@nettecoo, @sandyabbey @pines @ngorma25 I am sorry to hear of two cases of C diff in one family. Something we all dread. I have been super super concerned about infecting others especially my kids and grandkids and getting reinfected myself. I finally got appointments with an infectious disease specialist and a GI doctor who specialises in C. Diff. I asked a lot of questions about contagion. Here is what they both independently told me:
1. I am only contagious when I have active diarrhea. If i am colonized but do not have active diarrhea, I am not contagious.
2. As for my apartment and the spores lingering on counters etc. They said give it all a good cleaning, especially the toilet and surrounds, with a product that specifically works against C Diff (the K list at EPA website tells you which they are) , and then it is okay for any one to come to may apartment unless they are immune compromised. My little grandchildren, even the baby , are fine, they said.
3. The infectious disease expert said that C. Diff spores are spread all around and that the vast majority of people are not immune compromised and so are not made sick by them.

As for your question about whether we can get C Diff again without even taking an antibiotic --the doctors thought i probably would not get it again unless I took an antibiotic but they emphasized that I have underlying health issue (two markers in my blood that makes me somewhat immune compromised) . That made me wonder if maybe i could independent of taking an antibiotic. I have come to understand that it is really important whether or not there is some underlying condition that increases risk. I supposedly have that.