Prevalence and risk factors for surgical site infection after colorectal surgery: a multiple-center prospective study of 3,663 consecutive patients in China

Background: Surgical site infection (SSI) after colorectal surgery (CRS) remains a significant problem for its negative clinical outcomes. However, it is poorly understood in China . This study aims to investigate the prevalence, risk factors and microbiology of SSI after CRS. Methods: A nationwide prospective multicenter design was applied. Patients in 19 Chinese hospitals from 2015 to 2018 were prospectively monitored for SSI after CRS. Demographic data, hospital characteristics, and potential perioperative risk factors were collected and analyzed, using univariate and multivariate logistic regression models. Results: Among 3,663 study participants, 134(3.66%) episodes of SSI were identified. The prevalence rate of SSI decreased from 5.9 infections per 100 procedures in 2014 to 3.1 infections per 100 procedures in 2017 (prevalence rate ratio [PRR], 0.52; 95% CI, 0.28–0.94). The SSI rates were 1.88, 4.15, 6.27 and 11.58 per 100 operations for the National Nosocomial Infections Surveillance system (NNIS) risk index categories of 0, 1, and 2 or 3, respectively. Escherichia coli (54/134, 40.3%) and Klebsiella pneumoniae (10/134, 7.5%) were the most frequently isolated microorganisms. A high prevalence of antibiotic resistance were observed in our study, with rates of extended spectrum beta-lactamase-producing or carbapenem-resistant Escherichia coli and Klebsiella pneumonia of 50.0%(27/54) and 30.0%(3/10) respectively. Preoperative hospital stay ≥ 48h (OR=2.28, 95% CI: 1.03–5.02) and contaminated or dirty wound (OR=3.38, 95% CI: 1.88–6.06) were significantly associated with increasing risk of SSI after CRS. Conclusion: A statistically significant but modest decrease in the prevalence rate of CRS SSI over the 4-year study period was observed in this study. Noticeably, the relatively high rates of multidrug-resistant pathogens causing SSI after CRS should be alert despite of the small number of isolates identified in our survey.