Emergence of rifampin-resistant Haemophilus influenzae

Rifampin susceptibility of nasopharyngeal Haemophilus influenzae strains was determined before and after community-wide chemoprophylaxis with rifampin (children) and sequential minocycline-rifampin (adults). All strains were rifampin susceptible before prophylaxis, but 10.3% of the strains at 1 week and 7.5% of the strains at 9 weeks after prophylaxis were rifampin resistant.