Non-toxigenic tox gene-bearing Corynebacterium ulcerans in a traumatic ulcer from a human case and his asymptomatic dog

A non-toxigenic tox gene-bearing (NTTB) Corynebacterium ulcerans was grown from the wound of a 61-year-old gardener and in a nasal specimen from the patient's asymptomatic dog. The two isolates were similar in terms of antibiogram, multilocus sequence typing (ST341), virulence genes, and only three SNPs were found to differentiate the two NTTB C. ulcerans isolates supporting a zoonotic transmission to or between the patient and his dog. Of interest, we found that the two C. ulcerans isolates, although not expressing the diphtheria toxin tox, possessed 13 out of 14 recently described virulence candidate genes.