Microbiologic characteristics of persistent otitis media

Objective: To identify the pathogens isolated from children with acute otit is media who did not respond to antimicrobial drug therapy. Methods: Retrospective analysis of cultures obtained by tympanocentesis fro m 46 children. Results: Organisms were recovered from 34 children (74%), and 43 isolates w ere recovered from these individuals. The organisms were Streptococcus pneu moniae (16 isolates), Haemophilus influenzae non-type b (12 isolates), Mora xella catarrhalis (5 isolates), Streptococcus pyogenes (5 isolates), Staphy lococcus aureus (3 isolates), and Peptostreptococcus species (2 isolates). Resistance to the antimicrobial agent used was found in 27 (63%) of 43 isol ates found in 22 patients (48%). Of patients who did not respond to amoxici llin therapy, H influenzae predominated. Streptococcus pneumoniae was recov ered from 5 (56%) of 9 of those who did not respond to trimethoprim and sul famethoxazole therapy, 4 (44%) of 9 patients after azithromycin therapy, 3 (25%) of 12 patients after amoxicillin therapy, and 2 (40%) of 5 patients a fter cefixime therapy. Streptococcus pyogenes was recovered from 2 (40%) of 5 patients after trimethoprim and sulfamethoxazole therapy and from 2 (40% ) of 5 patients after cefixime therapy. Conclusions: The data illustrate the relation between resistance to antimic robial drug therapy and failure of patients with otitis media to improve. T hey also highlight the importance of diagnostic tympanocentesis in establis hing the presence of resistant microorganisms.