Mycobacterium tuberculosis is a member of the Mycobacteriaceae family and belongs to the Actinobacteria phylum. With around 190 known species, this bacterium has earned its name from the Greek word “myco,” meaning fungus, due to its resemblance to fungi on surface cultures. Throughout history, M. tuberculosis has posed a significant threat to humanity. Archaeological findings and bone examinations indicate its existence worldwide for over 4,000 years. As the primary cause of tuberculosis or TB, Mycobacterium tuberculosis is responsible for nine million cases and one million deaths annually.
Structure of Mycobacteria
Mycobacteria are characterized by their bacillary form, appearing as straight or slightly curved rods. Additionally, these bacteria have the ability to form capsules, which are large structures that surround the bacteria outside of the cell wall. These capsules contain a substance called amorphous viscid, which has the potential to diffuse into the surrounding area. When this diffusion occurs, it can lead to the formation of a slime layer, which may contribute to the development of illnesses. The combination of the capsule and slime layer forms a glycocalyx in mycobacteria.
Capsule and its Significance in Mycobacterium Tuberculosis
The capsule of Mycobacterium tuberculosis has a crucial role to play in the bacterium’s resistance to antibiotics and overall resilience. This protective layer provides bacteria with a distinct advantage upon entering the human body, enhancing their potential to cause illnesses. By cloaking themselves with capsules, bacterial cells can be engulfed by macrophages, a type of immune cell, without being destroyed. Moreover, capsules serve as a shield for bacterial cells in the environment, preventing them from detrimental effects. The water present within the capsule ensures that the bacterial cell does not undergo dessication or drying out. Additionally, certain capsules act as barriers against bacterial viruses and other harmful substances, safeguarding the integrity of the cell.