Murgie,I'm not sure if being on antibiotics too much causes our immune system to be decreased. Unfortunately, the lower immune system is just a part of having CF. I do wonder if steroids do cause that, though. His MRSA may not even respond to Cipro, though. I've recently been diagnosed w/ MRSA and ordered a copy of my sputum culture & it said my MRSA was resistant to Cipro & that's what my Dr Rx for me <img src="i/expressions/face-icon-small-mad.gif" border="0"> , so that was a whole other story I won't share here!I think minocycline would be a good option for your son, please ask your Dr about this. And then again, he may be sensitive to Cipro, where I wasn't & it's doing it's job just fine.I got a good ole staph infection when I was about his age & got over it w/ shots. Now just recently I've been dx w/ MRSA. I'm wondering where I got it too like you're wondering. I bet we'll never know!The precautions he could take at all Dr's appts are, maybe sit away from other kids/patients so as not to share MRSA w/ them and cough into napkins/kleenex. Does he have to wear a mask at the CF Clinic anyway, if so that should take care of it there. My Dr assured me that I could only spread this to immune compromised people, (i.e. chemo patients, CF people, and others w/ compromised immune systems). I asked about kissing my husband or daughter on the lips & I was assured that I wouldn't spread it to healthy people & even if I did spread it to them that their immune system would kick it out right away. I hope this has helped!