Sources and routes in postoperative wound infections

In a prospective study including 112 patients sources and routes in postoperative wound infections were traced by comparing wound cultures with cultures from the patient, other patients, personnel and from the environment in the operation unit, intensive care unit and in the ward. A total number of about 10 000 cultures was taken. The wound infection rate was 9.8% (8.1% in clean surgery and 13.2% in potentially contaminated surgery). The patient was a source of the bacteria in all cases of wound infection after potentially contaminated surgery and the wounds were probably contaminated intraoperatively. A possible intraoperative wound inoculation was registered at four instances and a postoperative wound inoculation at four instances in clean surgery. It is concluded that surgical wounds can be contaminated both at surgery and postoperatively. Postoperative wound contamination seems to be most important in clean surgery.