Molecular Mechanisms underlying the Interaction of Salmonella Enteritidis with the Hen Oviduct and Survival in Eggs

食品工业努力将沙门氏菌食物中毒的风险降至最低。在大约2500种不同类型的沙门氏菌（血清型）中，与食物有关的最重要的一种是肠炎沙门氏菌（SE），许多人通过食用受感染的鸡蛋而患病，尽管在英国以外，禽肉也可能受到污染。SE是一种非常重要的人类病原体，因为它不像几乎所有其他沙门氏菌那样局限于蛋壳，当鸡蛋还在母鸡体内时，它就可以感染鸡蛋内容物。这种细菌也比其他沙门氏菌更能在鸡蛋中存活和生长。英国蛋业在控制感染本国人的地方性SE菌株方面非常成功，因为母鸡被注射了抗SE疫苗。这一重要的控制政策正受到威胁，因为其他类型的沙门氏菌已被证明能够感染鸡蛋内容物。此外，从英国境外进口的鸡蛋已将不同类型的SE引入该国，这可能无法通过接种疫苗得到很好的控制，因为目前的疫苗是基于地方性SE菌株。SE似乎非常适合感染鸡。它在这种动物体内具有自然侵袭性，能够感染并持续存在于母鸡的生殖组织中，并从那里转移到正在形成的鸡蛋的内容物中。一旦进入鸡蛋，它就能比其他沙门氏菌更好地破坏蛋白的抗菌防御，而且一旦产下完整的鸡蛋，它就能更好地在鸡蛋中生长。世界范围内与鸡蛋有关的人类SE感染大流行已经感染了数百万人，夺去了数千人的生命。事实也证明，这对各国政府和国际蛋业来说是一个巨大的财政负担。尽管大流行持续了20多年，但人们对SE在母鸡中的行为知之甚少，也不知道为什么SE在体内如此擅长感染鸡蛋。如果要更好地保护消费者免受蛋源性沙门氏菌病的侵害，疫苗保护鸡免受不同类型SE的侵害至关重要。这需要更好地理解是什么使SE作为一种鸟类病原体变得特别。这项工作的目的是确定允许SE感染并在母鸡生殖组织中持续存在的特征，并将其与家禽中发现的其他沙门氏菌区分开来。这项工作将探索与其他沙门氏菌不同的SE表面结构允许细菌在组织中持续存在并感染鸡蛋的假设。更好地了解SE与母鸡之间的相互作用，最终可以通过开发改进的疫苗来提高动物福利和改善食品安全。

The food industry strives to minimise the risks of salmonella food poisoning for consumers. Of the ~ 2500 different types of salmonella (serovars) the most important one associated with food is Salmonella Enteritidis (SE) and many people become ill through the consumption of infected eggs although, outside the UK, poultry meat can also be contaminated. SE is so important as a human pathogen because it is not confined to egg shells like almost all other salmonellae and can infect egg contents while they are still inside the hen. The bacterium is also better able to survive and grow in egg contents than other salmonellas. The UK egg industry has been very successful in controlling the endemic strains of SE that infect people in this country because hens are given an anti-SE vaccine. This important control policy is under threat because other types of salmonella have been shown to be able to infect egg contents. In addition, the importation of eggs from outside the UK has introduced different SE types into the country, which might not be as well controlled by vaccination, as current vaccines are based on endemic SE strains. SE seems to be ideally suited to infect chickens. It is naturally invasive in this animal, is able to infect and persist in hen reproductive tissues and to move from there into the contents of the forming egg. Once inside the egg it is better able to subvert the anti-bacterial defences of the albumen than other salmonella and better able to grow in whole eggs, once they have been laid. The worldwide egg-associated pandemic of human SE infection has infected many millions of people and claimed many thousands of lives. It has also proved to be an enormous financial burden to governments and the international egg industry. Despite the pandemic lasting over 20 years, little is known about the behaviour of SE in the hen and why it is apparently so adept at infecting eggs in vivo. If consumers are to be better protected from egg borne salmonellosis it is vital that vaccines protect chickens from different types of SE. This requires a much better understanding of what makes SE special as an avian pathogen. The purpose of this work is to identify the characteristics that allow SE to infect and persist in hen reproductive tissues and that differentiate it from other salmonellae found in poultry. The work will explore the hypotheses that SE surface structures different from those in other salmonellae allow the bacterium is persist in the tissues and infect eggs. A better understanding of the interaction between SE and the hen could eventually enhance animal welfare and improve food safety by allowing the development of improved vaccines.