Nasal carriage of <i><scp>S</scp>taphylococcus aureus</i> in patients undergoing <scp>M</scp>ohs micrographic surgery is an important risk factor for postoperative surgical site infection: A prospective randomised study

Abstract

BACKGROUND: Surgical site infection (SSI) can be a problematic complication of Mohs micrographic surgery (MMS). Previous reports have cited nasal Staphylococcus aureus (S. aureus) carriage as a risk factor for SSI, but none thus far in dermatologic surgery. OBJECTIVE: The aim was to determine the difference in infection rates between nasal carriers of S. aureus and non-carriers, and whether decolonisation with intranasal mupirocin ointment and chlorhexidine wash would reduce the infection rate in nasal carriers. METHODS: In all, 738 patients presenting for MMS at the Oxford Day Surgery and Dermatology underwent a nasal swab to determine their S. aureus carriage status. S. aureus carriers were randomised for decolonisation with intranasal mupirocin ointment and chlorhexidine body wash. Non-carriers were untreated. All patients were followed up for SSI. RESULTS: The rate of SSI was 11 per cent in untreated S. aureus carriers, 4 per cent in treated carriers, and 3 per cent in non-carriers. The difference in infection rate between carriers and non-carriers was significant (P < 0.001). The difference between treated and untreated carriers was also significant (P = 0.05). CONCLUSION: Nasal S. aureus carriage is an important risk factor for SSI in MMS, conferring an over threefold increase in SSI risk. A pre-operative nasal swab provides a simple and effective risk stratification tool. The use of a topical decolonisation regimen reduces the infection rate in carriers to a level approaching non-carriers without exposure to systemic antibiotics.