Impact of long term exposure to food-associated stresses on the virulence potencial of Listeria monocytogenes Strains
Autor(a) principal: | |
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Data de Publicação: | 2017 |
Tipo de documento: | Dissertação |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10400.14/33805 |
Resumo: | Human listeriosis, caused by the consumption of food contaminated with Listeria monocytogenes, is on the top five most commonly reported zoonosis under the surveillance of the European Union (EU), and presents the highest fatality rate. This foodborne pathogen is particularly problematic for the food industry because it is widespread in the environment, and because of its ability to survive under several stress conditions such as refrigeration temperatures, high salt concentrations, low water activity (aw), or a wide pH range. Exposure to a single or multiple sublethal stresses, as those impaired by food processing and food matrices, can enhance tolerance of Listeria monocytogenes to stresses and increase its survival and pathogenesis. This knowledge is needed to develop efficient control strategies to improve food safety. The main objective of this study was to investigate and compare the impact of exposure to stress conditions, frequently encountered in food-associated environments, on the virulence potential of eight L. monocytogenes strains, including strains EDG-e, Scott A and Lm 2542, associated with a listeriosis outbreak occurred in Portugal. Strains were grown in Brain Heart Infusion (BHI) medium (i) at low temperature (11 ºC, cold stress), (ii) supplemented with 6% NaCl (w/v) at low temperature (11 ºC; cold-osmotic stress), and (iii) at standard conditions (37 ºC), and tested for their ability to invade the human intestinal epithelial Caco-2 cells. Our results demonstrated that long-term exposure to cold stress conditions contributed for enhanced invasion efficiency of the four tested strains when compared to cells grown at 37 ºC, while no differences were observed when cells were grown at high salt concentrations. Further experiments evaluated the effect of exposure to these stress conditions on the survival of three selected L. monocytogenes strains through an in vitro gastrointestinal (GI) tract digestion model, using Ultra High Temperature (UHT) milk as food matrix, and subsequent invasiveness potential. The exposure to cold-osmotic stress increased the survival of one L. monocytogenes strain (Lm 2542) through the GI tract, that subsequently presented a significantly higher invasion efficiency. More studies are necessary for a better understanding of the mechanisms that overlap between adaptation to stress improving and an increase in virulence-related characteristics in these specific strains of L. monocytogenes. |
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Impact of long term exposure to food-associated stresses on the virulence potencial of Listeria monocytogenes StrainsListeria monocytogenesVirulenceStressInvasionCaco-2 cellsVirulênciaInvasãoCélulas Caco-2Domínio/Área Científica::Ciências Naturais::Ciências BiológicasHuman listeriosis, caused by the consumption of food contaminated with Listeria monocytogenes, is on the top five most commonly reported zoonosis under the surveillance of the European Union (EU), and presents the highest fatality rate. This foodborne pathogen is particularly problematic for the food industry because it is widespread in the environment, and because of its ability to survive under several stress conditions such as refrigeration temperatures, high salt concentrations, low water activity (aw), or a wide pH range. Exposure to a single or multiple sublethal stresses, as those impaired by food processing and food matrices, can enhance tolerance of Listeria monocytogenes to stresses and increase its survival and pathogenesis. This knowledge is needed to develop efficient control strategies to improve food safety. The main objective of this study was to investigate and compare the impact of exposure to stress conditions, frequently encountered in food-associated environments, on the virulence potential of eight L. monocytogenes strains, including strains EDG-e, Scott A and Lm 2542, associated with a listeriosis outbreak occurred in Portugal. Strains were grown in Brain Heart Infusion (BHI) medium (i) at low temperature (11 ºC, cold stress), (ii) supplemented with 6% NaCl (w/v) at low temperature (11 ºC; cold-osmotic stress), and (iii) at standard conditions (37 ºC), and tested for their ability to invade the human intestinal epithelial Caco-2 cells. Our results demonstrated that long-term exposure to cold stress conditions contributed for enhanced invasion