The Koch’s postulates

A case study of the Scientific Method

Robert Koch published a refinement on criteria for establishing causative nature of microbes and disease called Koch’s postulates. These criteria were first developed with Friedrich Loeffler and borrowed concepts described by Jakob Henle. Koch’s four criteria were first applied to describe the etiology of cholera and tuberculosis. The four criteria of Koch’s postulates are:

1. The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms.
2. The microorganism must be isolated from a diseased organism and grown in pure culture.
3. The cultured microorganism should cause disease when introduced into a healthy organism.
4. The microorganism must be re-isolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.