基于免疫磁分离的7种产志贺毒素大肠埃希氏菌快速检测方法的评价

Evaluation of the rapid detection method for 7 kinds of Shiga toxin-producing Escherichia coli based on immunomagnetic separation

中文关键词:  免疫磁分离  产志贺毒素大肠埃希氏菌  快速检测

英文关键词:immunomagnetic separation  Shiga toxin-producing Escherichia coli  rapid detection

中文摘要:

      目的 评价基于免疫磁分离(immunomagnetic separation, IMS)的7种产志贺毒素大肠埃希氏菌(Shiga toxin-producing Escherichia coli, STEC)快速检测方法的灵敏度与特异性。方法 将大肠埃希氏菌O157:H7和大肠埃希氏菌O103不同稀释度的菌悬液用免疫磁珠富集后, 检测其携带毒力基因stx1、stx2和黏附基因eae以及O157:H7和O103的抗原基因。同时, 对菌悬液进行活菌计数, 进行灵敏度研究。对8株携带stx1、stx2、eae基因的目标菌菌悬液和25株非目标菌的标准菌株及分离菌株的菌悬液用免疫磁珠富集后, 检测其携带毒力基因stx1、stx2和黏附基因eae以及抗原基因, 进行特异性研究。结果 本方法检测大肠埃希氏菌O157:H7的stx1、stx2、eae以及抗原基因的灵敏度为102 CFU/mL, 检测大肠埃希氏菌O103抗原基因的灵敏度为 103 CFU/mL。8株目标菌检测结果与其携带的基因一致, 没有假阴性, 包容性达到100%。25株非目标菌检测结果与其携带的基因一致, 未发现有假阳性, 排他性达到100%。结论 该方法具有良好的灵敏性及特异性, 适用于食品中7种产志贺毒素大肠埃希氏菌的快速检测。

英文摘要:

      Objective To evaluate the sensitivity and specificity of the rapid detection method for 7 kinds of Shiga toxin-producing Escherichia coli (STEC) based on immunomagnetic separation (IMS). Methods The bacterial suspensions of Escherichia coli O157:H7 and Escherichia coli O103 with different dilutions were enriched with immunomagnetic beads. The virulence genes stx1, stx2, adhesion gene eae and antigen genes of O157:H7 and O103 were detected. At the same time, the number of viable bacteria in bacterial suspension was calculated and the sensitivity was studied. The bacterial suspensions of 8 strains of target bacteria carrying stx1, stx2 and eae genes and 25 strains of non target standard bacteria and isolated strains were enriched with immunomagnetic beads. The virulence genes stx1, stx2, adhesion genes eae and antigen genes were detected. Specific studies were conducted. Results The sensitivity of this method to detect stx1, stx2, eae and antigen gene of Escherichia coli O157:H7 was 102 CFU/mL, and the sensitivity to detect antigen gene of Escherichia coli O103 was 103 CFU/mL. The detection results of 8 strains of target bacteria were consistent with their genes, there was no false negative, and the inclusiveness reached 100%. The detection results of 25 strains of non target bacteria were consistent with their genes, no false positive was found, and the exclusivity was 100%. Conclusions The method has good sensitivity and specificity, and is suitable for the rapid detection of 7 kinds of Shiga toxin-producing Escherichia coli in food.