Mycobacterium tuberculosis complex

Mycobacterium tuberculosis complex refers to a genetically related group of Mycobacterium species that can cause tuberculosis in humans or other organisms.

It includes:

In addition, two branches exist which have phylogenetic similarities but are not completely described: the dassie and oryx bacilli.

References

Mycobacterium tuberculosis

Mycobacterium tuberculosis is an obligatepathogenic bacterial species in the family Mycobacteriaceae and the causative agent of most cases of tuberculosis. First discovered in 1882 by Robert Koch, M. tuberculosis has an unusual, waxy coating on its cell surface (primarily due to the presence of mycolic acid), which makes the cells impervious to Gram staining; M. tuberculosis can appear Gram negative and Gram positive in clinical settings. The Ziehl-Neelsen stain, or acid-fast stain, is used instead. The physiology of M. tuberculosis is highly aerobic and requires high levels of oxygen. Primarily a pathogen of the mammalian respiratory system, it infects the lungs. The most frequently used diagnostic methods for tuberculosis are the tuberculin skin test, acid-fast stain, and chest radiographs.

The M. tuberculosis genome was sequenced in 1998.

Pathophysiology

M. tuberculosis requires oxygen to grow and can be cultured in the laboratory. It does not retain any bacteriological stain due to high lipid content in its wall, hence Ziehl-Neelsen staining, or acid-fast staining, is used. Mycobacteria have an outer membrane.