网状分枝扩增方法检测志贺毒素2基因

目的 建立一种快速、灵敏检测志贺样毒素2(STX2)的方法。方法 用网状分枝扩增技术(RAM)和PCR检测合成的志贺样毒素2基因和临床分离的菌株，确定该方法的灵敏度和特异性。结果 RAM最少能检测10个志贺样毒素2的DNA分子，与PCR具有同样灵敏度。用PCR和RAM检测临床标本和食品中分离的33株大肠埃希菌，其中26株stx2基因为阳性，2种方法检测结果一致。结论 RAM与PCR方法相同的灵敏度和特异性，但操作简便，并且是在等温条件下扩增核酸，成本较低，适合检测食品和临床标本中大肠埃希菌志贺样毒素2。

Detection of shiga toxin 2 gene by ramification amplification method

Objective To develop a rapid and sensitive assay to detect shiga toxin-producing escherichia.coli.Methods The sensitivity and specificity of RAM were compared with those of PCR by detecting synthetic Shiga toxin DNA target and isolated from food and clinical specimens.Results The lowest number of targets detected by RAM assay was 10 molecules.Thirty-three strains from clinical samples and foods were detected by RAM and PCR,twenty-six among of which were positive for stx2 gene.The results of both methods were the same.Conclusion RAM assay could be an alternative to PCR to detect STEC in food product and clinical specimens because of its high sensitivity and specificity,simplicity and isothermal amplification.