Saccharomyces boulardii is a yeast that is used a probiotic and I have seen several references to its use in the treatment of c. difficile. I am going to look into its use further.
A history of CDD episodes dramatically increased the likelihood of further recurrences. Multivariate analysis revealed that patients treated with S boulardii and standard antibiotics had a significantly lower relative risk (RR) of CDD recurrence (RR, 0.43; 95% confidence interval, 0.20 to 0.97) compared with placebo and standard antibiotics. The efficacy of S boulardii was significant (recurrence rate 34.6%, compared with 64.7% on placebo; P=.04) in patients with recurrent CDD, but not in patients with initial CDD (recurrence rate 19.3% compared with 24.2% on placebo; P=.86). There were no serious adverse reactions associated with S boulardii.