C-Diff and infants?

Has anyone heard that c-diff is common in an infants stool? My specialty is geriatrics and when a pt has c-diff we treat it. My sister's baby is breastfed and 2 months old. She has had blood tinged mucus in her stool for the last month or so. Her samples came back negative except for the c-diff and the pediatrician says that this is common for infants to carry in their first year. He is thinking maybe a "milk" allergy and my sister is now on a dairy-free diet. My neice is continuing to have sx. I'm told her stool color varies from yellow to every shade of green there is....I won't actually see her for the first time until March. Any info you can share on C-diff experience with infants would be helpful. Thanks.