Virulence aspects of Listeria monocytogenes LO28 high pressure-resistant variants

Boeijen, Ineke K. H. Van; Casey, Pat G.; Hill, Colin; Moezelaar, Roy; Zwietering, Marcel H.; Gahan, Cormac G. M.; Abee, Tjakko

doi:10.1016/j.micpath.2013.04.007

Cited by 8 publications

(2 citation statements)

References 23 publications

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“…Additionally, their growth rate at 37°C and in vitro phospholipase and hemolysin activities are similar to those of the WT (12). Previously, virulence of the WT and variants was assessed in a mouse infection assay, which showed reduced performance of some variants, including two ctsR mutants, but all variants remained infective (56). Similar studies with selected rpsU mutants may provide further information on their virulence potential.…”

Section: Discussionmentioning

confidence: 81%

Modeling and Validation of the Ecological Behavior of Wild-Type Listeria monocytogenes and Stress-Resistant Variants

Metselaar

Abee

Zwietering

et al. 2016

Appl Environ Microbiol

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Listeria monocytogenes exhibits a heterogeneous response upon stress exposure which can be partially attributed to the presence of stable stress-resistant variants. This study aimed to evaluate the impact of the presence of stress-resistant variants of Listeria monocytogenes and their corresponding trade-offs on population composition under different environmental conditions. A set of stress robustness and growth parameters of the wild type (WT) and an rpsU deletion variant was obtained and used to model their growth behavior under combined mild stress conditions and to model their kinetics under single-and mixed-strain conditions in a simulated food chain. Growth predictions for the WT and the rpsU deletion variant matched the experimental data generally well, although some deviations from the predictions were observed. The data highlighted the influence of the environmental conditions on the ratio between the WT and variant. Prediction of performance in the simulated food chain proved to be challenging. The trend of faster growth and lower stress robustness for the WT than for the rpsU variant in the different steps of the chain was confirmed, but especially for the inactivation steps and the time needed to resume growth after an inactivation step, the experimental data deviated from the model predictions. This report provides insights into the conditions which can select for stress-resistant variants in industrial settings and discusses their potential persistence in food processing environments. IMPORTANCEListeria monocytogenes exhibits a heterogeneous stress response which can partially be attributed to the presence of genetic variants. These stress-resistant variants survive better under severe conditions but have, on the other hand, a reduced growth rate. To date, the ecological behavior and potential impact of the presence of stress-resistant variants is not fully understood. In this study, we quantitatively assessed growth and inactivation behavior of wild-type L. monocytogenes and its stress-resistant variants. Predictions were validated under different conditions, as well as along a model food chain. This work illustrates the effects of environmental factors on population dynamics of L. monocytogenes and is a first step in evaluating the impact of population diversity on food safety. D iversity exists within bacterial populations which can, for example, be observed by tailing of inactivation curves upon stress exposure. This tail can be caused by either phenotypic or genotypic heterogeneity. Phenotypic heterogeneity refers to transiently increased resistance with a physiological or epigenetic background. Reasons for phenotypic heterogeneity can include the presence of persisters (1), bistability caused by noise in stochastic gene expression (2-4), or epigenetic phenotype switching (5). Genotypic heterogeneity refers to the presence of stable stressresistant variants with an inheritable stress-resistant phenotype caused by genomic alterations (6). These stable stress-resistant variants have bee...

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Section: Discussionmentioning

confidence: 81%

Modeling and Validation of the Ecological Behavior of Wild-Type Listeria monocytogenes and Stress-Resistant Variants

Metselaar

Abee

Zwietering

et al. 2016

Appl Environ Microbiol

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“…Likewise, virulence and reduced motility may be the result of a mutation in this gene corresponding to the loss of a single amino acid. This suppression could be related to a high-pressure tolerance [70,103].…”

Section: Listeria Monocytogenesmentioning

confidence: 95%

The Impact of Environmental Stresses in the Virulence Traits of Listeria monocytogenes Relevant to Food Safety

Pereira¹,

Alves²,

Ferreira³

et al. 2018

Listeria Monocytogenes

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Listeria monocytogenes is a foodborne pathogen, which causes listeriosis disease among humans and other animal species. Infections in humans mainly occur in immunocompromised individuals and are caused by the consumption of ready-to-eat and raw food products contaminated with the pathogen. To ensure survival in nature, L. monocytogenes easily adapts to different environmental conditions, and that justifies the hurdles to prevent bacterial growth inside the food chain. Exposure to a single or multiple sublethal stresses, as those impaired by food processing, food matrices, and the gastrointestinal tract, can enhance tolerance of L. monocytogenes to stresses and increase its survival and pathogenesis. This chapter summarizes the current information on the adaptive response of L. monocytogenes to different stresses, namely (1) cold stress, (2) acid stress, (3) osmotic stress, (4) desiccation stress, and (5) high hydrostatic pressure, and the impact of these stresses on L. monocytogenes virulence. The objective is to provide the background information that is necessary for the development of scientifically sound control strategies to improve food safety and to reduce the uncertainty of microbial risk assessments, associated to limited knowledge on the behavior of cells capable to adapt and survive stresses.

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The Effects of Environmental Conditions and External Treatments on Virulence of Foodborne Pathogens

Venkitanarayanan

Upadhyay

Nair

et al. 2017

Foodborne Pathogens

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Virulence aspects of Listeria monocytogenes LO28 high pressure-resistant variants

Cited by 8 publications

References 23 publications

Modeling and Validation of the Ecological Behavior of Wild-Type Listeria monocytogenes and Stress-Resistant Variants

Modeling and Validation of the Ecological Behavior of Wild-Type Listeria monocytogenes and Stress-Resistant Variants

The Impact of Environmental Stresses in the Virulence Traits of Listeria monocytogenes Relevant to Food Safety

The Effects of Environmental Conditions and External Treatments on Virulence of Foodborne Pathogens

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