Independent impact of multidrug-resistant organisms on postoperative outcomes in acute appendicitis patients: a retrospective cohort study

Abstract Background The increasing prevalence of multidrug-resistant (MDR) bacteria in intra-abdominal infections has raised concerns regarding their impact on perioperative management and postoperative outcomes in patients with acute appendicitis.This study aimed to determine whether MDR status independently predicts postoperative infectious complications and healthcare resource utilization in patients undergoing laparoscopic appendectomy after adjusting for potential confounding factors. Methods We conducted a single-center retrospective cohort study including 500 patients who underwent laparoscopic appendectomy for acute appendicitis between January 2020 and December 2024. All patients received empirical third-generation cephalosporin therapy preoperatively and perioperatively, and intraoperative bacterial cultures with antimicrobial susceptibility testing were performed. MDR was defined as nonsusceptibility to at least one agent in three or more antimicrobial categories. The primary outcome was postoperative infectious complications, including surgical site infection and intra-abdominal abscess. The secondary outcomes included antibiotic escalation, length of hospital stay, postoperative antibiotic duration, and 30-day readmission. Multivariate logistic regression was used to identify independent predictors of infectious complications and antibiotic escalation, while multivariate linear regression was used to analyze factors influencing hospital stay and antibiotic duration. Results Compared with MDR-negative patients, those with MDR-positive infections had significantly longer postoperative hospital stays and postoperative antibiotic durations. These patients also had higher rates of surgical site infection, intra-abdominal abscess, overall postoperative infectious complications, antibiotic escalation, and 30-day readmission (all P < 0.05). According to the multivariate analysis, MDR-positivity was independently associated with postoperative infectious complications (adjusted OR = 6.51; 95% CI: 2.51–16.90; P < 0.001), indicating that its effect extends beyond baseline disease severity. MDR status was also an independent predictor of antibiotic escalation (adjusted OR = 11.59; 95% CI: 5.11–26.28; P < 0.001). After adjustment for confounders, MDR positivity was significantly associated with prolonged antibiotic therapy (β = 1.37; 95% CI: 1.01–1.74; P < 0.001) and prolonged postoperative hospital stay (β = 1.39; 95% CI: 0.98–1.79; P < 0.001). Conclusions MDR-positive culture was independently associated with postoperative infectious complications and antibiotic escalation in patients with acute appendicitis, and was associated with greater healthcare resource utilization. These findings suggest that MDR status and pathogen identification may be relevant considerations for individualized antimicrobial management and provide a basis for further evaluation of MDR risk stratification and pathogen-directed antimicrobial strategies.