Previously, Aeromonas sobria and A. salmonicida were identified to be the most prevalent species in salmonid farms in Korea. In this study, we evaluated the biochemical characteristics, antibiotic susceptibility and pathogenicity of A. salmonicida (3 isolates) and A. sobria (8 isolates) isolated from salmonids, and further investigated efficacy of A. salmonicida vaccine. In antibiotic susceptibility test, all of A. sobria isolates were resistant to amoxicillin and ampicillin. Six A. sobria and two A. salmonicida isolates were resistant to oxytetracycline. In challenge test, A. sobria isolates exhibited low pathogenicity in rainbow trout (Oncorhynchus mykiss) while one A. salmonicida isolate showed high pathogenicity with LD50 of 6.4 × 103 CFU/fish in rainbow trout and coho salmon (Oncorhynchus kisutch). Among virulence factors, secretion apparatus (ascV and ascC) and transcription regulatory protein (exsA) of type 3 secretion system and A-layer protein genes were differentially detected in DNA or cDNA of A. salmonicida isolates, indicating their contribution to the pathogenicity. A formalin-killed vaccine of highly pathogenic A. salmonicida isolate exhibited a protective effect with relative survival rate of 81.8% and 82.9% at 8 weeks and 16 weeks post-vaccination, respectively, in challenge test.

中文翻译：

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从韩国养殖鲑鱼中分离出的鲑鱼气单胞菌和索氏气单胞菌的鉴定，并开发了一种预防糠un病的疫苗。

以前，气单胞菌和沙门氏菌被认为是韩国鲑鱼养殖场中最流行的物种。在这项研究中，我们评估了从鲑鱼中分离出的沙门氏菌（3个分离株）和索氏曲霉（8个分离株）的生化特性，抗生素敏感性和致病性，并进一步研究了沙门氏菌疫苗的功效。在抗生素药敏试验中，所有的A. sobria菌株均对阿莫西林和氨苄青霉素具有抗药性。六个索非氏菌和两个沙门氏菌均对土霉素有抗药性。在挑战试验中，嗜盐曲霉分离株在虹鳟鱼（Oncorhynchus mykiss）中表现出低致病性，而一个鲑鱼分离株在虹鳟鱼和银大麻哈鱼（Oncorhynchus kisutch）中表现出高致病性，其LD50为6.4×103 CFU /鱼。在毒性因素中，在沙门氏菌分离株的DNA或cDNA中差异检测到3型分泌系统的分泌装置（ascV和ascC）和转录调节蛋白（exsA）以及A层蛋白基因，表明它们对致病性的贡献。在激发试验中，高致病性沙门氏菌分离株的福尔马林杀死的疫苗在疫苗接种后8周和16周显示出保护作用，相对存活率分别为81.8％和82.9％。