Microbiology of recurrent acute rhinosinusitis

Objective. We undertook to evaluate the microbiology of recurrent acute rhinosinusitis. Methods. Repeated aspirations of maxillary sinus secretions by endoscopy were performed in eight patients over a period of 98 to 185 days. Results. Bacteria were recovered for all 25 aspirates. A total of 31 isolates-14 Streptococcus pneumoniae, 11 Haemophilus influenzae, 5 Moraxella catarrhalis, and 1 Staphylococcus aureus-were recovered. The organism persisted in consecutive cultures in 13 instances and were eliminated in 8, and new organisms emerged in 6 instances. An increase in antimicrobial resistance was noted in 5 instances (3 in S. pneumoniae and 2 H. influenzae). Conclusions. This study illustrates the microbial dynamics of recurrent acute rhinosinusitis, and increased bacterial resistance that occurs over time.