Serotypes and antimicrobial susceptibility of Haemophilus influenzae.

During a one year prospective study of Haemophilus influenzae infections in patients treated in hospitals in the metropolitan area of Cape Town. H. influenzae type b accounted for 81.7% of 126 invasive isolates, whereas 86.1% of the 280 non-invasive isolates were non-typeable. Ampicillin resistance was detected among 10.8% of strains of which all but one produced beta-lactamase. All strains were susceptible to cefotaxime as were more than 95% to chloramphenicol, rifampicin, tetracycline but 20.4% were resistant to co-trimoxazole and 87.2% to erythromycin.