Aerobic and anaerobic bacteriology of peritonsillar abscess in children

Aspiration of peritonsillar abscess (quinsy) was aseptically performed in 16 children. Patients' median age was 10 years (range 6 to 17 years), and 12 were males. Unilateral abscess was present in all but one child. All aspirates were cultured for aerobes and anaerobes and yielded bacterial growth in all patients. Anaerobes were isolated in all patients; in 3 patients (19%), they were the only organism isolated, and in 13 (81%), they were mixed with aerobes. There were 91 anaerobic isolates (5.7 per specimen): 42 Bacteroides sp. (including 23 B. melaninogenicus, 5 B. oralis and 4 B. ruminicola ss. brevis); 18 anaerobic Gram-positive cocci (including 10 Peptostreptococcus sp., 4 Peptococcus sp. and 4 microaerophilic streptococci); 15 Fusobacterium sp.; and 3 Clostridium sp. There were 32 aerobic isolates (2.0 per specimen): 11 gamma-hemolytic streptococci, 8 alpha-hemolytic streptococci, 4 Group A beta-hemolytic streptococci, 4 Haemophilus sp. and 3 S. aureus. Beta-lactamase production was noted in 13 isolates recovered from 11 patients (68%). These were all isolates of S. aureus (3), 8 of 23 B. melaninogenicus (35%), and 2 of 5 B. oralis (40%). Our findings indicate the major role of anaerobic organisms in the polymicrobial etiology of peritonsillar abscesses in children, and demonstrate the presence of many beta-lactamase-producing organisms in two thirds of the patients.