Why did Robert Koch receive the 1905 Nobel Prize in Physiology or Medicine?

German physician Robert Koch, one of the founders of bacteriology, was awarded the 1905 Nobel Prize in Physiology or Medicine specifically for his groundbreaking research and discoveries regarding tuberculosis.12

In 1882, Koch successfully isolated and identified the tubercle bacillus as the causative agent of the disease. He achieved this by modifying staining methods and eventually growing the organism in pure culture, subsequently proving its etiologic role by inducing the disease in animal models. While his later development of tuberculin as a potential curative agent proved unsuccessful, his fundamental work in identifying the pathogen transformed the medical understanding of tuberculosis and laid the groundwork for future diagnostic and preventive measures.3