Nontoxigenic highly pathogenic clone of Corynebacterium diphtheriae, Poland, 2004-2012.

Twenty-five cases of nontoxigenic Corynebacterium diphtheriae infection were recorded in Poland during 2004-2012, of which 18 were invasive. Alcoholism, homelessness, hepatic cirrhosis, and dental caries were predisposing factors for infection. However, for 17% of cases, no concomitant diseases or predisposing factors were found.