Bacterial findings in middle ear effusion in children.

During 1983-87, tympanostomy tubes were inserted in a total of 4952 ears of 2575 children remitted to the ENT Department of our hospital because of chronic or recurrent otitis media problems. The children were included in a prospective study and referred to one of three groups for comparison of findings. Group 1 included all 6- to 12-month-old infants undergoing primary tube treatment; group 2, all children 1 year or older who had their first ventilation tube(s) inserted in connection with adenoidectomy; and group 3, all children in whom tympanostomy had been performed one or more times previously. Middle ear effusion was aspirated from 2392 ears (48%); 67.6% of all ears were negative for bacteria and 22.1% of the ears with effusion grew pathogenic bacteria. S. pneumoniae was the most frequently cultured pathogen among the 6 to 12 month olds in group 1, but in groups 2 and 3 H. influenzae occurred more frequently than S. pneumoniae. Beta-lactamase-producing strains of pathogenic bacteria were formed in only 4% of all ears with effusion: H. influenzae in 1.2% and B. catarrhalis in 2.8%. Compared with figures from the United states, the frequency of beta-lactamase-producing strains is low in the present series. This is probably explained by differences in antimicrobial treatment practices; in Finland and the Scandinavian countries, penicillin V is the primary drug for acute otitis media. In light of present results, it seems well-suited for treatment of otitis media in young children.