Vegetative Endocarditis and Thrombus Formation Associated with Escherichia coli in a Thoroughbred Horse

A 1-year and 8-month-old male, thoroughbred horse showed fever ($39.8^{\circ}C$), cardiac murmur, tachycardia up to 80 beats/min, anorexia, depression and lameness for about 2 months. The dead horse was referred to pathology laboratory at the College of Veterinary Medicine in Jeju National University. At necropsy, Severe protruding multiple rough cauliflower-like yellowish red nodules ranged $5{\sim}6{\times}2{\sim}3cm$ in size were attached on the mitral valve of the left heart. A yellowish red long stick-shaped thrombus $15{\times}3.5{\times}1.5cm$ in size was also present inside the right ventricle. Multifocal infarcts were scattered in the myocardium and renal cortex. Histopathologic examination revealed that morphologic diagnosis were vegetative endocarditis, thrombus in right ventricle, infarcts in myocardium and kidney, pulmonary congestion and edema, and splenic congestion. The isolated bacteria from vegetative lesions and thrombus were confirmed as Escherichia (E.) coli based on the bacterial culture and VITEK 2 system. Based on the gross and histopathologic features, and bacterial test, this case was diagnosed as vegetative endocarditis with thrombus formation associated by E. coli in a thoroughbred horse.