Bacteriology of acute otitis media in Japan and chemotherapy, with special reference to Haemophilus influenzae.

Middle ear effusions from 574 patients with acute otitis media (AOM) were sampled and cultured in metropolitan Tokyo. Sampling was done by myringectomy and from otorrhea after the occurrence of spontaneous perforation. Streptococcus pneumoniae and Haemophilus influenzae were isolated more widely in 'fresh' (myringotomized) cases than in 'old' cases. The freshness of cases, and the sampling and culture techniques appear to account for the difference in reports concerning causative pathogens of AOM from Japan on one hand and the U.S.A. and Scandanavia on the other. The relatively high detection rate of H. influenzae indicates its importance in all age groups. H. influenzae was isolated from a second group of 50 patients, and MIC values were determined. ABPC proved to be the most effective chemotherapy, except in cases (10%) of beta-lactamase producing H. influenzae. The correlation between the main causative pathogens of AOM and penicillin concentrations found in middle ear effusions was also investigated. The oral administration of 10-12 mg/kg of ABPC surpassed the 85% MIC level against H. influenzae.