Once the infection gets to the legbone, no amount of antibiotics will stop it. The staph infection quickly spreads throughout the body.
You can try Baytril. Here's a link where you can buy it. I recommend that you expedite shipping when ordering it...
Simply removing the scab doesnt mean the infection or kernal is going to be removed in that manner.
Soak in warm epsom salts water for 30 minutes. It will draw up the infection. Then cut open the scab and remove scab.
You have to squeeze the HECK out of the swollen footpad as much as possible...