efficiency of the four tested strains when compared to cells grown at 37 ºC, while no differences were observed when cells were grown at high salt concentrations. Further experiments evaluated the effect of exposure to these stress conditions on the survival of three selected L. monocytogenes strains through an in vitro gastrointestinal (GI) tract digestion model, using Ultra High Temperature (UHT) milk as food matrix, and subsequent invasiveness potential. The exposure to cold-osmotic stress increased the survival of one L. monocytogenes strain (Lm 2542) through the GI tract, that subsequently presented a significantly higher invasion efficiency. More studies are necessary for a better understanding of the mechanisms that overlap between adaptation to stress improving and an increase in virulence-related characteristics in these specific strains of L. monocytogenes.A listeriose é uma doença causada pelo consumo de alimentos contaminados com a bactéria Listeria monocytogenes, e está entre as cinco zoonoses mais frequentemente reportadas na União Europeia (UE), apresentando a taxa de mortalidade mais elevada. A L. monocytogenes é uma bactéria particularmente problemática para a indústria alimentar, visto que apresenta uma distribuição ubiquitária no meio ambiente e também a capacidade de sobreviver a várias condições de stresse, como por exemplo, temperaturas de refrigeração, concentrações elevadas de sal, valores de atividade da água (aw) baixos, e a uma ampla gama de pH. A exposição da bactéria a condições de stresse sub-letais, como os aplicados durante as diferentes fases de processamento e os encontrados na matriz alimentar, podem não só aumentar a tolerância a stresses subsequentes, como também aumentar a capacidade de sobrevivência e virulência de L. monocytogenes. Este conhecimento é essencial para desenvolver estratégias de controlo eficazes e garantir a segurança do produto. O principal objetivo deste estudo foi investigar e comparar o impacto da exposição a condições de stresse frequentemente encontradas em ambientes alimentares na potencial virulência de oito estirpes de L. monocytogenes, incluindo as estirpes EDG-e, Scott A e Lm 2542, associada a um surto de listeriose que ocorreu em Portugal. As estirpes foram cultivadas em meio de infusão de coração encefálico (BHI) (i) a baixa temperatura (11 ºC, stresse frio), (ii) suplementado com NaCl a 6% (w/v) a baixa temperatura (11 ºC, stresse frio-osmótico), e (iii) em condições padrão (37 ºC), e em seguida determinou-se para cada estirpe a eficiência de invasão in vitro na linha celular Caco-2 (células epiteliais intestinais). Os resultados obtidos demonstraram quatro das oito estirpes testadas apresentaram um aumento significativo da eficiência de invasão após exposição a ao stresse frio, em comparação aos valores obtidos para a condição padrão (37 ºC); por ouro lado, não foram detetadas diferenças significativas nos valores de eficiência de invasão entre a condição padrão e a exposição ao stress frio-osmótico. Três estirpes foram selecionadas para avaliar o efeito da exposição às condições de stresse na sobrevivência ao trato gastrointestinal (GI), utilizando um modelo de digestão in vitro, utilizando leite UHT (Ultra High Temperature) como matriz alimentar, e avaliar o potencial de invasão subsequente. A exposição ao stresse frio-osmótico aumentou a sobrevivência de uma estirpe L. monocytogenes (Lm 2542) ao trato GI, que posteriormente apresentou uma eficiência de invasão significativamente maior. Mais estudos serão necessários para uma melhor compreensão dos mecanismos que se sobrepõem entre a adaptação ao stresse e um maior potencial de virulência em estirpes específicas de L. monocytogenes.Teixeira, Paula Cristina MaiaFerreira, Vânia Alexandra BorgesVeritati - Repositório Institucional da Universidade Católica PortuguesaAlves, Ângela Sofia2021-06-21T17:08:21Z2018-04-2720172018-04-27T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10400.14/33805TID:201958139enginfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-07-12T17:39:22Zoai:repositorio.ucp.pt:10400.14/33805Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T18:27:24.576711Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Impact of long term exposure to food-associated stresses on the virulence potencial of Listeria monocytogenes Strains |
title |
Impact of long term exposure to food-associated stresses on the virulence potencial of Listeria monocytogenes Strains |
spellingShingle |
Impact of long term exposure to food-associated stresses on the virulence potencial of Listeria monocytogenes Strains Alves, Ângela Sofia Listeria monocytogenes Virulence Stress Invasion Caco-2 cells Virulência Invasão Células Caco-2 Domínio/Área Científica::Ciências Naturais::Ciências Biológicas |
