Best thing you can do is give them a bath with a betadine solution. Scrub it and leave it sit for a few minutes and then rinse it. Dry the leg completely every time you get them wet. Then spray it with one part bleach to twenty parts water. Repeat daily. This has worked for me in the past. In the summer for my horses, I use antibacterial soap after rides and dry the legs to prevent fungus.
Wash everything, brushes, sweat scrapers, towels, pads, boots with bleach and/or extremely hot water on color sensitive items. Things that come in contact with that area. Make sure that you dry out pads and boots before putting away.
Try not to share pads, boots, and/or brushes. Also try to keep them extra clean.