Exploring the potential of UFTM 2.6.1 in disrupting quorum sensing and attenuating virulence in .

INTRODUCTION

UFTM 2.6.1, isolated from unpasteurized milk, is a potentially probiotic strain exhibiting desirable properties previously demonstrated in vitro, along with a confirmed safe and promising genetic profile based on whole-genome analysis. Due to the limited research on the ability of species to synthesize compounds with anti-quorum sensing activity, this study aimed to investigate the potential of UFTM 2.6.1 to disrupt quorum sensing (QS) signaling and attenuate the virulence of , an important foodborne pathogen responsible for the zoonotic disease listeriosis.

METHODS

The effects of cell-free supernatant (-CFS) were evaluated on the growth, biofilm formation, motility, and expression of QS- and virulence-related genes in .

RESULTS

-CFS exhibited bacteriostatic activity against L. monocytogenes strains isolated from food and food processing environments ( = 21). Additionally, it consistently reduced biofilm formation and swarming motility, two well-known QS-regulated phenotypes in . Exposure to -CFS (0.25x MIC; 7.81 mg/mL), at 28°C for 24 h, significantly downregulated the relative expression of the genes , and , whereas the genes , and were upregulated.

CONCLUSION

This study represents the first report demonstrating the production of compounds by W. paramesenteroides aimed at disrupting the QS system of , offering novel insights into alternative approaches to attenuate pathogen virulence without relying on traditional antimicrobials.