Antivirulence effects of lactic acid bacteria: pioneering new probiotic applications

Lactic acid bacteria are a group of microorganisms recognised for their health-promoting properties, with several strains being commercially utilised as probiotics. Probiotics offer numerous benefits, including modulation of the immune system, enhancement of nutrient absorption, regulation of intestinal microbiota, protection against intestinal pathogens, and strengthening of the intestinal barrier. However, the precise mechanisms by which probiotics exert their effects remain incompletely understood. In recent years, research into new therapeutic applications for probiotics has intensified, driven by the urgent need for strategies to combat antibiotic-resistant bacteria. Among the newly discovered properties of probiotics is their ability to produce antivirulence compounds. These compounds reduce the virulence of pathogens without inhibiting microbial growth, thereby imposing less selective pressure for the development of resistance compared to traditional antibiotics. Given the potential for these compounds in clinical settings, this study aims to provide a comprehensive review of the antivirulence activities of probiotics, with particular focus on lactic acid bacteria. It discusses their effects on two-component and quorum sensing systems, which regulate the simultaneous expression of various virulence genes, as well as their anti-adhesion, anti-biofilm, anti-toxin, and anti-enzymatic activities against a range of pathogens. Thus, this review offers insight into the novel mechanisms by which lactic acid bacteria contribute to health, potentially broadening their applications.