i can't specifically answer your question, but when i was coaching youth wrestling , we had guidelines form the doctors about MRSA:
  • if one of the kids had anything that you suspected was MRSA get it treated soonest
  • disinfect (we used a hospital strength disinfectatnt which claimed to kill the staph involved) the mats and other surfaces that the wrestler was in contact with
  • no return to the mat for the infected until they had doctor's clearance

I would suspect the risk to others is pretty slim if you stayed in your waders, but I would think there is a high probablity you could reinfect yourself if the inside of your waders were contaminated