草鱼源维氏气单胞菌毒力基因及耐药性分析

    Analysis on the Virulence Genes and Drug Resistance of Aeromonas veronii in Ctenopharyngodon idellus

    • 摘要: 为了解草鱼Ctenopharyngodon idellus养殖过程中维氏气单胞菌Aeromonas veronii的流行季节及不同时期维氏气单胞菌毒力基因携带情况及防治方法,从福建省顺昌县某养殖场患病草鱼肝脏、肾脏、脾脏等组织分离得到7株致病菌进行研究。通过细菌分离培养、革兰氏染色镜检、生化鉴定、毒力基因、药敏试验、16S rRNA与gyrB基因测序对分离菌株进行分析。结果显示,从草鱼体内分离到的7株致病菌在培养基中呈圆形、表面湿润光滑、边缘整齐的淡黄色菌落;菌落周围呈β-溶血;革兰氏镜检呈阴性短杆菌;16S rRNA 、gyrB基因序列分析结合生化鉴定及质谱鉴定,鉴定结果均为维氏气单胞菌;8种毒力基因扩增结果显示,分离菌株均携带Lip 、Act、aerA、Alt、Exu及Fla 6种毒力基因;药敏试验结果显示,各菌株对8种抗菌药物敏感性一致,对盐酸土霉素、甲砜霉素、氟苯尼考、磺胺甲噁唑、磺胺二甲氧嘧啶、交沙霉素及恩诺沙星7种药物相对敏感,对氨苄西林钠、硫酸新霉素、磺胺嘧啶、磺胺间甲氧嘧啶、强力霉素及红霉素6种药物相对耐药。

       

      Abstract: In order to understand the epidemic season of Aeromonas veronii and the virulence gene carrying situation of Aeromonas veronii in different periods and its prevention and control methods during the aquaculture process of Ctenopharyngodon idellus, seven strains of pathogenic bacteria were isolated from the tissues of diseased Ctenopharyngodon idellus, such as liver, kidney, and spleen in the aquaculture farm of Shunchang County, Fujian Province. The isolated strains were analyzed by using the bacterial isolation & culture, gram staining microscopic examination, biochemical identification, virulence genes, drug sensitivity test, 16S rRNA and gyrB gene sequencing. The results showed that the seven pathogenic bacteria isolated from Ctenopharyngodon idellus showed the round yellowish bacterial colony with smooth moist surface and neat edge in the culture medium. β-hemolysis was observed around the colony, and the gram staining microscopic examination showed the negative brevibacterium. Through the 16S rRNA and gyrB gene sequencing analysis combined with the biochemical identification and mass spectrum identification, the identification results were all Aeromonas veronii. The PCR result of the eight kinds of virulence genes showed that all the isolated strains all carried 6 kinds of virulence genes including Lip, Act, aerA, Alt, Exu and Fla. The results of drug sensitivity test showed that all the strains had the same sensitivity to the eight kinds of antibiotics, and were relatively sensitive to the seven kinds of antibiotics, such as oxytetracycline hydrochloride, thiamphenicol, flufenicol, sulfamethoxazole, sulfadimethoxine, josamycin and enrofloxacin, while were relatively resistant to the six kinds of antibiotics, such as ampicillin sodium, neomycin sulfate, sulfadiazine, sulfamonomethoxine, doxycycline and erythromycin.

       

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