Inhibitory effects of the cell-free supernatants of Faecalibacterium prausnitzii on biofilm formation of Listeria monocytogenes

This study aimed to investigate the effects of the cell-free supernatant (CFS) of Faecalibacterium prausnitzii on biofilm formation and potential modes of action. Biofilm formed by Listeria monocytogenes poses a threat to food industry due to its resistance to disinfectants and its capacity to contaminate foods. Certain probiotics have been reported to inhibit L. monocytogenes biofilm formation. F. prausnitzii has recently emerged as a promising next generation beneficial microbe. However, its interaction with L. monocytogenes biofilm formation remains unexplored. The anti-biofilm activity of F. prausnitzii CFS was first evaluated. Then biofilm structure and components were examined as well as bacterial parameters associated with biofilm formation. Finally, the anti-biofilm efficacy of CFS in the real food system was determined. CFS significantly reduced biofilm mass by 97.3 % and decreased metabolic activity within the biofilm by 87.2 %. Fluorescence microscopy and Raman spectroscopy analyses demonstrated that CFS disrupted both the structural integrity and biochemical components of the biofilm. Furthermore, CFS of F. prausnitzii diminished cellular motility, reduced surface hydrophobicity, inhibited self-aggregation, and decreased biofilm formation on various food substrates and surfaces. RT-qPCR analysis demonstrated that CFS markedly suppressed the expression of genes associated with biofilm formation in L. monocytogenes. This study provides the first report of the anti-biofilm activity of F. prausnitzii CFS, enhancing our understanding of the beneficial properties of these bacteria. These findings indicate that CFS from F. prausnitzii might be developed as an alternative strategy to reduce L. monocytogenes biofilm and its associated contamination in food systems.