Wang Baotun, Hu Jianmei, Feng Juan, Zhang Yaqiu, Sun Yanxin, Jiang Biao, Li Wei, Liu Chun, Huang Yanhua, Su Youlu
Innovative Institute of Animal Healthy Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China; Key Laboratory of South China Sea Fishery Resources Development and Utilization, Ministry of Agriculture and Rural Affairs, Guangzhou, 510300, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China.
Key Laboratory of South China Sea Fishery Resources Development and Utilization, Ministry of Agriculture and Rural Affairs, Guangzhou, 510300, China.
Fish Shellfish Immunol. 2022 May;124:47-55. doi: 10.1016/j.fsi.2022.03.030. Epub 2022 Mar 31.
A previous study confirmed that spotted sea bass (Lateolabrax maculatus), an economically important cultured species in East Asia, is a new host of Aeromonas veronii, which can cause acute death in these fish, but there is little in-depth understanding of this disease. In the present study, the virulence of 10 isolates of A. veronii derived from spotted sea bass was determined. It was found that the 18BJ181 isolate was a virulent strain and led to the fastest death of spotted sea bass. Death was determined to be within in 2-12 h, and resulted in abdominal effusion and varying degrees of hemorrhage in internal organs. Bacterial colonization analysis showed that the bacterial load in the spleen was highest, and was up to 3.1 × 10 cfu g. In addition, the bacteria proliferated massively in the blood and reached 2.4 × 10 cfu mL at 12 h after 18BJ181 strain infection, which was also a typical feature of acute septicemia. Histopathology of the spleen revealed edema in interstitial tissue, degeneration, and necrosis in lymphoid tissue, and hemorrhage in the capillary network. Transcriptome analysis of the spleen showed that the expression level of HSP70, CCL19, and IL-1β was extremely significantly up-regulated at 8 h after infection (P < 0.01), and the expression of these genes was normal at 24 h. These results revealed that A. veronii infection could rapidly activate the chemokine signal pathway and stimulate the acute inflammatory response in the host. The bacterial colonization, pathological features, and gene expression patterns in immune pathways will help us to better understand acute septicemia in spotted sea bass caused by A. veronii.
先前的一项研究证实，花鲈（Lateolabrax maculatus）是东亚一种具有重要经济价值的养殖鱼类，是维氏气单胞菌（Aeromonas veronii）的新宿主，该菌可导致这些鱼类急性死亡，但对这种疾病的深入了解甚少。在本研究中，测定了从花鲈分离出的10株维氏气单胞菌的毒力。结果发现，18BJ181分离株是一株强毒株，导致花鲈死亡最快。确定死亡时间在2 - 12小时内，导致腹部积液和内脏不同程度出血。细菌定殖分析表明，脾脏中的细菌载量最高，可达3.1×10 cfu/g。此外，细菌在血液中大量增殖，在18BJ181菌株感染后12小时达到2.4×10 cfu/mL，这也是急性败血症的典型特征。脾脏组织病理学显示间质组织水肿、淋巴组织变性和坏死以及毛细血管网出血。脾脏转录组分析表明，感染后8小时HSP70、CCL19和IL-1β的表达水平极显著上调（P < 0.01），而在24小时这些基因的表达正常。这些结果表明，维氏气单胞菌感染可迅速激活趋化因子信号通路并刺激宿主的急性炎症反应。细菌定殖、病理特征以及免疫途径中的基因表达模式将有助于我们更好地了解维氏气单胞菌引起的花鲈急性败血症。
