AbstractObjective:To test the hypothesis that perioperative elimination of nasal carriage of Staphylococcus aureus using mupirocin nasal ointment reduces the surgical-site infection (SSI) rate in cardiothoracic surgery.Design:Unblinded intervention trial with historical controls.Setting:A university hospital, tertiary referral center for cardiothoracic surgery.Patients:Consecutive patients undergoing cardiothoracic surgery between August 1, 1989, and February 1, 1991 (historical control group), and between March 1, 1991, and August 1, 1992 (intervention group).Results:The historical control group consisted of 928 patients and the intervention group of 868, of whom 752 actually were treated. The 116 patients who were unintentionally not treated were considered as a concurrent control group. In the intention-to-treat analysis, a significant reduction in SSI rate was observed after the intervention (historical-control group 7.3% and intervention group 2.8%; P<.0001). The SSI rate in the concurrent control group was significantly higher than in the treated group (7.8% and 2.0%, respectively; P=.0023). Resistance of S aureus to mupirocin was not observed.Conclusion:The results of this study indicate that perioperative elimination of nasal carriage using mupirocin nasal ointment significantly reduces the SSI rate in cardiothoracic surgery patients and warrants a prospective, randomized, placebo-controlled efficacy trial. This preventive measure may be beneficial in other categories of surgical patients as well.