Acute otitis media in older children and adults treated with phenoxymethyl penicillin or erythromycin stearate. Bacteriological and immunological aspects.

Seventy-eight patients, all over 10 years of age, with clinical signs of acute otitis media, received either phenoxymethyl penicillin or erythromycin stearate, in a randomized manner, and the clinical, bacteriological and immunological effects were studied. Haemophilus influenzae and Streptococcus pneumoniae were the major pathogens isolated from the nasopharynx in 30 and 28 patients, respectively. Increased levels of C-reactive protein (CRP) were detected in 53 (68%) of the patients. There was no statistical difference in the CRP-levels depending on species of bacteria isolated. The highest incidence was observed in cases with Branhamella catarrhalis and H. influenzae. Persistence of H. influenzae during antibiotic therapy was demonstrated in 70% and after therapy in 63% compared to 4% and 11% persistence of S. pneumoniae. The type of antibiotic treatment did not influence persistence. An immune response to H. influenzae and S. pneumoniae was detected significantly more often in patients treated with erythromycin stearate than with phenoxymethyl penicillin.