Comparative analysis of the detection of antibiotic genotypic resistance with gastric mucosa, gastric fluid, and fecal samples in patients with Helicobacter pylori infection

Genotypic methods for detecting antibiotic resistance in Helicobacter pylori infection offer a rapid, convenient, and accurate approach for tailored therapy. However, existing studies predominantly examine single sample types and lack comparative analyses across different samples. This study comprehensively detects and compares genotypic resistance to clarithromycin and levofloxacin in gastric mucosa, gastric fluid, and fecal samples from the same patients. The study enrolled 183 participants, comprising 124 H. pylori-positive and 59 H. pylori-negative patients. All participants provided fecal samples and underwent gastroscopy for the collection of gastric mucosa and gastric fluid. Real-time PCR was employed to detect genotypic resistance to clarithromycin and levofloxacin in conjunction with bacterial culture and antibiotic susceptibility testing. Genotypic resistance detection rates for clarithromycin were 100% in gastric mucosa, 99.2% in gastric fluid, and 79.8% in fecal samples. For levofloxacin,detection rates were 97.6%, 96.8%, and 72.6%, respectively. The results showed that PCR detection for clarithromycin exhibited high sensitivity (0.94-0.95) and specificity(0.88-0.89) across all sample types. However, PCR detection for levofloxacin demonstrated slightly lower sensitivity (0.79-0.89) and specificity (0.79-0.83). The comparison of genotypic resistance results by PCR among the three sample types showed that gastric mucosa and gastric juice exhibited higher consistency, while the consistency between feces and both gastric mucosa and gastric juice was lower. This study confirmedgood consistency between genotypic and phenotypic resistance in clarithromycin and levofloxacin. While both gastric mucosa and gastric fluid samples demonstrated high detection performance, the efficiency of detecting fecal samples was constrained by challenges in DNA extraction.