In vitro activity of new antibiotics against Haemophilus influenzae

The activity of sulbactam/ampicillin, aztreonam, cefetamet, cefixime, ciprofloxacin, enoxacin, fleroxacin and ofloxacin was determined against 160 Haemophilus influenzae strains using a standardized microdilution method. The strains were categorized into four groups according to beta-lactamase production and their resistance to ampicillin, chloramphenicol, erythromycin, tetracycline and cotrimoxazole. All isolates tested, regardless of their beta-lactamase production or resistance to the above mentioned drugs, were susceptible to the nine antibiotics. The most active antimicrobial agents were aztreonam, cefixime, and the two quinolone derivatives ciprofloxacin and ofloxacin.