Sorry about the MRSA...
My daughters both culture MRSA and have for many years. On a normal basis they are treated with Bactrim when they have a flare-up with symptoms such as increased cough. If they are not having any symptoms, they are not treated.
Kayla has been pretty sick with the MRSA before, and has been on IV Vanc for two weeks. It really helped knock down the bacteria counts from abundant down to moderate.
She did great for about six months and had another flare up, and that time her dr. put her on oral Zyvox. It tasted horrible, but it was great. It actually knocked down the bacteria where she didn't culture it for about a year. Actually,I wonder if it had rid her lungs of it and she just caught it again from her sister, or if it just kept it down for a long time. Who knows!
Hannah has never taken anything but Bactrim to keep hers under control.
I do think that MRSA can be damaging...b/c in Kayla's case she had only cultured MRSA and Staph (up until a few months ago) and she has moderate lung damage in her right upper lobe. BUT, on the other hand, Hannah's lungs have always looked perfect (and she cultures MRSA, Staph, and has cultured PA several times!!).
I don't really know if there are any studies that if you hit it hard early that you can get rid of it.