应用DPO-PCR方法特异性检测志贺氏菌

Specific Detection of Shigella Using DPO-PCR Method

本研究利用一种高特异性PCR引物设计方法——双启动寡核苷酸引物（dual-primingoligonucleotide，DPO），以志贺氏菌属侵袭性质粒抗原（ipaH）基因为靶基因，设计DPO引物，建立了特异性检测志贺氏菌属的DPO—PCR方法。结果显不，所建立的DPO-PCR方法检测灵敏度为1．65×10^2CFU／mL；与常规PCR引物相比，DPO引物设计简易，简化了PCR引物设计；DPO引物退火温度范围宽，在50-70℃退火温度内均可对靶基因进行高效扩增；DPO引物结构特殊，具有比常规PCR引物更高的特异性，反应中无非特异性扩增产生。实践检测结果显示，利用该方法对133份冻／鲜肉类、果蔬类、鲜牛奶、鸡蛋和熟食样本进行检测，共检出15份志贺氏菌阳性样本，经国标法（GB／T4789．5-2012）复检，两者检测结果一致，显示出良好的实用性和可靠性，为志贺氏菌快速、准确的检测提供了新手段。

In this study, a dual-priming oligonucleotide （DPO） based PCR method for specific detection of Shigella was es- tablished using ipaH gene of Shigella as the target gene. The results showed that detection sensitivity of the DPO-PCR meth- od was 1.65 ×102 CFU/mL. Compared with conventional PCR primers, the DPO primers were easily designed, which simpli fled the design procedure of PCR primers. DPO primers were not sensitive to annealing temperature, which could efficiently amplify the target gene in the annealing temperature range from 50 to 70 ℃. Moreover, due to the special structure of DPO primers, it had a higher specificity than conventional PCR primers, and none nonspecific amplifications were produced in reac tion. In the practical application, tests on 133 samples including frozen/fresh meat, fruits and vegetables, fresh milk, eggs and cooked food by the DPO-PCR method showed that 15 samples were Shigella positive, which were in accordance with the tes ting results using GB method （GB/T 4789.5 2012）, showing good practicality and reliability. The DPO-PCR method provid- ed a new tool for fast and accurate detection of Shigella.