Timing of antimicrobial initiation and reduced infection risk in open limb fractures: a cohort study.

To assess whether early administration of antimicrobials in open fractures of the limbs reduces infection risk. A historical cohort study included all adult patients admitted with an open fracture of the limbs, between January 1, 2012, and December 31, 2016. Epidemiological, clinical, and microbiological data was collected and analyzed. Microbiological infection was defined by positive wound cultures during the first 30 days, and clinical infection as defined by the treating physician. Of 167 patients, microbiological infection was identified in 12 (7%) patients, and clinical infection in 27 (16%) patients. All patients received the first dose of antimicrobials within 15 h of admission (median 1.29 h). Very early administration of the first dose did not reduce the risk of infection (median of 1.06 h and 1.31 h for patients that did vs. did not develop infection, respectively P = 0.58). In multivariate logistic regression, location of fracture in the lower limbs was associated with an increased risk of infection (OR 4.654, CI 1.407-15.398), and Gustilo-Anderson classification grade 1 or 2 was associated with a decreased risk of infection (OR 0.301, CI 0.104-0.872). Very early administration of antimicrobials did not reduce risk of infection in open limb fractures.