Bacteriology of chronic maxillary sinusitis in adults.

Aspirates of 72 chronically inflamed maxillary sinuses were processed for aerobic and anaerobic bacteria. Bacterial growth was present in 66 of the 72 specimens (92%). Anaerobic bacteria were isolated in 58 of the 66 culture-positive specimens (88%). Anaerobes only were recovered in 37 cases (56%) and in 21 (32%) they were mixed with aerobic or facultative bacteria. Aerobic or facultative bacteria were present in eight cases (12%). A total of 185 isolates (2.8 per specimen)--131 (2.0 per specimen) anaerobes and 54 (0.8 per specimen) aerobes or facultatives--were isolated. The predominant anaerobic organisms were anaerobic cocci and Bacteroides sp, and the predominant aerobes or facultatives were Streptococcus sp and Staphylococcus aureus. Twelve of the 27 Bacteroides sp that were tested for beta-lactamase (44%) produced the enzyme. These findings indicate the major role of anaerobic organisms in chronic sinusitis.