Relationship Between Drug Resistance and cagA Gene in Helicobacter pylori

Abstract

Background: Currently, there are evidences for the existence of diverse strains of Helicobacter pylori with different levels of virulence. In other way, the most important reason of therapeutic failure is resistance to the antibiotics. Objectives: The aim of this study was to evaluate the relationship between H. pylori drug resistance and the presence of cagA gene. Patients and Methods: Gastric biopsy specimens were cultured for H. pylori isolation. Resistance to antimicrobial agents, including clarithromycin, metronidazole, and amoxicillin were detected by modified disk agar diffusion tests. The cagA gene was detected using PCR, and the results were analyzed by χ2 and Fishers exact tests using SPSS software version 16. Results: A total of 123 H. pylori-positive patients (68 males, 55 females, mean age 35 ± 18 years old) were studied. The rate of resistance to clarithromycin, metronidazole and amoxicillin were 17.07, 78.86 and 27.64%, respectively. In this study, the cagA was detected in 84 of 123 strains (68.3%). The frequency of resistance to clarithromycin, metronidazole and amoxicillin in cagA positive confirmed microorganisms were, 16 (13.01%), 67 (54.47%) and 24 (19.51%), respectively. While the results for cagA negative ones were 5 (4.06%), 30 (24.39%) and 10 (8.13%), respectively. Conclusions: Our results indicated that the overall antibiotic resistance of H. pylori was high, and the relationship between drug resistance and cagA status was not statistically significant. Therefore, different treatment regimens are not recommended for patients with H. pylori- cagA positive infections.