Antibiotic resistance and virulence genotypes оf Heliсоbасter рylоri in Mongolia

Abstract

Introduction: Helicobacter pylori infection has been reported in more than 70% of Mongolian adults and is one of the most common reasons for gastric cancer. However, the resistance of Helicobacter pylori to antibiotics is considered to be increasing and optimal eradication regimens have not been satisfactory. The current study aimed to determine and assess the resistance to antibiotics and clarithromycin point mutations and EPIYA genes among Helicobacter pylori isolated from patients in different provinces, as well as in Ulaanbaatar. Materials and methods: In total, 293 patients with dyspepsia were selected from Ulaanbaatar and provinces. Helicobacter pylori cultures were collected from gastric biopsies to achieve a yield of 61 isolates. Antimicrobial susceptibility testing was determined by E-test and EUCAST breakpoints. Real-time PCR and biopsy samples were analyzed for clarithromycin resistance mutations A2142C/G and A2143G. Results: Resistance to clarithromycin and amoxicillin was 19.7% for both, and no resistance to tetracycline was observed. The resistance to three antibiotics was observed in 9.8% of the isolates. The rural population showed higher resistance to metronidazole and to amoxicillin of 82.8% and 27.6%, respectively, as opposed to the urban population, which demonstrated 62.5% and 12.5%, respectively. The mutations were A2142G in 21.5% in biopsy samples analyzed by real-time PCR. There were no mutations for A2143G. Conclusion: The resistance to metronidazole and levofloxacin and to clarithromycin and amoxicillin found in our study is higher than the Asian average. The findings are in favor of preferring either BSM-based regimens or S-based regimens over CM-based triple therapy in Mongolia. The observed difference in resistance patterns in this region and presence of EPIYA patterns of a Western type are enough to support a need for development of guidelines for each region to achieve optimal eradication success and to lower national incidence of gastric malignancies.