General Information: Causes opportunistic infections. This genus comprises a number of Gram-positive, acid-fast, rod-shaped aerobic bacteria and is the only member of the family Mycobacteriaceae within the order Actinomycetales. Like other closely related Actinomycetales, such as Nocardia and Corynebacterium, mycobacteria have unusually high genomic DNA GC content and are capable of producing mycolic acids as major components of their cell wall. Mycobacterium smegmatis was initially isolated from human smegma. It is associated with soft tissue lesions following trauma or surgery. It is also reported as a possible factor in penile carcinogenesis.