I wonder if ingestion of relatively large amounts of robust probiotics would have helped. I've tended kefir grains off and on for the last 20 years or so, and have read that the curd that forms from kefir remains intact a bit deeper into the GI tract than e.g. yogurt. Some people eat the grains themselves which seems like it would be a large, robust colony of mostly helpful bacteria that I assume would fight for territory against c diff.

Reminds me, it's probably time to source some more kefir grains!