Oral antibiotics versus topical decolonization to prevent surgical site infection after Mohs micrographic surgery--a randomized, controlled trial.

Background: The optimal method of reducing the risk of surgical site infection (SSI) after dermatologic surgery is unclear. Empiric, preoperative antibiotic use is common practice but lacks supporting evidence for its efficacy in preventing SSI. Risk stratification for patients at high risk of postoperative SSI based on a nasal swab is a viable strategy when coupled with topical decolonization for positive carriers. We compared the rates of infection in patients undergoing Mohs micrographic surgery (MMS) with nasal carriage of Staphylococcus aureus who received oral antibiotics or topical decolonization.

Methods: A randomized, controlled trial with 693 patients was conducted over a 30-week period at a single surgical practice. Patients were stratified into nasal carriers or noncarriers of S. aureus based on a preoperative nasal swab. Nasal carriers of S. aureus were randomized to receive topical decolonization with intranasal mupirocin twice daily plus 4% chlorhexidine gluconate body wash daily for 5 consecutive days before surgery or statim pre- and postoperative doses of oral cephalexin.

Results: One hundred seventy-nine patients (25.8%) were identified as carriers of S. aureus. Ninety received topical decolonization, and 89 received oral antibiotics. These groups were compared with a swab-negative Mohs surgical cohort over the same time period. There were no significant differences between the groups in terms of demographic characteristics or comorbidities. Nine percent of patients receiving oral antibiotic prophylaxis and 0% receiving topical decolonization developed early SSI (p = .003).

Conclusion: In patients with demonstrable carriage of S. aureus, topical decolonization resulted in fewer SSI than in patients receiving perioperative oral antibiotics. Antibiotics should be reserved for clinically suspected and swab-proven infections rather than being prescribed empirically. Further efforts should be directed toward optimizing endogenous risk factor control for all patients presenting for MMS.