A mechanic with a bad valve: blood-culture-negative endocarditis

A 33-year-old man with a known bicuspid aortic valve presented with fever, chills, progressive fatigue, anorexia, and night sweats. Echocardiography confirmed aortic-valve endocarditis, but blood cultures remained negative. Bartonella henselae endocarditis was ultimately confirmed by serology as well as by immunohistochemistry and PCR testing of the excised valve. The patient recovered with appropriate antibiotic therapy. B henselae is a common cause of culture-negative endocarditis. It predominantly affects men with underlying valvular disease, and has a predilection for aortic valves. Diagnosis is usually made serologically and with either tissue culture, immunohistochemistry, or PCR. Treatment of this destructive endocarditis consists of a combination of long-term antibiotic therapy and surgical valve repair. This case is used to discuss the approach towards the treatment of patients with endocarditis that is blood-culture negative.