Introduction to Mycobacterium tuberculosis
Classification of Mycobacterium tuberculosis:
Mycobacterium tuberculosis (MTB) is a bacterium that causes tuberculosis (TB), a potentially fatal infectious disease that primarily affects the lungs. TB is one of the leading causes of death worldwide, and it is estimated that approximately one-third of the world’s population is infected with MTB.
Classification of Mycobacterium tuberculosis
Mycobacterium tuberculosis belongs to the genus Mycobacterium, which is classified within the family Mycobacteriaceae. The genus Mycobacterium includes over 190 species of bacteria, many of which are pathogenic to humans, animals, and plants.
The classification of Mycobacterium tuberculosis is based on a variety of factors, including its morphology, physiology, and genetic makeup. The following sections will provide an overview of the classification of MTB.
Morphology
Mycobacterium tuberculosis is a rod-shaped bacterium with a length of approximately 2-4 micrometers and a width of approximately 0.2-0.5 micrometers. It is an acid-fast bacterium, which means that it retains the stain even after being treated with an acid-alcohol solution. This property is due to the presence of mycolic acid in its cell wall, which makes it resistant to many chemical and physical agents.
Physiology
Mycobacterium tuberculosis is an obligate aerobe, which means that it requires oxygen to grow. It grows best at a temperature of 37°C, which is the normal body temperature of humans. It is a slow-growing bacterium, with a generation time of approximately 24 hours.
Genetics
Mycobacterium tuberculosis has a complex genetic makeup, with a genome size of approximately 4.4 million base pairs. It has a high GC content, which makes it difficult to sequence and analyze. The genome of MTB contains many unique genes that are not found in other bacteria, which are thought to be involved in its pathogenicity.
Subspecies and Strains
Mycobacterium tuberculosis is divided into several subspecies based on genetic differences. These subspecies include:
- M. tuberculosis sensu stricto: This subspecies is responsible for the majority of human TB cases worldwide.
- M. africanum: This subspecies is primarily found in West Africa and is responsible for a small percentage of TB cases.
- M. bovis: This subspecies primarily infects cattle but can also infect humans.
- M. microti: This subspecies primarily infects rodents but can also infect humans.
- M. canettii: This subspecies is rare but has been found in some TB cases in Africa and Asia.
Within each subspecies, there are also different strains of Mycobacterium tuberculosis. These strains can be differentiated based on genetic differences and can also have different virulence and drug resistance profiles.
Conclusion:
Mycobacterium tuberculosis is a complex bacterium that is responsible for causing tuberculosis, a serious infectious disease that affects millions of people worldwide. The classification of MTB is based on a variety of factors, including its morphology, physiology, and genetics. Understanding the classification of MTB is essential for developing effective strategies for the prevention and treatment of TB.
What are the 4 types of Mycobacterium tuberculosis?
Tuberculosis was found in a genetically related complex group of Mycobacterium species called Mycobacterium tuberculosis complex that has at least 9 members:
- tuberculosis sensu stricto.
- africanum.
- canetti.
- bovis.
- caprae.
- microti.
- pinnipedii.
- mungi.
