Anaerobic isolates in chronic recurrent suppurative otitis media. Treatment with carbenicillin alone and in combination with gentamicin.

Tympanocentesis was performed in 32 pediatric patients with chronic recurrent suppurative otitis media. The aspirate was cultured aerobically and anaerobically. Aerobes were isolated from ten patients (31.2%); anaerobes from one patient; and both aerobes and anaerobes from 21 patients (65.6%). There were 46 aerobic isolates. The aerobes commonly recovered were Pseudomonas aeruginosa (24 isolates) Proteus sp. (5) and Staphylococcus aureus (3). There were 32 anaerobes isolated including anaerobic gram-positive cocci (19 isolates) and Bacteroides sp., the latter of which included Bacteroides fragilis group and Bacteroides melaninogenicus (9). The patients were treated by parenteral carbenicillin 300 to 400 mg per kg per day given in four dosages administered for a period of 12 to 21 days (average 17 days). An aminoglycoside (gentamicin) was added in 15 patients. The clinical response was good in 17 patients and poor in 15. There were no side effects or adverse reactions noted during therapy. The above findings demonstrate the polymicrobial etiology of chronic recurrent suppurative otitis media and suggest that treatment directed against the aerobic and anaerobic isolates is efficacious in more than half of the cases.