Postoperative wound infection surveillance by use of bacterial contamination categories

A prospective 2-year surveillance of 7129 wounds was conducted on all surgical services of the University Hospital in Seattle to determine the postoperative infection rates by surgical wound category. Rates on all services for clean (0.8%), clean-contaminated (3.4%), contaminated (3.6%), and dirty (9.9%) wounds were recorded and compared to rates reported in the surgical literature. The overall wound infection rate was 1.7%. When the incidence of infection for a specific service in a category was observed to be in excess of a previously reported upper rate, patient charts were critically reviewed to determine if host, pathogen, or technical factors could be implicated in the excessive infection rates. Extending postoperative wound surveillance to include critical chart analysis in these categories provides hospital staff members responsible for infection control the opportunity to organize corrective measures against excessive rates in a broader category of wounds.