Endocarditis is a rare but serious complication of brucellosis. We report h
ere a case of Brucella abortus endocarditis occurring on a prosthetic mitra
l valve. The diagnosis was established by positive serology, the presence o
f vegetation on the mitral prosthesis and isolation of B. abortus from the
blood and valve cultures. The patient was successfully treated with combine
d medical and surgical therapy.