A multicenter study was conducted in which the in vitro activity of cefpodoxime (the active metabolite of the prodrug ester cefpodoxime proxetil) was compared with those of cefixime, cefuroxime, cefaclor, cefadroxil, and clarithromycin against 5556 recent clinical isolates. Cefpodoxime demonstrated potent activity against members of the Enterobacteriaceae, in particular against species generally resistant to the established oral cephalosporins such as Proteus vulgaris [minimum inhibitory concentration (MIC)50, 0.12 mug/ml], Providencia rettgeri (MIC50, 0.015 mug/ml), and Serratia marcescens (MIC50, 2 mug/ml). Cefpodoxime was very effective against the fastidious organisms most frequently associated with respiratory infections, such as Streptococcus pneumoniae (MIC90, 0.12 mug/ml), Haemophilus influenzae (MIC90, 0.12 mug/ml), and Moraxella catarrhalis (MIC90, 1 mug/ml). In contrast to other orally administrated third-generation cephalosporins (cefixime or ceftibuten), cefpodoxime demonstrated reasonable activity against oxacillin-susceptible staphylococci, with MIC90 ranging from 1 to 2 mug/ml. All cephalosporins tested demonstrated poor activity against Pseudomonas spp., Xanthomonas spp., Enterococcus spp., and oxacillin-resistant staphylococci. Cefpodoxime had the widest spectrum of activity of all tested oral cephalosporins.
