Flavobacterium psychrophilum, the causative agent of bacterial coldwater disease (BCWD), causes significant economic losses worldwide, particularly in farmed Rainbow Trout Oncorhynchus mykiss. Over the last decade, multilocus sequence typing has revealed >30 clonal complexes (CCs) globally, comprised of >320 F. psychrophilum sequence types (STs). Despite the large number of CCs worldwide, CC-ST10, which is currently the largest CC affecting Rainbow Trout, has been the primary focus of F. psychrophilum virulence studies, leaving the role of other CCs as primary causes of BCWD epizootics unclear. To this end, fingerling Rainbow Trout were experimentally challenged with F. psychrophilum strains belonging to the CC now recognized as the second largest in the world (CC-ST191) alongside CC-ST10 strains. Cumulative percent mortality was 100% in 7-month-old Rainbow Trout and between 27.8% and 61.1% in 8-month-old Rainbow Trout. All examined F. psychrophilum STs were virulent to Rainbow Trout, and no significant differences in virulence between CC-ST10 and CC-ST191 were detected. Due to their wide distribution and high pathogenic potential, both CC-ST191 and CC-ST10 F. psychrophilum strains are excellent candidates for further research aimed at preventing and controlling BCWD.

中文翻译：

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体内实验提供证据表明，属于多位点序列分型克隆复合体 ST191 的嗜冷黄杆菌菌株对虹鳟鱼有毒

Flavobacterium psychrophilum 是细菌性冷水病 (BCWD) 的病原体，在世界范围内造成重大经济损失，尤其是养殖的虹鳟Oncorhynchus mykiss。在过去十年中，多位点序列分型已在全球范围内揭示了 >30 种克隆复合体 (CC)，包括 >320种嗜冷嗜热菌序列类型 (ST)。尽管全球有大量 CCs，但 CC-ST10 是目前影响虹鳟鱼的最大 CC，一直是F. psychrophilum毒力研究的主要焦点，而其他 CCs 作为 BCWD 流行病的主要原因的作用尚不清楚。为此，用F. psychrophilum 对虹鳟鱼鱼种进行了实验性挑战属于 CC 的菌株现在被认为是世界上第二大菌株 (CC-ST191)，与 CC-ST10 菌株一起。7 个月大的虹鳟鱼的累积死亡率为 100%，8 个月大的虹鳟鱼的死亡率在 27.8% 到 61.1% 之间。所有检查的F. psychrophilum STs 对虹鳟鱼都具有毒性，CC-ST10 和 CC-ST191 之间的毒性没有显着差异。由于其广泛分布和高致病潜力，CC-ST191 和 CC-ST10 F. psychrophilum菌株都是旨在预防和控制 BCWD 的进一步研究的极好候选者。