title_short |
Impact of long term exposure to food-associated stresses on the virulence potencial of Listeria monocytogenes Strains |
title_full |
Impact of long term exposure to food-associated stresses on the virulence potencial of Listeria monocytogenes Strains |
title_fullStr |
Impact of long term exposure to food-associated stresses on the virulence potencial of Listeria monocytogenes Strains |
title_full_unstemmed |
Impact of long term exposure to food-associated stresses on the virulence potencial of Listeria monocytogenes Strains |
title_sort |
Impact of long term exposure to food-associated stresses on the virulence potencial of Listeria monocytogenes Strains |
author |
Alves, Ângela Sofia |
author_facet |
Alves, Ângela Sofia |
author_role |
author |
dc.contributor.none.fl_str_mv |
Teixeira, Paula Cristina Maia Ferreira, Vânia Alexandra Borges Veritati - Repositório Institucional da Universidade Católica Portuguesa |
dc.contributor.author.fl_str_mv |
Alves, Ângela Sofia |
dc.subject.por.fl_str_mv |
Listeria monocytogenes Virulence Stress Invasion Caco-2 cells Virulência Invasão Células Caco-2 Domínio/Área Científica::Ciências Naturais::Ciências Biológicas |
topic |
Listeria monocytogenes Virulence Stress Invasion Caco-2 cells Virulência Invasão Células Caco-2 Domínio/Área Científica::Ciências Naturais::Ciências Biológicas |
description |
Human listeriosis, caused by the consumption of food contaminated with Listeria monocytogenes, is on the top five most commonly reported zoonosis under the surveillance of the European Union (EU), and presents the highest fatality rate. This foodborne pathogen is particularly problematic for the food industry because it is widespread in the environment, and because of its ability to survive under several stress conditions such as refrigeration temperatures, high salt concentrations, low water activity (aw), or a wide pH range. Exposure to a single or multiple sublethal stresses, as those impaired by food processing and food matrices, can enhance tolerance of Listeria monocytogenes to stresses and increase its survival and pathogenesis. This knowledge is needed to develop efficient control strategies to improve food safety. The main objective of this study was to investigate and compare the impact of exposure to stress conditions, frequently encountered in food-associated environments, on the virulence potential of eight L. monocytogenes strains, including strains EDG-e, Scott A and Lm 2542, associated with a listeriosis outbreak occurred in Portugal. Strains were grown in Brain Heart Infusion (BHI) medium (i) at low temperature (11 ºC, cold stress), (ii) supplemented with 6% NaCl (w/v) at low temperature (11 ºC; cold-osmotic stress), and (iii) at standard conditions (37 ºC), and tested for their ability to invade the human intestinal epithelial Caco-2 cells. Our results demonstrated that long-term exposure to cold stress conditions contributed for enhanced invasion efficiency of the four tested strains when compared to cells grown at 37 ºC, while no differences were observed when cells were grown at high salt concentrations. Further experiments evaluated the effect of exposure to these stress conditions on the survival of three selected L. monocytogenes strains through an in vitro gastrointestinal (GI) tract digestion model, using Ultra High Temperature (UHT) milk as food matrix, and subsequent invasiveness potential. The exposure to cold-osmotic stress increased the survival of one L. monocytogenes strain (Lm 2542) through the GI tract, that subsequently presented a significantly higher invasion efficiency. More studies are necessary for a better understanding of the mechanisms that overlap between adaptation to stress improving and an increase in virulence-related characteristics in these specific strains of L. monocytogenes. |
publishDate |
2017 |
dc.date.none.fl_str_mv |
2017 2018-04-27 2018-04-27T00:00:00Z 2021-06-21T17:08:21Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10400.14/33805 TID:201958139 |
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http://hdl.handle.net/10400.14/33805 |
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TID:201958139 |
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eng |
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eng |
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openAccess |
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application/pdf |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
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RCAAP |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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