# Bile Culture, Antimicrobial Susceptibility, and Hepatobiliary Pathology in Dogs Undergoing Cholecystectomy for Gallbladder Mucocele

## TL;DR

This study examines gallbladder disease in dogs, finding that some bacterial infections are resistant to antibiotics, emphasizing the importance of testing and careful treatment.

## Contribution

The study highlights the clinical relevance of bile culture and susceptibility testing in managing gallbladder disease in dogs.

## Key findings

- Bile culture was positive in 21.3% of dogs, with Escherichia coli and Enterococcus spp. being the most common isolates.
- Approximately 18% of isolates showed multidrug or extensive drug resistance.
- Toy Poodles were significantly over-represented among affected dogs.

## Abstract

Gallbladder mucocele is increasingly recognized in small-breed dogs. This retrospective study analyzed 65 dogs that underwent cholecystectomy at a veterinary referral hospital in Seoul, Korea, between 2022 and 2025. Toy Poodles were the most frequently affected breed. Preoperative abnormalities in liver enzyme activities and elevated C-reactive protein levels were common. Bile culture was positive in 21.3% of cases, and approximately 18% of isolates showed multidrug- or extensively drug-resistant patterns, most often Escherichia coli and Enterococcus spp. Although culture positivity was modest, clinically important antimicrobial resistance was identified. These findings highlight the value of bile culture and susceptibility testing in dogs with gallbladder disease and support the use of concurrent liver biopsy and careful perioperative management to enhance diagnostic assessment and guide individualized clinical decision-making.

Gallbladder mucocele is a major cause of biliary disease in dogs, particularly affecting elderly and small-breed populations. Background: This study retrospectively evaluated 65 dogs that underwent cholecystectomy at a referral hospital in Seoul, Korea, (2022–2025) to characterize clinical features, bile culture results, antimicrobial susceptibility, and histopathologic findings. Methods: Signalment, ASA grade, preoperative laboratory data, bile culture and susceptibility results, and postoperative outcomes were reviewed. Results: Bile culture was positive in 21.3% (13/61) of cases, most frequently isolating Escherichia coli 38.5% (5/13) and Enterococcus spp. 30.8% (4/13). Approximately 18% of isolates were multidrug- or extensively drug-resistant, showing reduced susceptibility to β-lactams but retained sensitivity to imipenem and florfenicol. Preoperative increases in liver enzyme activities and C-reactive protein were common. Histopathology revealed gallbladder mucosal hyperplasia 90.4% (47/52) and inflammation 61.5% (35/52), often accompanied by hepatic inflammation or fibrosis. Toy Poodles were significantly over-represented (35.4%; OR = 3.1, p < 0.001). Antibiotic matching was not significantly associated with complications or the length of hospital stay (LOS). Conclusions: Although the bile-culture positivity rate was modest, the frequent detection of multidrug-resistant (MDR) and extensively drug-resistant (XDR) organisms highlights the clinical value of culture-guided antibiotic therapy. Routine bile culture with susceptibility testing, concurrent liver biopsy, and careful perioperative management may improve diagnostic accuracy and outcomes in canine gallbladder disease.