杂交鲟源温和气单胞菌的分离鉴定及生物学特性的研究  

Isolation,identification,and biological characterization ofAeromonas sobria from hybrid sturgeon

作　　者：彭小倩 任朝颖 邓雪玥 刘晓云 詹泽玉 张雪扬 郑永华[1] 朱成科[1,2] PENG Xiao-qian;REN Chao-ying;DENG Xue-yue;LIU Xiao-yun;ZHAN Ze-yu;ZHANG Xue-yang;ZHENG Yong-hua;ZHU Cheng-ke(College of Fisheries,Southwest University,Chongqing 402460,China;Key Laboratory of Freshwater Fish Reproduction and Development,Ministry of Education,College of Fisheries,Southwest University,Chongqing 402460,China)

机构地区：[1]西南大学水产学院,重庆402460 [2]西南大学水产学院淡水鱼类资源与生殖发育教育部重点实验室,重庆402460

出　　处：《淡水渔业》2023年第3期62-70,共9页Freshwater Fisheries

基　　金：科技部“科技助力经济2020”重点专项(SQ2020YFF0425122);重庆市技术创新与应用发展专项(cstc2020jscx-lyjsAX0011)。

摘　　要：为探明引起彭水县某鲟养殖场杂交鲟(Acipenser baerii♀×A.schrencki♂)患病的病原,本研究从患病杂交鲟的腹水中分离出一株细菌(A20)。通过菌落形态观察、革兰氏染色、溶血性实验、生理生化特征、16S rDNA基因和gyrB基因序列分析对菌株A20进行鉴定,同时探究菌株A20的耐受性、毒力基因、半致死浓度和药物敏感性等生物学特性。结果显示:菌株A20鉴定为气单胞菌属(Aeromonas spp.)短杆状革兰氏阴性菌温和气单胞菌(A.sobria);菌株A20生长的最适pH为7,对温度和盐度的耐受力较强;该菌携带hlyA、ompA、alt、aer 4种毒力基因;人工回归感染实验结果表明菌株A20为导致杂交鲟患病的病原菌,LD 50为1.37×10^(7)CFU/mL;药敏结果表明,该菌对氟苯尼考、恩诺沙星等15种抗菌药物敏感。The hybrid sturgeon(Acipenser baerii♀×A.schrencki♂)is an important aquaculture species in China.But disease outbreaks have frequently occurred in the breeding process because of the deterioration of water quality in recent years.A large number of hybrid sturgeon died on a farm in Pengshui County,Chongqing,and the cumulative mortality rate reached 10%to 15%in August 2022.The diseased hybrid sturgeon showed symptoms such as sluggishness,surface bleeding,visceral congestion,and ascites.To explore the pathogen causing the disease of the hybrid sturgeon,a bacterial strain(A20)was isolated from the ascites of the diseased hybrid sturgeon in this study.The strain A20 was identified by analyzing the colony morphology,Gram staining,hemolysis test,physiological and biochemical characteristics,16S rDNA gene,and gyrB gene sequence analysis.Simultaneously explored biological characteristics such as the growth curve,pH tolerance,temperature tolerance,salinity tolerance,virulence gene,semi-lethal concentration,and drug sensitivity of strain A20.The results of physiological characteristics showed that the strain A20 was Aeromonas spp.,a short rod-shaped Gram-negative bacterium withβ-hemolytic.And the molecular biological identification further showed that the strain A20 was A.sobria.The results of the growth curve showed that A.sobria was in the logarithmic growth phase between 4 h to 7 h.The tolerance test showed that the optimal pH of A.sobria was 7,and it had a strong tolerance to temperature and salinity.The results of the virulence gene test showed that A.sobria carried four virulence genes,hlyA,ompA,alt,and aer.The results of the artificial regression infection test showed that A.sobria was the pathogenic bacteria that caused the disease of the hybrid sturgeon,and the cumulative LD 50 in 7 d was 1.37×107 CFU/mL.The antibiotics susceptibility results showed that A.sobria was sensitive to 15 antibiotics including florfenicol,and enrofloxacin.The above test results show that A.sobria has strong pathogenicity to hybrid

关 键 词：杂交鲟(Acipenser baerii♀×A.schrencki♂) 温和气单胞菌(Aeromonas sobria) 分离鉴定 耐受性实验 毒力基因 药敏实验 

分 类 号：S943[农业科学—水产养殖]