Lactocin AL705 as quorum sensing inhibitor to control Listeria monocytogenes biofilm formation

MELIAN, C.; SEGLI, F.; GONZALEZ, R.; VIGNOLO, G.; CASTELLANO, P.

JOURNAL OF APPLIED MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2019 vol. 127 p. 911 - 920

1364-5072

Aims: The control of Listeria monocytogenes biofilm formation using lactocinAL705 bacteriocin at sub-minimum inhibitory concentrations (MICs) throughan antiquorum sensing strategy, was preliminarily investigated.Methods and Results: The screening for biofilm formation of different Listeriaspecies at 10°C allowed selecting L. monocytogenes FBUNT for its use asbiofilm producer. MIC and minimum bactericidal concentration of lactocinAL705 purified extract against the pathogen was determined. Bacteriocin sub-MICs were used to evaluate biofilm reduction. Concentrations between 25?20 AU ml1 of lactocin AL705 produced significant decreases in biofilmformation without affecting the growth of the pathogen after 3 days ofincubation. When bacteriocin concentrations (5?20 arbitrary units per millilitre(AU ml1)) were investigated as quorum sensing (QS) inhibitors using Vibrioharveyi as reporter strain, a significant reduction in luminescence by lactocinAL705 (20 AU ml1) was observed. Even when L. monocytogenes produced AI-2 like molecules as recognized by the reporter strain, bacteriocins did notinterfere with this compound.Conclusion: Antilisterial lactocin AL705 used to disrupt QS through a signalmolecule inactivation was able to control L. monocytogenes FBUNT biofilmformation. Other molecule(s) different from the AI-2 involved during biofilmformation could be acting as target of the bacteriocin.Significance and Impact of the Study: The use of bacteriocins derived fromfood-grade micro-organisms as a QS inhibition represents an effective strategyto control pathogens as well as an environmentally friendly sanitation methodto mitigate postprocessing food contamination.