Although there have been different randomized studies comparing the efficacy of different types of systemic antibiotics for preventing surgical-site infection there has been no studies analyzing the effect of preoperative skin antisepsis. In the January 7^th issue of the New England Journal of Medicine a group of researchers from the United States describe their findings comparing chlorhexidine–alcohol with povidone–iodine. This was a prospective, randomized clinical trial performed at six university–affiliated hospitals in the United States during a 4 year period. The researchers recruited 897 patients undergoing clean-contaminated surgery (i.e., colorectal, small intestinal, gastroesophageal, biliary, thoracic, gynecologic, or urologic operations). They were randomly assigned to a study group where the skin at the surgical site was preoperatively scrubbed with either 2% chlorhexidine gluconate and 70% isopropyl alcohol (431 patients), or an aqueous solution of 10% povidone–iodine (466 patients). 813 patients were finally included in the study (391 in the chlorhexidine–alcohol group and 422 in the povidone–iodine group), while 36 were excluded. All patients received systemic prophylactic antibiotics within 1 hour before the initial incision. The overall rate of surgical-site infection was significantly lower in the chlorhexidine–alcohol group (9.5%) than in the povidone–iodine group (16.1%, P = 0.004). The relative risk of any surgical-site infection among patients whose skin was preoperatively cleansed with chlorhexidine versus povidone–iodine was 0.59 (95% confidence interval, 0.41 to 0.85). The authors estimated that the number of patients who would need to undergo skin preparation with chlorhexidine–alcohol instead of povidone–iodine in order to prevent one case of surgical-site infection was 17. This study clearly shows that skin preparation with chlorhexidine–alcohol is superior to povidone-iodine for preventing surgical-site infections. As two thirds of these surgical infections are confined to the siteof incision, skin antisepsis before surgery could result in a significant clinical benefit. This results are probably also applicable to cutaneous surgery, and therefore preoperative use of chlorhexidine–alcohol should be recommended over povidone–iodine. (more…)