Ummmmm - The doctor is baffled so his answer is to do nothing?????? What about referring you to some specialists? What about running tests to see if something, other than bacteria may be causing the problem? What about doing some research, on his own (which is what doctors are supposed to do) to try to help himself and help you???
Have you thought about getting another doctor?
I do hope that you get some answers!
Peace and Blessings