Correlation between microbiology and previous sinus surgery in patients with chronic maxillary sinusitis.

Aspirates of 108 chronically inflamed maxillary sinuses were processed for aerobic and anaerobic bacteria. There were 295 bacterial isolates: 109 aerobic and facultative, and 186 anaerobic. The predominant aerobic isolates were Staphylococcus aureus (17 isolates), alpha-hemolytic streptococci (14), Pseudomonas aeruginosa (12), Moraxella catarrhalis (10), and Haemophilus spp (8). The predominant anaerobes were Peptostreptococcus spp (61), Prevotella spp (45), Fusobacterium spp (15), and Propionibacterium acnes (14). Analysis of the medical histories revealed a correlation only between the microbial results and previous sinus surgery. Pseudomonas aeruginosa and gram-negative aerobic bacilli (GNAB) were more often isolated in patients who had surgery (9 of 33 patients had P aeruginosa and 17 had GNAB) than in patients who did not have surgery (3 of 75 had P aeruginosa and 7 had GNAB; p < .001). Anaerobes were isolated more often in patients who did not have surgery (69 of 75 patients) than in those who had previous surgery (21 of 33 patients; p < .001). These findings illustrate the unique microbiological features of chronic maxillary sinusitis that persist after sinus surgery.