大口黑鲈源维氏气单胞菌致病菌的分离鉴定及其毒力和耐药基因分析  

Isolation,Identification,Virulence and Drug Resistance Genes Analysis of Aeromonas veronii from Micropterus salmoides

作　　者：何雪雯 赵浩航 温依铭 夏洪丽 喻大鹏 夏立群[1,2] 鲁义善 HE Xuewen;ZHAO Haohang;WEN Yiming;XIA Hongli;YU Dapeng;XIA Liqun;LU Yishan(College of Fisheries,Guangdong Ocean University/Guangdong Key Laboratory of Aquatic Animal Disease Control and Healthy Culture/Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes,Zhanjiang 524088,China;Shenzhen Institute of Guangdong Ocean University,Shenzhen 518120,China)

机构地区：[1]广东海洋大学水产学院/广东省水产动物病害防控与健康养殖重点实验室/广东省水产经济动物病害控制重点实验室,广东湛江524088 [2]广东海洋大学深圳研究院,广东深圳518120

出　　处：《广东农业科学》2024年第7期57-65,共9页Guangdong Agricultural Sciences

基　　金：国家重点研发计划项目(2020YFD0900201);中山市社会公益与基础研究项目(2021B2056)。

摘　　要：【目的】分离大口黑鲈(Micropterus salmoides)患病组织中的致病菌,鉴定致病菌的生理特性,分析其毒力和耐药基因,以期指导临床科学用药。【方法】从广东湛江某养殖鱼厂的患病大口黑鲈病变组织中采集样本,采用稀释涂布法分离细菌,经16S rRNA基因序列比对和生化试验鉴定种属,并进行毒力基因、耐药基因和药敏特性等鉴定。【结果】分离出菌落形态呈圆形、表面光滑呈乳白色、不透明的细菌,编号为MSB-2。经革兰氏染色、生理生化反应等表型鉴定为革兰氏阴性菌中的气单胞菌属(Aeromonas)。通过扩增16S rRNA基因序列并构建系统发育树,进一步鉴定该菌为维氏气单胞菌(A.veronii)。该菌株具有act、aer、aexT等毒力相关基因及tetC、tetA、sull等耐药相关基因。药敏试验结果表明,该菌对羧苄西林、多西环素、头孢氨苄、新霉素、庆大霉素、头孢拉定、米诺环素、头孢唑林等药物敏感。对健康大口黑鲈进行人工回归感染病原菌后,出现与病鱼相似的临床症状,如腹鳍及胸鳍基部充血、肛门红肿、腹部明显膨大等,解剖发现腹腔有大量积液,与自然患病的症状相同。【结论】维氏气单胞菌是引起此次大口黑鲈疾病的致病菌,养殖过程中可选用新霉素、多西环素等批准渔用药物进行防治。【Objective】The causative agent was isolated from the diseased Micropterus salmoides tissue.The physiological properties of the pathogenic bacteria were identified,and their virulence genes and drug resistance genes were analyzed,with an aim to provide guidance for the scientific use of drugs in clinical practice.【Method】Samples were collected from pathologic tissues of diseased M.salmoides from a fish breeding factory in Zhanjiang,Guangdong Province,China.The bacteria were isolated by dilution coating method,the 16S rRNA sequence comparison and biochemical tests were performed to identify the species,and the virulence genes,drug resistance genes and drug sensitivity characteristics were also identified.【Result】Bacteria with round colony morphology,smooth milky white surface and opaque color were isolated from pathologic tissues of M.salmoides,and numbered as MSB-2,which was identified as Aeromonas in Gram-negative bacteria through phenotypic identification by Gram staining and physiological and biochemical reactions.By amplifying the 16S rRNA gene sequence and constructing a phylogenetic tree,the bacterium was further identified as A.veronii.The strain had virulencerelated genes such as act,aer and aexT and resistance-related genes such as tetC,tetA and sull.The results of the drug sensitivity test showed that the bacterium was sensitive to carbenicillin,doxycycline,cefalexin,neomycin,gentamicin,cefradine,minocycline,cefazolin and etc.Artificial regression of healthy M.salmoides infected with A.veronii showing clinical signs similar to those of diseased fish,which were the same as those of the naturally occurring disease,such as congestion of the ventral and pectoral fin bases,redness and swelling of the anus,and obvious enlargement of the abdomen,etc.And a large amount of fluid in the abdominal cavity was found by autopsy.【Conclusion】The above results indicate that A.veronii is the pathogenic bacterium causing this disease of M.salmoides,and the approved fishery drugs such as neomycin and doxycyc

关 键 词：大口黑鲈 维氏气单胞菌 分离与鉴定 毒力基因 耐药基因 药敏特性 

分 类 号：S965.199[农业科学—水产养殖] Q93.3[农业科学—水产科学]