一株门多萨假单胞菌的分离鉴定及药物敏感性分析

试验旨在确定感染黄颡鱼的病原菌并探讨其耐药性。采用细菌培养、生理生化鉴定及16S rDNA序列分析方法进行菌株分离鉴定，运用PCR方法扩增耐药基因，用纸片扩散法对分离菌进行药敏试验。结果显示，分离菌与门多萨假单胞菌基本一致，16S rDNA基因长度为1 442 bp。同源性及系统进化树分析显示，该菌16S rDNA序列与门多萨假单胞菌NK-01同源性为99.6%，亲缘关系最近。综合判定分离菌为门多萨假单胞菌，命名为fsznc-01。耐药基因检测结果显示，分离菌fsznc-01含有β-内酰胺类耐药基因TEM，氨基糖苷类耐药基因aph（3'）-Ⅱa、aac（6）-Ⅰb、aac（3）-Ⅱa及磺胺类耐药基因Sul1和Sul2，未检测出磺胺类耐药基因Sul3。药敏试验结果显示，分离菌fsznc-01对头孢他啶、庆大霉素和哌拉西林等药物敏感，对头孢氨苄、头孢唑林和头孢拉定耐药。本试验结果可为预防门多萨假单胞菌感染导致的鱼类疾病提供参考依据。

Isolation,Identification and Drug Susceptibility Analysis of a Strain of Pseudomonas mendocina

The trial was designed to identify pathogens infected with Pelteobagrus fulvidraco and explore their resistance.The bacteria were isolated and identified by bacterial culture,physiological and biochemical identification and 16S rDNA sequence analysis.PCR method was used to amplify drug resistance genes.The resistance of drugs was detected by agar disk diffusion test.The results showed that the isolate was basically identical to Pseudomonas mendocina,and the 16S rDNA gene was 1 442 bp in length.Homology and phylogenetic tree analysis showed that the 16S rDNA sequence of this bacterium was 99.6% homologous to Pseudomonas mendocina NK-01,and their genetic relationship was the closest.The isolated strain was identified to be Pseudomonas mendocina,named as fsznc-01.The results of drug resistance gene test showed that the isolate fsznc-01 contained β-lactams resistance gene TEM,aminoglycosides resistance genes aph(3')-Ⅱa,aac(6)-Ⅰb and aac(3)-Ⅱa,and the sulfonamide resistance genes Sul1 and Sul2,and sulfonamide resistance genes Sul3 was not detected.The results of drug susceptibility test showed that the isolate fsznc-01 was sensitive to ceftazidime,gentamicin and piperacillin,and was resistant to cephalexin,cefazolin and cefradine.The results of this test could provide a reference for the prevention of fish diseases caused by Pseudomonas mendocina infection.