Tuberculosis Bacteria

Scanning electron micrograph of Mycobacterium tuberculosis

Latin Name
Mycobacterium tuberculosis (MTB)
Common Name
Tuberculosis Bacteria
2 to 4 ┬Ám
Doubling Time
15 to 20 hours

Phylum Actinobacteria

  • actinobacteria are important for the decomposition of organic material (ex. cellulose and chitin)
  • some actinobacteria inhabit plants and humans
  • well known as secondary metabolites (organic compounds not directly involved in growth or reproduction of organisms)
  • most are aerobic
  • some are responsible for the strange odor from the soil after rainfall

About Tuberculosis Bacteria

Mycobacterium tuberculosis (MTB) is a pathogen and the causative agent of Tuberculosis. It is a small bacillus that lacks an outer cell membrane, and requires high levels of oxygen to grow (obligate aerobe). MTB is a pathogen of the
respiratory system in mammals. It infects human lungs. MTB divides every 15 to 20 hours, which is very slow compared to other bacteria.

A unique feature of MTB is its capability of withstanding weak disinfectants.This could possibly be due to its high lipid content of its cell wall. It has an unusual, waxy coating on the cell surface. MTB can also survive in a dry state for weeks.

In the lungs, MTB is attacked by white blood cells, but they are unable to digest them. The
fusion of the phagosome with a lysosome is prevented by its cell wall (blocks the bridging molecule). However, this does not prevent the fusion of vesicles filled with nutrients. MTB prevents the acidification of the phagosome through the UreC gene it carries.

Hypervirulent strains of MTB often cause outbreaks of Mycobacterium. Studies have shown that deletions in the cell wall of the majority of these hypervirulent mutants, modify enzymes that respond to environmental stimuli. These mutants have the ability to create a protective niche that enables the bacteria to sustain a long-term persistent infection.

Range on Earth

Population infected with tuberculosis

Interesting Facts

MTB may lie dormant in the body for many years. It has been estimated that only approximately 10% of people infected with MTB develop tuberculosis.

The leading cause of death in the world from a bacterial infectious disease is tuberculosis. 1.8 billion people are affected per year by this disease. This is almost equal to one third of the entire world's population!


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(2010, November 11). Mycobacterium tuberculosis. Retrieved from