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

Abstract

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 2Á5-20 AU ml À1 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 À1 )) were investigated as quorum sensing (QS) inhibitors using Vibrio harveyi as reporter strain, a significant reduction in luminescence by lactocin AL705 (20 AU ml À1 ) 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.Journal of Applied Microbiology 127, 911--920

Antimicrobial Photoinactivation Approach Based on Natural Agents for Control of Bacteria Biofilms in Spacecraft

“…In order not to exclude search results that could be significant for the investigation, a general search term (keyword) "biofilm" was used. According to the scientific articles found in the PubMed database regarding biofilm inhibition and control, all methods, based on their nature, can be divided into six groups: (1) natural (biological) [53][54][55];…”

“…In order not to exclude search results that could be significant for the investigation, a general search term (keyword) "biofilm" was used. According to the scientific articles found in the PubMed database regarding biofilm inhibition and control, all methods, based on their nature, can be divided into six groups: (1) natural (biological) [53][54][55]; (2) chemical [56][57][58]; (3) physical [59,60]; (4) physicochemical [61][62][63]; (5) physical in combination with natural [64], and (6) natural in combination with chemical [65]. A summary of the bacterial biofilm inhibition/control methods described in the past two years is shown in Figure 1.…”

Proteomic Analysis of Listeria monocytogenes FBUNT During Biofilm Formation at 10°C in Response to Lactocin AL705

“…curvatus CRL1579 in MRS broth was centrifuged (11,000 g, 20 min at 4°C) (Avanti J-25I centrifuge, Beckman, United States) to remove bacterial cells. The bacteriocin was precipitated from the supernatant with 60% saturated ammonium sulphate (Cicarelli-Reagents S.A); the purification was performed following the protocol described by Melian et al (2019). Antimicrobial activity of the semi-purified bacteriocin solution was determined by a well diffusion assay according to Castellano et al (2004).…”

“…They can be used directly as a semi-purified compound or indirectly via the bacteriocin-producing organism (Castellano and Vignolo, 2006). Accordingly, the potential of bacteriocinogenic LAB and their bacteriocins as biosanitizers to prevent the attachment of L. monocytogenes to food facilities' surfaces has been evaluated (Desai et al, 2012;Zhao et al, 2013;Pérez Ibarreche et al, 2016;Melian et al, 2019). In particular, L. monocytogenes biofilm treated with enterocin AS-48 (Caballero Gómez et al, 2013), nisin (García-Almendárez et al, 2008), and different Lactobacillus extracts (Winkelströter et al, 2015;Camargo et al, 2016) were evaluated.…”

“…In particular, L. monocytogenes biofilm treated with enterocin AS-48 (Caballero Gómez et al, 2013), nisin (García-Almendárez et al, 2008), and different Lactobacillus extracts (Winkelströter et al, 2015;Camargo et al, 2016) were evaluated. In a recent study, antilisterial lactocin AL705 was able to control L. monocytogenes FBUNT biofilm formation by a disruption of quorum sensing through a signal molecule inactivation; however, a lack of interference with autoinducer-2 (AI-2) signaling molecule was observed, suggesting that other molecule(s) different from AI-2 involved in biofilm formation were are the target of the bacteriocin (Melian et al, 2019). On this basis, the aim of this study was to analyze L. monocytogenes FBUNT proteome changes during biofilm formation at 10°C, exposed or not to lactocin AL705, by using a comparative proteomic approach.…”