Naturally concurrent infections of bacterial and viral pathogens in disease outbreaks in cultured Nile tilapia (Oreochromis niloticus) farms
Naturally concurrent infections of bacterial and viral pathogens in disease outbreaks in cultured Nile tilapia (Oreochromis niloticus) farms
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DOI：
10.1016/j.aquaculture.2015.06.027
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发表时间：
2015-11-01
期刊：
影响因子：
4.5
通讯作者：
Rodkhum, Channarong
中科院分区：
文献类型：
--
作者：
Ha Thanh Dong;Vuong Viet Nguyen;Rodkhum, Channarong
养殖场因多种病原体感染造成的死亡损失可能超过单一感染。在这里，我们描述了尼罗罗非鱼(Oreochromis Niloticus)自然暴发疾病中潜在并存病原体的分离和鉴定，以及它们在红罗非鱼指龄模型中的致病性。在两个受影响的养殖场发现了细菌和虹彩病毒的混合感染。根据常规表型试验和16S rDNA片段序列分析，优势菌主要为柱状黄杆菌和韦氏气单胞菌，其余为无乳链球菌、志贺氏邻单胞菌和霍乱弧菌。用选定的单一细菌菌株进行的实验感染表明，α和β溶血弧菌对罗非鱼鱼种都有较高的致病性，而柱状芽孢杆菌和无乳链球菌的致病力较弱，志贺氏菌对罗非鱼无毒力。暴露于金黄色葡萄球菌或赤霉菌的鱼分别模仿自然感染鱼的主要内部和外部临床症状。这表明在本研究中，Veronii和F.Columnare是导致罗非鱼养殖场死亡损失的两个主要病原体，而其余的病原体可能是疾病暴发的机会性病原体。相关声明：作者强烈相信，我们的论文将为鱼类养殖，特别是尼罗罗非鱼(Oreochromis Niloticus)提供重要的知识。(C)2015爱思唯尔B.V.保留所有权利。
The reality of dead-loss in cultured fish farms due to multiple pathogen infections probably outweighs single infection. Here, we describe the isolation and characterization of the potential pathogens concurrently infected in natural disease outbreaks of Nile tilapia (Oreochromis niloticus) and their pathogenicity in the red tilapia finger-ling model. Co-infection of bacteria and Iridovirus was found in two affected farms. Based on conventional phenotypic tests and sequence analysis of 16S rDNA fragment, most predominant bacteria were identified as Flavobacterium columnare and Aeromonas veronii, and remainders were Streptococcus agalactiae, Plesiomonas shigeloides and Vibrio cholerae. Experimental infection with selected single bacterial isolates demonstrated that both alpha-and beta-hemolytic A. veronii isolates were highly pathogenic to tilapia fingerling, whereas F. columnare and S. agalactiae were less virulent and P. shigeloides was avirulent. The fish exposed to A. veronii or F. columnare mimicked major internal and external clinical signs of naturally infected fish respectively. This suggests that A. veronii and F. columnare are two main pathogens co-responsible for the dead-loss of cultured tilapia farms in the present study, whereas remaining pathogens might serve as opportunistic pathogens in the disease outbreaks.Statement of relevance: The authors strongly believe that our manuscript would provide significant knowledge to fish aquaculture especially to that of the Nile tilapia (Oreochromis niloticus). (C) 2015 Elsevier B.V. All rights reserved.