E.coli outbreak

The outbreak that I want to investigate is the E.coli outbreak. The purpose of these questions is to verify the diagnosis

and defining & identifying cases of the outbreak. I would like some references for each question as I will be able to read the sources.

1. What steps will you need to take to be able to speak with patients?
2. What barriers might you run into in accessing patients? (Examples: Did they die? Do you speak the same language? Are they willing to speak to you? Are there legal issues you need to account for? This is not an all-inclusive list of possibilities.)
3. What laboratory tests are needed? For example, would PCR testing be appropriate in this situation? (Don’t forget to think about tests appropriate for each part of the epidemiologic triad.)
4. What are the criteria for your case definition?