Bacteriology of chronic sinusitis and acute exacerbation of chronic sinusitis.

OBJECTIVE: To establish the microbiological characteristics of acute exacerbation of chronic sinusitis (AECS).

SETTING: Academic medical center.

PATIENTS: Thirty-two patients with chronic sinusitis and 30 patients with AECS.

MAIN OUTCOME MEASURE: The aerobic and anaerobic microbiology of maxillary AECS and chronic maxillary sinusitis.

RESULTS: A total of 81 isolates (33 aerobic and 48 anaerobic) were recovered from the 32 cases (2.5 per specimen) with chronic sinusitis. Aerobes alone were recovered in 8 specimens (25%), anaerobes only were isolated in 11 (34%), and mixed aerobes and anaerobes were recovered in 13 (41%). The predominant aerobic and facultative bacteria were Enterobacteriaceae and Staphylococcus aureus. The predominant anaerobic bacteria were Peptostreptococcus subspecies, Fusobacterium subspecies, anaerobic gram-negative bacilli, and Propionibacterium acnes. Twenty-one beta-lactamase-producing bacteria were recovered from 17 specimens (53%). A total of 89 isolates (40 aerobic and facultatives, and 49 anaerobic) were recovered from the 30 patients (3.0 per specimen) with AECS. Aerobes were recovered in 8 instances (27%), anaerobes only in 11 (37%), and mixed aerobes and anaerobes were recovered in 11 (37%). The predominant aerobes were Streptococcus pneumoniae, Enterobacteriaceae, and S aureus. The predominant anaerobes were Peptostreptococcus subspecies, Fusobacterium subspecies, anaerobic gram-negative bacilli, and P acnes. Thirty-six beta-lactamase-producing bacteria were recovered from 28 specimens (53%).

CONCLUSIONS: This study demonstrates that the organisms isolated from patients with AECS were predominantly anaerobic and were similar to those generally recovered in patients with chronic sinusitis. However, aerobic bacteria that are usually found in acute infections (eg, S pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis) can also emerge in some of the episodes of AECS.