Our hospital handles this well (I think). We have a rule that all CFer's have a mask on outside rooms, they wash hands upon leaving their room and returning. We have scheduled "private times" for all cf kids. During those times they are scheduled to be in the playroom, teen room etc., for an hour of playtime. Then everything they have touched is cleaned.
For activities like bingo (teens) and movie night (entire hospital) the kids are kept 3 feet away from each other. For Bingo they have vinyl bean bag chairs that they spread way out, and during the movies the kids are spaced way out.
You are not allowed to be told who does and doesn't have CF or what they are culturing, HOWEVER, ALL staff should know and make proper accomodations for all kids wanting to play. I have worked some of these "events" and always know who has what.
Another suggestion is to talk with the hospitals Infectious Disease doctors about how they ensure your child's safety while hospitalized. Perhaps they would be able to help you work out a plan that would make you feel comfortable as well while you are there.
Good luck!
Sandy