Multiplex fluorescent PCR-based detection of Helicobacter pylori nucleic acid and antibiotic resistance genes in clinical stool samples: a performance evaluation from Gansu Province, China.

BACKGROUND

The increasing antibiotic resistance of Helicobacter pylori (H. pylori) undermines empirical treatment efficacy. Rapid, non-invasive methods simultaneously detecting H. pylori and resistance mutations are needed. However, the clinical performance of multiplex fluorescent PCR kits on stool samples in Chinese populations remains under-evaluated.

METHODS

A total of 535 patients with suspected H. pylori infection were enrolled. Stool samples were tested by the new multiplex fluorescent PCR kit for H. pylori DNA and resistance mutations (23 S rRNA and gyrA). Gastric biopsies were cultured for H. pylori and antimicrobial susceptibility testing (AST; disk diffusion). Stool DNA was also analyzed by Sanger sequencing for resistance mutations. A commercial H. pylori PCR kit was used as a comparator. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated against culture/AST and sequencing. Agreement with the comparator kit was assessed using kappa. Resistance mutation frequencies were summarized. Associations between H. pylori infection and demographic factors (age, gender) were assessed using chi-square tests.

RESULTS

Culture confirmed H. pylori in 383/535 patients (71.6%). AST revealed high resistance rates: metronidazole 92.0%, levofloxacin 51.3%, clarithromycin 51.0%. The dominant clarithromycin resistance mutation was A2144G (81.2%). Against culture, the MFQ-PCR showed 99.5% sensitivity (95% CI: 98.3-99.9%) and 94.7% specificity (95% CI: 90.5-97.6%) for H. pylori detection. For clarithromycin resistance, sensitivity/specificity were 95.5%/95.7% vs. AST, and 97.5%/99.5% vs. sequencing. For quinolones, sensitivity/specificity were 94.4%/92.6% vs. AST, and 99.5%/95.9% vs. sequencing. Agreement with the comparator PCR kit was excellent (κ = 0.931). Age < 40 years was associated with higher infection rate (P = 0.012).

CONCLUSION

This multiplex fluorescent PCR kit demonstrates high accuracy for non-invasive H. pylori detection and resistance profiling, supporting its utility as a first-line diagnostic tool, particularly in settings with limited laboratory resources for H. pylori isolation and AST.