Endoscopically guided aerobic cultures in postsurgical patients with chronic rhinosinusitis

Background: There is considerable amount of debate in the literature regarding the microbial flora of normal, acutely infected, and chronically infected paranasal sinuses. Few studies have specifically looked at the microbial flora of healthy and infected sinus cavities after functional endoscopic sinus surgery. Methods: One hundred thirty-four cultures were studied. All cultures were obtained using a standard technique. The nasal cavities were decongested and anesthetized, and nasal endoscopy was performed. When purulent secretions were identified, specimens of purulent secretions were obtained for incubation. Sensitivities were tested according to microorganisms identified. Empiric therapy generally consisted of a fluoroquinolone, amoxicillin/clavulanate, or a later-generation cephalosporin, and adjustment in individual instances when appropriate. Results: Twelve cultures showed no growth, 86 grew a single microorganism, and 35 grew two or more microorganisms for a total of 151 microorganisms identified. The most common microorganisms were Staphylococcus aureus, coagulase-negative staphylococci, and Pseudomonas aeruginosa. Other organisms that were cultured <5% of the time included Streptococcus pneumoniae, Haemophilus influenza, Moraxella catarrhalis, Serratia liquefaciens, Stenotrophomonas (Xanthomonas) maltophilia, alcaligenes, Fusobacterium, Escherichia coli, diphtheroids, Acinetobacter species, Klebsiella species, skin flora, and mixed Gram-negative and Gram-positives. Conclusion: Endoscopically guided aerobic cultures in postsurgical patients with acute exacerbations of chronic rhinosinusitis most commonly grew S. aureus, coagulase-negative staphylococci, and pseudomonal species. These cultures altered antibiotic treatment management decisions in a significant number of cases regardless of patients' clinical characteristics or history of previous culture.