Prospective evaluation of surgical site infection rate among patients with Mohs micrographic surgery without the use of prophylactic antibiotics.

BACKGROUND: Antibiotics may be indiscriminately given to patients undergoing Mohs micrographic surgery (MMS) for the prevention of surgical site infections, despite a low risk of infection in these patients.

OBJECTIVE: We sought to evaluate the rate of wound infections among patients undergoing MMS without the use of prophylactic antibiotics.

METHODS: We prospectively evaluated 1000 consecutive patients undergoing MMS for nonmelanoma skin cancer or modified MMS/"slow Mohs" for lentigo maligna melanoma in situ.

RESULTS: The overall wound infection rate among 1000 patients with 1115 tumors was 0.7% (8/1115 tumors). Five (62.5%) of 8 infections occurred on the nose with an overall 1.7% (5/302) nose infection rate. Seven (87.5%) of 8 infections occurred after flap reconstruction with an overall 2.4% (7/296) flap closure infection rate. Four (50%) of 8 infections occurred in patients requiring more than one Mohs stage for tumor clearance with a 0.8% (4/487) overall infection rate in cases requiring multiple Mohs stages. Two (25%) of 8 infections had cultures positive for oxacillin-resistant Staphylococcus aureus. No wound infections occurred in cases involving the lips or ears, skin-graft closures, or below-knee or modified MMS procedures.

LIMITATIONS: This was a prospective single institution uncontrolled study.

CONCLUSION: Rates of infections among patients undergoing MMS or modified MMS are exceedingly low. Indiscriminate use of antibiotics increases patient risk to adverse drug reactions and antibiotic resistance. Administration of antibiotics to patients undergoing MMS should be on a case-by-case basis according to the known risk factors combined with clinical judgment.