Culture-negative endocarditis caused by Bartonella henselae.

A 4-year-old girl presented with clinical evidence of infective endocarditis involving her aortic valve, but blood cultures were sterile. Serologic studies and analysis of resected valve by immunohistochemistry and polymerase chain reaction established the diagnosis of Bartonella henselae endocarditis. Clinicians should be aware that B. henselae can cause apparent culture-negative endocarditis in children.