MULTICENTER COMPARATIVE-STUDY ON THE ANTIBACTERIAL ACTIVITY OF FK-037, A NEW PARENTERAL CEPHALOSPORIN

The in vitro antibacterial activity of FK-037, a new parenteral cephalosporin structurally related to cefpirome and cefepime, was compared with that of cefotaxime, ceftazidime, aztreonam, cefpirome, cefepime, imipenem and meropenem against 1,837 clinical isolates obtained from three Spanish hospitals. FK-037 inhibited 90 % of Enterobacteriaceae isolates at less than or equal to 0.25 mu g/ml, with the exception of Enterobacter aerogenes (MIC90 1 mu g/ml), Enterobacter cloacae and Citrobacter freundii (MIC90 8 mu g/ml). In cefotaxime- and ceftazidime-resistant Klebsiella pneumoniae strains producing SHV-2 and SHV-6 beta-lactamases, the activity of FK-037, cefpirome and cefepime was similar (MIG range 0.25-32 mu g/ml). In Enterobacteriaceae strains hyperproducing chromosomally inducible beta-lactamases, FK-037 (MIC90 range, 0.25-8 mu g/ml) was 8- to 16-fold more active than cefotaxime and ceftazidime but two- to eightfold less active than cefpirome and cefepime. FK-037 and cefpirome were twofold more active than ceftazidime and cefepime against Pseudomonas aeruginosa isolates, with MIC90 values of 16 mu g/ml. The activity of FK-037, cefpirome and cefepime was two- to eightfold lower in ceitazidime-resistant derepressed Pseudomonas aeruginosa mutants. FK-037 (MIG range, 0.12-2 mu g/ml) and the other beta-lactam agents tested were active against methicillin-susceptible staphylococci; however, only cefpirome and, particularly, FK-037 (MIC90 of 32 mu g/ml) displayed some activity against methicillin-resistant strains. In penicillin-susceptible, -intermediate and -resistant Streptococcus pneumoniae isolates, the MIC90s of FK-037 were 0.03, 0.5 and 1 mu g/ml, respectively. The corresponding values for Streptococcus viridans isolates were 0.1 2, 1 and 8 mu g/ml, respectively, In both Streptococcus pneumoniae and Streptococcus viridans isolates, FK-037 displayed activity similar to that of cefotaxime and cefpirome and slightly higher than that of cefepime.