摘要
为确定南京地区某渔场异育银鲫出血性败血症的病原体,采集该渔场3个饲养塘口患病鱼脏器进行细菌分离培养,基于气单胞菌DNA促旋酶B亚单位(gyr B)基因序列设计引物,PCR扩增后测序进行细菌鉴定;同时,对病原菌生物学特性如溶血性、蛋白酶活性、生物被膜形成能力、运动能力以及对斑马鱼的毒力等进行分析,并进行多位点序列分型(MLST)。结果在3个饲养塘口均分离到嗜水气单胞菌,分别命名为GL-15、GL-17和GL-18;MLST分型显示三株分离菌均为ST251型;生物学特性实验表明,均有溶血性、蛋白酶活性以及运动性,生物被膜形成能力较强,OD595均超过0.5,对斑马鱼的LD50在1.4×103~3.9×103 CFU/尾,属强毒株。本研究为有效防控南京地区嗜水气单胞菌引发的出血性败血症的暴发流行提供了依据。
Aeromonas hydrophila is a Gram-negative bacterium,which is widely distributed in the water environment. Pathogenic strains can cause sepsis in a variety of aquatic animals. In Sept. 2015,crucian carp（Carassius carassius） in one farm of Nanjing showed symptoms of haemorrhagic septicaemia. Samples from diseased fish in three ponds were collected and the pathogenic bacteria were isolated. Three A. hydrophila isolates were identified based on sequencing of the housekeeping gene gyr B,and named GL-15,GL-17 and GL-18,respectively. Then the three A. hydrophila strains were typed using multilocus sequence typing（MLST） based on six housekeeping genes. Also,all the three isolates were analyzed for hemolytic and proteolytic characterizations and pathogenicity in zebrafish. The results showed that all the three strains presented hemolytic and proteolytic activities,and the abilities of biofilm formation in which OD595 is more than 0.5 and also had swarming and swimming motility. And they were highly virulent strains,with the LD50 values of 1.4×103 to 3.9×103 CFU. This study provided a basis for control of MAS caused by A. hydrophila in Nanjing area.
出处
《水产学报》
CAS
CSCD
北大核心
2017年第1期134-141,共8页
Journal of Fisheries of China
基金
国家自然科学基金(31372454)
江苏省水产三新工程项目(D2015-13)~~
关键词
嗜水气单胞菌
鉴定
ST251
生物学特性
Aeromonas hydrophila
identification
ST251
biological characteristics
