Routes and sources of Staphylococcus aureus transmitted to the surgical wound during cardiothoracic surgery: possibility of preventing wound contamination by use of special scrub suits.

Abstract

To trace the routes of transmission and sources of Staphylococcus aureus found in the surgical wound during cardiothoracic surgery and to investigate the possibility of reducing wound contamination, with regard to total counts of bacteria and S. aureus, by wearing special scrub suits. A total of 65 elective operations for coronary artery bypass graft with or without concomitant valve replacement were investigated. All staff present in the operating room wore conventional scrub suits during 33 operations and special scrub suits during 32 operations. Bacteriological samples were taken from the hands of the scrubbed team after surgical scrub but before putting on sterile gowns and gloves and from the patients' skin (incisional area of sternum and vein harvesting area of legs) after preoperative skin preparation with chlorhexidine gluconate. Air samples were taken during operations. Bacteriological samples also were taken from the subcutaneous walls of the surgical wound just before closing the wound. Total counts of bacteria on sternal skin and wound walls (colony-forming units [CFUs]/cm2) were calculated, as well as total counts of bacteria in the air (CFUs/m3). Strains of S. aureus recovered from the different sampling sites were compared by pulsed-field gel electrophoresis (PFGE). Special scrub suits significantly reduced total counts of bacteria in air compared to conventional scrub suits (P=.002). The number of air samples in which S. aureus was found was significantly reduced by special scrub suits compared with conventional scrub suits (P=.016; relative risk, 4.4; 95% confidence interval [CI95], 1.3-14.91). By use of PFGE, it was possible to identify two cases of possible airborne transmission of S. aureus when wearing conventional scrub suits, whereas no case was found when wearing special scrub suits. When exposed to airborne S. aureus, the concomitant sternal carriage of S. aureus was a risk factor for having S. aureus in the wound. Use of tightly woven special scrub suits reduces the dispersal of total counts of bacteria and of S. aureus from staff in the operating room, thus possibly reducing the risk of airborne contamination of surgical wounds. The importance of careful preoperative disinfection of the patient's skin should be stressed.