Infective endocarditis due to non-toxigenic Corynebacterium diphtheriae in a child. A case report.

A case of infective endocarditis (IE) in a 5 1/2-year-old boy in whom blood and bone marrow cultures yielded an unusual organism, a non-toxigenic strain of Corynebacterium diphtheriae, is reported. This proved fatal, and at autopsy congenital valvar aortic stenosis was found, but the vegetations occurred on an anatomically normal mitral valve. Organisms such as C. diphtheriae should not be ignored when isolated from blood cultures in suspected cases of IE.