Clarithromycin-based regimens are commonly used as a first-line therapy for Helicobacter pylori-positive patients; however, resistance to clarithromycin has led to treatment failures. The aim of this study was to evaluate the feasibility of using stool samples to detect the presence of H. pylori DNA while concurrently detecting mutations associated with resistance to clarithromycin. For this purpose, total DNA was extracted from 294 raw stool specimens from H. pylori-positive and -negative patients. TaqMan real-time PCR amplification was used to detect the presence of H. pylori as well as to predict the phenotype of the organism and the related outcome for patients treated with clarithromycin. Clarithromycin resistance was determined upon analysis of the PCR result. Patients were also tested by a urea breath test and were subjected to esophagogastroduodenoscopy, followed by histology, culture, and a rapid urease test, in order to obtain a consensus patient infection status. Of 294 total stool samples, 227 were deemed true positive. The sensitivity of H. pylori detection by PCR was 93.8%. Of 213 true-positive samples that were sequenced, 36.2% showed point mutations associated with clarithromycin resistance (A2142C, A2142G, A2143G). The final correlation of the mutant genotypes as determined by sequencing with the eradication of infection was 86%. We found that Helicobacter pylori DNA can be detected in human stool specimens with high sensitivity and can therefore be used to determine the presence of the bacterium without obtaining a biopsy sample. Moreover, genotypic resistance to clarithromycin can be predicted without obtaining a biopsy sample, facilitating the choice of the right therapeutic approach.
Current guidelines recommend that all patients with documented H. pylori infection should be treated with an appropriate antibacterial therapy. Clarithromycin-based regimens are commonly used as a first line therapy in H. pylori positive patients, however soon after the introduction of clarithromycin-based therapies, treatment failures associated with resistance to clarithromycin were reported. In this study, we evaluated the feasibility of using a non-invasive sample type, stool, to detect the presence of H. pylori by molecular methods while concurrently detecting mutations associated with the resistance to clarithromycin. The sensitivity for H. pylori detection by PCR was 93.8% compared to composite reference methods with gastric tissue biopsy. Out of 213 true positives that were sequenced, 36.2% showed point mutations associated with CLA resistance (A2142C, A2142G, A2143G). The correlation of sequencing and PCR was 98%. The correlation of sequencing and eradication of the infection was 86%. The results of this test may be used as a tool for guiding treatment of H. pylori infection.To cite this article: Erin Beckman, et al. A new non-invasive tool for guiding H. pylori treatment.
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