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

J Appl Microbiol. 2019 Sep;127(3):911-920. doi: 10.1111/jam.14348. Epub 2019 Jul 2.


Aims: The control of Listeria monocytogenes biofilm formation using lactocin AL705 bacteriocin at sub-minimum inhibitory concentrations (MICs) through an antiquorum sensing strategy, was preliminarily investigated.

Methods and results: The screening for biofilm formation of different Listeria species at 10°C allowed selecting L. monocytogenes FBUNT for its use as biofilm producer. MIC and minimum bactericidal concentration of lactocin AL705 purified extract against the pathogen was determined. Bacteriocin sub-MICs were used to evaluate biofilm reduction. Concentrations between 2·5-20 AU ml-1 of lactocin AL705 produced significant decreases in biofilm formation without affecting the growth of the pathogen after 3 days of incubation. When bacteriocin concentrations (5-20 arbitrary units per millilitre (AU ml-1 )) were investigated as quorum sensing (QS) inhibitors using Vibrio harveyi as reporter strain, a significant reduction in luminescence by lactocin AL705 (20 AU ml-1 ) was observed. Even when L. monocytogenes produced AI-2 like molecules as recognized by the reporter strain, bacteriocins did not interfere with this compound.

Conclusion: Antilisterial lactocin AL705 used to disrupt QS through a signal molecule inactivation was able to control L. monocytogenes FBUNT biofilm formation. Other molecule(s) different from the AI-2 involved during biofilm formation could be acting as target of the bacteriocin.

Significance and impact of the study: The use of bacteriocins derived from food-grade micro-organisms as a QS inhibition represents an effective strategy to control pathogens as well as an environmentally friendly sanitation method to mitigate postprocessing food contamination.

Keywords: Listeria; bacteriocin; biocontrol; biofilm; quorum sensing.

MeSH terms

  • Bacteriocins / pharmacology*
  • Biofilms / drug effects*
  • Food Contamination
  • Listeria / drug effects
  • Listeria monocytogenes / drug effects*
  • Listeria monocytogenes / physiology
  • Microbial Sensitivity Tests
  • Quorum Sensing / drug effects*


  • Bacteriocins
  • lactocin