Evaluation of the Frequency of gyr A mutations leading to ciprofloxacin resistance in Helicobacter pylori in FFPE samples of patients with gastric adenocarcinoma

Abstract

Introduction: Gastric adenocarcinoma is the fourth leading cause of malignancy in the world. Helicobacter pylori is involved in many common gastrointestinal disorders. Resistance to antibiotics like ciprofluoxacin occurs through point mutations in the quinolone resistance domain of the gyrA gene at amino acids 87 and 91. Aim: we aim to investigate the frequency of gyrA mutations that lead to resistance of Helicobacter pylori to ciprofloxacin in FFPE samples of patients with gastric adenocarcinoma.Methods: Tissue samples are collected from the pathology department of Imam Reza hospitals.To confirm the presence of H. pylori DNA the samples, the Urease C gene will be amplified by PCR.Genotypic study of ciprofloxacin resistance pattern related to gyr A displacement mutations in Helicobacter pylori is performed by Real-Time PCR. In this method, a fragment of gyrase gene is amplified simultaneously with product identification by probe hybridization and melting curve analysis is performed. Results: Out of 80 paraffinized samples, 75 DNA samples were obtained, of which 54 (31 cancer samples and 23 control samples) had urease gene. The results of real-time PCR and melting point showed that 8 (25.8%) of cancer patients are resistant to this antibiotic, of which 5 cases only in position 87 and 2 cases only in position 91 and 1 case in both They had the place of mutation. Examination of the melting curve obtained from control subjects also showed that out of 23 DNAs obtained, 5 were ciprofloxacin resistant DNA (21.73), all of which had 81 Tm changes in DNA sensitive at position 81.Conclusion: the rate of resistance to this antibiotic was higher in patients with gastric cancer than in controls, but this difference was not statistically significant.