Objective:To examine the distribution of pathogens that cause postoperative nosocomial infections in patients with rectal cancer(RC)and to construct a predictive nomogram for nosocomial infection.Methods:The clinical data of 1537 RC patients admitted to Sir Run Run Shaw Hospital between January 2021 and December 2022 were collected.Patients were assigned 1∶1 by propensity score matching(PSM)to the infection group(n=83)and control group(n=83)based on the occurrence of nosocomial infection.The dis-tribution and drug resistance of bacteria in patients with nosocomial infection were analyzed.Risk factors for postoperative nosocomial infection were identified by least absolute shrinkage and selection operator(LASSO)regression,and a predictive nomogram was con-structed using multivariate logistics regression.The predictive performance of the model was evaluated by receiver operating character-istic(ROC)curve,calibration curve,and decision curve analysis(DCA).Results:A total of 93 strains of pathogens were isolated from the 83 infected patients,including 62 strains of Gram-negative bacteria(66.67%;predominantly Escherichia coli and Pseudomonas ae-ruginosa),25 strains of Gram-positive bacteria(26.88%;mainly Enterococcus faecalis),and 6 strains of fungi(6.45%;all Candida albicans).LASSO and multivariate logistics regression showed that smoking(odds ratio[OR]=3.97,95%CI=1.27-12.43),the dwelling time of drainage tube(OR=1.19,95%CI=1.08-1.30),difference in preoperative and postoperative neutrophil counts(OR=1.23,95%CI=1.01-1.49),and difference between preoperative and postoperative C-reactive protein levels(OR=1.05,95%CI=1.03-1.07)were inde-pendent risk factors for postoperative nosocomial infection in RC patients.The area under the ROC curve of the nomogram constructed based on the above factors was 0.933(95%CI=0.896-0.969).The calibration curve showed that the predicted risk was in good agree-ment with the actual observed risk of infection.In addition,DCA demonstrated that the nomogram has good clinical utility and high net clinical benefits in predicting nosocomial infection.Conclusion:The nomogram constructed in this study has a good predictive perfor-mance in postoperative nosocomial infection in RC patients.