Li Xixi, Zhou Yifan, Jiang Qun, Yang Hui, Pi Daming, Liu Xiaodan, Gao Xiaojian, Chen Nan, Zhang Xiaojun
College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China.
College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China.
Microb Pathog. 2019 Feb;127:166-171. doi: 10.1016/j.micpath.2018.12.002. Epub 2018 Dec 4.
Macrobrachium rosenbergii is one of the most economically important freshwater shimp, with fast growth and high nutrient content in the agricultural development of China. However, it had been suffering diseases infection, causing mass death and great economic losses. In the present study, a bacteria strain was isolated from the diseased zoea of M. rosenbergii and was identified as Vibrio vulnificus by biochemical characteristics and 16S rRNA homologous analysis. The infection test showed that the strain GXFL1-3 was pathogenic to zoea and postlarva of M. rosenbergii, and the half lethal dose (LD) were 1.16 × 10 CFU/mL and 1.45 × 10 CFU/mL, respectively. Detection of virulence-associated genes by PCR indicated that GXFL1-3 was positive for fur, OmpU, acfA, flaA, vvhA, vvp and tcp, the detection of extracellular enzymes and hemolysin showed that GXFL1-3 was positive for protease, amylase, lecithin, urease and hemolysin activity, further supporting its pathogenicity. A duplex PCR for rapid detection of V. vulnificus was established. Only V. vulnificus could amplify two specific bands of flaA and fur, while the other six strains of Vibrio were negative. The minimum detectable amount of template was 2.4 × 10 CFU/mL through sensitivity test.
罗氏沼虾是中国农业发展中经济价值最重要的淡水虾之一，生长迅速且营养成分高。然而，它一直遭受疾病感染，导致大量死亡和巨大经济损失。在本研究中，从患病的罗氏沼虾蚤状幼体中分离出一株细菌，通过生化特性和16S rRNA同源性分析鉴定为创伤弧菌。感染试验表明，菌株GXFL1-3对罗氏沼虾的蚤状幼体和后期幼体具有致病性，半数致死剂量（LD）分别为1.16×10 CFU/mL和1.45×10 CFU/mL。通过PCR检测毒力相关基因表明，GXFL1-3的fur、OmpU、acfA、flaA、vvhA、vvp和tcp呈阳性，细胞外酶和溶血素检测表明，GXFL1-3的蛋白酶、淀粉酶、卵磷脂、脲酶和溶血素活性呈阳性，进一步支持其致病性。建立了一种用于快速检测创伤弧菌的双重PCR。只有创伤弧菌能扩增出flaA和fur的两条特异性条带，而其他六种弧菌菌株均为阴性。通过敏感性试验，模板的最低检测量为2.4×10 CFU/mL。
