Extending prophylactic antimicrobial use beyond 48 h postoperatively fails to reduce surgical site infections and other healthcare-associated infections in patients undergoing colorectal resection: a Propensity Score Matching study

It is controversial whether antibiotic should be used prophylactically 48 h after colorectal resection. Hence, the association of prophylactic antimicrobial (PA) use beyond 48 h postoperatively with the incidence of surgical site infections (SSI) and other healthcare-associated infections (HAI) in patients receiving colorectal resection surgery was evaluated. A retrospective analysis was performed on 2691 patients who underwent colorectal resection between March 1, 2023, and December 31, 2025. Patients were categorized into the non-PA beyond 48 h postoperatively group ( n = 1934) and the PA beyond 48 h postoperatively group ( n = 757) based on whether prophylactic antibiotic use exceeded 48 h postoperatively. Propensity Score Matching (PSM) was used to balance differences in covariates between the two groups, subsequently, the relationship between prophylactic antibiotic use and infection was analyzed. The incidence of surgical site infections (SSI) in patients undergoing colorectal resection was 8.51% (229/2691), while the incidence of other healthcare-associated infections (HAI) was 8.06% (217/2691). After PSM, both non-PA beyond 48 h postoperatively group and PA beyond 48 h postoperatively group were divided into 757 cases each. Multiple regression analysis showed that PA beyond 48 h postoperatively was not associated with SSI(OR = 0.85, 95% CI 0.59 -1.21, P = 0.356) and other HAI (OR = 0.81, 95% CI 0.54-1.23, P = 0.325) after adjustment for the confounding effect of age, sex, diabetes, hypertension, anemia, hypoproteinemia. Subsequent to adjustment for all confounding factors, PA beyond 48 h postoperatively was still not a influence factor for SSI (OR = 0.85, 95% CI 0.59-1.22, P = 0.372) and other HAI (OR = 0.77, 95% CI 0.50-1.18, P = 0.229). The total cost (¥57349.60 vs. ¥55039.10, P = 0.0006) were higher in the PA beyond 48 h postoperatively group than non-PA beyond 48 h postoperatively group, and no statistically significant differences were observed between the two groups in postoperative hospital stay ( P > 0.05). Extending prophylactic antimicrobial use beyond 48 h postoperatively following colorectal resection surgery was not associated with lower morbidity rate of SSI and other HAI, nor did it shorten the postoperative hospital stay; however, it resulted in elevated costs. Nonetheless, this study may contribute to the development of strategies for standardizing prophylactic medication management during the perioperative period of colorectal resection. Not applicable