肠出血性大肠杆菌变种的RAPD分型研究

RAPD Typing of Enterohemorrhagic E. coli Mutants

对4株肠出血性大肠杆菌(EHEC)进行随机扩增多态性(RAPD)分析,并结合主要毒力基因如eae和hly,以及志贺毒素滴度,探讨RAPD实验对大肠杆菌致病菌进行基因分型结果的可靠性。实验菌株中有两株变种携带stx基因但不能正常表达志贺毒素,其中一株变种EC169与另两株正常表达志贺毒素的O157菌株具有相似的扩增图谱,而另一株非O157变种EC130与其他菌株聚类明显不同。从20条随机引物中筛选出了重复性强且具有多态性的随机引物G2、G7、G8、G11、G12,可用于大肠杆菌致病菌快速鉴别和食物中毒溯源。

Four enterohemorrhagic Escherichia coli （EHEC） strains were analyzed by random amplified polymorphic DNA （RAPD） method, and the reliability of genotyping of pathogenic E. coli by RAPD was discussed in terms of the major toxic genes, eae and hly and Shiga toxin titer. Two of the test strains carried stx genes but did not express Shiga toxins. Of them, one mutant strain, O157 EC169, had a similar RAPD profile with the other two O157 strains which could express Shiga toxins, while the other mutant, O157 EC130 revealed significant cluster difference from other strains. Several primers with strong repeatability and polymorphism that are available for fast identification of E. coli pathogenic bacteria and the food poisoning traceability were selected from 20 random primers.