Synergistic Effect of Postbiotic Yeast ABB C22® on Gut Inflammation, Barrier Function, and Protection from Rotavirus Infection in In Vitro Models

Diarrhoea is a serious cause of mortality worldwide that can lead to dehydration, gut barrier function impairment, nutrient malabsorption, and alterations of the gut microbiota (dysbiosis). The current solutions for its management, such as oral rehydration salts (ORS), inhibitors of gut motility, antibiotics, and living probiotics, only partially counteract the mechanisms of the disease and do not provide a full coverage of the problem. The potential risks of the use of living probiotic strains, particularly in immunocompromised patients, can be eliminated with the use of tyndallized (heat-killed) postbiotic bacteria and yeast. ABB C22® is a postbiotic combination of three tyndallized yeasts, namely Saccharomyces boulardii, Saccharomyces cerevisiae, and Kluyveromyces marxianus. To assess the action of the postbiotic combination on diarrhoea, immune and gut epithelial cell signalling assays, the gut barrier formation assay, and the rotavirus gene expression assay were performed. ABB C22® showed a strong anti-inflammatory effect, an induction of the build-up of the gut epithelium, and a degree of protection against rotavirus infection. These experimental studies support the use of the postbiotic ABB C22® as a solution for the management of diarrhoea and gastrointestinal conditions, alone or in combination with existing but incomplete treatments.