Cluster of Nontoxigenic Corynebacterium diphtheriae Infective Endocarditis and Rising Background C. diphtheriae Cases—Seattle, Washington, 2020–2023

Nontoxigenic Corynebacterium diphtheriae, often associated with wounds, can rarely cause infective endocarditis (IE). Five patients with C. diphtheriae IE were identified within 12 months at a Seattle-based hospital system. We reviewed prior C. diphtheriae-positive cultures to determine if detections had increased over time and evaluated epidemiologic trends.