The same, unknown bacteria is isolated from 20 sick individuals. Their samples were grown in culture and then placed in 10 healthy mice. Those mice started to show signs of a heightened immune response. According to Koch’s postulates what is the next step in determine whether the bacteria is pathogenic?
Classify the bacteria as a noncommunicable disease.
Classify the bacteria as a communicable disease.
Reisolate it, and determine if it is the original unknown bacteria.
Treat the original 20 individuals with antibiotics.

Reisolate it, and determine if it is the original unknown bacteria.

Explanation:

According to Koch's postulates, to determine the toxicity of a microorganism the following steps should be taken:

1) Isolate the microorganism from the organism in which it is present.

2) Introduce these microorganisms in other organisms.

3) Check if the disease or infection has occurred in the  organisms in which the microorganism was injected.

4) If yes, then reisolate the bacteria. Check if it is the same bacteria that caused the disease in the initial organisms.

5) perform lab experiments on the microorganism and determine it.