Microbiology of chronic maxillary sinusitis: comparison between specimens obtained by sinus endoscopy and by surgical drainage.

The aerobic and anaerobic microbiology of sinus aspirates obtained during surgery was compared with culture of samples obtained by endoscopy. Six patients with chronic maxillary sinusitis were evaluated. Polymicrobial flora was found in all specimens (two-to-five isolates/sample). A total of 24 isolates (18 anaerobic, five aerobic and one micro-aerophilic) was obtained from sinus aspirates, and 25 isolates (16 anaerobic and nine aerobic) were found in endoscopic specimens. The predominant organisms were Prevotella spp., Fusobacterium nucleatum, Peptostreptococcus spp. and Staphylococcus spp. Concordance in the type and concentration of organisms was found in all cases. Sixteen of the 18 anaerobes isolated from sinus aspirates were also found in the concomitant endoscopic sample. Five aerobic isolates were found in both sinus aspirates and endoscopic samples and their concentration was similar. However, four aerobic gram-positive bacteria (<10(4) cfu/sample) were found only in endoscopy samples. This pilot study demonstrates the usefulness of endoscopic aspiration in the isolation of bacteria from chronically infected maxillary sinuses.