Ceftibuten (Sch39720) is highly active against Haemophilus influenza , Escherichia coli , Klebsiella sp., and Proteus sp. and moderately active against Serratia sp. and Streptococcus pyogenes . Ceftibuten is relatively inactive against enterococci and staphylococci and is only weakly active against Pseudomonas aeruginosa and obligate anaerobes. It is also stable in the presence of most β-lactamase-producing organisms except β Bacteroides fragilis . Ceftibuten is very active against strains of the family Enterobacteriaceae (mean MIC for 90% of strains=0.25 μg/ml) but less active against Campylobacterjejuni (mean MIC for 90% of strains=16.0 μg/ml).
Ceftibuten, a biologically stableβ-lactam antibiotic, has been shown to be transported by the small peptide transport system, to have relatively high affinity for the carrier and to show clear stereoselective and proton-gradient dependent transport characteristics in rat intestinal brush-border membrane vesicles.