Mycobacterium tuberculosis is the bacterium that causes tuberculosis (TB). It is a slow-growing aerobic bacterium with a lipid-rich cell wall containing mycolic acid. TB is transmitted via airborne droplets when people with active TB disease cough, sneeze or spit. Symptoms include cough, fever, fatigue and weight loss. TB is treated with a combination of antibiotics taken over 6-9 months to combat drug-resistant strains. While the BCG vaccine is used in high prevalence countries, it is not recommended in the US due to low risk and variable effectiveness.