Purpose: We conducted a prospective survey of 2 663 surgical patients in a Japanese teaching hospital to look for any risk factors predisposing to surgical site infection (SSI) other than the National Nosocomial Infection Surveillance (NNIS) System risk indices; namely, performance status, operative time, wound classification, and endoscopic use.
Methods: Our Infection Control Team recorded data for 5 years using the Japanese SSI surveillance system. We divided the incidence of SSI for each risk index category by the NNIS reference data to produce the standardized infection ratio (SIR).
Results: The representative procedure, SSI rate, and SIR in the 2663 patients were as follows: colectomy, 6.0%, 0.917; esophagectomy, 19.4%, 6.020; mastectomy, 0.5%, 0.401; rectal surgery, 8.7%, 1.136; thoracic surgery, 1.5%, 1.137; and biliary surgery, 13.4%, 1.937. We also found age to be a significant risk factor.
Conclusions: The NNIS system risk indices should separate rectal surgery from colorectal surgery, and separate esophagectomy from other gastrointestinal surgery. Age should also be included as an SSI risk index.