Therapeutic effects of cefpirome, a new cephalosporin, on various models of infections in mice and rats.

Cefpirome (HR 810) is a new cephalosporin with a 2,3-cyclopentenopyridine group in the 3-position side chain. It was compared with other cephem antibiotics in protective and therapeutic effects on various experimental infections, systemic and local, in mice and rats. HR 810 had more potent protective effect than ceftazidime (CAZ), cefoperazone (CPZ), and cefotaxime (CTX) on systemic infections induced by Escherichia coli Ec-31, Staphylococcus aureus SMITH, and Serratia marcescens Sm-6 in mice. Against systemic infection with Pseudomonas aeruginosa HR 810 was as effective as CAZ. Mice with leukopenia induced by cyclophosphamide were systemically infected with methicillin-resistant S. aureus (MRSA), methicillin-susceptible S. aureus (MSSA), Enterobacter cloacae, Acinetobacter calcoaceticus, and Enterococcus faecalis. HR 810 was superior to cefuzonam (CZON) and cefmetazole against MRSA and MSSA and was much more active than any other antibiotics tested against E. cloacae and A. calcoaceticus. In the activity against E. faecalis, HR 810 was inferior to ampicillin but superior to CZON. In mice with pyelonephritis caused by E. coli Ec-7, the rank order of activities was HR 810 greater than CAZ greater than CTX greater than CPZ. HR 810 was more effective than latamoxef, CAZ, CTX, and CPZ in improving lung infections induced by Streptococcus pneumoniae HL 438 and Klebsiella pneumoniae Kp-51 in mice. HR 810 was superior to CTX and CPZ and comparable to cefazolin in therapeutic effects on intrauterine infections with E. coli Ec-89 and S. aureus SMITH in rats.