MRSA by itself is not actually that bad at all. My brother in law had it a few years ago (he is in the medical profession) and it just gave him time off work to avoid infecting people who have weak immune systems. Were you sick with something else at the time?
It's an interesting question that I really can't answer. It all started my right leg swelled up from knee to my ankle and got all red and splotchy. I had a cut on my thigh that was gross. After a few days I went to the doc-in-a-box. He "diagnosed" MRSA by sight. He took a swab of the cut. It hurt like hell. Put me on meds and said if it wasn't looking much better by Monday (this was a Friday) to come back. It wasn't, so I went back. He wasn't there. Some other noob didn't do shit, so I went to my regular doctor. She put me on different meds. They didn't do shit. The test results came back and said it was a "small growth" of MRSA, according to the first doctor. I eventually went to the ER and they pumped some IV meds in me. Didn't do shit. I went to an infectious disease specialist. He said it was very odd for that part of my leg to be all fucked up and swollen after all those meds and with the actual wound having completely healed up by then. I got an MRI that showed nothing but cellulitis (sp?). He told me to do another round of the meds. Then, the swelling went down and the red splotches went away.
I said it's a hard question to answer because he seemed to think there was a chance that something else was going on other than the MRSA and that it was a coincidence that I had MRSA when the other part of my leg swelled up, but blood tests didn't show anything.
Also, I have ulcerative colitis, which is a gastro thing but it involves a fucked up/weak immune system. In the week immediately preceeding me getting the MRSA, I trained at my gym (private gym where everyone knows everyone) my BJJ gym, and my friend's MMA gym. Nobody else got sick, but with the UC, if one guy is going to, it will probably be me. As someone else pointed out, I don't think I got it at any one of those places, though, as that shit is everywhere these days.
I also want to note that I didn't stop doing BJJ because of the MRSA. I was getting bored with it and there were serious time constraints before the MRSA. It caused me to miss about 2 months tops, but I just didn't go back. I carry the wipes to the gym to be extra cautious for everyone else, moreso than myself, as I think I'm fairly likely to pick something up somewhere else and bring it in, moreso than catching it there. I also started using regular soap instead of gel, and use hand sanitizer fairly reguarly.
