It is true, in time some bacterial and diseases do become resistant to treatment. There is a strain of AFB that (after over 30 years of use) has proven to be resistant to terramycin. The strain is however treatable with tylocin.
Does a hive become "contaminated" with the antibiotics? The fact is that terramycin has a half life of 4-5 days in a hive enviroment. This means that it loses half of its efficacy (potentcy) in 4-5 days and half again in another 4-5 days, etc., etc. This being the case, by the time I put my honey supers back on my hives in the spring the terramycin will have retained less than 0.00001% efficacy. If this is the definition of "contaminated", then I'm afraid that my honey is contaminated by a lot more things that are harmful to me than terramycin.
Irregardless, it seems that there are a number of people on this forum that don't believe in treating their hives with medication and are willing to take a chance on their hives well being with little or no treatment. I'm just glad that none of their hives are anywhere near mine.