Immune response to anaerobic bacteria in patients with peritonsillar cellulitis and abscess.

The role of four oral organisms (Fusobacterium nucleatum. Prevotella intermedia, Porphyromonas gingivalis, and Actinobacillus actinomycetemcomitans) was investigated in 19 children with peritonsillar abscess, and 17 with peritonsillar cellulitis. Antibody titers to these organisms were measured by enzyme- linked immunosorbent assay in the patient, as well as in 32 control patients. Serum levels in the patients were determined at day 1 and 42-56 days later. Significantly higher antibody levels to F. nucleatum and P. intermedia were found in the second serum sample of patients with peritonsillar cellulitis or abscess, as compared to their first sample or the levels of antibodies in controls. A total of 136 bacterial isolates, 100 anaerobic and 36 aerobic were isolated from the 19 peritonsillar abscesses. Anaerobic bacteria were found in all abscesses, and they were mixed with aerobic bacteria in 5 (26%). F. nucleatum was recovered in 14 (74%) abscesses and P. intermedia was isolated in 13 (68%). The elevated antibody levels to F. nucleatum and P. intermedia, known oral pathogens, suggest a pathogenic role for these organisms in peritonsillar infections.