➤ Although there is some evidence that scrubs, masks, and head coverings reduce bacterial counts in the operating room, there is no evidence that these measures reduce the prevalence of surgical site infection. ➤ The use of gloves and impervious surgical gowns in the operating room reduces the prevalence of surgical site infection. ➤ Operating-room ventilation plays an unclear role in the prevention of surgical site infection. ➤ Exposure of fluids and surgical instruments to the operating-room environment can lead to contamination. Room traffic increases levels of bacteria in the operating room, although the role of this contamination in surgical site infection is unclear.