Most likely the doctor will look at you cross eyed - most doctors fall in this category. It is very helpful to know what you are dealing with via testing but testing is well known to be inaccurate - here is a list of preferred providers
Resistance can play a factor in any organism and is a growing concern - it is a good idea to use multi ingredient products and try to rotate those. Some of my better ones I tried are Himalaya DiarCare, Banyan Botanical ParaCleanse and Western Botanicals parasite formula. You have to keep constant pressure on them.
Pay attention to #9 on that link, I have outlined the observations regarding resistance.