[Risk factors of surgical wound infection]

Surgical Site Infection (SSI) continues to be a major source of morbidity following operative procedures. The aging of the population means that not only will the number of operations likely increase, but the National Nosocomial Infections Surveillance (NNIS) Risk Index, which standardizes the risk of SSI for an aging population, will be greater. The NNIS report for 1986-1996 described an SSI rate of 2.6% for all operations at the reporting hospitals. It seems likely that overall SSI rates are likely to be greater than reported. All surgical wounds are contaminated by bacteria, but only a minority actually demonstrate clinical infection. The SSI are the biological summation of several factors: the inoculum of bacteria introduced into the wound during the procedure, the unique virulence of contaminants, the microenvironment of each wound, and the integrity of the patients host defense mechanisms. Risk factors were studied in single and multivariate analyses. Although an SSI rate of zero may not be achievable, continued progress in understanding the biology of infection at the surgical site and consistent applications of proven methods of prevention will allow us to further reduce the frequency, cost, and morbidity associated with SSI.