growth of mycobacterium

The most important pathogen, M. tuberculosis, shows enhanced growth in 10% carbon
dioxide and at a pH of about 6.5 to 6.8. Nutritional requirements vary among species
and range from the ability of some nonpathogens to multiply on the washers of water
faucets to the strict intracellular parasitism of M. leprae, which does not grow in artificial media or cell culture. Mycobacteria grow more slowly than most human pathogenic bacteria because of their hydrophobic cell surface, which causes them to clump and inhibits permeability of nutrients into the cell. Addition of a surfactant (Tween 80) to cultures of M. tuberculosis wets the surface and leads to dispersed and more rapid growth.