Corynebacterium ulcerans

Corynebacterium ulcerans is a rod-shaped, aerobic, and Gram-positive bacterium. Most Corynebacterium species are harmless, but some cause serious illness in humans, especially in immunocompromised humans. C. ulcerans has been known to cause diphtheria and diphtheria-like infections in patients. Previously thought to simply be contaminants recovered from diphtheria patients, “coryneform” or “diphtheroids” are now believed to be the cause of such infections.