Streptococcus species are of major concern for both warm-water and cold-water salmonid species, and have zoonotic importance. While Lactococcus garvieae, associated with warm-water streptococcosis, causes thousands of tons of mortalities, Vagococcus salmoninarum, the causative agent of cold-water streptococcosis, leads to chronic disease and devastating mortality in broodstock. In the present study, five bacterial samplings were performed from outbreaks that occurred between winter 2019 and summer 2020 in rainbow trout broodstock. The isolates were comprehensively characterized by phenotypic tests, using the API 20 Strept, Rapid ID 32 Strept and BIOLOG GENIII test kits. The antimicrobial susceptibilities of the strains were compared by the disk diffusion method, according to the guidelines of the Clinical & Laboratory Standards Institute (CLSI), additionally on commonly used media such as mueller-hinton agar and tryptic soy agar. Following a genomic approach, we analyzed the VS-1 strain by whole-genome sequencing. Virulence genes and correlation data were supported with the histopathological examination of the affected organs and tissues. The genome of the VS-1 strain included 69 virulence genes and 31 antimicrobial resistance genes. This study is one of the most comprehensive researches on V. salmoninarum, and elucidates the phenotypic, genotypic, antimicrobial resistance and virulence characteristics of this species.

链球菌物种是温水和冷水鲑鱼物种的主要关注点，并且具有人畜共患重要性。尽管格氏乳球菌，用温水链球菌有关，导致成千上万吨的死亡率，Vagococcus鲑，冷水链球菌病的病原体，导致亲体的慢性疾病和毁灭性的死亡率。在本研究中，从 2019 年冬季至 2020 年夏季期间虹鳟亲鱼的爆发中进行了五次细菌采样。使用 API 20 Strept、Rapid ID 32 Strept 和 BIOLOG GENIII 测试试剂盒，通过表型测试对分离株进行了全面表征。根据临床和实验室标准协会 (CLSI) 的指导方针，通过圆盘扩散法比较菌株的抗菌敏感性，此外还使用常用培养基，如穆勒-欣顿琼脂和胰蛋白酶大豆琼脂。遵循基因组方法，我们通过全基因组测序分析了 VS-1 菌株。受累器官和组织的组织病理学检查支持毒力基因和相关数据。VS-1 菌株的基因组包括 69 个毒力基因和 31 个抗微生物基因。这项研究是最全面的研究之一V.salmoninarum，并阐明了该物种的表型、基因型、抗菌素耐药性和毒力特征。