What is Saccharomyces boulardii (S. boulardii)?

From the Guidelines

Saccharomyces boulardii may be beneficial in reducing the recurrence of diarrhea and increasing the cessation of diarrhea in patients with Clostridioides difficile infection (CDI) when used in conjunction with conventional antibiotics, as evidenced by the largest study 1. The use of S. boulardii as a probiotic has been explored in various studies, with the most recent and highest quality study published in 2020 1. This study, a technical review on the role of probiotics in the management of gastrointestinal disorders, found that S. boulardii may increase the cessation of diarrhea and decrease the recurrence of diarrhea in patients with CDI.

Key Findings

• The largest study analyzed 124 subjects receiving metronidazole or vancomycin for initial or recurrent CDI and reported that S. boulardii may increase the cessation of diarrhea (RR, 1.33; 95% CI, 1.02–1.74, Low CoE) 1.
• The same study found that S. boulardii may decrease the recurrence of diarrhea (RR, 0.59; 95% CI, 0.35–0.98, Low CoE) 1.
• Another study examined S. boulardii among 32 adults with recurrent CDI receiving either metronidazole or high-dose or low-dose vancomycin and reported decreased recurrence of diarrhea in the probiotic arm compared to placebo 1.

Recommendations

• S. boulardii may be considered as an adjunct therapy in patients with CDI, particularly those with recurrent disease 1.
• The typical dose of S. boulardii used in the studies was 1 g per day, containing 3 × 10^10 CFU/d 1.
• Patients should be advised to take S. boulardii at least 2 hours apart from antibiotics and continue for several days after completing antibiotic treatment.

Safety and Side Effects

• S. boulardii is generally considered safe, but those with compromised immune systems, central venous catheters, or yeast allergies should avoid it 1.
• Minor side effects may include gas or bloating when first starting supplementation 1.

From the Research

Overview of Saccharomyces boulardii

• Saccharomyces boulardii is a non-pathogenic yeast that has been widely used to prevent antibiotic-associated diarrhea (AAD) 2, 3.
• Studies have shown that S. boulardii can reduce the incidence of AAD in hospitalized patients, with a significant reduction in the risk of developing AAD by more than half 4.

Efficacy of Saccharomyces boulardii in Preventing AAD

• A prospective study found that S. boulardii reduced the incidence of AAD in hospitalized patients from 22% to 9.5% 3.
• A randomized, double-blind, placebo-controlled trial found that S. boulardii reduced the prevalence of diarrhea in children receiving antibiotics from 23% to 8% 5.
• However, another study found no evidence for an effect of S. boulardii in preventing AAD or CDAD in a population of hospitalized patients without particular risk factors apart from systemic antibiotic treatment 6.

Safety and Tolerability of Saccharomyces boulardii

• Studies have shown that S. boulardii is well-tolerated and has no discernable adverse effects 2, 3, 5.
• No serious adverse events related to S. boulardii were reported in the studies reviewed 6.

Mechanism of Action of Saccharomyces boulardii

• The exact mechanism of action of S. boulardii in preventing AAD is not fully understood, but it is thought to involve the inhibition of Clostridium difficile toxin production and the modulation of the gut microbiota 2, 4.
• Further studies are needed to fully elucidate the mechanism of action of S. boulardii and its effects on the gut microbiota 6.