Ultrasonographic Gallbladder Findings and Bile Culture Results in Dogs with Extrahepatic Biliary Disorders: A Retrospective Exploratory Case Series.

BACKGROUND

The role of bacterial infection in canine extrahepatic biliary disease remains inconsistently characterized. This retrospective case series evaluated associations between ultrasonographic gallbladder findings and bile culture results in dogs.

MATERIALS AND

METHODS

Sixty-seven dogs were screened between March 2024 and December 2025, of which 49 met inclusion criteria (clinical, biochemical, and ultrasonographic evidence of gallbladder disease) and underwent bile sampling by ultrasound-guided cholecystocentesis (n = 45) or intraoperative collection (n = 4). Samples were cultured aerobically and anaerobically; isolates identified by MALDI-TOF MS were further tested for in vitro antimicrobial susceptibility using Kirby-Bauer disk diffusion method.

RESULTS

Among the 49 included dogs, ultrasonography identified cholecystitis (75.5%), cholelithiasis (16.3%), and biliary mucocele (8.2%). Bile cultures were positive in 43/49 dogs (87.8%), yielding only aerobic bacteria. Escherichia coli (46.5%) and coagulase-positive Staphylococci (30.2%) were most frequently isolated organisms. However, these findings should be interpreted cautiously due to small subgroup sizes and the exploratory nature of the analysis.

CONCLUSIONS

In this selected referral population, bacterial isolates were frequently recovered from bile samples, particularly in dogs with cholecystitis. Prospective studies involving larger populations are warranted to confirm these results, define the bacterial prevalence and clinical significance of bacterial colonization or infection, and further refine evidence-based diagnostic and treatment strategies for dogs with extrahepatic biliary disease.