Prevalence of bactibilia in apparently healthy dogs

Abstract

Bacterial cholecystitis in dogs is a histological diagnosis, however in clinical practice bactibilia accompanying bacterial cholecystitis is usually diagnosed based on a combination of bile cytology findings and the isolation of bacteria on bile culture. There is currently a paucity of data available regarding the prevalence of bactibilia in healthy dogs and its subsequent clinical implications. The association between raised liver enzymes and bactibilia, as well as the value of bile culture in determining the likelihood of clinically significant cholecystitis in dogs with suspected biliary disease is unknown. The aims of this study were to a) determine the prevalence of asymptomatic bactibilia in apparently healthy dogs; b) determine if differences between bactibillic and non-bactibillic healthy dogs occur with regards to serum liver enzymes alkaline phosphatase (ALP), alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) activities; and c) determine if differences between bactibillic and non-bactibillic healthy dogs occur with regards to liver and gallbladder histopathology. A cross-sectional, prospective study was performed at the Animal Anti-Cruelty League Epping. Sixty-five apparently healthy, abandoned dogs euthanased for non-medical reasons were used. Whole blood, aspirated bile, gallbladder wall and liver section samples were collected aseptically from all dogs within 25 minutes of euthanasia. Bile samples of all dogs involved in the study were submitted for cytology as well as aerobic and anaerobic culture. After determining the prevalence of bactibilia, sectioned gallbladder wall and liver samples from all dogs with bactibilia and from 9 dogs without bactibilia (control group) were submitted for histopathological evaluation. Measurement of ALP, ALT and GGT was performed on all blood samples. Bactibilia was present in 10.77% (7/65) of dogs, with a diagnosis in 9.23% (6/65) of dogs made on cytology and 4.62% (3/65) on bile culture. There was weak agreement between bile cytology and culture (0.408, Cohens kappa; p = 0.001; CI (0.007, 0.824)). No significant differences in median liver enzyme activities and hepatobiliary histopathology were found between the bactibilic and non-bactibilic dogs in this study. However, the possibility of these differences existing in the population could not be excluded based on the results of this study. The reasons for these differences possibly not being identified in this study include the study being underpowered, the cross-sectional nature of the study with median liver enzyme activities and hepatobiliary histopathology only evaluated at a single point in time, and the collection of hepatobiliary histopathology samples after euthanasia which may have led to the histopathological findings not being reflective of liver and gallbladder pathology in the apparently healthy dog population. This study showed that the prevalence of bactibilia in asymptomatic dogs is 10.77%. Further studies are needed to determine if significant differences in median liver enzyme activities and hepatobiliary histopathology are present between the bactibilic and non-bactibilic dogs.