Non-toxigenic Corynebacterium diphtheriae: two cases and review of the literature.

Non-toxigenic Corynebacterium diphtheriae infections are being reported with increasing frequency. We present two cases of C. diphtheriae endocarditis requiring early valve replacement. Both cases were complicated by cerebral embolic phenomena and pseudoaneurysm formation in lower limb arterial vessels. Non-toxigenic C. diphtheriae septicaemia must be excluded when 'diphtheroids' are isolated from blood cultures.