Comparative study of the antibacterial activity of cefpodoxime against enterobacteria producing beta lactamases

Cefpodoxime proxetil (RU 51 807) is the oral prodrug of cefpodoxime (RU 51 763), a third generation cephalosporin. The antibacterial activity of cefpodoxime was compared with the activities of amoxicillin in combination with clavulanic acid (AUG), cefaclor (CCl), cefuroxime (CXM) and cefotaxime (CTX), against species of Enterobacteriaceae showing a resistance pattern against ampicillin (AMP), ticarcillin (TIC), cefalothin (CFT) and cefotaxime (CTX) respectively. For strains AMP and TIC R, CFT and CTX S, MICs 90% of cefpodoxime were 1 mg/l (E. coli), 0.5 (K. pneumoniae), 0.06 (P. mirabilis), 0.5 (Shigella sp.) and 1 (Salmonella sp.); they were 4 to 16 times as high for AUG -CCL -CXM and 4 to 16 times as low for CTX. For K. pneumoniae AMP and TIC R, CFT I/R and CTX S, similar résults were obsereved for the 5 beta-lactam antibiotics, but with an activity 10 times as low. Among the species AMP R, TIC S, CFT R and CTX S, cefpodoxime was active against P. rettgeri, P. stuartii, C. diversus, E. aerogenes and Y. enterocolitica (MICs 90% ranging from 2 to 4 mg/l; from 0.12 to 1 mg/l for CTX) and less active or inactive against P. vulgaris, E. cloacae, S. marcescens, M. morganii and E. coli (MICs 90% ranged from 16 to 32 mg/l; from 1 to 4 mg/l for CTX).(ABSTRACT TRUNCATED AT 250 WORDS)