[Surveillance of operative site infections in an orthopedic and traumatology surgery department: an example of methodology].

PURPOSE OF THE STUDY: A program for the prevention of nosocomial infections, including operative site infections (OSI) is a legal obligation in France. According to the CDC, in orthopedic surgery, nosocomial infection is defined as any infection occurring within 30 days of operation, or within one year in the event of material implantation. No surveillance system has been validated and the rate of OSI is unknown in orthopedic surgery. We report the number of OSI observed during a three year period in our unit and describe the characteristic features.

MATERIAL AND METHODS: Data were collected from the bacteriology reports on operative site samples with a positive culture. A group of specialists determined the infective nature of the germ and the nosocomial nature of the OSI. Clinical and bacteriological data were noted on a standard datasheet used for prospective follow-up of the number of cases and data processing. During a three-year period (2000, 2001, 2002), among 9397 orthopedic and traumatology operations performed, 86 OSI were identified. Mean patient age was 58 years and mean body mass index was 25.7. The ASA score was >or=II for 72% of patients.

RESULTS: The OSI involved an arthroplasty in 23 cases, a traumatology procedure in 21, and tumor treatment in 24. The diagnosis was established within 30 days of operation for 75% and after discharge from hospital in 65.4%. Single-germ infections predominated (n=59). Staphylococcus aureus was isolated in 80.23% of infections. For tumor surgery, the statistically more frequent multiple-germ infections associated coagulase negative Staphylococcus and Gram-negative bacilli. There were six OSI-related deaths.

DISCUSSION: Two criticisms can be formulated concerning our surveillance system. First, infections with no identified germ could be missed. The frequency of such infections has been estimated at 2.8 to 19% by different authors. Although patients are automatically recalled for consultation, we were unable to determine the number of patients lost to follow-up at one year. It was thus not possible to determine a precise rate of OSI. Data in the literature have not demonstrated any system providing an exhaustive surveillance, particularly because of the long postoperative period after material implantation. Excepting tumor surgery, Staphylococcus aureus infections predominated. Factors of risk of OSI include the patient's general status, particularly for arthroplasty. We had a mortality rate of 7% for our OSI, corroborating earlier studies and illustrating the severity of such infections.

CONCLUSION: Surveillance of OSI in orthopedic surgery requires the development of a system responding to the problem of a long observation period. It would be important to know the precise number of OSI and their characteristic features in order to develop comparison tools.