Wound infections in general surgery. Wound contamination, rates of infection and some consequences

Rates of wound infection have been studied in a clinic performing to an equal degree both clean surgery and potentially contaminated surgery. Included in the study were 2827 patients with 213 (7.5%) postoperative wound infections. The postoperative mortality was 2.1%. Primary illness and cardiovascular complications were the main causes of postoperative death, while infectious complications (pneumonia, peritonitis and wound infection) were associated with or caused 1/3 of all postoperative deaths. Positive cultures from the wound before closure and from the wound dressings, immediately after operation, were followed by an increased risk of wound infection compared to negative cultures. Rates of wound infection were significantly higher in potentially contaminated operations compared to clean operations. Gram negative bacteria dominated in isolates from infected wounds after the former type of surgery, while S. aureus was the most common bacteria in wound infections after clean surgery. The time interval between operation and the discovery of wound infection was in the mean 10 days for staphylococci, and 9 days for Gram negative bacteria. The average time of hospitalization for patients contracting postoperative wound infections was 9 days longer than that for non-infected patients, which means that 3.4% of all nursing days were lost owing to excess hospitalization of infected patients.