I have always been told that unless there is an allergy to the animal, pets are ok for CFers. Pseudomonas is everywhere and you are never going to be able to completely protect your child from the nasty bug. Pet, or no pet.
I will add, though, that we do not have pets. I keep a pretty clean house, not because I feel that it will keep my son from picking up germs, but because I feel that every little bit helps. (Not to mention I'm a bit anal, so I've been told, in the cleaning department.) I would have to think that animals, especially those that go outside, will pick up outside germs and bring them in. They roll on the ground, they walk through mud puddles, etc. etc.
I'm not saying Andew never rolls on the ground or stomps in mud puddles..he does. But kids get cleaned up at the door before they drag that stuff in with them. That's not as easy to do each time a dog goes outside.
But this is an easy decision for us having started off with no pets when Andrew was born. If we were already in love with a pet when his diagnosis was made, I'm sure I would still have my pet!<img src="i/expressions/heart.gif" border="0">