Which of the following statements is NOT one of Koch's postulates?

Show Answers

The microorganism must be isolated from the infected host.The microorganism may or may not induce disease when introduced into a healthy host.It is possible to obtain pure cultures of the microorganism.The microorganism should be re-isolated from the experimentally infected host.The microorganism must be present in every case of the disease.

Explanation

Koch's postulates require that the microorganism be isolated from diseased tissue, grown in pure culture, cause disease when introduced into a healthy host, and be re-isolated from the experimentally infected host. The statement that the microorganism may or may not cause disease when introduced contradicts Koch's criteria, making option B incorrect.