Characterization of the Ability of Yeast Probiotics and Paraprobiotics to Directly Interact with Gram-Positive and Gram-Negative Bacteria
Posadas, Gabriel Alviola
AdvisorDonaldson, Janet R.
CommitteeThornton, Justin A.
Carroll, Jeffery A.
Yeast probiotics and paraprobiotics, live and inactivated yeast cells, respectively, improve health and performance of livestock by stabilizing the intestinal microbial community. They have also been used for infection prevention and treatment. Despite much research already conducted, the mechanism of direct antagonism, or adhesion of bacteria to the probiotic/paraprobiotic, is under characterized. Additionally, it is unknown which probiotic/paraprobiotic is optimal to use for specific infections. The interactions between the yeast and certain pathogens were analyzed qualitatively with scanning electron microscopy (SEM) and quantitatively with membrane filtration assays. Gram-positive bacteria were found to exhibit specificity under SEM. Through membrane filtration, Listeria monocytogenes exhibited binding to all samples (P<0.05), while Salmonella Typhimurium exhibited binding (P<0.001) with all samples except with 2338. Escherichia coli O157:H7 only bound to the probiotics (P<0.001). With a better understanding of how specific yeast probiotics and paraprobiotics interact with bacteria, specific therapies can be administered to combat infections.