Hepatic yersiniosis caused by Yersinia enterocolitica 4:O3 in an adult dog.

A 2-year-old Pekinese dog was diagnosed with hepatic yersiniosis. Grossly, white-to-yellow nodules consisting of degenerated inflammatory cells, cell debris, and bacterial clumps were scattered throughout the liver. Histopathologically, suppurative and necrotizing hepatitis was apparent. Yersinia enterocolitica biotype 4, serotype O3 (4:O3) was identified and confirmed in the liver immunohistochemically, using a monoclonal antibody. The virulence genes ystA and ail were detected, but the isolate was negative for autoagglutination and calcium-dependent growth. To confirm systemic yersiniosis in animals, it is imperative that the organism(s) be identified because the hepatic lesions are similar to those of Y. pseudotuberculosis and other diseases, including plague, which is also a zoonotic pathogen.