In vivo sensitivity test in otitis media: efficacy of antibiotics

During a 10-year period, antibiotics were assigned in random, double-blind fashion in six combinations to treat 948 episodes of otitis media in children. Exudate from the middle ear of all patients was cultured before treatment. Three follow-up visits were conducted; the first follow-up visit was three to five days after the start of therapy, and the second and third visits were 14 and 31 days after onset of treatment. Exudates were recultured for 75% of the patients on the first follow-up visit. Comparison of treatment results showed that triple sulfonamide combined with either phenoxymethyl penicillin, or benzathine and procaine penicillin G given intramuscularly (IM) was as effective as was ampicillin or amoxicillin. Phenoxymethyl penicillin and cyclacillin alone were usually effective against pneumococci but relatively ineffective against Haemophilus influenzae. Cefaclor and trimethoprim-sulfamethoxazole produced unsatisfactory results in about half the cases caused by pneumococci or H influenzae. Although production of beta-lactamase by some otitis-causing Haemophilus and Staphylococcus species may explain the ineffectiveness of some treatments, the percentage of organisms positive for beta-lactamase was too small to be responsible for the poor results with certain drugs.