Detection of genotypic clarithromycin-resistant Helicobacter pylori by string tests

Area of Science:

• Medical Microbiology
• Molecular Diagnostics

Background:

• Helicobacter pylori (H. pylori) infection is a global health concern.
• Antibiotic resistance, particularly to clarithromycin, complicates H. pylori eradication.
• Accurate genotypic resistance detection is crucial for effective treatment strategies.

Purpose of the Study:

• To evaluate the diagnostic utility of the string test for detecting genotypic clarithromycin resistance in H. pylori.
• To assess the performance of PCR-restriction fragment length polymorphism (PCR-RFLP) using the string test for H. pylori resistance detection.

Main Methods:

• Patients with H. pylori infection underwent endoscopic procedures and subsequent string tests.
• DNA was extracted from string test samples, and specific 23S rRNA gene segments were amplified.
• PCR-RFLP analysis was performed using BbsI and BsaI restriction enzymes to identify resistance-associated mutations.

Main Results:

• The string test demonstrated high specificity (97.3%) and positive predictive value (80%) for detecting genotypic clarithromycin resistance.
• Sensitivity was 66.7% and negative predictive value was 94.7%.
• A significant correlation was observed between genotypic resistance detected by string test and phenotypic resistance.

Conclusions:

• The string test, combined with molecular analysis, offers a less invasive approach for pre-treatment genotypic H. pylori resistance detection.
• This method holds promise for guiding personalized H. pylori eradication therapy.
• Larger studies are warranted to validate these findings and clinical utility.