Synonyms: Opportunistic Mycobacterial Infection, Non-tuberculous Mycobacterial Infection. This is an uncommon infection, more frequently seen in the cat than the dog. It occurs secondary to traumatic implantation of the organisms. The most common mycobacteria that can be isolated are M. fortuitum and M. chelonei. This is the picture of a cat with several ulcerated dermal and subcutaneous nodules.