Introduction: One of the main theories in development of sinonasal polyposis involves the effect of Staphylococcus aureus super antigens and microbial biofilm. The aim of this study was to evaluate the effect of topical vancomycin on Staphylococcus aureus removal from sinus mucosa following surgery.

Methods: In this randomized triple-blind clinical trial, 35 patients, who underwent sinus polyp surgery and whose sinus culture was positive for Staphylococcus aureus before surgery, were divided to two groups. For the case group, nasal irrigation with normal saline solution containing vancomycin and for the control group, nasal irrigation with normal saline solution was administered for eight weeks. During the second month of treatment, all patients underwent nasal endoscopy. Patients were assessed for Staphylococcus aureus culture during the second month. All data were analyzed using two independent samples t-test and Fisher's exact tests. The level of statistical significance was considered as P < 0.05.

Results: Culture of Staphylococcus aureus in the second month was significantly lower in the case group than the control one (P < 0.05).

Conclusion: It seems that the use of topical vancomycin solution has an effect on eradication of Staphylococcus aureus in sinonasal polyposis after surgery