Mitral valve bacterial endocarditis in a dog

A four year old male Spitz dog was presented with approximately a month old history of progressive depression, inappetance and lethargy. Clinically investigation showed leukocytosis, neutrophilia and monocytosis. Rectal temperature was 103°F, both rate and effort of respiration were increased. Heart rate was 110 b. p. m. with a bounding pulse and an audible cardiac murmur over the left heart base. The animal collapsed the next day and a necropsy examination was carried out. Large vegetations approximately 1 centimeter across extending from the mitral valve into the left atrial mural endocardium was observed together with a large embolic fragment about 0.5 centimeter in length in the left ventricular chamber. The lungs appeared congested and infarcts were observed on the spleen and kidneys. Urinalysis at post-mortem showed mild proteinuria. Histologically, the vegetation was composed of an irregular, amorphous thrombo-necrotic mass embedded with colonies of gram positive beaded filamentous bacteria. Micrometry of bacterial filaments ranged from 21.3–85.2 micrometer in length. Although, bacterial isolation was not carried out, the morphological and staining characteristics were indistinguishable from Erysipelothrix sp. Cause of death was attributed to severe left cardiac failure.