frequent utis...

So is it possible that some people are just naturally inclined to getting utis when they have sex? Even after the vitamin c, azo, cranberry products, extra water, wiping before and after, peeing a lot, etc.? Is it possible that for some people it just happens no matter what they do too prevent it? If so... would it also be out of the question just to continuously take medication for infections at a lower dosage continuously? What kind of treatment happens at that point? Yes I have a doctors appointment coming up but I was just curious too see if this has happened to anyone else or maybe someone heard something about that?