In vitro evaluation of ceftibuten (7432-S, SCH 39720), a novel orally administered cephalosporin.

7432-S (SCH 39720) was the most active beta-lactam tested against the Enterobacteriaceae, inhibiting 92% of strains at less than or equal to 8.0 micrograms/ml compared to 82%, 65% and 39% of strains inhibited by cefixime, cefuroxime and cefaclor, respectively. 7432-S was also very effective against Haemophilus influenzae (MIC90, less than or equal to 0.25 microgram/ml), Branhamella catarrhalis (MIC90, 4.0 micrograms/ml) and Neisseria meningitidis (MIC90, less than or equal to 0.25 microgram/ml). Serogroup B streptococci and the penicillin-resistant pneumococci were generally less susceptible to 7432-S and comparison cephems than Streptococcus pyogenes or penicillin-susceptible S. pneumoniae isolates. Pseudomonas spp., enterococci, Acinetobacter spp. and Staphylococcus spp. were routinely resistant to 7432-S (MIC50s, greater than or equal to 32 micrograms/ml).