Abstract:

Objective　To investigate the efficiency of gastric juice for detecting H.pylori infection，clarithromycin resistance，and CYP2C19 polymorphism. Methods　The specimens of gastric jjice were collected from all patients while receiving gastroscopy. DNA was extracted from gastric juice and then cagH were amplified by polymerase chain reaction（PCR） for detecting the existence of H.pylori. By PCR restriction fragment length polymorphism（PCR-RFLP），the 23SrRNA of H.pylori and CYP2C19 genotypes of host were examined respectively. During endoscopy examination，biopsy-based specimens were also collected. We compared the results of gastric juice tests with the biopsy-based specimens. Results　The sensitivity of gastric juice real-time PCR for the diagnosis of H.pylori infection was 100%（94/94）. The accuracy was 76.4%（94/123），the sensitivity to detect clarithromycin resistance was 98.9%（90/91），the specificity was 66.7%（2/3），and the positive predictive value was 98.9%（90/91）. The negative predictive value was 66.7%（2/3） and the accuracy was 97.9%（92/94）. The accuracy of detecting host CYP2C19 metabolome was 90.0%（90/100）. Conclusion　Gastric juice real-time polyme rase chain reaction is an effective method to detect Helicobacter pylori infection，clarithromycin sensitivity and host CYP2C19 gene metabolization in children，and it is worthy of promotion in children.

Key words: helicobacter pylori, gastric juice, antibiotic resistance, CYP2C19 metabolite, child

摘要： 目的　探讨胃液实时聚合酶链反应（real-time PCR）检测儿童幽门螺杆菌（HP）感染、克拉霉素敏感性和宿主CYP2C19基因代谢型方法的准确性，旨在寻求一种方便、快速、准确检测儿童HP感染，克拉霉素敏感性和CYP2C19基因代谢型的方法。方法　选取2013年7月至2014年11月北京儿童医院消化科123例13C呼气试验检查阳性的胃炎或消化性溃疡患儿进行电子胃镜检查，胃镜下取胃黏膜并收集胃液标本。从胃液中提取DNA，然后通过聚合酶链式反应（PCR）扩增RnaseP酶和cagH以检测幽门螺旋杆菌的存在。通过PCR限制性片段长度多态性（PCR-RFLP）分别检测HP23SrRNA和宿主CYP2C19基因代谢型。研究共利用5对引物和9条探针进行HPcagH基因和23SrRNA基因，以及人RnaseP基因和CYP2C19∗2、CYP2C19∗3基因检测。将胃液结果与胃黏膜活检标本HP培养和E-test药敏试验及CYP2C19基因代谢型检测结果进行比较分析。结果　以胃黏膜HP培养、E-test药敏试验及CYP2C19基因代谢型检测结果为金标准，胃液实时PCR检测HP感染诊断敏感度为100%（94/94）、准确度为76.4%（94/123）；检测克拉霉素是否耐药敏感度为98.9%（90/91）、特异度为66.7%（2/3），阳性符合率为98.9%（90/91）、阴性符合率为66.7%（2/3）、准确度为97.9%（ 92/94）；检测宿主CYP2C19基因代谢型的准确度为90.0% （90、100）。结论　胃液实时聚合酶链反应是检测儿童HP感染、克拉霉素敏感性和宿主CYP2C19基因代谢型有效方法，儿童临床值得推广。

关键词: 幽门螺杆菌, 胃液, 耐药, CYP2C19基因代谢型, 儿童