scholarly journals Strain dependent expression of stress response and virulence genes of Listeria monocytogenes in meat juices as determined by microarray

2012 ◽  
Vol 152 (3) ◽  
pp. 116-122 ◽  
Author(s):  
Kalliopi Rantsiou ◽  
Anna Greppi ◽  
Matteo Garosi ◽  
Alberto Acquadro ◽  
Marios Mataragas ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Stress Response ◽  
Virulence Genes ◽  
Strain Dependent

σ B-dependent gene induction and expression in Listeria monocytogenes during osmotic and acid stress conditions simulating the intestinal environment

Microbiology ◽  
2004 ◽  
Vol 150 (11) ◽  
pp. 3843-3855 ◽  
Author(s):  
David Sue ◽  
Daniel Fink ◽  
Martin Wiedmann ◽  
Kathryn J. Boor
Keyword(s):  
Listeria Monocytogenes ◽  
Stress Response ◽  
Virulence Genes ◽  
Acid Stress ◽  
Exponential Phase ◽  
Wild Type ◽  
Transcript Accumulation ◽  
Gastrointestinal Infections ◽  
Stress Response Genes ◽  
Foodborne Infections

Listeria monocytogenes must overcome a variety of stress conditions in the host digestive tract to cause foodborne infections. The alternative sigma factor σ B, encoded by sigB, is responsible for regulating transcription of several L. monocytogenes virulence and stress-response genes, including genes that contribute to establishment of gastrointestinal infections. A quantitative RT-PCR assay was used to measure mRNA transcript accumulation for the virulence genes inlA and bsh, the stress-response genes opuCA and lmo0669 (encoding a carnitine transporter and an oxidoreductase, respectively) and the housekeeping gene rpoB. Assays were conducted on mid-exponential phase L. monocytogenes cells exposed to conditions reflecting osmotic (0·3 M NaCl) or acid (pH 4·5) conditions typical for the human intestinal lumen. In exponential-phase cells, as well as under osmotic and acid stress, inlA, opuCA and bsh showed significantly lower absolute expression levels in a L. monocytogenes ΔsigB null mutant compared to wild-type. A statistical model that normalized target gene expression relative to rpoB showed that accumulation of inlA, opuCA and bsh transcripts was significantly increased in the wild-type strain within 5 min of acid and osmotic stress exposure; lmo0669 transcript accumulation increased significantly only after acid exposure. It was concluded that σ B is essential for rapid induction of the tested stress-response and virulence genes under conditions typically encountered during gastrointestinal passage. As inlA, bsh and opuCA are critical for gastrointestinal infections in animal models, the data also suggest that σ B contributes to the ability of L. monocytogenes to cause foodborne infections.

scholarly journals Organic Acid Exposure Enhances Virulence in Some Listeria monocytogenes Strains Using the Galleria mellonella Infection Model

2021 ◽  
Vol 12 ◽  
Author(s):  
Minghao Li ◽  
Charles E. Carpenter ◽  
Jeff R. Broadbent
Keyword(s):  
Transcription Factor ◽  
Listeria Monocytogenes ◽  
Organic Acids ◽  
Virulence Genes ◽  
Galleria Mellonella ◽  
Acid Resistance ◽  
Infection Model ◽  
Bile Resistance ◽  
Strain Dependent

Prior research has suggested that the use of organic acids in the food industry may unintentionally enhance pathogenicity of Listeria monocytogenes strain N1-227 and R2-499. This study explored the connection between habituation to L-lactic acid or acetic acid and virulence in L. monocytogenes strains N1-227 and R2-499 using selected gene expression analysis and the in vivo Galleria mellonella wax worm model for infection. Expression of transcription factors (sigB and prfA) and genes related to acid resistance (gadD2, gadD3, and arcA) and bile resistance (bsh and bilE) or to virulence (inlA, inlB, hly, plcA, plcB, uhpT, and actA) was investigated by quantitative real-time PCR (qRT-PCR), while in vivo virulence was assessed by following the lethal time to 50% population mortality (LT50) of G. mellonella larvae after injection of untreated and habituated L. monocytogenes. Twenty minutes of habituation to the organic acids at pH 6.0 significantly increased expression of key acid and bile stress response genes in both strains, while expression of virulence genes was strain-dependent. The expression of transcription factor sigB was strain-dependent and there was no significant change in the expression of transcription factor prfA in both strains. Habituation to acid increased virulence of both strains as evidenced by decreased LT50 of G. mellonella larvae injected with Listeria habituated to either acid. In summary, habituation of both L. monocytogenes strains to organic acids up-regulated expression of several stress and virulence genes and concurrently increased virulence as measured using the G. mellonella model.

