What Causes Bloody Stools In A Child Who Is On Flagyl ?

Hello, I have a 2 year old who was hospitalized for Staph infection from a dog scratch below her eye. They gave her Cladamyacin and Cedfir (sorry spelling bad) through IV. She had diarrhea from day one in the hospital and after 11 days of it getting worse, we brought her back to find out she tested positive for C. Diff. She was prescribed Flaygle 70mg 4 x a day. It is now 10 days of being on it and her bloody stools are only getting worse. She went from 14 diarrhea diapers a day to now 4 a day but the blood is worse. It is obvious to see how much. She was just checked for Anemia and her numbers were fine. My question is why is her bloody stools getting worse after being on Flaygl? And how long should we wait for her to be seen by a gastro doctor? They want to keep her on Flaygl for 4 more days. She has no fever, or abdominal pain. I am a very concerned mother who just wants to see her get better. Any advice would be helpful, Thank you.