Enterococcus faecalis–associated infective aortic endocarditis as a cause of arterial thromboembolism in a cat

Infective endocarditis (IE) is a rare but potentially fatal cause of feline arterial thromboembolism (ATE), most commonly affecting the mitral or aortic valves. Although Enterococcus faecalis is rarely reported in cats, it can induce severe endocardial infection and systemic embolic complications. This case report describes a one-year-old neutered male British Longhair cat that presented with acute hindlimb paralysis and dyspnoea lasting one day. The cat had a three-month history of lower urinary tract infection, but no known cardiac disease. On admission, all the classical signs of arterial obstruction were evident. Laboratory tests revealed neutrophilic leukocytosis and markedly increased serum amyloid A, indicating systemic inflammation. Echocardiography revealed thickened aortic valve leaflets with irregular vegetations and severe regurgitation, with no evidence of intracardiac thrombus. Left ventricular systolic function assessed by two-dimensional speckle-tracking echocardiography was mildly reduced compared with reference values. Blood culture confirmed the presence of E. faecalis, which was susceptible to β-lactams but intrinsically resistant to cephalosporins. Initial empirical therapy included furosemide, low-molecular-weight heparin, and broad-spectrum antibiotics. This was later adjusted to ampicillin–sulbactam, and metronidazole upon receiving the culture results. This report emphasises the importance of considering xone,E. faecalis-associated infective aortic endocarditis in the diagnostic and therapeutic evaluation of feline ATE cases.