Molecular interactions of Pasteurellaceae from porcine tonsil

在许多动物中，扁桃体在宿主免疫反应中发挥着重要作用，它是抵御抗原进入上呼吸道和胃肠道的第一道屏障。矛盾的是，它们也是许多生物体定居的重要场所，并可以作为许多重要病原体进入的门户。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，不会造成任何问题，但根据菌株和未知因素的不同，这些微生物可能会入侵并导致败血症和脑膜炎等致命疾病。许多研究试图确定这两个物种的致病机制和毒力因素，但特别是在副猪嗜血杆菌的情况下，还没有发现毒素等因素来解释观察到的病理。然而，越来越多的证据表明，在混合感染中，细菌病原体的毒力可能会增加。我们实验室最近的研究表明，当猪链球菌和副猪链球菌一起生长时，许多表型，包括生长速度和对血清和抗生素的抵抗力都会发生变化。在接下来的5年里，我们计划描述在开始模拟体内条件(例如，与血清、唾液、抗生素)的培养基中共培养的副猪嗜血杆菌和猪链球菌的其他选定血清型菌株之间的相互作用。我们还将制作副猪链球菌和猪链球菌的荧光标记染色，并用激光扫描共聚焦显微镜研究双物种生物膜的性质。此外，选定的毒力基因在单一和联合培养中的表达将通过qRT-PCR进行测量，全球基因的表达将使用RNA序列进行评估。除了这些体外研究，我们还计划利用我们的体外扁桃体器官培养系统和原代扁桃体上皮细胞，在猪细胞存在的情况下，通过qRT-PCR和RNA序列来评估细菌基因的表达。这项工作应该为猪上呼吸道重要的细菌病原体如何相互作用以及它们如何从开始共生转变为侵入性病原体提供新的见解。通过了解这些相互作用，我们希望能够确定开发更好的治疗和预防策略的目标，从而减少抗菌剂的使用，并减少副猪链球菌和猪链球菌以及其他重要的猪细菌性病原体的经济影响。

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.