Introduction Bile fluid is aseptic under normal conditions; however, in the presence of cholecystitis, its susceptibility to bacterial colonisation varies, with reported rates of 20%–70% of cases. This process is referred to as bactibilia and/or bacteriobilia and can be considered a secondary complication of biliary stasis and cholecystitis in general. In the management of acute cholecystitis, the antibiotic regimen should be prescribed based on the presumed pathogens involved, taking into consideration the risk factors for resistance patterns according to demographics and local exposure. The aim of this study is to determine the predictive factors for bile culture positivity and antibiotic resistance in patients who underwent laparoscopic cholecystectomy in the Méderi Hospital Network. We hope to develop a predictive model that allows us to better guide antibiotic therapy. Methods and analysis This is a prospective observational cohort study with prognostic prediction model. Patients who will undergo laparoscopic cholecystectomy and have bile cultures taken in the Méderi Hospital Network during the study period will be included. The dependent variables will be positive bile culture and antibiotic resistance, and the predictive variables will be age, presence of diabetes, diagnosis of choledocholithiasis, diagnosis of cholecystitis and severity of cholecystitis according to the Tokyo criteria. The minimum sample size has been calculated at 703 patients. Follow-up will continue until a control appointment 15 days after the procedure. The primary outcomes are bile culture positivity and phenotypical antibiogram resistance. For each outcome, a multivariate logistic regression will be performed using frequentist and Bayesian prediction techniques. Ethics and dissemination This study was approved by the Méderi network research department committee (CIMED) and by Universidad del Rosario’s Research Ethics Committee (CEI-UR; DVO005 2555-CV1837). Written informed consent is required for participation. The results will be disseminated through the submission of an academic article to a high-impact scientific journal, presentations at academic conferences, and sharing with our institution's faculty to inform antimicrobial therapy management based on local epidemiological data. Trial registration number NCT06314399.

Objectives: To evaluate bile culture microbiology and factors associated with resistance patterns in patients taken to laparoscopic cholecystectomy to better guide empiric antibiotic therapy. Methods: Prospective cohort study with a logistic regression model in a middle-income public hospital network of two institutions. Inclusion criteria were patients taken to laparoscopic cholecystectomy over 18 years of age due to benign biliary disease without other concomitant surgical procedures taken to bile culture and antibiogram testing to evaluate bile culture positivity considered as a “resistant pattern”. Results: 226 cultures tested positive for at least one microorganism, and 218 were included in the study. Overall, bile cultures classified as resistant were associated with age, comorbidities, acute signs of cholecystitis, and longer antibiotic therapy. Bile microorganisms found consisted mostly of Enterobacteriaceae. In the logistic regression model, previous ERCP, Charlson comorbidity index and duration of antibiotic therapy yielded as statistically significant (p 0.03, p 0.003 and 0.004, respectively) for presenting resistant patterns. Conclusions: Patients taken to laparoscopic cholecystectomy have a higher probability of being resistant to empirical therapy for managing acute cholecystitis if they had a higher Charlson comorbidity index, previous ERCP and longer preoperative antibiotic therapy, and thus intraoperative cultures should be considered for guided antibiotic therapy. Trial registration number: NCT06314399.