MYCOBACTERIUM

Gram-negative and gram-positive bacteria are themost common types of bacteria in most soil habitats. Only two genera of bacteria, Mycobacterium and Nocardia, are known to have an acid-fast envelope (5). Mycobacterium and Nocardia are present in many soils, and several species are pathogenic to animals or humans. Both groups are classified with the actinomycetes, a distinctive group of soil bacteria.

Mycobacterium is a bacterium which produces and gives out an easily detectable amount of niacin into an agar medium. It is a member of a group of bacteria which include human pathogens responsible for diseases like tuberculosis or leprosy.