Acute cholangitis is a significant cause of mortality and morbidity, particularly in elderly patients and those with comorbidities. However, the optimal duration of antibiotic therapy following biliary drainage remains unclear. This study aimed to evaluate clinical outcomes based on the duration of antibiotic therapy after successful biliary drainage in adults with acute cholangitis.

We conducted a retrospective cohort study of patients treated for acute cholangitis at a university hospital in Colombia between 2014 and 2022. Short-course antibiotic therapy was defined as ≤4 days after successful post-ERCP drainage. The primary outcome was a composite of in-hospital mortality, ICU admission, or hospital readmission within 30 days of discharge. Univariate and multivariate logistic regression analyses were performed to examine the association between antibiotic duration and the primary outcome.

All in all, 317 patients were included. Escherichia coli was the most frequently isolated microorganism, with 54 % manifesting full antimicrobial susceptibility. Fifty-nine patients received short-course therapy, while 258 received long-course therapy. There were no significant differences in the primary outcome between the groups (p = 1). However, longer hospital stays were observed in the long-course group (p  <  0.001). Tokyo III severity (OR 32.07; 95 % CI 11.84–113.16; p  <  0.001) and carbapenem resistance (OR 4.07; 95 % CI 1.02–16.96; p = 0.04) were identified as independent risk factors for the composite outcome.

Shorter antibiotic courses following ERCP drainage may be a viable option for patients with acute cholangitis. Further randomized controlled trials and pragmatic studies are necessary to confirm these findings.