Heinrich Hermann Robert Koch (December 11, 1843 - May 27, 1910) was a German physician. He became famous for the discovery of the tubercle bacillus (1882) and the cholera bacillus (1883) and for his development of Koch's postulates. He was awarded the Nobel Prize in Physiology or Medicine in 1905. He is considered one of the founders of bacteriology.
After Casimir Davaine showed the direct transmission of the anthrax bacillus between cows, Koch studied anthrax more closely. He invented methods to purify the bacillus from blood samples and grow pure cultures. He found that, while it could not survive outside a host for long, anthrax built persisting spores that could last a long time. These spores, embedded in soil, were the cause of unexplained "spontaneous" outbreaks of anthrax. Koch published his findings in 1876, and was rewarded with a job at the Imperial Health Office in Berlin in 1880.
In Berlin, he improved the methods he used in Wollstein, including staining and purification techniques, and bacterial growth media, including agar plates and the Petri dish (named after R.J. Petri), both of which are still used today. With these techniques, he was able to discover the bacterium causing tuberculosis (mycobacterium tuberculosis) in 1882 (he announced the discovery on March 24). Tuberculosis was the cause of one in seven deaths in the mid-19th century. The importance of his findings raised Koch to the level of Louis Pasteur in bacteriological research.
In 1883, Koch worked with a French research team in Alexandria, Egypt, studying cholera. Koch identified the vibrio bacterium that caused cholera, though he never managed to prove it in experiments. In 1885, he became professor for hygiene at the university of Berlin, and later, in 1891, director of the newly formed Institute of Infectious Diseases, a position which he resigned from in 1904. He started traveling around the world, studying diseases in South Africa, India, and Java.
Probably as important as his work on tuberculosis, which he was awarded a Nobel Prize for, are the Koch's postulates, which say that to establish that an organism is the cause of a disease, it must be :
- found in all cases of the disease examined
- prepared and maintained in a pure culture
- capable of producing the original infection, even after several generations in culture
- could be retrieved from an inoculated animal and cultured again.
He died in Baden-Baden, Germany.