IN-VITRO ANTIBACTERIAL ACTIVITIES OF FK037 - A NEW PARENTERAL CEPHALOSPORIN

The antibacterial and bactericidal activities and the stability of FK0 37 to beta-lactamases were investigated and compared with those of cef pirome, flomoxef, ceftazidime, ceftizoxime, and vancomycin. Against cl inical isolates of methicillin-sensitive and methicillin-resistant Sta phylococcus aureus, FK037 was less active than vancomycin but more pot ent than the other drugs tested. Among highly methicillin-resistant st aphylococci (MIG for methicillin: 200 mg/l or higher), none of the str ains were highly resistant to FK037 (MIG greater than or equal to 100 mg/l) unlike the other cephalosporins. With the exception of Enterococ cus faecalis, FK037 had an activity equipotent to that of cefpirome an d far superior to those of flomoxef, ceftazidime and ceftizoxime again st other gram-positive clinical isolates. The activity of FK037 agains t Pseudomonas aeruginosa and Pseudomonas cepacia was equipotent to tha t of cefpirome but 2- to 4-fold less active than that of ceftazidime. FK037 inhibited 90% of Enterobacter cloacae and Citrobacter freundii g rowth at a concentration of 6.25 mg/l; it was as active as cefpirome a nd much more active than ceftazidime. Against the other gramnegative b acteria, 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 str ains with the exception of some CXase-producing strains and a cephalos porinase-producing C.freundii; and against strains other than P. aerug inosa FK037 was as active as cefpirome and 2- to 32-fold more active t han ceftazidime. FK037 displayed highly potent activities against ceph alosporinase-producing E. cloacae, C.freundii and Serratia marcescens which were resistant to flomoxef and ceftizoxime. FK037 was highly bac tericidal against S. aureus and Escherichia coli at its MIC or higher.