Subacute infectious endocarditis due to the agent of cat scratch fever: Bartonella Henselae.

The diagnosis of severe mitral stenosis with left atrial thrombus was recti fied at valvular replacement in a 48-year old immune-competent man who was a cat owner. The mass in the left atrium was, in fact, a large endocarditic vegetation. Pre- and postoperative blood cultures were negative as was cul ture of the excised mitral valve. The diagnosis of infectious endocarditis (IE) due to Bartonella Henselae was made from a positive serological test ( 1600) and identification of the germ by genetic amplification. Antibiotic t herapy was continued for 6 months and the patient was cured with a follow-u p of 4 years. Bartonella Henselae IE is very rare (14 reported cases) and affects mainly the aortic valve, often giving rise to very large vegetations which, in hal f the cases, are complicated by systemic emboli. Germs like Batonella are s ensitive to most antibiotics, especially the aminosides and macrolides. In Bartonella Henselae IE, valve replacement is the rule (13 out of 14 cases) and the prognosis is usually good. Sero-diagnosis of Bartonellosis should be part of the systematic investigat ion of all blood culture negative IE.