In-vitro activities of trospectomycin, cefpodoxime, and second-generation cephalosporins against Haemophilus influenzae type b.

The in-vitro activities of trospectomycin, cefpodoxime, cefamandole, cefonicid, and cefuroxime against beta-lactamase-negative and -positive invasive clinical isolates of Haemophilus influenzae type b were determined by the agar dilution method. Trospectomycin and cefpodoxime inhibited 90% of the strains at concentrations of 5 and 0.06 mg/l, respectively, and no differences between the susceptibilities of the beta-lactamase-negative and -positive strains were noted. The activity of cefpodoxime was minimally affected by increased inoculum size, but significant inoculum effects were noted with cefamandole, cefonicid, and cefuroxime with beta-lactamase positive strains.