How did Robert Koch identify the bacterium that causes tuberculosis?

Robert Koch identified the bacterium responsible for tuberculosis by refining staining techniques to visualize the tubercle bacillus within the tissues of infected humans and animals.1

Although he initially struggled to grow the organism in a pure culture, he eventually succeeded by using a succession of growth media. To confirm the bacillus as the disease's cause, he inoculated animals with the isolated organism and successfully induced the disease, thereby establishing its etiologic role. On March 24, 1882, Koch formally announced his discovery to the Physiological Society of Berlin. This groundbreaking work in bacteriology earned him the Nobel Prize for Physiology or Medicine in 1905.12