Beyond probiotics and pathobionts: mechanistic roles of enterococcus-derived bioactive components in health and disease.

The Enterococcus genus comprises an unusual subset of the human microbiota with the dual role of beneficial commensals and opportunistic pathogens. The biological activity of Enterococcus species is not limited to colonization and is mainly driven by numerous bioactive compounds. Metabolites, extracellular vesicles (EVs), exopolysaccharides, and cell wall structures serve as mediators of complex host-microbe interplay. Through the transfer of these bioactive substances, Enterococcus-derived EVs shape host signaling pathways and help bacteria to adapt to environmental conditions. Additionally, structural molecules such as peptidoglycan, lipoteichoic acid, and adhesins bind to pattern recognition receptors, triggering signaling cascades responsible for both innate and adaptive immunity. Moreover, biological roles of metabolites, exopolysaccharides, and bacteriocins include the modulation of oxidative stress, antimicrobial activity, regulation of immunometabolic pathways, maintenance of intestinal barrier integrity, and others. This review presents a summary of biological activities and molecular mechanisms of Enterococcus-derived bioactive compounds with a focus on their role in health and the pathophysiology of diseases.