类鼻疽假单胞菌核糖分型

Ribotyping of Pseudomonas pseudomallei with identical serotype

目的 用rRNA基因 (rDNA)的限制性片段长度多态性 (RFLPs)将同一血清型类鼻疽菌株进行基因分型。方法 应用PCR技术 ,从大肠杆菌中分别扩增出 16S、2 3S rDNA作探针。对不同来源的 9株血清Ⅰ型类鼻疽菌染色体DNA进行酶切 ,通过Southern杂交 ,获得各菌株rDNA限制图谱。结果 BamHI、PstI、ApaI和EcoRI单酶切的rDNA指纹图分别显示 6、3、3和 3个不同的核糖型 (ribotypes) ,尤以BamHI区别效果最为显著。综合四种限制酶图谱 ,计算出各菌株间相似度 ,并绘制其系统关系图。结论 在类鼻疽菌仅根据不耐热抗原的有无分血清Ⅰ和Ⅱ型的情况下 ,核糖分型 (Ribotyping)无疑是对血清分型的一个有力补充 ,提供了一种敏感性高、重复性强的分子流行病学调查工具。

Aim Restriction fragment length polymorphisms(RFLPs) of rRNA genes(rDNA) were evaluated as a method of determining genetypes of P pseudomallei with identical serotype Methods 16S and 23S rDNA,which could be used as probes,were amplified from E coli with PCR DNA from P pseudomallei were digested by restriction endonucleases The DNA fragments carrying rRNA genes were localized by Southern-blotted hybridization with rDNA probe Results 9 strains of identical serotype were differentiated by BamHI、PstI、ApaI、EcoRI in six,three,three,ahd three,ribotypes respectively.The sensibility of the method was dependent on the enzymes used to digest DNA It was the highest for BamHI,which separated 6 of 9 strains Conclusion To date,epidemiological associations among strains of P pseudomallei are based exclusively on serotyping,which may be of limited value if a single serotype is involved rDNA fingerprinting,which proved to be reproductive and reliable,could be used in molecular epidemiological investigation