Modification of a virulence-associated phenotype after growth of Listeria monocytogenes on food
Modification of a virulence-associated phenotype after growth of Listeria monocytogenes on food
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DOI：
10.1111/j.1365-2672.2006.02925.x
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发表时间：
2006-08-01
影响因子：
4
通讯作者：
Malle, P.
中科院分区：
文献类型：
--
作者：
Midelet-Bourdin, G.;Leleu, G.;Malle, P.
目的：为了评估不同食物对不同单核细胞增生李斯特菌株的体外毒力相关表型水平的影响，这些食物是否与李斯特菌病有关。单核细胞增多症的研究与体外细胞试验的基础上空斑形成试验与人类腺癌细胞系（HT-29）单层。3株L.单核细胞增多症在不同食物提取物的制备物（匀浆、1 μ m滤液或0.2 μ m滤液）中生长，所述食物提取物包括“rillettes”（罐装切碎的猪肉）、牛奶、生鲑鱼和冷熏鲑鱼]或在对照培养基、脑心浸液（BHI）中。将在37 ℃下在食物提取物或BHI中生长的细菌悬浮液用其生长培养基（食物提取物或BHI）或最低必需培养基稀释，然后接种在汇合的HT-29细胞单层上。食物提取物的过滤对细菌形成的噬菌斑数量没有显著影响。与其他食物提取物和BHI相比，当它们在rillettes提取物中生长时，注意到三种菌株的噬菌斑数量显著减少。在Rillettes提取物中生长后，菌株的体外毒力相关表型水平与弱毒力内部参考菌株L相似或低于其水平。442. history of life在牛奶和冷熏鲑鱼中生长后，对毒力相关表型的影响取决于菌株。与此相反，空斑形成试验表明，增加的毒力相关的表型时，菌株从营养丰富的培养基（食品提取物或BHI）切换到最低必需medium.Conclusions：在体外毒力相关的表型水平的研究菌株生长在BHI或冷熏鲑鱼是相同的控制强毒株EGD。相比之下，存在于细沟中的营养物因此可以显著减少噬斑的数量，但不会减少L.单核细胞增多症利用最低必需培养基作为稀释剂衰减改变的影响，食品提取物对毒力相关的表型在vitro.Conclusions：在本研究的实验设计，我们表明，食品的性质可以影响在体外毒力相关的表型水平的L。单核细胞增多症
Aim: To assess the effect of different foods, which have been implicated or not in cases of listeriosis, on the in vitro virulence-associated phenotype level of different Listeria monocytogenes strains.Methods and Results: The virulence-associated phenotype level of L. monocytogenes was studied with the in vitro cell test based on a plaque-forming assay with a human adenocarcinoma cell line (HT-29) monolayer. Three strains of L. monocytogenes were grown in preparations (homogenate, 1-mu m filtrate or 0.2-mu m filtrate) of different food extracts ['rillettes' (potted minced pork), milk, raw salmon and cold-smoked salmon] or in a control medium, brain heart infusion (BHI). The bacterial suspensions grown in food extracts or in BHI at 37 degrees C were diluted with their growth medium (food extract or BHI) or with minimum essential medium before seeding on confluent HT-29 cell monolayers. Filtration of food extracts had no significant effect on the plaque numbers formed by the bacteria. A significant decrease in the plaque numbers was noted for the three strains when they grew in the rillettes extracts, compared with the other food extracts and BHI. The levels of in vitro virulence-associated phenotype of the strains after growth in the rillettes extract were similar to or lower than that of the hypovirulent internal reference strain L. monocytogenes 442. After growth in milk and cold-smoked salmon, the impact on virulence-associated phenotype depended on the strain. In contrast, plaque-forming assay indicated increased virulence-associated phenotype when the strains were switched from a nutrient-rich medium (food extract or BHI) to a minimum essential medium.Conclusions: In vitro virulence-associated phenotype level of the studied strains grown in BHI or cold-smoked salmon was the same as the control virulent strain EGD. In contrast, the nutrients present in rillettes may therefore substantially reduce the number of plaques but not the growth of L. monocytogenes. The utilization of minimum essential medium as diluent attenuates changes the effect of the food extract on virulence-associated phenotype in vitro.Conclusions: In the experimental design of this study, we showed that the nature of the food could affect the in vitro virulence-associated phenotype level of L. monocytogenes.