Koch’s postulates

Definition

Koch’s postulates are a set of criteria established by Robert Koch to identify the causative agent of a particular disease. They are used to demonstrate that a specific microorganism causes a specific disease.

5 Must Know Facts For Your Next Test

1. Koch’s postulates require the microorganism to be found in all cases of the disease and not in healthy individuals.
2. The microorganism must be isolated from the diseased host and grown in pure culture.
3. The cultured microorganism should cause disease when introduced into a healthy, susceptible host.
4. The same microorganism must be re-isolated from the newly infected host and identified as identical to the original causative agent.
5. Koch's postulates have limitations, especially with pathogens that cannot be grown in pure culture or diseases caused by multiple factors.

Review Questions

• What are Koch’s postulates used for?
• Why is it important for the microorganism to be isolated in pure culture according to Koch's postulates?
• What are some limitations of Koch's postulates?

Related terms

Pathogen:

A microorganism that can cause disease.

Epidemiology:

The study of how diseases spread and can be controlled within populations.

Pure Culture: A laboratory culture containing a single species of organism.