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Inhibition of In Vitro Clostridioides difficile Biofilm Formation by the Probiotic Yeast Saccharomyces boulardii CNCM
Pierre-Alexandre Lacotte1, Alexis Simons1,2, Sylvie Bouttier1
1INRAE, Université Paris-Saclay, AgroParisTech, Micalis Institute, 92290 Châtenay-Malabry, France.
Abstract:
Clostridioides difficile is responsible for post-antibiotic diarrhea and most of the pseudomembranous colitis cases. Multiple recurrences, one of the major challenges faced in C. difficile infection (CDI) management, can be considered as chronic infections, and the role of biofilm formation in CDI recurrences is now widely considered. Therefore, we explored if the probiotic yeast Saccharomyces boulardii CNCM I-745 could impact the in vitro formation of C. difficile biofilm. Biomass staining and viable bacterial cell quantification showed that live S. boulardii exerts an antagonistic effect on the biofilm formation for the three C. difficile strains tested. Confocal laser scanning microscopy observation revealed a weakening and an average thickness reduction of the biofilm structure when C. difficile is co-incubated with S. boulardii, compared to the single-species bacterial biofilm structure. These effects, that were not detected with another genetically close yeast, S. cerevisiae, seemed to require direct contact between the probiotic yeast and the bacterium. Quantification of the extrapolymeric matrix components, as well as results obtained after DNase treatment, revealed a significant decrease of eDNA, an essential structural component of the C. difficile biofilm matrix, in the dual-species biofilm. This modification could explain the reduced cohesion and robustness of C. difficile biofilms formed in the presence of S. boulardii CNCM I-745 and be involved in S. boulardii clinical preventive effect against CDI recurrences.
Insights
The probiotic yeast Saccharomyces boulardii CNCM I-745 inhibits Clostridioides difficile biofilm formation in vitro. This effect, mediated by reduced extracellular DNA, may explain its clinical role in preventing recurrent C. difficile infections.
Area of Science:
- Microbiology
- Gastroenterology
- Probiotics
Background:
- Clostridioides difficile infection (CDI) frequently recurs, posing a significant clinical challenge.
- Biofilm formation by C. difficile is increasingly recognized as a key factor in infection recurrence.
- Understanding mechanisms to prevent CDI recurrence is crucial for patient management.
Purpose of the Study:
- To investigate the impact of the probiotic yeast Saccharomyces boulardii CNCM I-745 on in vitro C. difficile biofilm formation.
- To elucidate the specific mechanisms by which S. boulardii may interfere with C. difficile biofilm structure.
Main Methods:
- In vitro co-incubation of C. difficile strains with S. boulardii CNCM I-745.
- Biofilm biomass staining and viable cell quantification.
- Confocal laser scanning microscopy for structural analysis.
- Quantification of extracellular matrix components, including eDNA, with and without DNase treatment.
Main Results:
- Live S. boulardii CNCM I-745 demonstrated an antagonistic effect on C. difficile biofilm formation across tested strains.
- Co-incubation resulted in weakened biofilm structure and reduced thickness compared to single-species biofilms.
- The effect was specific to S. boulardii CNCM I-745 and not observed with S. cerevisiae, suggesting a specific interaction.
- A significant decrease in extracellular DNA (eDNA) was observed in dual-species biofilms, indicating reduced biofilm cohesion.
Conclusions:
- Saccharomyces boulardii CNCM I-745 actively inhibits C. difficile biofilm formation in vitro.
- The reduction in eDNA content appears to be a key mechanism underlying the observed anti-biofilm effect.
- These findings support a potential role for S. boulardii in preventing recurrent C. difficile infections by disrupting biofilm integrity.
