Corynebacterium diphtheriae endocarditis.

Two patients with Corynebacterium diphtheriae endocarditis have been observed in the past ten years. Both cases occurred sporadically. In one case toxigenic C. diphtheriae caused endocarditis in an immunized child with congenital heart disease. The second patient developed rapidly progressive valve destruction caused by a nontoxigenic strain of C. diphtheriae. These cases illustrate that C. diphtheriae may produce endocarditis in addition to its previously described diseases spectrum.