I think KC is a strictly viral disease. The fact that your dog got better after a treatment of ABX doesn't mean it actually had any curative action on the disease. I maintain the dog would have gotten well just as fast without the ABX. An old saying around here is "When you have a cold or flu, you can go to the doctor and get a shot and meds and get well in about 3 or 4 days ... or you can do nothing and get well in about 3 or 4 days." I'm a believer in that saying.