Analysis of virulence genes and molecular typing of Listeria monocytogenes isolates from human, food, and livestock from 2008 to 2016 in Iran

2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Masoud Naghizadeh Heidarlo ◽  
Lida Lotfollahi ◽  
Saber Yousefi ◽  
Vahid Lohrasbi ◽  
Gholamreza Irajian ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Molecular Typing ◽  
Virulence Genes ◽  
Human Food

Low Potential Virulence Associated with Mutations in the inlA and prfA Genes in Listeria monocytogenes Isolated from Raw Retail Poultry Meat

2013 ◽  
Vol 76 (1) ◽  
pp. 129-132 ◽  
Author(s):  
VICTORIA LÓPEZ ◽  
JAIME NAVAS ◽  
JOAQUÍN V. MARTÍNEZ-SUÁREZ
Keyword(s):  
Listeria Monocytogenes ◽  
Gel Electrophoresis ◽  
Virulence Genes ◽  
Pulsed Field Gel Electrophoresis ◽  
Poultry Meat ◽  
Pathogenic Potential ◽  
Molecular Serotyping ◽  
Potential Source ◽  
Raw Foods ◽  
Over Time

Packaged raw foods can represent a potential source of Listeria monocytogenes contamination when opened at home, and listeriosis is associated with the consumption of undercooked raw foods. The aim of this study was to characterize a group of L. monocytogenes strains isolated from 56 packages of raw chicken meat from a single brand in order to determine the diversity of the strains that dominate in a particular food over time, as well as their pathogenic potential. Forty (71%) samples were found to be positive for L. monocytogenes, and three isolates per sample were subjected to PCR molecular serotyping. Subtyping of 45 isolates from different manufacturing dates (n = 40) or different molecular serotype within the same sample (n = 5) identified 11 different L. monocytogenes subtypes as defined by pulsed-field gel electrophoresis and sequencing of virulence genes actA and inlA. Two of the subtypes accounted for 51% of the isolates. About 40% of isolates (three subtypes) were found to potentially present attenuated virulence because of the presence of mutations in the prfA and inlA genes.

scholarly journals Transport and Catabolism of Pentitols by Listeria monocytogenes

2016 ◽  
Vol 26 (6) ◽  
pp. 369-380 ◽  
Author(s):  
Takfarinas Kentache ◽  
Eliane Milohanic ◽  
Thanh Nguyen Cao ◽  
Abdelhamid Mokhtari ◽  
Francine Moussan Aké ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Pentose Phosphate ◽  
Phosphotransferase System ◽  
Virulence Gene Expression ◽  
Transposon Insertion ◽  
Encoding Gene ◽  
High Concentrations ◽  
Transcription Activators

Transposon insertion into <i>Listeria monocytogenes lmo2665</i>, which encodes an EIIC of the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS), was found to prevent <smlcap>D</smlcap>-arabitol utilization. We confirm this result with a deletion mutant and show that Lmo2665 is also required for <smlcap>D</smlcap>-xylitol utilization. We therefore called this protein EIIC<sup>Axl</sup>. Both pentitols are probably catabolized via the pentose phosphate pathway (PPP) because <i>lmo2665</i> belongs to an operon, which encodes the three PTS<sup>Axl</sup> components, two sugar-P dehydrogenases, and most PPP enzymes. The two dehydrogenases oxidize the pentitol-phosphates produced during PTS-catalyzed transport to the PPP intermediate xylulose-5-P. <i>L. monocytogenes</i> contains another PTS, which exhibits significant sequence identity to PTS<sup>Axl</sup>. Its genes are also part of an operon encoding PPP enzymes. Deletion of the EIIC-encoding gene <i>(lmo0508)</i> affected neither <smlcap>D</smlcap>-arabitol nor <smlcap>D</smlcap>-xylitol utilization, although <smlcap>D</smlcap>-arabitol induces the expression of this operon. Both operons are controlled by MtlR/LicR-type transcription activators (Lmo2668 and Lmo0501, respectively). Phosphorylation of Lmo0501 by the soluble PTS<sup>Axl</sup> components probably explains why <smlcap>D</smlcap>-arabitol also induces the second pentitol operon. Listerial virulence genes are submitted to strong repression by PTS sugars, such as glucose. However, <smlcap>D</smlcap>-arabitol inhibited virulence gene expression only at high concentrations, probably owing to its less efficient utilization compared to glucose.

Comparison of the Stress Response of Listeria monocytogenes Strains with Sprout Colonization

2008 ◽  
Vol 71 (8) ◽  
pp. 1556-1562 ◽  
Author(s):  
LISA GORSKI ◽  
DENISE FLAHERTY ◽  
JESSICA M. DUHÉ
Keyword(s):  
Oxidative Stress ◽  
Statistical Analysis ◽  
Listeria Monocytogenes ◽  
Stress Response ◽  
Foodborne Pathogen ◽  
Acid Stress ◽  
Broccoli Sprouts ◽  
Alfalfa Sprouts ◽  
Different Strains ◽  
And Oxidative Stress

Twenty-nine strains of the foodborne pathogen Listeria monocytogenes were tested for their ability to colonize alfalfa, radish, and broccoli sprouts and their capacity to withstand acid and oxidative stress, two stresses common to the sprouting environment. Wide variation in the ability of different strains to colonize alfalfa sprouts were confirmed, but the variations among radish and broccoli sprouts were not as large. With a few exceptions, strains that were poor colonizers of alfalfa tended to be among the poorer colonizers of radish and broccoli and vice versa. The strains also were variable in their resistance to both acid and oxidative stress. Statistical analysis revealed no correlation between acid stress and sprout colonization, but there was a positive correlation between resistance to oxidative stress and colonization of all three sprout types. Although the response to oxidative stress is important for L. monocytogenes virulence, it also may be important for life outside of a host.

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