The Impact of an Antibiotic (Cefazolin) Before Surgery on the Microbiome in Patients With Stage I-II Melanoma

PRIMARY OBJECTIVE: I. To investigate whether the use of pre-operative prophylactic antibiotics administered during surgical resection substantially alters the patient's gut microbiome. SECONDARY OBJECTIVES: I. To characterize the dynamics of the immune response to surgical intervention in the absence and presence of pre-operative prophylactic antibiotics, focusing on the immune profile of the peripheral blood leukocytes as well as the balance of circulating pro- and anti-inflammatory cytokines and metabolomic profiles. II. To assess surgical site infection (SSI) in the absence and presence of pre-operative prophylactic antibiotics at time of surgical resection. OUTLINE: Patients are randomized to 1 of 2 arms. ARM A: Patients receive cefazolin intravenously (IV) and then undergo standard of care surgical resection within 1 hour. ARM B: Patients undergo standard of care surgical resection. After completion of study treatment, patients are followed up at 3 days, 2 weeks, and 3 months.