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

食品行业努力将沙门氏菌食物中毒的风险降至最低。在约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，尽管在英国以外的地方，禽肉也可能受到污染。作为一种人类病原体，硒是如此重要，因为它不像几乎所有其他沙门氏菌那样局限于蛋壳，而且可以在鸡蛋内容物仍在母鸡体内时感染它们。与其他沙门氏菌相比，这种细菌在卵子内容物中生存和生长的能力也更强。英国蛋业在控制感染该国人民的地方性SE菌株方面取得了非常成功的成绩，因为母鸡被接种了抗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，从英国以外进口鸡蛋将不同的SE类型引入该国，这可能不会受到疫苗接种的很好控制，因为目前的疫苗是基于流行的SE毒株。SE似乎非常适合感染鸡。在这种动物中，它具有天然的侵袭性，能够感染并持续存在于母鸡的生殖组织中，并从那里进入形成卵子的内容物中。一旦进入鸡蛋，它比其他沙门氏菌更能破坏蛋白的抗菌防御，而且一旦产下鸡蛋，就能更好地在整个鸡蛋中生长。全球范围内与鸡蛋相关的人类SE感染大流行已经感染了数百万人，并夺走了数千人的生命。事实证明，这也给各国政府和国际蛋业带来了巨大的财政负担。尽管这场大流行持续了20多年，但人们对SE在母鸡体内的行为以及为什么它显然如此擅长在体内感染鸡蛋知之甚少。如果要更好地保护消费者免受鸡蛋传播的沙门氏菌病的影响，疫苗保护鸡免受不同类型的沙门氏菌感染是至关重要的。这需要更好地了解SE作为禽类病原体的特殊之处。这项工作的目的是确定允许SE感染并持续存在于母鸡生殖组织中的特征，以及将其与家禽中发现的其他沙门氏菌区分开来的特征。这项工作将探索这样的假设，即SE不同于其他沙门氏菌的表面结构允许细菌在组织中存活并感染虫卵。通过更好地了解SE和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.