Thank you for the reply. I will go to a podiatrist eventually, I haven't done it yet as so far, it has been a waste of time with doctors and I've read that I am not alone in this experience among people with bad BO.
I am quite confident there is no athlete's foot in my case, as I do not have any symptoms (nothing visual, no itching plus the fact that I'm living with someone that has no problem with their feet, I'd imagine they would have it as well if it were athlete's foot).
I'll definitely go to a doctor and try to get a clear idea of the bacteria that's causing this odor, although with the amount of antibacterials and antifungal substances I've tried and was disappointed with, I'd be surprised to find something that works for good.