Molecular interactions of Pasteurellaceae from porcine tonsil

在许多动物中，扁桃体在宿主免疫应答中发挥重要作用，作为第一道防御进入上呼吸道和胃肠道的抗原。巧合的是，它们也是许多生物体的重要定居点，可以作为许多重要病原体的入口。副猪嗜血杆菌和猪链球菌是在几乎所有猪的软腭扁桃体中发现的两种细菌。它们通常会持续存在而不会引起任何问题，但根据菌株和未知因素，这些生物体可能会入侵并导致致命的疾病，如败血症和脑膜炎。大量的研究试图确定这两种菌的致病机制和毒力因子，特别是H。在副猪种中，没有发现毒素等因素可以解释观察到的病理学。然而，越来越多的证据表明，细菌病原体的毒力可能会在合并感染中增加。本实验室最近的研究表明，当S. suis和H.寄生猪是一起长大的在接下来的5年里，我们计划对其他菌株的相互作用进行研究。parasuis和S.在开始模拟体内条件（例如，用血清、唾液、抗生素）的培养基中的共培养物中生长的猪。我们还将制作荧光标记的H。parasuis和S.利用激光扫描共聚焦显微镜研究了双物种生物膜的性质。同样，将通过qRT-PCR测量单一培养物和共培养物中选定毒力基因的表达，并使用RNA seq评价总体基因表达。除了这些体外研究之外，我们还计划使用我们的离体扁桃体器官培养系统和原代扁桃体上皮细胞在猪细胞存在下培养单培养物和共培养物时，通过qRT-PCR和RNA seq评估细菌基因表达。这项工作应提供新的见解如何重要的细菌病原体的上呼吸道的猪相互作用，以及他们如何可以从开始的入侵性病原体的转换。 在了解这些相互作用的过程中，我们希望能够确定开发更好的治疗和预防策略的目标，从而减少抗菌药物的使用并减少H. parasuis和S. suis和其他重要的猪细菌病原体。

In many animals, tonsils play a significant role in the host immune response by acting as a first defence against antigens entering the upper respiratory and gastrointestinal tracts. Paradoxically, they are also an important site of colonisation of many organisms and can act as a portal of entry for a number of important pathogens. Haemophilus parasuis and Streptococcus suis are two bacterial species found in the tonsil of the soft palate of almost all pigs. They often persist without causing any problems, but depending on the strain and unknown factors, these organisms can invade and cause fatal diseases such as septicaemia and meningitis. Numerous studies have been done to try to identify mechanisms of pathogenesis and virulence factors of these two species, but especially in the case of H. parasuis, no factors such as toxins have been identified that explain the observed pathology. There is growing evidence, however, that the virulence of bacterial pathogens may be increased in co-infections. Recent studies in our laboratory have revealed that many phenotypes including growth rate and resistance to serum and antibiotics are altered when S. suis and H. parasuis are grown together. Over the next 5 years we plan to characterize the interactions of additional strains of selected serovars of H. parasuis and S. suis grown in co-culture in media that begin to mimic in vivo conditions (e.g. with serum, saliva, antibiotics). We will also make fluorescently tagged stains of H. parasuis and S. suis and investigate the nature of dual species biofilms by laser scanning confocal microscopy. As well, the expression of selected virulence genes in mono-and co-cultures will be measured by qRT-PCR and global gene expression will be evaluated using RNA seq. In addition to these in vitro studies, we also plan to evaluate bacterial gene expression by qRT-PCR and RNA seq when mono and co-cultures are grown in the presence of swine cells using our ex vivo tonsil organ culture system and with primary tonsil epithelial cells. This work should provide novel insights into how important bacterial pathogens of the upper respiratory tract of swine interact and to how they can switch from begin commensals to invasive pathogens. In understanding these interactions, we hope to be able to identify targets for the development better treatment and prevention strategies that will lead to decreased antimicrobial usage and reduce the economic impact of H. parasuis and S. suis and other important bacterial pathogens of swine.