鱼源嗜水气单胞菌质粒的指纹图谱及其与耐药性的关系

Analysing plasmid fingerprinting and relationship between plasmids and resistance in Aeromonas hydrophila from fish

摘要:

为了解国内各地嗜水气单胞菌的耐药性、质粒指纹图谱及质粒大小与其耐药性之间的关系,分离、收集了40株不同时期来源于国内各地的鱼源嗜水气单胞菌,通过KB纸片法检测对29种抗生素的耐药性,碱裂解法小量提取质粒后,采用限制性内切酶EcoRⅠ及HindⅢ对质粒DNA进行酶切并对质粒菌株采用溴化乙锭消除处理,通过琼脂糖凝胶电泳获得质粒指纹图谱,研究质粒与耐药性的关系。试验结果显示,嗜水气单胞菌耐药情况严重,且多重耐药普遍;40株嗜水气单胞菌的质粒检出率为37.5%;质粒指纹图谱与耐药相关性分析表明,嗜水气单胞菌的耐药性与所携带质粒的数量和大小无直接关系,来源相同、耐药类型相似的菌株质粒图谱及酶切质粒图谱相似;质粒消除试验发现质粒消除率为100%,但都只能消除部分质粒;其中12株菌部分耐药表型消失,提示质粒和染色体分别编码耐药基因,2.01 kb的质粒与该菌对萘啶酸、万古霉素的耐药性有关。

Abstract:

To survey antimicrobial resistance,plasmid fingerprinting and relationship between the size of plasmids and resistance in Aeromonas hydrophila strains which were isolated and collected from fish at different time and in different areas in China.Antimicrobial susceptibility of 40 strains to 29 different antimicrobials were tested by K-B;plasmids DNA were obtained by alkaline lysis and digested by EcoRⅠand HindⅢ,plasmids elimination were treated by EB,then analyzed by agarose gel electrophoresis.Results showed that Aeromonas hydrophila exhibited high antimicrobial resistance,almost was multi-drug resistance;Out of 40 strains,15 strains(37.5%)contained plasmids;The relationship between the antimicrobial resistance and plasmid fingerprinting showed that the number and size of plasmids the strain carried had no significant correlation with its antimicrobial resistance.Plasmid fingerprinting indicated that the strain with the same source and similar antimicrobial resistance would have similar plasmid profile and macrorestriction map.The rate of plasmid elimination for 15 isolates was 100%,but partially eliminated;meanwhile,the resistance phenotype of 12 isolates partially disappeared,suggesting that plasmid and chromosome encoding the resistance genes,2.01 kb plasmid was associated with the resistance to Nalidixie acid and Vancomycin.