Association of intracellular Staphylococcus aureus with prognosis in chronic rhinosinusitis.

Staphylococcus aureus (S. aureus) has been shown to exist within nasal epithelial cells in chronic rhinosinusitis (CRS) patients. This study investigates the localization of intracellular S. aureus (ICSA) in CRS patients, the associated histopathology changes, and their effect on long-term postoperative outcomes. A prospective study of patients with CRS with and without polyps and control patients (n = 25, 15, and 8, respectively) undergoing endoscopic sinus surgery was performed. Validated patient reported symptom scores and objective endoscopic scores were collected preoperatively and 12 months postoperatively. Mucosal tissue samples were collected and examined for the presence of ICSA using immunohistochemical analysis. Tissue also underwent routine hematoxylin and eosin and Sirius Red staining to evaluate the inflammatory cell load and extent of fibrosis. ICSA appeared to localize to the perinuclear region of the pseudostratified columnar respiratory epithelium. ICSA was more prevalent in CRS without nasal polyps (CRSsNP) than in CRS with nasal polyps (CRSwNP) or controls (80% vs 56% vs 38%, respectively). ICSA positive status did not appear to influence symptom or endoscopic scores at the time of surgery nor 12 months postoperatively. Lymphocytes and total inflammatory cells were significantly increased in ICSA(+) group than ICSA(-) groups (36.4 vs 22.4 cells/area and 53.8 vs 29.1 cells/area, respectively). There was no difference found in fibrosis. This study indicated that ICSA was most prevalent in CRSsNP patients and was associated with increased lymphocytia and total inflammatory cells but not with worse symptomatology, endoscopy results, or basement membrane (BM) thickening.