[The prevalence of mutations underlying development of Helicobacter pylori resistance to antibiotics in Kazan].

Background: One of the reasons for the decrease of Helicobacter pylori eradication effectiveness is its resistance to antibiotics.

Aim: To examine the prevalence of H. pylori point mutations responsible for clarithromycin and levofloxacin resistance among the patients with upper gastrointestinal (GI) tract disorders in Kazan.

Materials and methods: The study included 203 patients with symptoms of dyspepsia who underwent upper GI endoscopy at the University Hospital of Kazan Federal University (Kazan, Russia) in 2019-2021. DNA isolation from gastric antrum mucosal biopsies was performed using PureLink Genomic DNA Mini Kits (Thermo Fisher Scientific, USA). Polymerase chain reaction was performed using primers specific for the V-region of the 23S gene and the A subunit DNA gyrase encoding gyrA gene region. The sequencing of obtained DNA fragments was performed on 3730 DNA Analyzer. The sequences were searched for point mutations responsible for H. pylori resistance to clarithromycin (A2143G, A2142G and A2142C193 mutations) and levofloxacin (mutations of the gyrA gene).

Results: H. pylori was detected in 47.78% of biopsy specimens using polymerase chain reaction. The proportion of H. pylori strains with mutations leading to clarithromycin resistance was 17.53%. Amino acid substitutions in the gyrA gene were found in 12.37% of samples. In case of two H. pylori strains (2.06%), dual resistance to clarithromycin and levofloxacin was found.

Conclusion: So high incidence of mutations underlying the development of H. pylori resistance to clarithromycin and levofloxacin was observed among examined patients in Kazan.