Preventing surgical site infections: a randomized, open-label trial of nasal mupirocin ointment and nasal povidone-iodine solution.

An estimated 290,000 surgical site infections occur after a procedure in the United States annually, accounting for 22% of all healthcare associated infections [1]. Deep surgical site infections (SSI) after arthroplasty or spine fusion surgery complicate up to 2% of cases, and result in revision surgery and prolonged antibiotic use [2, 3]. The patient morbidity and healthcare system cost is tremendous, with an estimated $566 million spent annually in hospital treatment costs for arthroplasty SSI alone [4]. Staphylococcus aureus is a frequent and feared cause of these infections, given its unique pathogenicity and ability to adhere to prosthetic material [5, 6]. Studies indicate S. aureus colonization prior to surgery is a risk of subsequent infection, with the nasal mucosa serving as a reservoir for S. aureus colonization and a source of secondary transmission to other body sites [7, 8]. Prevention of SSI by treatment of S. aureus colonization with intranasal topical mupirocin has been studied. A short-term suppression rate of 83% after multiple doses of nasal mupirocin was achieved in one randomized, placebo-controlled trial of 891 S. aureus colonized patients, resulting in a statistically significant reduction of invasive S. aureus infection [9]. Several controlled trials suggest a reduction in SSI with the use of pre-operative topical antiseptics [10, 11]. When nasal mupirocin was combined with use of chlorhexidine soap in a randomized, double-blind, placebo-controlled trial including 808 S. aureus colonized surgical patients, a significant reduction in deep S. aureus SSI was realized [12]. To reduce the risk of SSI after arthroplasty and spine fusion surgery at our institution, we historically provided a prescription for brand mupirocin ointment specifically formulated for application on intranasal mucosal surfaces twice a day for the five days prior to surgery, and instructions for the use of chlorhexidine soap the evening before surgery. After implementation of this protocol, we conducted an anonymous patient survey to measure compliance. Although 94% of patients used the chlorhexidine soap, only 86% applied the mupirocin ointment and 8% of patients stated they found it hard or very hard to purchase the mupirocin due to cost [13]. The brand nasal mupirocin ointment specifically produced for application on intranasal mucosal surfaces is only formulation currently available; although generic mupirocin ointment for topical use on skin is available at less cost, application of this formulation on mucosal surfaces may cause irritation. Our survey results, plus reports of emerging mupirocin resistance, led us to search for alternatives [14–19]. Povidone-iodine solution is a broad-spectrum antiseptic suitable for suppression of S. aureus in nasal secretions [20]. In contrast to the application of nasal mupirocin antibiotic ointment to eradicate S. aureus in the nares before surgery, the application of povidone iodine is intended to transiently suppress S. aureus in the nares during surgery. Our hypothesis was a one-time application of nasal povidone iodine just prior to surgery would be as effective as twice daily applications of nasal mupirocin during the five days before surgery in preventing SSI, and provide a more convenient option for patients at lower cost.