In vitro antibacterial activities of FK037: a new parenteral cephalosporin.

The antibacterial and bactericidal activities and the stability of FK037 to beta-lactamases were investigated and compared with those of cefpirome, flomoxef, ceftazidime, ceftizoxime, and vancomycin. Against clinical isolates of methicillin-sensitive and methicillin-resistant Staphylococcus aureus, FK037 was less active than vancomycin but more potent than the other drugs tested. Among highly methicillin-resistant staphylococci (MIC for methicillin: 200 mg/l or higher), none of the strains were highly resistant to FK037 (MIC > or = 100 mg/l) unlike the other cephalosporins. With the exception of Enterococcus faecalis, FK037 had an activity equipotent to that of cefpirome and far superior to those of flomoxef, ceftazidime and ceftizoxime against other gram-positive clinical isolates. The activity of FK037 against Pseudomonas aeruginosa and Pseudomonas cepacia was equipotent to that of cefpirome but 2- to 4-fold less active than that of ceftazidime. FK037 inhibited 90% of Enterobacter cloacae and Citrobacter freundii growth at a concentration of 6.25 mg/l; it was as active as cefpirome and much more active than ceftazidime. Against the other gram-negative bacteria tested, FK037 was equipotent to cefpirome and ceftazidime and was more effective than flomoxef. FK037, like cefpirome, portrayed a high stability to various beta-lactamases except type II penicillinase and oxyimino-cephalosporinase (CXase). FK037 scored an MIC range of 0.013-6.25 mg/l against numerous beta-lactamase-producing bacterial strains with the exception of some CXase-producing strains and a cephalosporinase-producing C. freundii; and against strains other than P. aeruginosa FK037 was as active as cefpirome and 2- to 32-fold more active than ceftazidime. FK037 displayed highly potent activities against cephalosporinase-producing E. cloacae, C. freundii and Serratia marcescens which were resistant to flomoxef and ceftizoxime. FK037 was highly bactericidal against S. aureus and Escherichia coli at its MIC or higher.