Background: Group A streptococcus (GAS) is known to cause of a variety of infections. Transmission of GAS from patient to healthcare worker (HCW) has been reported, most commonly resulting in pharyngitis. Secondary transmission of invasive GAS has been rarely described, primarily among household contacts with prolonged exposure to the index patient. Transmission of invasive GAS from an index patient to a surgeon who had performed operative debridement on the patient has not been previously reported. Objective: To describe an investigation of nosocomial transmission of invasive GAS. Methods: Epidemiologic evaluation of the index patient, HCWs, and patients who had contact with symptomatic HCWs. A root cause analysis (RCA) was also conducted. Results: On Day 1, an extensive debridement procedure and amputation of the left leg was performed on a patient with necrotizing fasciitis. Blood and intraoperative cultures were positive for Streptococcus pyogenes. On Day 3, Surgeon A developed pharyngitis. Rapid streptococcal antigen testing was positive, but throat culture was not obtained. On Day 8, Surgeon B developed malaise and subjective fever with chills. Worsening fatigue and the development of right foot and thigh erythema with edema subsequently developed. Given a history of right hip arthroplasty, magnetic resonance imaging of the hip was performed and was notable for findings consistent with cellulitis and lymphangitis. Physical examination was also notable for tinea pedis. Blood cultures were obtained and antimicrobial therapy was initiated. Clinical deterioration occurred and within 72 hours of admission, operative debridement of the right leg was performed. Intraoperative findings were consistent with necrotizing fasciitis. Blood cultures were positive for S. pyogenes. A total of 28 HCWs were screened for GAS. All except Surgeons A and B received throat culture. Only the 2 HCWs described here had evidence of colonization or infection. Molecular typing of isolates from the index patient and Surgeon B (figure) demonstrated that the strains were identical. The RCA revealed that the index operation was associated with gross contamination of the clothing of both Surgeons A and B. Easy access to replacement scrubs and shower facilities was not available. Both HCWs wore contaminated clothing after the index case initial operation had concluded. Conclusions: Transmission of invasive GAS from patient to HCW is a rare but serious event. The case described here is presumed to have resulted from gross contamination of Surgeon B's clothing and shoes where tinea pedis may have served as a portal of entry. This case serves as a reminder that cleaning of any contaminated skin should occur immediately after exposure, contaminated clothing should be removed as soon as possible, and healthcare facilities must design systems that facilitate these actions.