Physiological characterization of non-Saccharomyces yeasts from agro-industrial and environmental origins with possible probiotic function

Probiotics are defined as live microorganisms, which when administered in adequate amount confer a health benefit to the host. Most of studied or commercialized probiotics contain bacteria and very few of them present yeast in its composition. In this last case, the microorganisms almost always belong to Saccharomyces genus. In the present study, it was of interest to screen among 103 non-Saccharomyces yeasts a candidate for probiotic by using in vitro and in vivo criteria. In vitro assays included growth at 37A degrees C and production of antagonistic compounds against enteropathogenic indicators, and the in vivo assays evaluated the colonization ability of mouse gastrointestinal tract without pathologic consequences and the protective ability in mice experimentally challenged with Clostridium difficile. In conclusion, Pichia kluyveri strain 898 showed to be a potential candidate for probiotic use, based on the criteria cited above, particularly as demonstrated by its protective effect against experimental infection in mice. Interestingly, an in vivo inhibition against C. difficile observed in the animal models did not correlate with the results obtained with the in vitro assays.