Saccharomyces cerevisiae show low levels of traversal across the human blood brain barrier in vitro.

Background:   Saccharomyces cerevisiae is generally considered safe, and is involved in the production of many types of foods and dietary supplements. However, some isolates, which are genetically related to strains used in brewing and baking, have shown virulent traits, being able to produce infections in humans, mainly in immunodeficient patients. This can lead to systemic infections in humans. Methods: In this work, we studied S. cerevisiae isolates in an in vitro human endothelial barrier model, comparing their behaviour with that of several strains of the related pathogens Candida glabrata and Candida albicans. Results: The results showed that this food related yeast is able to cross the endothelial barrier in vitro. However, in contrast to C. glabrata and C. albicans, S. cerevisiae showed very low levels of traversal. Conclusions: We conclude that using an in vitro human endothelial barrier model with S. cerevisiae can be useful to evaluate the safety of S. cerevisiae strains isolated from foods.