Healthcare-associated infections after elective surgery for gastrointestinal cancer in a Romanian tertiary center: incidence, microbiological profile, and the role of neoadjuvant radiotherapy as an independent risk factor.

BACKGROUND: Healthcare-associated infections following gastrointestinal cancer surgery are typically reported in terms of surgical site infection alone, with limited data on the broader infectious spectrum, comparative microbiology between upper and lower gastrointestinal surgery, and antimicrobial resistance in Eastern European centers. We aimed to describe the incidence, types, risk factors, and microbiological profile of all healthcare-associated infections occurring within 30 days of surgery in a Romanian tertiary referral center for oncological surgery. METHODS: In a prospective single-center observational study, 211 consecutive adult patients undergoing elective surgery for gastric or colorectal cancer between May 2023 and July 2024 were followed for 30 days postoperatively. Healthcare-associated infections were defined according to Centers for Disease Control and Prevention/National Healthcare Safety Network surveillance criteria, and multidrug- and extensively drug-resistant isolates were classified using consensus international definitions. Risk factors were assessed by univariate analysis and multivariable logistic regression with three pre-specified predictors: neoadjuvant radiotherapy, surgery duration, and male sex. RESULTS: Thirty-three patients (15.6%) developed at least one healthcare-associated infection, accounting for 39 episodes. The infection profile differed by surgical site: surgical site infection was the predominant infection type following lower gastrointestinal surgery (~46% of episodes), whereas device-associated and respiratory infections were relatively more common following upper gastrointestinal surgery (~38% of episodes together). Neoadjuvant radiotherapy-containing treatment was an independent risk factor in colorectal patients (adjusted odds ratio [OR] 3.25, 95% confidence interval [CI] 1.15-9.19, p = 0.026). Of 27 culture-positive isolates, 44.4% were classified as multidrug- or extensively drug-resistant, including a dual-carbapenemase-producing Klebsiella pneumoniae, a metallo-β-lactamase-producing Pseudomonas aeruginosa, and a single Candida auris isolate. Microbiological documentation was missing for 36.4% of infected patients, and infection-attributable 30-day mortality was 1.9%. CONCLUSION: Postoperative healthcare-associated infection in gastrointestinal cancer surgery extends substantially beyond surgical site infection and carries a high antimicrobial resistance burden in this Romanian tertiary-center cohort. Neoadjuvant radiotherapy warrants heightened postoperative surveillance, though this independent association requires confirmation in larger multicenter studies. The substantial proportion of culture-negative or unsampled infections highlights a concrete quality-improvement target, while the documented resistance profile indicates that institution-specific surveillance data may complement broader national or European epidemiological information when developing local stewardship strategies.