MRSA is an adaptation of the original bacteria to antibiotics. Sulfa drugs are an older class of meds-one that fortunately still works in some cases...but I think MRSA is becoming resistant to that as well. There's a lot of talk about the possible "End of Antibiotics." The thing is, bacteria freely swap DNA as most of them have no nucleus, thus they pass resistance amongst each other. We may come to a point where major surgery, particularly, abdominal surgery, becomes very problematic due to resistant bacteria. Even more fun, read up on biofilms. Bacteria form communicating colonies that actively combine resources to resist antibiotics.