What is the primary organism responsible for tuberculosis?

Mycobacterium tuberculosis is the primary organism responsible for tuberculosis (TB). This bacterium is an acid-fast rod and is known for its slow growth and ability to survive in harsh conditions. Tuberculosis primarily affects the lungs but can also affect other parts of the body. It is transmitted from person to person through airborne particles, making it a significant public health concern in various parts of the world.

In the context of TB, Mycobacterium tuberculosis has several unique characteristics that enable it to evade the immune system, leading to chronic infections. The cell wall of this organism is rich in mycolic acids, providing a thick lipid barrier that makes it resistant to many common disinfectants and antibiotics, complicating treatment and control efforts.

Other options listed do not relate to tuberculosis. For instance, Streptococcus pneumoniae is primarily associated with pneumonia and meningitis, Listeria monocytogenes is known for causing listeriosis, particularly in pregnant women and immunocompromised individuals, and Escherichia coli mainly causes gastrointestinal infections and urinary tract infections. Therefore, Mycobacterium tuberculosis stands out as the sole organism responsible for tuberculosis.