Prevention and Treatment of Clostridioides difficile Infection with Saccharomyces boulardii

Primary Evidence-Based Indication

The American Gastroenterological Association conditionally recommends S. boulardii for preventing C. difficile infection in patients on antibiotics (RR 0.41; 95% CI 0.22-0.79), demonstrating superior efficacy compared to placebo 1, 2
S. boulardii reduces both the cessation of diarrhea (RR 1.33; 95% CI 1.02-1.74) and recurrence of C. difficile-associated diarrhea (RR 0.59; 95% CI 0.35-0.98) 1
The unique advantage of S. boulardii is that antibiotics do not kill yeast, allowing it to survive concurrent antibiotic exposure and colonize disrupted gut niches that opportunistic pathogens would otherwise exploit 2, 3

Effective dosing is 1 gram (or 3×10¹⁰ CFU) daily, started at the beginning of antibiotic therapy and continued throughout the entire antibiotic course 3, 4

The AGA makes no recommendation for S. boulardii in IBS due to lack of efficacy, with three studies involving 232 adults with IBS finding no difference between S. boulardii and placebo for abdominal pain scores (standardized MD 0.26; 95% CI -0.09 to 0.61) 6, 8, 7
Treatment with probiotics including S. boulardii is not recommended for bloating or distention 9
The AGA suggests against the use of probiotics including S. boulardii in children with acute infectious gastroenteritis in the United States and Canada (conditional recommendation, moderate quality evidence) 6, 7

S. boulardii is absolutely contraindicated in immunocompromised patients due to risk of fungemia or systemic yeast infection 3, 4
Patients with severe underlying illnesses should avoid S. boulardii due to potential harms outweighing benefits 1

Recommend S. boulardii 1 gram daily starting with first antibiotic dose and continuing throughout entire antibiotic course for patients with moderate-to-high C. difficile risk 3
Discuss optional use based on patient values regarding cost versus small absolute benefit for healthy outpatients with low C. difficile risk 1, 5

The overall certainty of evidence for S. boulardii in C. difficile prevention is low, downgraded due to unclear or high risk of bias in most trials, heterogeneous populations, and potential publication bias 1, 2
Despite low quality evidence, S. boulardii remains the best-studied single-strain probiotic for this indication with consistent directional benefit 2, 3