This study evaluates the potential of various yeast strains as probiotic and postbiotic agents for agglutinating enteric pathogens, offering a preventive approach to gastrointestinal infections. Different yeast species were tested in vitro against a range of pathogenic bacteria, including enterotoxigenic Escherichia coli ETEC, Shigella flexneri, Salmonella enterica serovar Typhimurium, and Salmonella enterica serovar Enteritidis, to assess their capacity for pathogen agglutination. Additionally, inactivated yeasts were obtained using a novel chemical treatment and employed to explore their efficacy as postbiotic agents. The results suggest that both live and inactivated yeasts are able to agglutinate the different pathogens, potentially limiting bacterial colonization. Notably, we also demonstrated that Wickerhamomyces anomalus, Saccharomyces cerevisiae, and Pichia fermentans, exhibiting agglutination activity, were capable of reducing bacterial adhesion to HeLa cells in vitro. This research highlights yeast’s probiotic and postbiotic potential and supports the development of novel yeast-based products for preventing enteric infections.

Enteric diseases are a leading cause of morbidity and economic loss in livestock production, and the search for effective, antibiotic-free alternatives has intensified in recent years. Among emerging strategies, yeast-derived postbiotics—non-viable microbial cells and their metabolites—have gained attention for their potential to enhance gut health and disease resistance in farm animals. This review synthesizes current knowledge on the composition, mechanisms of action, and practical applications of yeast postbiotics, particularly those derived from Saccharomyces cerevisiae and related species. Key bioactive components, such as β-glucans, mannan oligosaccharides, peptides, and organic acids, are discussed in the context of their immunomodulatory, anti-inflammatory, and pathogen-inhibitory properties. Evidence from in vivo and in vitro studies across multiple livestock species—including poultry, swine, and ruminants—demonstrates beneficial effects on intestinal barrier function, microbial balance, and performance under disease-challenged conditions. Despite promising outcomes, challenges remain in standardizing postbiotic preparations, elucidating dose–response relationships, and tailoring applications to species-specific needs and production systems. This review highlights the potential of yeast postbiotics as a sustainable tool in enteric disease management and outlines research priorities for their broader implementation in animal agriculture.

Among the many concerns surrounding global health, antimicrobial resistance (AMR) is widely recognized as a major threat, especially critical within livestock production, where restrictions on antibiotic use demand effective preventive alternatives. The documented health benefits and structural stability have positioned yeast-derived postbiotics as an attractive alternative, but research has largely focused on Saccharomyces cerevisiae, leaving non-Saccharomyces yeast species underexplored. To this end, in this study nine non-conventional yeast strains were selected and subjected to different thermal and chemical inactivation methods to determine the most suitable conditions for postbiotic obtention. Based on their physicochemical characterization and scalability potential, heat-treated postbiotics were selected for subsequent in vitro evaluation. Immunomodulatory assays demonstrated that heat-inactivated postbiotics from the different yeast strains were internalized by macrophages and induced dose-and-species-dependent expression of maturation markers CD40 and CD86, as well as TNF-α production, eliciting a proinflammatory response in vitro. Moreover, among all the species evaluated in this work, Rhodotorula mucilaginosa and Wickerhamomyces anomalus stood out for their ability to significantly reduce the adhesion of the enteropathogen enterotoxigenic Escherichia coli (ETEC) to intestinal cells in vitro. These results highlight the species-dependent immunomodulatory and anti-infective properties of selected yeast-derived postbiotics.