Yeah, it's just very important to be diligent when you're trying to keep your current rats healthy.

You can always keep a spray bottle of properly diluted chlorhexidine(Valley Vet.com has the best prices on the gallon of concentrate), and you can spray yourself and your shoes(especially the bottoms). I always spray my face too, just in case.

Ask the vet for a combo of Baytril and Doxycycline. That should cure pretty much any respiratory problem she has. I'd keep her on it for 10-14 days, twice a day. Just ask the vet for it and he should comply