作　　者： ; ; ; ; ; ; ; ; ;

机构地区： 中国水产科学研究院珠江水产研究所

出　　处： 《中国水产科学》 2009年第6期891-904,共14页

摘　　要： 从患暴发性流行病的西伯利亚鲟(Acipenser baerii)肝脏和心脏中各分离到1株细菌,分离纯化后获得2个分离株,编号分别为AeBF070904、AbHT070912,对分离菌进行了菌株鉴定、致病性分析及药敏实验。分别应用常规生理生化鉴定、全自动细菌测定卡API20STREP和ID32STREP进行检测,结果表明,2个分离株均为停乳链球菌(Streptococcus dysgalactiae)。对2个分离株的16S rRNA基因进行PCR扩增和测序,并与GenBank中收录的链球菌16S rRNA基因进行序列分析并构建系统进化树,结果显示,2个分离株的16S rRNA基因序列相同,与停乳链球菌同源性最高达97.3%,在系统进化树上与停乳链球菌聚为一簇,进一步确认2个分离株均为停乳链球菌。从人工感染后发病鱼的内脏组织再分离的细菌特性与原感染菌相同,确认停乳链球菌是西伯利亚鲟的致病菌。2个分离株对西伯利亚鲟、杂交鲟及剑尾鱼均有致死毒性,37℃培养的细菌毒力比28℃培养的细菌毒力强。2个分离株均对青霉素、诺氟沙星等7种药物敏感;对头孢唑啉、庆大霉素等2种药物耐受;对红霉素中等敏感;对卡那霉素等8种药物菌株之间出现差异。 Siberian sturgeon,Acipenser baerii is one of the major cultured sturgeons in China in recent years.In this study,ultra-thin section and transmission electron microscope observation,bacteria isolation and identification,artificial infection tests were used for analysis the cause of the severe disease.Bacterial cocci were found in kidney,spleen,liver and heart tissue sections under electron microscope.And bacteria were isolated from the four tissues using 5% sheep blood agar and BHI agar.Two isolates,one named AeBF070904 isolated from the liver of sturgeon cultured in flowing water pond in Beijing and the other named AbHT070912 isolated from the heart of sturgeon cultured in cage of reservoir in Hebei Province were obtained.The biochemical and physiological characteristics of the two isolates were learned by using conventional method,API System（20 STREP）and ATP Expression System（ID32 STREP）. The tests showed that the isolates were Gram-positive cocci arranging in chains andα-haemolytic on 5%sheep blood agar.They grew at 20℃,28℃and 37℃,but not at 10℃and 45℃.They grew in 1%NaCl,2%NaCl and 3%NaCl,but not in 6.5%NaCl.CAMP test and Voges-Proskauer test were negative.They producedβ-glucuronidase,leucine arylamidase and alanine-phenylalanine-proline arylamid ase but not urease,arginine dihydrolysis,hippurate hydrolysis,β-glucosidase,β-galactosidase,α-galactosidase,pyroglutamic acid arylamidase,glycyl-tryptophane arylamidase and acetyl-β-glucosaminidase.They utilized trehalose,ribose,amygdaline,sucrose,pullulan and Maltose.They didn’t utilize 12 kinds of tested sugar such as lactose,salicin,raffinose.Both the isolates were identified by conventional method,API System（20 STREP）and ATP Expression System（ID32 STREP）as Streptococcus dysgalactiae,59.1%S.dysgalactiae subsp.dysgalactiae and 97.9%S.dysgalactiae subsp.equisimilis,respectively.The 16S rRNA gene sequence of the two isolates were amplified and compared with those of other Streptococcus retrieved from GenBank.The 16S rRNA gene sequence

关 键 词： 西伯利亚鲟 停乳链球菌 致病性 细菌鉴定 基因序列 药物敏感

领　　域： [农业科学] [农业科学]