Comparison of Bacteriology Between Eosinophilic and Noneosinophilic Chronic Rhinosinusitis With Nasal Polyps

Objective To compare culture results between eosinophilic chronic rhinosinusitis (CRS) with nasal polyps (ECRSwNP) and noneosinophilic CRS with nasal polyps (nECRSwNP). Study Design Retrospective study. Setting Tertiary medical center. Methods We retrospectively analyzed a cohort of CRSwNP patients undergoing primary functional endoscopic sinus surgery. Prior to surgery, swab samples for bacterial culture were collected from their middle meatus using cotton tips. After surgery, postoperative specimens were histologically examined for tissue eosinophilia. A tissue eosinophil density of >10 cells at high power magnification was used to discriminate between ECRSwNP and nECRSwNP. Results A total of 295 patients were studied with polyps present on 471 sides of the nasal cavity. Among them, 236 sides were ECRSwNP, and the remaining 235 sides were nECRSwNP. Bacterial growth was found in 94 ECRSwNP sides, and in 88 nECRSwNP sides. Culture rates were similar between ECRSwNP and nECRSwNP sides (p = .595). However, Gram-negative aerobes were found in 25 of 236 ECRSwNP sides, and in 42 of 235 nECRSwNP sides. The Gram-negative culture rate was significantly higher in nECRSwNP than in ECRSwNP sides (p = .024). Conclusion The bacteriology of CRS was different between ECRSwNP and nECRSwNP. The Gram-negative aerobes were present more in nECRSwNP than in ECRSwNP.