The Impact of Compounds Released from Damaged Salad Leaves on the Growth and Virulence of <i>Listeria monocytogenes</i>

Background: Fresh produce such as leafy green salads have recently become recognized as a potential source of food-borne infection by enteric pathogens This study investigated whether compounds released from damaged salad leaves were recognized by <i>Listeria monocytogenes</i> strain EGD...

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Main Authors: Asma Alsharif, Lama Aldawsari, Giannis Koukkidis, Primrose Freestone
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Microorganisms
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Online Access:https://www.mdpi.com/2076-2607/13/2/252
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author Asma Alsharif
Lama Aldawsari
Giannis Koukkidis
Primrose Freestone
author_facet Asma Alsharif
Lama Aldawsari
Giannis Koukkidis
Primrose Freestone
author_sort Asma Alsharif
collection DOAJ
description Background: Fresh produce such as leafy green salads have recently become recognized as a potential source of food-borne infection by enteric pathogens This study investigated whether compounds released from damaged salad leaves were recognized by <i>Listeria monocytogenes</i> strain EGD and if they impacted its growth and virulence. Methods: The effects of extracts of salad leaves or salad bag fluids were tested on the growth, biofilm formation, and colonization of salad leaves and host cell virulence. Results: The presence of salad extract at a concentration of less than 0.5% <i>v</i>/<i>v</i> and salad bag fluids at a concentration of 10% <i>v</i>/<i>v</i> enhanced the growth in water and serum-based medium by more than 10,000 times over un-supplemented control cultures. Light and scanning electron microscopy, as well as eukaryotic Caco-2 and <i>Galleria mellonella</i> models of infection, showed that leafy green extracts from rocket, lettuce, spinach, and their salad bag fluids significantly increased the ability of <i>Listeria</i> to establish biofilms and infect host cells. Conclusions: This investigation showed that salad leaf extracts can markedly enhance bacterial virulence, which has implications for bagged salad leaf consumer safety if the leaves become contaminated with pathogenic bacteria such as <i>Listeria</i>.
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spelling doaj-art-744b720cad30441fa14464b64c8d33e52025-08-20T03:12:19ZengMDPI AGMicroorganisms2076-26072025-01-0113225210.3390/microorganisms13020252The Impact of Compounds Released from Damaged Salad Leaves on the Growth and Virulence of <i>Listeria monocytogenes</i>Asma Alsharif0Lama Aldawsari1Giannis Koukkidis2Primrose Freestone3Department of Respiratory Sciences, University of Leicester, University Road, Leicester LE1 7RH, UKDepartment of Respiratory Sciences, University of Leicester, University Road, Leicester LE1 7RH, UKDepartment of Respiratory Sciences, University of Leicester, University Road, Leicester LE1 7RH, UKDepartment of Respiratory Sciences, University of Leicester, University Road, Leicester LE1 7RH, UKBackground: Fresh produce such as leafy green salads have recently become recognized as a potential source of food-borne infection by enteric pathogens This study investigated whether compounds released from damaged salad leaves were recognized by <i>Listeria monocytogenes</i> strain EGD and if they impacted its growth and virulence. Methods: The effects of extracts of salad leaves or salad bag fluids were tested on the growth, biofilm formation, and colonization of salad leaves and host cell virulence. Results: The presence of salad extract at a concentration of less than 0.5% <i>v</i>/<i>v</i> and salad bag fluids at a concentration of 10% <i>v</i>/<i>v</i> enhanced the growth in water and serum-based medium by more than 10,000 times over un-supplemented control cultures. Light and scanning electron microscopy, as well as eukaryotic Caco-2 and <i>Galleria mellonella</i> models of infection, showed that leafy green extracts from rocket, lettuce, spinach, and their salad bag fluids significantly increased the ability of <i>Listeria</i> to establish biofilms and infect host cells. Conclusions: This investigation showed that salad leaf extracts can markedly enhance bacterial virulence, which has implications for bagged salad leaf consumer safety if the leaves become contaminated with pathogenic bacteria such as <i>Listeria</i>.https://www.mdpi.com/2076-2607/13/2/252green salad leaves<i>Listeria</i>growthvirulence
spellingShingle Asma Alsharif
Lama Aldawsari
Giannis Koukkidis
Primrose Freestone
The Impact of Compounds Released from Damaged Salad Leaves on the Growth and Virulence of <i>Listeria monocytogenes</i>
Microorganisms
green salad leaves
<i>Listeria</i>
growth
virulence
title The Impact of Compounds Released from Damaged Salad Leaves on the Growth and Virulence of <i>Listeria monocytogenes</i>
title_full The Impact of Compounds Released from Damaged Salad Leaves on the Growth and Virulence of <i>Listeria monocytogenes</i>
title_fullStr The Impact of Compounds Released from Damaged Salad Leaves on the Growth and Virulence of <i>Listeria monocytogenes</i>
title_full_unstemmed The Impact of Compounds Released from Damaged Salad Leaves on the Growth and Virulence of <i>Listeria monocytogenes</i>
title_short The Impact of Compounds Released from Damaged Salad Leaves on the Growth and Virulence of <i>Listeria monocytogenes</i>
title_sort impact of compounds released from damaged salad leaves on the growth and virulence of i listeria monocytogenes i
topic green salad leaves
<i>Listeria</i>
growth
virulence
url https://www.mdpi.com/2076-2607/13/2/252
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