CSIRNET LIFESCIENCES: KOCH'S POSTULATES

KOCH'S POSTULATES

First Direct Demonstration of the Role of Bacteria in causing disease came from the study of anthrax by the German physician Robert Koch (1843–1910).

Figure 1.6 Robert Koch. Koch (1843–1910) examining a
specimen in his laboratory

Koch used the criteria proposed by his former teacher, Jacob Henle (1809–1885), to establish the relationship between Bacillus anthracis and anthrax, and published his findings in 1876 (Techniques &Applications 1.1 briefly discusses the scientific method)

Koch injected healthy mice with material from diseased animals, and the mice became ill.
After transferring anthrax by inoculation through a series of 20 mice, he incubated a piece of spleen containing the anthrax bacillus in beef serum. The bacilli grew, reproduced, and produced endospores.
When the isolated bacilli or their spores were injected into mice, anthrax developed.
His criteria for proving the causal relationship between a microorganism and a specific disease are known as Koch’s postulates (table 1.1).
Koch’s proof that B. anthracis caused anthrax was independently confirmed by Pasteur and his coworkers.
They discovered that after burial of dead animals, anthrax spores survived and were brought to the surface by earthworms. Healthy animals then ingested the spores and became ill.
Although, Koch used the general approach described in the postulates during his anthrax studies, he did not outlined them fully until his work on the cause of tuberculosis (table 1.1).
In 1884, he reported that this disease was caused by a rod-shaped bacterium, Mycobacterium tuberculosis; he was awarded the Nobel Prize in Physiology
or Medicine in 1905 for his work.
Koch’s postulates quickly became the cornerstone of connecting many diseases to their causative agent. However, their use is at times not feasible (Disease 1.2).
some organisms, like Mycobacterium leprae, the causative
agent of leprosy, cannot be isolated in pure culture