Stool-Based Diagnosis of Helicobacter Pylori, Detection of Virulence Genes and Molecular Analysis of Clarithromycin Resistance in Patients With Gastrointestinal Complaints

Abstract

Aim: This study aimed to detect Helicobacter pylori DNA, major virulence genes (cagA, vacA s1/s2, iceA1/A2), and clarithromycin resistance-associated mutations directly from stool samples of patients presenting with gastrointestinal complaints using molecular techniques. Material and Method: Stool samples from 60 patients collected between April and July 2023 were included in the study. Following DNA extraction, conventional PCR was performed to detect H.pylori and its virulence genes (cagA, vacA s1/s2, iceA1/A2). Real-time PCR (qPCR) was used to identify mutations associated with clarithromycin resistance. Results: H.pylori DNA was detected in 28.3% (n=17) of the samples. Among positive cases, the cagA gene was identified in 17.6% and the vacA s1 subtype in 23.5%. The vacA s2 and iceA1/ A2 genes were not detected. In qPCR analysis, clarithromycinresistance mutations were found in 68.4% of the H.pylori–positive samples (n=19). Conclusion: Molecular stool-based testing appears to be a relevant non-invasive approach for both diagnosis and antibiotic resistance profiling of H.pylori. However, technical limitations such as low DNA yield, PCR inhibitors, and small sample size may have reduced sensitivity. Non-invasive molecular strategies may serve as practical and effective alternatives for treatment stratification, particularly in settings where endoscopic procedures are not readily accessible.

Keywords

• Helicobacter pylori
• clarithromycin resistance
• stool
• molecular diagnosis
• cagA
• vacA

References

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