The nasopharyngeal microflora of otitis-prone children, with emphasis on H. influenzae.

The nasopharyngeal microflora was monitored during a prospective study of 52 otitis-prone children and 33 age-matched controls up to the age of 30 months. The relation between nasopharyngeal culture results and corresponding otoscopic findings was investigated. In contrast to pneumococci, the rate of H. influenzae isolation was correlated to the degree of otologic disease, thus it was found more often in connection with AOM than with a normal otologic status, with OME in an intermediate position. Also in contrast to pneumococci, in children with AOM, H. influenzae was commoner in the otitis-prone group than in the control group. H. influenzae biotype II was found in 77% in association with AOM in the control group. In the otitis-prone group the difference in frequency of biotypes I, II and III causing AOM were less pronounced. Turnover of H. influenzae strains as judged by change in biotype was found to occur more often in connection with treatments with penicillin-V than treatments with amoxicillin.