Coryneform bacteria (“diphtheroids”) are ubiquitous in nature. They are found on human skin and mucous membranes, on plants, in soil, and in freshwater and saltwater. Humans are the only known reservoir of C. diphtheriae, although a novel strain was isolated from cats in West Virginia.

Are diphtheroids normal flora?

Diphtheroids have traditionally been considered part of the normal Page 2 commensal flora of the skin and mucous membranes of the respiratory tract, urinary tract and conjuctiva. In fact, about 12-30% of humans carry C. urealyticum as part of their normal skin flora.

Where does Corynebacterium come from?

Habitat. Corynebacterium species occur commonly in nature in soil, water, plants, and food products. The nondiphtheiroid Corynebacterium species can even be found in the mucosa and normal skin flora of humans and animals.