Ampicillin resistance in Haemophilus influenzae.

Fourteen out of 150 (9.3%) consecutive strains of Haemophilus influenzae isolated on culture of sputum in the Bacteriology Department, Belfast City Hospital, during 1982/83 were found to be ampicillin-resistant (beta-lactamase-producing). Susceptibility testing to other antibiotics of these ampicillin-resistant strains showed that cefuroxime, cefotaxime, gentamicin, and amoxycillin with clavulanic acid were reliable alternatives. Other useful alternatives included tetracycline, trimethoprim and co-trimoxazole. Erythromycin was of limited usefulness.