Characterization of Listeria monocytogenes enhanced cold-tolerance variants isolated during prolonged cold storage

Research output: Contribution to journalJournal article – Annual report year: 2019Researchpeer-review

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Characterization of Listeria monocytogenes enhanced cold-tolerance variants isolated during prolonged cold storage. / Hingston, Patricia A.; Hansen, Lisbeth Truelstrup; Pombert, Jean-Francois; Wang, Siyun.

In: International Journal of Food Microbiology, Vol. 306, 108262, 2019.

Research output: Contribution to journalJournal article – Annual report year: 2019Researchpeer-review

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@article{7de1d8158b814b0fac29c17e8647387c,
title = "Characterization of Listeria monocytogenes enhanced cold-tolerance variants isolated during prolonged cold storage",
abstract = "In this study, we show that growth and prolonged storage of Listeria monocytogenes at 4 °C can promote the selection of variants with enhanced cold and heat tolerance. Enhanced cold-tolerance (ECT) variants (n = 12) were successfully isolated from a strain with impaired cold growth abilities following 84 days of storage at 4 °C in brain heart infusion broth (BHIB). Whole genome sequencing, membrane fatty acid analysis, and stress tolerance profiling were performed on the parent strain and two ECT variants: one displaying regular-sized colonies and the other displaying small colonies when grown at 37 °C on BHI agar. Under cold stress conditions, the parent strain exhibited an impaired ability to produce branched-chain fatty acids which are known to be important for cold adaptation in L. monocytogenes. The ECT variants were able to overcome this limitation, a finding which is hypothesized to be associated with the identification of two independent single-nucleotide polymorphisms in genes encoding subunits of acetyl-coA carboxylase, an enzyme critical for fatty acid biosynthesis. While the ECT phenotype was not found to be associated with improved salt (BHIB + 6{\%} NaCl, 25 °C), acid (BHIB pH 5, 25 °C) or desiccation (33{\%} RH, 20 °C) tolerance, the small-colony variant exhibited significantly (p < 0.05) enhanced heat tolerance at 52 °C in buffered peptone water compared to the parent strain and the other variant. The results from this study demonstrate that the continuous use of refrigeration along the food-supply chain has the potential to select for L. monocytogenes variants with enhanced cold and heat tolerance, highlighting the impact that microbial intervention strategies can have on the evolution of bacterial strains and likewise, food safety.",
keywords = "Whole-genome sequencing, Cold toleranceMembrane-lipid profiling, Stress-tolerance profiling, Single-nucleotide polymorphisms",
author = "Hingston, {Patricia A.} and Hansen, {Lisbeth Truelstrup} and Jean-Francois Pombert and Siyun Wang",
year = "2019",
doi = "10.1016/j.ijfoodmicro.2019.108262",
language = "English",
volume = "306",
journal = "International Journal of Food Microbiology",
issn = "0168-1605",
publisher = "Elsevier",

}

RIS

TY - JOUR

T1 - Characterization of Listeria monocytogenes enhanced cold-tolerance variants isolated during prolonged cold storage

AU - Hingston, Patricia A.

AU - Hansen, Lisbeth Truelstrup

AU - Pombert, Jean-Francois

AU - Wang, Siyun

PY - 2019

Y1 - 2019

N2 - In this study, we show that growth and prolonged storage of Listeria monocytogenes at 4 °C can promote the selection of variants with enhanced cold and heat tolerance. Enhanced cold-tolerance (ECT) variants (n = 12) were successfully isolated from a strain with impaired cold growth abilities following 84 days of storage at 4 °C in brain heart infusion broth (BHIB). Whole genome sequencing, membrane fatty acid analysis, and stress tolerance profiling were performed on the parent strain and two ECT variants: one displaying regular-sized colonies and the other displaying small colonies when grown at 37 °C on BHI agar. Under cold stress conditions, the parent strain exhibited an impaired ability to produce branched-chain fatty acids which are known to be important for cold adaptation in L. monocytogenes. The ECT variants were able to overcome this limitation, a finding which is hypothesized to be associated with the identification of two independent single-nucleotide polymorphisms in genes encoding subunits of acetyl-coA carboxylase, an enzyme critical for fatty acid biosynthesis. While the ECT phenotype was not found to be associated with improved salt (BHIB + 6% NaCl, 25 °C), acid (BHIB pH 5, 25 °C) or desiccation (33% RH, 20 °C) tolerance, the small-colony variant exhibited significantly (p < 0.05) enhanced heat tolerance at 52 °C in buffered peptone water compared to the parent strain and the other variant. The results from this study demonstrate that the continuous use of refrigeration along the food-supply chain has the potential to select for L. monocytogenes variants with enhanced cold and heat tolerance, highlighting the impact that microbial intervention strategies can have on the evolution of bacterial strains and likewise, food safety.

AB - In this study, we show that growth and prolonged storage of Listeria monocytogenes at 4 °C can promote the selection of variants with enhanced cold and heat tolerance. Enhanced cold-tolerance (ECT) variants (n = 12) were successfully isolated from a strain with impaired cold growth abilities following 84 days of storage at 4 °C in brain heart infusion broth (BHIB). Whole genome sequencing, membrane fatty acid analysis, and stress tolerance profiling were performed on the parent strain and two ECT variants: one displaying regular-sized colonies and the other displaying small colonies when grown at 37 °C on BHI agar. Under cold stress conditions, the parent strain exhibited an impaired ability to produce branched-chain fatty acids which are known to be important for cold adaptation in L. monocytogenes. The ECT variants were able to overcome this limitation, a finding which is hypothesized to be associated with the identification of two independent single-nucleotide polymorphisms in genes encoding subunits of acetyl-coA carboxylase, an enzyme critical for fatty acid biosynthesis. While the ECT phenotype was not found to be associated with improved salt (BHIB + 6% NaCl, 25 °C), acid (BHIB pH 5, 25 °C) or desiccation (33% RH, 20 °C) tolerance, the small-colony variant exhibited significantly (p < 0.05) enhanced heat tolerance at 52 °C in buffered peptone water compared to the parent strain and the other variant. The results from this study demonstrate that the continuous use of refrigeration along the food-supply chain has the potential to select for L. monocytogenes variants with enhanced cold and heat tolerance, highlighting the impact that microbial intervention strategies can have on the evolution of bacterial strains and likewise, food safety.

KW - Whole-genome sequencing

KW - Cold toleranceMembrane-lipid profiling

KW - Stress-tolerance profiling

KW - Single-nucleotide polymorphisms

U2 - 10.1016/j.ijfoodmicro.2019.108262

DO - 10.1016/j.ijfoodmicro.2019.108262

M3 - Journal article

VL - 306

JO - International Journal of Food Microbiology

JF - International Journal of Food Microbiology

SN - 0168-1605

M1 - 108262

ER -