Helicobacter pylori infection is mainly diagnosed noninvasively, with susceptibility testing traditionally requiring endoscopy. Treatment is empirical, with clarithromycin-based triple therapy recommended where resistance rates are below 15%. Rising rates of clarithromycin resistance, resulting in high clarithromycin-based therapy failure rates, are seen worldwide, but U.S. data are limited. We developed a real-time PCR assay for simultaneous detection of H. pylori and genotypic markers of clarithromycin resistance directly from stool specimens. The assay was validated by testing 524 stool samples using an H. pylori stool antigen test as the reference method for detection accuracy and Sanger sequencing to confirm genotypic susceptibility results. A separate set of 223 antigen-positive stool samples was tested and retrospective medical record review conducted to define clinical utility. PCR resulted in 88.6% and 92.8% sensitivity in the validation and clinical study sets, respectively. Sequencing confirmed correct detection of clarithromycin resistance-associated mutations in all positive validation samples. The PCR-predicted clarithromycin resistance rate was 39% in the clinical data set overall and 31% in treatment-naive patients; the clarithromycin-based triple therapy eradication rate in treatment-naive patients was 62%. The clarithromycin-based triple therapy success was lower when resistance was predicted by PCR (41%) than when no resistance was predicted (70%; P = 0.03). PCR results were positive in 98% of antigen-positive stools from patients tested for eradication. The described PCR assay can accurately and noninvasively diagnose H. pylori, provide genotypic susceptibility, and test for eradication. Our findings support the need for susceptibility-guided therapy in our region if a clarithromycin-based regimen is considered.

中文翻译：

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直接从粪便中同时检测幽门螺杆菌和克拉霉素耐药基因型标志物的实时 PCR 检测的临床评价

幽门螺杆菌感染主要通过非侵入性诊断，敏感性测试传统上需要内窥镜检查。治疗是经验性的，在耐药率低于 15% 时推荐使用基于克拉霉素的三联疗法。克拉霉素耐药率上升，导致以克拉霉素为基础的治疗失败率高，在世界范围内可见，但美国数据有限。我们开发了一种实时 PCR 检测方法，用于直接从粪便样本中同时检测幽门螺杆菌和克拉霉素耐药性的基因型标志物。通过使用幽门螺杆菌测试 524 个粪便样本来验证该测定粪便抗原试验作为检测准确性和Sanger测序确认基因型易感性结果的参考方法。测试了一组单独的 223 个抗原阳性粪便样本，并进行了回顾性医疗记录审查以确定临床效用。PCR 在验证和临床研究集中分别导致 88.6% 和 92.8% 的敏感性。测序证实在所有阳性验证样本中正确检测到克拉霉素耐药相关突变。PCR 预测的克拉霉素耐药率在整个临床数据集中为 39%，在未接受治疗的患者中为 31%；未接受治疗的患者中以克拉霉素为基础的三联疗法根除率为 62%。P = 0.03）。经根除试验的患者的 98% 的抗原阳性粪便 PCR 结果为阳性。所描述的 PCR 检测可以准确无创地诊断幽门螺杆菌，提供基因型易感性，并测试根除情况。如果考虑以克拉霉素为基础的治疗方案，我们的研究结果支持在我们地区进行敏感性指导治疗的必要性。