was the only cephalosporin tested with significant activity against Lancefield Group D streptococci. Bacteroides spp. (with the exception of Bact. ureolyticus) were resistant to cefpirome. The compound was bactericidal to all the susceptible strains studied with the exception of Lancefield Group D streptococci. The major target site for cefpirome was PBP 3 and the protein binding was low.