克氏原螯虾烂尾病病原的分离鉴定及其相关特性分析

Isolation,Identification and Related Characteristics Analysis of Pathogen Isolated from Red Swamp Crayfish Procambarus clarkii with Tail-Rotted Disease

为研究克氏原螯虾烂尾病病原种类及其相关特性,从患病虾尾部病灶分离出2种具有不同菌落形态和色泽的代表菌株,分别编号LW2047-1和LW2047-2,经人工感染试验确定病原菌为菌株LW2047-2。对菌株LW2047-2进行细菌学观察,分析形态特征和生理生化特性,并对16S rRNA和gyrB基因测序分析,最终将其鉴定为弗氏柠檬酸杆菌。检测该菌株定居因子CFA基因和几丁质酶chi基因,分析其黏附性和几丁质分解特性。药物敏感性试验结果表明,菌株LW2047-2对恩诺沙星和硫酸新霉素2种抗菌药物高度敏感,对磺胺类药物均不敏感。

The purpose of this experiment was to study the species and related characteristics of pathogen which caused tail-rotted disease of red swamp crayfish Procambarus clarkii.Two representative bacterial strains with different colony morphologies and colors were isolated from infectious location of diseased red swamp crayfish,and known as LW2047-1 and LW2047-2.The pathogen bacteria were confirmed as strain LW2047-2 by artificial infection test.We observed strain LW2047-2 with bacteriological methods and analyzed that by morphological,physiological and biochemical characteristics.Finally,strain LW2047-2 was identified as Citrobacter freundii when 16S rRNA and gyrB gene were sequenced and analyzed.CFA gene and chi gene were detected for analysis of adhesion and chitin decomposition characteristics.Results of antimicrobial sensitivity test showed that strain LW2047-2 was sensitive to enrofloxacin and neomycin sulfate and insensitive to sulfa drugs.