Question

For several months a graduate student has been working with a pure culture of a suspected bacterial pathogen in an attempt to determine whether it causes disease in various animal models. she had initially found that the organism was highly virulent in mice, but when she attempted to replicate her early experiments weeks later, all of the new experimentally infected mice survived. the student has brought her surprising findings to the lab's weekly research meeting. what advice could you give her

Answer 1

The bacterial strain may had became attenuated