Answer the questions below as completely and as thoroughly as possible and where appropriate include a specific example to illustrate. Answer the question in essay form (not as an outline or as bullets) using complete sentences. Cite sources of information you used to answer the questions or that support your answer.

Vibrio cholerae is isolated from a GI sample and testing for cholera toxin is negative. Upon coculture with a bacteriophage, testing for the exotoxin becomes positive. How did this switch from a nontoxic strain to a toxic strain occur? As part of your explanation name the type of gene transfer and mechanism and the type of exotoxin and how it causes disease in the host.