Hi M......my heart goes out to you with a sick little 3 year old girl and a 10 month old baby! So I will start out by saying that I am a nurse and we see this quite often in the hospital because off all the immune-compromised patients who are, of course, all on antibiotics-and LOTS of them! However, I don't know how common it is in the "real" world. I DO knopw it can become quite serious but it sounds like your little girl is under medical care for it, which is good. The most common antibitotic they use for this is Flagyl but I believe there are others they use, as well. There is of course the super-antibiotic, Vancomycin, they use as a last resort when others have failed. My concern is for you all as a family as far as cross-contamination goes, especially with a baby in the house. I hope your M.D. discussed this with you and offered info on thow to prevent this. If he didn't, I would ask more questions and insist on more answers. I will offer that I know alcohol-based disinfectants do not kill C. Diff spores and you must use cleaners containing bleach. And, of course, excellent hand-washing is a must: srub with soap and warm water for 15-20 seconds, rinse and dry thoroughly. Again, antibacterial stuuf will not work on C. Diff spores. I am sure you have looked up stuff on-line but here are a couple decent, basic sites. The first might be a little much but it has some good info:
http://en.wikipedia.org/wiki/Clostridium_difficile
The second one is a little basic but speaks in non-medical terms and I liked it:
http://www.cdiffsupport.com/aboutcdiff.html
Anyways, I hope this helped and I hope it wasn't too long-winded. I wish you all the best and happy, healthy children! Please feel free to contact me if you have any other questions. Good Luck! :)