大肠埃希氏菌O157和O111能力验证样品的研制

目的研制植物源性成分绿豆基质中O157和O111检测能力验证样品,建立有效的样品制备流程来考核实验室检测致泻大肠埃希氏菌O157和O111的能力,根据参加实验室检测结果是否准确及可靠来评价实验室检测水平,并促进实验室检测体系进一步完善。方法选用O157和O111的ATCC标准菌株制备样品,以绿豆粉为基质,真空冷冻干燥技术制备样品。采用显色培养基、荧光定量PCR、全自动细菌生化鉴定仪、VIDAS全自动免疫荧光分析仪和血清型鉴定进行定性检测,并进行菌落计数。结果随机选取每一批阳性样品中的30个样品,每个样品中目标菌数在21~60 CFU之间,并且A组与B组阳性样品中均检测出目标菌,而阴性样品中均没有出现目标菌。结论表明采用本方法制备的能力验证样品均一稳定,能较好地评价实验室致泻大肠埃希氏菌O157和O111的检测能力。

Preparation of Escherichia coli O157 and O111 samples for proficiency pest

Objective To develop O157 and O111 proficiency testing samples of plant-derived ingredients of mung matrix, and an effective sample preparation process was established to assess the ability of the laboratories to detect diarrheogenic Escherichia coli O157 and O111. According to the accuracy and reliability of test results of laboratories participate in the test to evaluate the detectable levels of laboratories, and to promote the laboratory testing system to get a further improvement. Methods The O157 and O111 ATCC standard strain were used for sample preparation, with mung bean powder as matrix, the samples were made by using vacuum freeze drying technology. The chromogenic medium, fluorescence quantitative PCR, full automatic bacterial biochemical identification instrument, VIDAS automatic immune fluorescence analyzer and serotype identification were used for qualitative detection, and the number of colonies were counted. Results Totally 30 samples were selected randomly in each batch of positive samples, the target bacteria number of each sample should be between the 21~60 CFU. Target bacteria was detected in the positive samples of both group A and group B, while no target bacteria were detected in the negative samples. Conclusion Proficiency testing samples were uniform and stable, and the ability of laboratories to detect diarrheogenic Escherichia coli O157 and O111 got a better evaluation.