Identification of Streptococcus phocae pathotypes by comparing virulence-associated traits of harbor seal isolates in primary airway epithelial cell models

海洋哺乳动物是海洋生态系统健康状况的指示物种，受到众多生物和非生物因素的威胁。在德国海岸，斑海豹（Phoca vitulina）最常见的疾病是呼吸道感染。嗜盐链球菌（Streptococcus phocae）是常见的呼吸道感染病原菌之一，具有革兰氏阳性、β-溶血性、兼性厌氧、过氧化氢酶阴性和血清学异质性等特征。其分子感染机制几乎是未知的。因此，我们的目标是在应用项目中表征与毒性相关的特征，包括粘附、定殖、生物膜形成、侵袭和不同S.从斑海豹中分离的phocae菌株。将在用于研究呼吸道病原体的两种模型中进行研究：气液界面（ALI）培养物和从新鲜尸体中取样或由合作伙伴h.c.教授提供的港海豹精密切割肺切片（PCLS）。厄休拉·西伯特医生这两种模型包括高度分化的原代气道上皮细胞，并将使我们能够模仿自然条件，并调查病原体在其自然水库。此外，我们希望通过将表型与适当的基因型进行比较来识别致病型。一组不同的S. phocae菌株将由来自柏林的Marcus Fulde教授和博士提供。该项目的结果将有助于了解参与感染的海豹肺上皮细胞的分子机制。作为S. phocae是野生动物中的一种新出现的病原体，这可能很重要，即使其可能的人畜共患病潜力尚未得到澄清。

Marine mammals are indicator species for the health status of the marine ecosystem and threaten by numerous biotic and abiotic factors. At the German coast, the most common diseases in harbour seals (Phoca vitulina) are respiratory infections. Streptococcus phocae is one of the frequently isolated bacterial pathogen associated with those respiratory infections and characterized as gram-positive, beta-haemolytic, facultative anaerobic, catalase-negative and serologically heterogeneous. Its molecular infection mechanisms are nearly unknown. Thus, we aim within the applied project to characterize virulence-associated features including adherence, colonization, biofilm formation, invasion and cytotoxic effects of different S. phocae strains isolated from harbour seals. Investigations will be performed in two models that are used to study respiratory pathogens: air–liquid-interface (ALI) cultures and precision-cut lung slices (PCLS) of harbour seals that will be sampled from fresh carcasses or provided by the cooperation partner Prof. Prof. h.c. Dr. Ursula Siebert. Both models comprise highly differentiated primary airway epithelial cells and will allow us to mimicry natural conditions and to investigate a pathogen in its natural reservoir. In addition, we want to identify pathotypes by comparing the phenotypes with the appropriate genotypes. Genome sequences of a collection of different S. phocae strains will be provided by Prof. Dr. Marcus Fulde from Berlin. The outcome of this project will help to understand the molecular mechanisms that are involved in the infection of epithelial lung cells of harbour seals. As S. phocae being an emerging pathogen in wildlife this might be important, even as its possible zoonotic potential is not clarified yet.