1株乌鳢源杀鲑气单胞菌杀鲑亚种的分离与鉴定

Isolation and Identification of Pathogens Aeromonas Salmonicida SalmonicidaSubsp.From Northern Snakehead(Ophicephalus Argus)

从自然发病的养殖乌鳢肝脏、肾脏中分离纯化得到优势菌株,定名为DSY1301。该菌株在普通营养肉汤及TSA上生长缓慢,在血平板上生长迅速。通过回归感染试验证实为致病菌,其LD50为1.896×103cfu/mL。细菌16SrDNA全序列测定后在GenBank中进行序列比对分析,结果与多种气单胞菌属的细菌同源性都高达99%,通过扩增杀鲑气单胞菌表面阵列蛋白基因VapA确认为杀鲑气单胞菌,结合梅里埃ATB Expression生化结果最终确定为杀鲑气单胞菌杀鲑亚种。通过药敏试验发现对氟苯尼考和氯霉素敏感。

A pathogenic bacterium （DSY1301） was isolated from the liver and kidney of naturally dis- eased Northern snakehead. This strain grew slowly on the ordinary nutrient broth and TSA, and grew fast on the blood agar plate. It was confirmed to be the pathogen of the disease by artificial infection ex- periments. The artificial infection tests verified that the strain had a strong virulence with LD50^ of 1. 896 × 103^cfu/mL. 16S rRNA gene sequence was compared in GenBank. The Blast showed that the strain of DSY1301 had the maximum homologies （i. e. , 99%） with a variety of Aeromonas bacteria. The strain of DSY1301 was identified as Aeromonas salrnonicida through amplifying the VapA of surface array protein gene of Aeromonas salmonicida. Combined with ATB Expression biochemical results, DSY1301 was eventually identified as Aerornonas salmonicida salmonicida subsp. By testing with medicaments, high sensitivity for the strain was found to Chloramphenicol and Florfenicol.