摘要
试验旨在对贵州省某养鱼场发病杂交鲟体内分离的优势菌株进行鉴定、致病力探究及耐药性分析。本试验通过革兰染色、生化鉴定、细菌16S rDNA基因分析、动物回归试验、药敏试验、部分毒力基因检测与耐药基因检测。结果显示:分离菌为革兰阴性短杆菌,细菌16S rDNA扩增测序与比对,得大小为1 477 bp的片段,其片段基因序列与GenBank中的维氏气单胞菌序列相似度达99.00%,药敏试验显示:分离菌对环丙沙星、氟苯尼考、头孢哌酮等药物敏感,对四环素、磺胺异恶唑、苯唑西林药物出现耐药,耐药基因检测显示:分离菌含有耐磺胺基因(Sul1,sul2)、Ⅰ类整合子(Intl1)3种耐药基因,毒力基因检测显示:分离菌含有气溶素(Aer)和粘附素(Aha)两种毒力基因。综合本试验结果,分离菌为维氏气单胞菌(A.veronii),含有毒力基因,并对环丙沙星、氟苯尼考、头孢哌酮等药物敏感。本试验对贵州地区鲟发病流行的病因做出准确诊断,为该地区细菌性鱼病预防与合理用药提供依据。
The purpose of the experiment was to identify the dominant strains isolated from the diseased sturgeon in a fish farm in Guizhou Province, explore the pathogenicity and analyze the drug resistance. The results showed that the isolates were Gram-negative Brevibacterium spp. and 16 S rDNA amplification, sequencing and alignment of bacteria were performed. The size of the 16 S rDNA fragment was 1477 bp. The gene sequence of the fragment was similar to that of Aeromonas Virginis in GenBank. The similarity was 99.00%. Drug susceptibility test showed that the isolates were sensitive to ciprofloxacin, florfenicol and cefoperazone, and resistant to tetracycline, sulfamidoxazole and oxacillin. Drug resistance gene detection showed that the isolates contained sulfonamide-resistant genes(Sul1, sul2) and class I integron(Intl1). Virulence gene detection showed that the isolates contained aerosol. Aer and Aha were two virulence genes. According to the results of this experiment, the isolated strain is Aeromonas veronii, which contains virulence genes and is sensitive to ciprofloxacin, florfenicol and cefoperazone. This experiment did an accurate diagnosis of the causes of the occurrence and epidemic of sturgeon in Guizhou, and provided a basis for the prevention and rational use of bacterial fish diseases in Guizhou
引文
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