Predictors of surgical site infection in dirty urological surgery

Risk factors for surgical site infection (SSI) following urologic dirty operations have not been clearly identified. This study was conducted to describe incidence, potential risk factors and common causative pathogens of the SSI in such operations.

Medical records of patients who had undergone simple nephrectomy or lumbotomy for suppurative renal infection at our institutions from 1999 to 2006 were retrospectively evaluated. The following data were retrieved: presence of SSI, demographic data, laboratory findings, comorbidities, microbiological data, type of renal suppuration, type of urological surgery and antibiotic regimen. Risk factors for SSI were evaluated using the multiple logistic regression model.

Sixty-five patients (mean age 55.6 +/- 13.1 years) were eligible for data analysis. In 20 of them (30.8%) a SSI was identified. The most common isolated pathogens were gram-negative bacteria. At univariate logistic regression analysis risk factors significantly associated with SSI included: presence of emphysematous infection, hypoalbuminemia, number of predisposing conditions, emergency operations, isolation of Enterobacteriaceae, positive pus culture. The use of trimethoprim/sulfamethoxazole was associated with a decreased risk for SSI. Multiple logistic model identified only the emergency operations and isolated Enterobacteriaceae as independent predictors of SSI (odds ratio [OR] = 11.1) (95% confidence interval [CI] = 3.0-40.8) and OR = 3.9 (1.0-14.8), respectively.

Patients with suppurative renal infections are submitted to life-saving emergency surgery. Urological surgeons should keep in mind that this carries a high risk for subsequent SSI. Effective preventive measures in these circumstance cannot be identified. Further research in this area is necessary to clarify this issue.