鳜鱼致病性迟缓爱德华氏菌的分离鉴定及药敏试验

吴勇亮 苗鹏飞 于辉 谭淑雯 杨虹 彭钟琴 杨映

摘要：【目的】明确鳜鱼发病死亡的原因，并进行病原菌分离鉴定及药敏特性分析，为生产养殖中有效防治迟缓爱德华菌病提供参考依据。【方法】从患病鳜鱼肝脏中分离优势菌株，采用回归感染试验确定其致病性，通过细菌生理生化及16S rDNA序列分析对菌株进行鉴定，并以K-B纸片扩散法进行药物敏感性检测。【结果】分离出的菌株FS170808具有一定致病力，可使健康鳜鱼发病死亡，其半致死剂量为9.5×105 CFU/mL；菌株FS170808经生理生化和16S rDNA序列分析鉴定均为迟缓爱德华氏菌（Edwardsiella tarda），其对氨苄西林、头孢曲松、头孢呋辛、庆大霉素、卡那霉素、氧氟沙星、四环素和多西环素等17种药物高度敏感，对头孢氨苄、头孢拉定、头孢他啶、新霉素和多粘菌素B中度敏感，对苯唑西林、复方新诺明、麦迪霉素和万古霉素已产生耐药性。【结论】迟缓爱德华氏菌可引起鳜鱼发病死亡，生产养殖中可选用氨苄西林、头孢曲松、头孢呋辛和庆大霉素等高度敏感性药物进行防治。

关键词： 鳜鱼；迟缓爱德华氏菌；分离鉴定；16S rDNA；药敏试验

中图分类号： S965.199 文献标志码：A 文章编号：2095-1191（2018）04-0794-06

Isolation，identification and drug susceptibility test of pathogenic Edwardsiella tarda in Siniperca chuatsi

WU Yong-liang， MIAO Peng-fei， YU Hui， TAN Shu-wen， YANG Hong，

PENG Zhong-qin， YANG Ying*

（College of Life Science and Engineering， Foshan University， Foshan， Guangdong 528225， China）

Abstract：【Objective】Death causes of Siniperca chuatsi were studied， isolation and identification of pathogenic bacteria and analysis of drug susceptibility were conducted to provide reference for effective prevention and treatment to Edwardsiella tarda disease in aquaculture. 【Method】Dominant strain was isolated from liver tissue of ill S. chuatsi. Pathogenicity of the strain was determined by recursive infection experiment. The strain was identified by using bacteria physiological and biochemical analysis and 16S rDNA sequence analysis. K-B paper disk diffusion was applied to test its drug susceptibility. 【Result】Isolated strain FS170808 had certain pathogenicity and could lead to morbidity and death of healthy S. chuatsi. Its median lethal dose was 9.5×105 CFU/mL. The strain FS170808 was identified as E. tarda through physiological and biochemical identification and 16S rDNA sequence analysis. The strain was highly susceptible to 17 kinds of drugs including ampicillin， cefatriaxone， cefuroxime， gentamicin， kanamycin， ofloxacin， tetracycline， doxycycline and the others， intermediately susceptible to cephalexin， cefradine， ceftazidine， neomycin， polymyxin B， and resistant to oxacillin， selectrin， aboren， and vancomycin. 【Conclusion】E. tarda can lead to the morbidity and death of S. chuatsi. The highly susceptible drugs such as ampicillin， cefatriaxone， cefuroxime and gentamicin can be used for prevention and treatment in aquaculture.

Key words： Siniperca chuatsi； Edwarsdsiella tarda； isolation and identification； 16S rDNA； drug susceptibility test

0 引言

【研究意義】迟缓爱德华氏菌（Edwardsiella tarda）为肠杆菌科爱德华菌属的革兰氏阴性短杆菌，广泛存在于溪水、湖泊和海洋等水环境中，能感染鱼类、两栖类、爬行类、鸟类甚至哺乳类动物（Wang et al.，2014；Su et al.，2015），因具有兼性胞内寄生特性，成为人—鱼—兽共患病的条件致病菌。近年来，迟缓爱德华氏菌对鱼类健康的危害越来越凸显（Xu and Zhang，2014），可使鱼类腹部积水肿胀、体表出血、肠内出现黏液等，并造成大量死亡。……