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 cephal osporin structurally related to cefpirome and cefepime, was compared w ith that of cefotaxime, ceftazidime, aztreonam, cefpirome, cefepime, i mipenem and meropenem against 1,837 clinical isolates obtained from th ree Spanish hospitals. FK-037 inhibited 90 % of Enterobacteriaceae iso lates at less than or equal to 0.25 mu g/ml, with the exception of Ent erobacter aerogenes (MIC90 1 mu g/ml), Enterobacter cloacae and Citrob acter freundii (MIC90 8 mu g/ml). In cefotaxime- and ceftazidime-resis tant Klebsiella pneumoniae strains producing SHV-2 and SHV-6 beta-lact amases, the activity of FK-037, cefpirome and cefepime was similar (MI G 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 eightfo ld lower in ceitazidime-resistant derepressed Pseudomonas aeruginosa m utants. FK-037 (MIG range, 0.12-2 mu g/ml) and the other beta-lactam a gents 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 pne umoniae isolates, the MIC90s of FK-037 were 0.03, 0.5 and 1 mu g/ml, r espectively. The corresponding values for Streptococcus viridans isola tes were 0.1 2, 1 and 8 mu g/ml, respectively, In both Streptococcus p neumoniae and Streptococcus viridans isolates, FK-037 displayed activi ty similar to that of cefotaxime and cefpirome and slightly higher tha n that of cefepime.