Hou TY, Gan HQ, Zhou JF, et al. - Researchers investigated the incidence, risk factors and microbiology of surgical site infection (SSI) after colorectal surgery (CRS) via performing a nationwide multicenter study. Among 3,663 study participants from 19 Chinese hospitals from 2015 to 2018, 134 (3.66%) episodes of SSI were identified. Over the 4-year study period, a statistically significant but modest decrease in the incidence rate of CRS SSI was observed. For the National Nosocomial Infections Surveillance system risk index categories of 0, 1, and 2 or 3, they observed SSI rates of 1.88, 4.15, 6.27 and 11.58 per 100 operations, respectively. The most frequently isolated microorganisms were Escherichia coli and Klebsiella pneumoniae. In this study, they observed a high prevalence of antibiotic resistance, 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. Increased risk of SSI after CRS was observed in significant correlation with preoperative hospital stay ≥ 48 h and contaminated or dirty wound. They commonly noted controversies among those surveys, including this study, examining risk factors of SSI after colorectal surgery, and suggest the necessity for well-designed cohort with large population or meta-analysis. .