Biliary samples in dogs with surgically managed cholelithiasis often yield positive bacterial cultures

Objective To describe the prevalence of positive bacterial culture and associated bacterial species in 45 dogs with surgically managed cholelithiasis. Methods Medical records of dogs from a multicenter small-animal specialty surgical private practice treated surgically for cholelithiasis from January 1, 2010, through December 31, 2020, were evaluated. For this descriptive observational study, medical records were retrospectively reviewed to identify dogs with culture and susceptibility testing. Dogs were included if they had an extrahepatic biliary surgery for a diagnosis of cholelithiasis and results of culture and susceptibility testing. Prior antimicrobial use, specific surgical procedure performed, bacterial culture type and source, organisms isolated, and antimicrobial resistance phenotypes were evaluated. Prevalences of positive culture and antimicrobial phenotypes were recorded. Results 45 dogs met inclusion criteria. Twenty-four of 45 dogs (53%) had a positive bacterial culture. Seven of 24 positive cultures (29%) were polymicrobial. The most common bacterial isolates were Escherichia coli and Enterococcus spp. Seven of 32 isolates (22%) were considered multidrug-resistant organisms (MDROs). Prior antimicrobial use was not significantly associated with the presence of a positive culture result, a culture including an MDRO, or an isolate being classified as an MDRO. Conclusions Nearly half of dogs undergoing surgery for cholelithiasis had positive biliary cultures. Nearly a fourth of detected bacterial isolates were classified as MDROs. Clinical Relevance Perioperative antimicrobial use may be indicated in dogs with surgically managed cholelithiasis. Previous antimicrobial use does not appear to be associated with the presence of multidrug resistance.