Saccharomyces cerevisiae variant boulardii (S. boulardii)

Saccharomyces cerevisiae variant boulardii is a non-pathogenic, tropical yeast widely utilized as a probiotic biotherapeutic agent for the prevention and treatment of various gastrointestinal disorders. Unlike bacterial probiotics, this eukaryotic organism is naturally resistant to antibacterial antibiotics, allowing it to be administered concurrently with antibiotic therapy to maintain intestinal flora. Its primary biological functions include the competitive inhibition of enteric pathogens, the neutralization of bacterial toxins through the secretion of proteases, and the enhancement of the host's intestinal barrier function. Furthermore, it exerts immunomodulatory effects by stimulating the production of secretory IgA and downregulating pro-inflammatory signaling pathways such as NF-kappaB and MAP kinases. Clinically, it is most frequently indicated for antibiotic-associated diarrhea and Clostridioides difficile infections, though it is also explored for inflammatory bowel disease and irritable bowel syndrome. While generally safe for the general population, its use carries a risk of systemic fungemia in severely immunocompromised individuals or those with central venous catheters.

Other names

Saccharomyces boulardiiS. boulardiiSaccharomyces cerevisiae var. boulardiiSaccharomyces cerevisiae Hansen CBS 5926S. boulardii CNCM I-745Biotherapeutic agentFlorastor

Proteolytic degradation of bacterial toxins (e.g., C. difficile Toxin A and B); Competitive exclusion of pathogens from intestinal adhesion sites; Stimulation of host intestinal brush-border enzymes (e.g., disaccharidases); Upregulation of secretory IgA (sIgA) production; Inhibition of pro-inflammatory signaling pathways including NF-kB and MAPK; Enhancement of tight junction integrity to restore intestinal barrier function.