Acute Calculous Cholangitis: Causative Aerobic Bacteria and Antibiotic Susceptibility Patterns from a Retrospective Multicenter Study in Vietnam

Background: Acute calculous cholangitis is commonly associated with biliary tract infections and is predominantly caused by enteric bacteria. Increasing antimicrobial resistance, particularly among extended-spectrum β-lactamase (ESBL)-producing Gram-negative organisms, has become a major concern in Southeast Asia, including Vietnam. Updated local microbiological data are essential to guide appropriate empirical antibiotic therapy. Methods: This retrospective multicenter study analyzed clinical and microbiological data from patients diagnosed with acute calculous cholangitis. Bacterial culture results were collected from Hanoi Medical University Hospital, Thanh Nhan Hospital, and E Hospital between June 2022 and December 2024. Results: Gram-negative bacteria were predominant (286/366, 78.14%), while Gram-positive bacteria accounted for 80/366 (21.86%). Escherichia coli was the most frequently isolated organism (133/366, 36.34%), of which 77/133 (57.89%) were ESBL producing. Klebsiella spp. accounted for 60/366 (16.39%), with 17/60 (28.33%) ESBL-producing isolates. Enterococcus spp. (n = 80) exhibited high susceptibility to vancomycin (69/80, 86.15%) and complete susceptibility to linezolid (80/80, 100%). Conclusions: This multicenter study highlights evolving pathogen distributions and antimicrobial resistance patterns in acute calculous cholangitis in Vietnam. These findings provide valuable evidence to support the optimization of empirical antibiotic regimens in clinical practice.