摘要
从海南省某水产养殖场患病奥尼罗非鱼(Oreochromis aureus×Oreochromis niloticus)中,分离到1个编号为LFY-08-23的菌株。经过对分离菌株进行生理生化特性鉴定、Biolog系统鉴定以及利用原核生物16S rRNA基因通用引物进行16S rRNA基因的克隆及序列分析,结果发现LFY-08-23菌株与无乳链球菌(Streptococcus agalactiae)的生理生化特性相似,16S rRNA基因克隆及序列分析结果与S.agalactiae(EF092913,DQ303183,AF459432)自然构成一个分支,相似性高达99.8%。用分离的S.agalactiaeLFY-08-23菌株对异育银鲫和斑点叉尾鮰进行人工感染试验,结果表明,当注射菌浓度达到1.0×109cfu/mL时,2种鱼全部死亡。S.agalactiaeLFY-08-23菌株对头孢氨噻肟、丙氟哌酸、利福平等13种药物高度敏感,对呋喃妥因、新生霉素、强力霉素等7种药物中度敏感,对卡那霉素、链霉素、磺胺异恶唑等5种药物不敏感。
The dominant bacterial strain,designated as LFY-08-23,was isolated from the diseased hybrid tilapia,Oreochromis niloticus×Oreochromis aureus in Hainan Province.The biochemical and physiological characteristics of the isolates were studied by using conventional method and Biolog System.The test showed that the isolates were Gram-positive cocci arranging in chains,catalase negative,β-haemolytic on 5% sheep blood agar and serogroup B.According to their 16S rRNA gene sequence and molecular phylogenetic dendrogram,the strain LFY-08-23 was most close to Streptococcus agalactiae with a similarity of 99.8%.The virulent test was carried out by using the pure culture of the bacteria artificially infected Ictalurus punctatus and Carassius auratus gibelio.The two species of experimental fish all died at bacterial concentration of 1.0×109cfu/mL.The morphological and biochemical characteristics of the re-isolated bacteria from the artificially infected diseased fish were the same as those of the original infected bacteria.The susceptibility test to antibiotics demonstrated that the isolate strain LFY-08-23 was sensitive to most of the tested antibiotics,especially highly sensitive to 13 kinds of antibiotics,such as Cefotaxime,Ciprofloracin,Rifampicin,and resistant to 5 antibiotics,such as Kanamycin,Streptomycin,Gantrisin.
出处
《华中农业大学学报》
CAS
CSCD
北大核心
2010年第6期745-751,共7页
Journal of Huazhong Agricultural University
基金
国家"973"项目(2009CB118700)
农业公益性行业科研专项经费项目(200803013)资助
关键词
奥尼罗非鱼
无乳链球菌
鉴定
系统发育分析
人工感染
药物敏感
hybrid tilapia（Oreochromis niloticus×Oreochromis aureus）
Streptococcus agalaciate
identification
phylogenetic analysis
artificial infection
chemotherapeutant sensitivity
