Robert Koch
Founder of Medical Bacteriology
Koch was born in Klausthal-Zellerfeld, Germany, on December 11, 1843. He studied botany, physics, and mathematics at the University of Göttingen, graduating in 1866. After briefly running a private medical practice, he served from 1870 to 1871 as a field surgeon in the FrancoPrussian War. He then became a district surgeon at Wollstein, Germany, and led the life of a smalltown doctor. After his wife gave him a microscope for a birthday gift, however, he neglected his practice. He built a laboratory in his home, where he began to investigate pathogenic (disease causing) organisms.
Friedrich Henle, who in 1840 had been among the first to suggest that many diseases are caused by microscopic organisms, was one of Koch’s instructors at Göttingen. Koch had embraced Henle’s idea. In 1876, Koch announced the results of studies on anthrax: he had isolated the anthrax bacterium and shown that it multiplies via spores that can remain dormant yet infectious for years. It was the first time that a bacterium had been demonstrated definitively to cause a specific disease. Koch theorized that each infectious disease has its own particular bacterium as its cause—a new idea in medicine.
Koch introduced and improved methods for the isolation and cultivation of microorganisms in the laboratory. Using microscopes, microtomes (tools for cutting microscope specimens), incubators, and nutrient solutions, he observed microorganisms’ complete life cycles. He applied his laboratory techniques to the study of wounds, isolating the microorganisms responsible for several types of infection. He experimented with stains, which make the smallest microbes visible, and then took photographs of the microbes.
In 1881 Koch began to study tuberculosis, a disease that was responsible for one in seven deaths in Europe at that time. He successfully isolated the tuberculosis bacterium in 1882. In 1883 he traveled to India (where cholera was epidemic), identified the cholera bacterium, and showed that it is transmitted primarily through drinking water.
In the 1890s, Koch broadened his research to include leprosy, rinder pest, bubonic plague, surra, Texas fever, and malaria. In 1905 he won the Nobel Prize for Physiology or Medicine for his work on tuberculosis. He died in BadenBaden, Germany, on May 27, 1910.
Robert Koch’s Legacy
Koch’s investigations of bacteria revolutionized the understanding of infectious disease and led to improvements in public health.
Koch’s work crystallized the theory that infectious diseases are caused by microorganisms. This theory was first put forth in the 1830s and 1840s, but scientists were reluctant to accept it and held fast to the predominant idea that bad air was responsible for disease. In the 1860s, LOUIS PASTEUR, JOSEPH LISTER, and others made strides toward proving the microorganism theory. Koch’s demonstration that a bacterium causes anthrax convinced nonbelievers of the theory’s accuracy.
Within 15 years of Koch’s discovery of the anthrax bacterium, the bacterial agents of numerous diseases were identified. A school of adept students trained in Koch’s effective lab techniques flourished around him and inaugurated the field of medical bacteriology. By 1892 the organisms responsible for typhoid, pneumonia, diphtheria, colic, meningitis, and salmonella had been identified.
A groundbreaking advance in public health evolved from Koch’s studies of the tuberculosis and cholera bacteria. An effective method of diagnosing the presence of tuberculosis developed immediately, and, as cases could be identified at earlier stages, the spread of the infection slowed. Koch’s identification of drinking water as the primary mediator of cholera led to a drop in cholera infections.
Koch’s work established the modern criteria (now known as Koch’s postulates) for determining that a specific organism causes a particular disease. The criteria include: the organisms presence in every examined case of the disease; the preparation of a laboratory culture of the organism; and the ability of the culture to remain infectious through several generations. The set of criteria remains a helpful tool in battling new, unknown, and uninvestigated diseases.
Robert Koch – 1843-1910