Figure 1.

How probiotic influence the microbiota and the course of diseases. Probiotics and next-generation beneficial bacteria influence eukaryotic cells by different mechanisms. For instance, Short Chain Fatty Acids (SCFAs) are able to activate specific G-protein coupled receptors (e.g., GPR41/43) expressed on enteroendocrine L-cells, thereby triggering the secretion of different gut peptides (i.e., GLP-1, GLP-2) involved in the regulation of energy metabolism and gut barrier function. SCFAs can also modulate gene transcription through the inhibition of histone deacetylase activity. Besides SCFAs, some gut microbes dialogue with the host cells through the production of other specific metabolites or cell components. Therefore, such interactions result in a variety of effects on the host ranging from the improvement of behavior in psychopathological conditions (e.g., alcoholism, autism), but also impacts on skin health and host metabolism by the mean of immune interaction and Gut—Brain—Skin axis. Also, bacteria colonizing the normal microbiota as Barnesiella have been associated with a reduced susceptibility to gut colonization with Vancomycin resistant Enterococcus, whereas, Lactobacillus treatment reduced the carriage of multi-drug resistant potential pathogens.