I'm not in the medical field but I'd say :Handwashing, handwashing, handwashing! Make sure everyone in the house (including her) is regularly washing hands, especially before meal or after playing on the floor.
You may also need to clean her toys more regularly than you already do. Hot soapy water or warm water and a little bleach should do it. You could also spray them down with lysol after they've been washed and leave them to dry overnight.
Also, do you use a humidifier regularly? Those things are breeding grounds for bacteria, even with regular cleaning. I'd switch to a vaporizer instead. Use it only when needed or if your house is super dry, use it in a room other than hers.
at 7:58 PM on Jan. 13, 2009