A retrospective study of the antibiotic-resistant phenotypes and genotypes of strains in China.

antibiotic resistance is a serious concern in China, where it severely influences treatment for infection. To overcome this, it is essential to apply personalized therapies based on local or individual data on antibiotic-resistant phenotypes or genotypes. We conducted a large-scale multi-center study with a retrospective cross-sectional observational design to investigate the antibiotic-resistant phenotypes and genotypes of in China. Strains were isolated from the gastric biopsy samples of -infected patients from five different regions in China. The strains were tested for antibiotic-resistant phenotypes and genotypes, and the agreement between the two was assessed. In total, 4242 strains were isolated and cultured, with an 84.43% success rate. The primary and secondary antibiotic resistance rates of were 37.00% and 76.93% for clarithromycin, 34.21% and 61.58% for levofloxacin, 2.20% and 6.12% for amoxicillin, 1.61% and 3.11% for furazolidone, 1.18% and 3.31% for tetracycline, and 87.87% and 93.48% for metronidazole, respectively. The dual-resistance patterns for metronidazole/clarithromycin, metronidazole/levofloxacin, and clarithromycin/levofloxacin were 43.6%, 38.4%, and 26.1%, respectively. Clarithromycin- and levofloxacin-resistant phenotypes and genotypes showed satisfactory agreement. Based on these findings, clarithromycin- and levofloxacin-resistant genotype testing could partially replace traditional antibiotic susceptibility testing in China. Continuous monitoring and personalized treatments based on individual and local antibiotic-resistance data remain necessary.