锦鲤荧光假单胞菌的分离鉴定及药敏试验

Drug Susceptibility,Isolation and Identification of Pathogenic Bacterium Pseudomonas fluorescens from Koi Carp(Cyprinus carpio)

对锦鲤赤皮病病原菌进行分离鉴定,自患病锦鲤心脏、皮肤病变组织中离到1株革兰氏阴性杆菌(KC-1),通过细菌形态学观察、生理生化特征、16SrRNA、gyrB基因克隆测序以及构建发育进化树分析,测序结果获得该菌株的16SrRNA、gyrB基因片段大小分别为1501bp、1215bp,与荧光假单胞菌标准菌株LMG5831的16SrRNA序列同源性为99.87%,系统发育进化树分析显示KC-1菌株与荧光假单胞菌(登录号:GU198110)的亲缘关系最近,自然聚类为一支,最终鉴定KC-1菌株为荧光假单胞菌。药敏试验结果显示,KC-1菌株对庆大霉素、丁胺卡那霉素、乙基西梭霉素、诺氟沙星、氧氟沙星、哌拉西林、头孢哌酮、四环素等8种抗生素敏感,对氨苄西林、阿莫西林等24种抗生素耐药。

A gram-negative bacillus, KC-1 strain, was isolated from heart and skin of koi carp （Cyprinus carpio） with red-skin disease, and then was identified as Pseudomonas fluorescens by morphological, and physiological methods, biochemical characters, 16S rRNA and gyrB gene sequencing and analysis of phylogenetic trees. The results showed that the 1501 bp 16S rRNA and 1215 bp gyrB gene fragments of the KC- 1 isolate were obtained, and the sequence homology of 16S rRNA was 99.87M with P. fluorescens type strain LMG5831. Furthermore, the phylogenetic tree analysis showed that the KC-1 strain was clustered closely with P. fluorescens （GenBank accession number of GU198110）, and grouped into one cluster. Drug sensitivity test showed that KC-1 strain was sensitive to gentamicin, amikacin, netilmicin, norfloxacin, ofloxaein, piperacillin, cefoperazone and tetracycline, and resistant to 24 antibiotics such as ampicillin, amoxicillin, vancomycin,erythrocin, neomycin and furantoin. The findings will provide a scientific reference to identification of P. fluorescens in fish and to prevention of red-skin disease in koi carp.