Streptococcus pneumoniae and Haemophilus influenzae are leading pathogens of acute otitis media (AOM), and there are recent reports indicating increasing resistance of these bacteria to penicillin and other β-lactams. In this study, we examined the detectable bacteria of middle ear and nasopharynx of 331 children with AOM, under 10 years of age, in Sendai City. The resistance of S. pneumoniae to penicillin and other β-lactams was identified by the polymerase chain reaction (PCR). Of the strains of Streptococcus pneumoniae, penicillin insensitive (PISP) and penicillin resistant S. pneumoniae (PRSP) were identified in 12%-16% and 23-31%, respectively. Similarly, of the strains of H. influenzae, 3% were found to be β-lactamasepositive and 8% were found to be β-lactamase-negative ampicillin resistant (BLNAR). These percentages of resistant strains in the S. pneumoniae and the H. influenzae are increasing compared with those reported in 1996.
