Recurrent endocarditis of a bicuspid aortic valve due to Q fever.

A 46-year-old man was referred to our institution for a recurrent endocarditis with negative blood culture. Clinical examination and complementary investigations confirmed the diagnosis of aortic valve endocarditis with left ventricular fistula. Blood culture was negative but serological tests were positive for Coxiella burnetti. Aortic valve replacement and fistula repair were done. A combination of Doxycycline and Chloroquine antibiotics was given postoperatively with a clinical improvement. Coxiella burnetti should be systemically searched for in all cases of endocarditis even with negative blood cultures. This case is interesting because of its rarity, diagnosis, therapeutic problems and its severe complication.