肠出血性大肠埃希菌遗传基因分型方法比较
Study on genotype of enterohemorrhagic Escherichia coli O157： H7 isolates by pulsed-field gel electrophoresis and multiple-locus variable number tandem repeat analysis
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摘要: 目的 对肠出血性大肠埃希菌(EHEC)O157:H7的遗传基因型别进行不同分子分型方法的对比研究,以对EHEC的分子流行病学追踪提供更为行之有效的方法.方法 采用核酸脉冲场凝胶电泳(PFGE)与多位点串联重复序列(VNTR)分析(MLVA)两种方法对16株EHEC O157:H7进行分析.结果 在PFGE的研究中,依据经XbaI及确认BlnI酶切后,具有相同电泳图谱的菌株被定义为PFGE同一群落的菌株,将16株菌株分成6个型别.MLVA通过对9个位点的串联重复序列的比较研究,16株菌株在3个位点上没有显示出区别,在另外6个位点上等位基因的数目为2~7种,16株细菌被分为14个MLVA的型别.流行病学资料表明,这些菌株为散发病例分离株,分离地域上基本没有关联,因此,MLVA的结果与流行病学信息高度相关.结论 MLVA能够区分无法区分的PFGE型别,且可以区分来自于不同地理区域的散发菌株,具有区分肠出血性大肠埃希菌O157:H7的潜力.Abstract: Objective To study genotype of enterohemorrhagic Escher ichia coli(EHEC)O157:H7 with differ ent subtyping methods and compare effectiveness of the methods.Methods 16 isolates of EH EC O157:H7 were analyzed by pulsed -field gel electrophor esis(PFGE)and multilocus var iable-number tandem repeat(VNT R)analysis(MLVA).Results Strains in PF GE clusters were defined by using Xba?and the confirmatory enzyme Bln?.MLVA was per for med by compar ing the number of tandem repeats at nine loci,where three loci showed no variations and six loci showed 2 to 7 variations in the 16 isolates,resulting in 14 MLVA types among the 16 isolates.While by PFGE,only 6 types were found among the 16 isolates.Conclusion The results of MLVA is highly relevant to epidemiological information.MLVA appears to have profound potential for discrimination of EHEC O157:H7 strains.isolates.Conclusion The results of MLVA is highly relevant to epidemiological information.MLVA appears to have profound potential for discrimination of EHEC O157:H7 strains.
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