Chile is currently the second largest producer of farmed salmon worldwide, but Flavobacterium psychrophilum, as one of the most detrimental pathogens, is responsible for major losses during the freshwater culturing step in salmonid fish farms. An antigenic study conducted 10 years ago reported four serological groups using 20 F. psychrophilum Chilean strains. To reduce disease outbreaks and to develop vaccine candidates, antigenic knowledge needs to be regularly updated using a significant number of additional recent F. psychrophilum isolates. The present study aimed at investigating the serological diversity of 118 F. psychrophilum isolates collected between 2006 and 2018 from farmed Atlantic salmon (Salmo salar ), rainbow trout (Oncorhynchus mykiss ) and coho salmon (Oncorhynchus kisutch ). The current study supports an expansion of the known antigenic groups in Chile from 4 to 14. However, the use of the slide‐agglutination technique for serotyping is costly, is labour‐intensive and requires significant technical expertise. Addressing these points, the mPCR‐based procedure was a very useful tool for serotyping the collected Chilean F. psychrophilum isolates. This technique revealed the presence of diverse mPCR serotypes (i.e. types 0, 1, 2 and 4). Therefore, mPCR should be employed to select the bacterial strain(s) for vaccine development and to conduct follow‐up, selective breeding or epidemiological surveillance in Chilean fish farms. Given the presented findings, changes to Chilean fish‐farming practices are vital for ensuring the continued productivity and well‐being of farmed salmonids.

中文翻译：

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嗜冷黄杆菌的血清学多样性：使用从智利鲑鱼养殖场获得的分离株进行的重要更新。

智利目前是全球养殖鲑鱼的第二大生产国，但是，淡水杆菌是最有害的病原体之一，在鲑鱼养殖场的淡水养殖步骤中造成了重大损失。十年前进行的一项抗原研究报道了使用20株智利嗜热链球菌菌株的四个血清学组。为了减少疾病暴发和开发候选疫苗，需要使用大量其他近期的嗜热链球菌分离株定期更新抗原知识。本研究旨在调查2006年至2018年间从养殖的大西洋鲑鱼（Salmo salar）中收集的118株嗜热镰刀菌的血清学多样性），虹鳟鱼（Oncorhynchus mykiss）和银大麻哈鱼（Oncorhynchus kisutch）。目前的研究支持智利已知抗原组的数量从4个增加到14个。但是，使用滑动凝集技术进行血清分型的方法成本高昂，劳动强度大，并且需要大量的专业技术知识。针对这些问题，基于mPCR的程序是一种非常有用的工具，可以对收集的智利F. Psychrophilum进行血清分型。隔离株。这项技术揭示了多种mPCR血清型（即0、1、2和4型）的存在。因此，应该使用mPCR来选择用于细菌开发的细菌菌株，并在智利养鱼场进行后续，选择性育种或流行病学监测。根据提出的调查结果，对智利鱼类养殖方式的改变对于确保养殖鲑鱼的持续生产力和福祉至关重要。