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The effect of wine on the survival and invasiveness ability of listeria monocytogenes
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Abstract(s)
Listeria monocytogenes é um patogénio de origem alimentar conhecido pela gravidade
da sua infeção, a listeriose, e pela sua capacidade de crescer em condições adversas, como
temperaturas de refrigeração, ampla gama de valores de pH, atividade de água baixa e elevada
salinidade. L. monocytogenes pode induzir a sua própria fagocitose por células epiteliais do
intestino do hospedeiro, seguido de replicação e de transferência direta para outras células. O
vinho é uma solução de composição complexa e tem atividade antimicrobiana comprovada
devido, principalmente, ao seu conteúdo de etanol, ácidos orgânicos e compostos fenólicos.
Este trabalho centrou-se em (i) comparar a suscetibilidade de estirpes de L. monocytogenes de
origem alimentar e clínica à ação antimicrobiana do vinho, e (ii) na avaliação da influência do
vinho sobre a capacidade de invasão de L. monocytogenes utilizando a linhagem de células
Caco- 2 (células epiteliais intestinais humanas).
Foram utilizados 39 isolados de L. monocytogenes, 22 de origem alimentar e 17 de
origem clínica pertencentes a diferentes serogrupos. Para medir o efeito de inativação do
vinho tinto, cada isolado foi submetido a uma diluição de 1:10 de vinho, durante 120
segundos, a 25 ºC. Verificou-se que o vinho exerceu um forte efeito antilisterial, porém
observou-se uma alta variabilidade fenotípica entre os isolados – os isolados clínicos
mostraram ser significativamente mais resistentes ao vinho do que os isolados alimentares.
Células viáveis de uma estirpe clínica (isolada a partir de um surto de listeriose que ocorreu
em Portugal) recolhidas após a exposição ao vinho durante 15 seg evidenciaram uma maior
capacidade de invadir a linha de células humanas Caco-2 em comparação com o controlo
correspondente não exposto ao vinho. Este efeito não foi observado quando o teste de invasão
foi realizado em dois outros isolados mais resistentes ao vinho. Tanto quanto é do nosso
conhecimento, este é o primeiro estudo que utiliza um número substancial de isolados de L.
monocytogenes de diferentes origens e com diversidade fenotípica e genética para estudar a
sua suscetibilidade ao vinho. O trabalho também é inovador na avaliação da influência do
vinho sobre as características de virulência de um organismo patogénio. Os resultados deste
estudo evidenciam que o vinho tinto pode atuar como uma barreira ao crescimento e
sobrevivência de L. monocytogenes, quando em contacto com alimentos contaminados.
Listeria monocytogenes is a foodborne pathogen known for the severity of its infection, listeriosis, and for its capability of growing at harsh conditions such as refrigeration temperatures, wide pH range, low water activity and high salinity. L. monocytogenes can induce its own phagocytosis by the host’s intestinal epithelial cells, followed by replication and direct transfer to other cells. Wine is a complex solution with proved antimicrobial activity due to its content of ethanol, organic acids and phenolics. This work focused on (i) comparing the susceptibility of food and clinical strains of L. monocytogenes towards wine, and (ii) on the evaluation of the influence of wine on the invasiveness ability of L. monocytogenes using the human intestinal epithelial cells Caco-2 cell line. Thirty-nine isolates of L. monocytogenes were used in this study, 22 of food and 17 of clinical origin belonging to different serogroups. To measure the inactivation effect of red wine, each isolate was subjected to a 1:10 dilution of wine, during 120 seconds, at 25 ºC. Wine was found to exert an antilisterial effect, though a high phenotypic variability was observed among isolates - clinical isolates were found to be significantly more resistant to red wine than food isolates. Viable cells of one clinical strain (isolated from a listeriosis outbreak occurred in Portugal), collected after exposure to wine for 15 sec showed enhanced ability to invade the human intestinal Caco-2 cell line when compared to the corresponding unexposed control. This effect was not observed when the invasion test was done on two other isolates more resistant to wine. This is, to the best of our knowledge, the first study using a substantial number of L. monocytogenes strains from different origins and diverse phenotypic and genetic characteristics to study the susceptibility to wine. It is also innovative on assessing the influence of red wine on virulence traits of a foodborne pathogen. The results of this study give evidence that red wine can be seen as a significant barrier to the growth and survival of L. monocytogenes when in contact with contaminated food (food consumption scenario, for example).
Listeria monocytogenes is a foodborne pathogen known for the severity of its infection, listeriosis, and for its capability of growing at harsh conditions such as refrigeration temperatures, wide pH range, low water activity and high salinity. L. monocytogenes can induce its own phagocytosis by the host’s intestinal epithelial cells, followed by replication and direct transfer to other cells. Wine is a complex solution with proved antimicrobial activity due to its content of ethanol, organic acids and phenolics. This work focused on (i) comparing the susceptibility of food and clinical strains of L. monocytogenes towards wine, and (ii) on the evaluation of the influence of wine on the invasiveness ability of L. monocytogenes using the human intestinal epithelial cells Caco-2 cell line. Thirty-nine isolates of L. monocytogenes were used in this study, 22 of food and 17 of clinical origin belonging to different serogroups. To measure the inactivation effect of red wine, each isolate was subjected to a 1:10 dilution of wine, during 120 seconds, at 25 ºC. Wine was found to exert an antilisterial effect, though a high phenotypic variability was observed among isolates - clinical isolates were found to be significantly more resistant to red wine than food isolates. Viable cells of one clinical strain (isolated from a listeriosis outbreak occurred in Portugal), collected after exposure to wine for 15 sec showed enhanced ability to invade the human intestinal Caco-2 cell line when compared to the corresponding unexposed control. This effect was not observed when the invasion test was done on two other isolates more resistant to wine. This is, to the best of our knowledge, the first study using a substantial number of L. monocytogenes strains from different origins and diverse phenotypic and genetic characteristics to study the susceptibility to wine. It is also innovative on assessing the influence of red wine on virulence traits of a foodborne pathogen. The results of this study give evidence that red wine can be seen as a significant barrier to the growth and survival of L. monocytogenes when in contact with contaminated food (food consumption scenario, for example).