Biliary Microbiology and Antimicrobial Treatment Modification in Patients Undergoing Percutaneous Cholecystostomy for Acute Cholecystitis: A Single-Centre Retrospective Cohort Study.

Objective: To describe bile culture yield, organism distribution and antimicrobial treatment modification in patients undergoing percutaneous cholecystostomy (PC) for acute cholecystitis who were unsuitable for early cholecystectomy. Methods: We retrospectively reviewed 84 consecutive patients who underwent PC between December 2021 and December 2025. Index bile cultures were classified as positive, no growth, or not obtained. We analysed organisms, polymicrobial growth, empirical antimicrobial therapy, treatment modification and clinical outcomes by culture status and disease severity. Results: Bile was cultured in 71 patients (84.5%), and 33 cultures were positive (46.5% of sampled patients; 39.3% of the cohort). Seven positive cultures (21.2%) were polymicrobial. The leading isolates were Conclusion: Bile obtained during PC had a substantial microbiological yield and grew predominantly enteric organisms. Treatment modification was more frequent in clinically severe disease, but no statistically significant difference was detected between positive-culture and no-growth groups. Bile culture should inform a structured reassessment of antimicrobials after source control, rather than automatic treatment escalation.