Impact of Antimicrobial Resistance on Outcomes in Biliary Tract Infections: A Retrospective Study from a Tertiary Care Center

Abstract

Biliary tract infections (BTI) are common intra-abdominal infections associated with significant morbidity and mortality. We aimed to evaluate the causative agents of BTIs, their resistance profiles, and factors associated with resistant infections and mortality. This retrospective study included patients aged ≥18 years who had bile cultures obtained for BTI between January 2022 and January 2024 in a tertiary health-care center. A total of 148 bile cultures from 101 patients were analyzed. Pathogens were identified in 73% of the cultures; Escherichia coli and Enterococcus spp. were the most common pathogens. Extended-spectrum β-lactamase (ESBL) production was detected in 37.3% of Enterobacterales isolates, and ampicillin resistance was observed in 50% of enterococci. Among all identified pathogens, 31 (28.7%) were resistant microorganisms. The 30-day mortality rate was 13% and was significantly higher in patients with resistant infection, health care-associated infection, or malignancy. In multivariate analysis, resistant infections were associated with an eightfold increase in mortality. Currently antimicrobial resistance is becoming one of the leading causes of death. Resistant pathogens were frequently identified, even in community-acquired infections, and were associated with a significant increase in mortality. It is crucial to identify factors influencing resistant infections and mortality for optimizing empirical treatment strategies.