Tuberculosis (TB) is a contagious bacterial infection primarily caused by Mycobacterium tuberculosis. It primarily affects the lungs but can also involve other parts of the body, such as the kidneys, spine, and brain. TB is spread through the air when an infected person coughs or sneezes, releasing bacteria that others can inhale. While it can be treated effectively with antibiotics, drug-resistant strains pose a significant challenge to public health.