Molecular basis of foodborne disease risk of variants of Salmonella Typhimurium DT193 and U288

沙门氏菌每年在全世界造成约1.25亿起疾病，近100万人死亡。这种病原体引起的发病率和死亡率对资源丰富和资源贫乏的国家的经济都有重大影响。大多数非伤寒沙门氏菌病例被认为是由食物和食品的粪便污染引起的，无论是直接在食物链中还是在家庭或餐馆中交叉污染。其中一个常见的关键步骤是细菌从通常发现这种病原体的牲畜和家禽进入食物链。然而，尽管几乎所有类型的沙门氏菌都有可能导致人类疾病，并不是所有的沙门氏菌都与人类疾病有关。了解这些过程是如何工作的，对于检测牲畜中的高风险沙门氏菌类型和食物链，并努力减少沙门氏菌进入这些环境的可能性。我们建议研究两种常见的沙门氏菌，这两种沙门氏菌都存在于猪群黄油中，对食品安全具有不同的风险。我们将在遗传和行为水平上研究这些细菌，以了解不同类型的细菌如何在英国的猪群中传播，以及它们如何进入我们的食物并在其中生存。首先，将对鼠伤寒沙门氏菌的猪和食物链分离株进行全基因组测序，并将其基因组中的变异用于定义它们如何传播到食物链和人类中。然后，我们将研究可能影响食物变异所构成威胁的重要行为变异。由于待研究的沙门氏菌的类型在遗传上密切相关，因此遗传差异的数量很少，这使得有可能识别与变异体的行为改变相关的候选差异。沙门氏菌类型的遗传差异是监测的潜在候选目标，以确定更有可能对食品安全构成风险的类型，或采取其他干预策略，以降低它们进入食物链的可能性。

The bacterium Salmonella accounts for about 125 million incidents of disease worldwide each year, and nearly a million deaths. The morbidity and mortality caused by this pathogen has a significant impact on the economies of both resource rich and resource poor countries. Most cases of non-typhoidal Salmonella are thought to result from fecal contamination of food and food products, either directly in the food chain or by cross contamination in the home or restaurants. A common and therefore critical step for this is the entry of the bacterium into the food chain from livestock and poultry in which this pathogen is commonly found. However, even though virtually all types of Salmonella have the potential to cause disease in man, not all are commonly associated with disease in man. Understanding how these processes work is critical to the detection of high risk types of Salmonella in livestock and the food chain, and efforts to decrease the likelihood of Salmonella entering these environments. We propose to study two common types of Salmonella that are both present in pig herds butter present distinct risk to food safety. We will study these bacteria at a genetic and behavioural level to understand how the different types circulate in pig populations in the UK and how they enter and survive in our food. First a collection of pig and food chain isolates of Salmonella Typhimurium will be whole genome sequenced and the variation in their genome used to define the how they spread into the food chain and into the human population. Then we will study important behavioural variations that may impact the threat posed by the variants in food. As the types of Salmonella to be studied are genetically closely related, the number of genetic differences are small, which makes it possible to identify candidate differences associated with altered behaviours of the variants. Genetic differences in types of Salmonella are potential candidates targets for surveillance to identify types more likely to represent a risk to food safety or for other intervention strategies aimed at decreasing the likelihood that they will enter the food chain.