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 confirmed good 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.

Importance: This study, with a large sample size, comprehensively tested both Helicobacter pylori-negative and -positive patients, including rapid urease test, histopathological evaluation and staining, bacterial culture, susceptibility testing, and resistance gene mutation analysis. By simultaneously examining gastric mucosa, gastric juice, and fecal samples from the same individuals, we minimized confounding factors arising from different sample sources, ensuring the reliability of our results. This approach effectively delineated the differences and characteristics in detection performance among different sample types, offering crucial reference data for selecting appropriate detection samples and identifying areas for improvement. The findings revealed robust concordance between genotypic and phenotypic resistance, with both gastric mucosa and gastric juice samples demonstrating excellent detection performance. However, the efficiency of detecting resistance in fecal samples was hampered by challenges in DNA extraction.