Molecular characterization and antibiotic susceptibility profiles of Helicobacter pylori isolated from patients with Gastrodeudenal diseases in Jordan

Abstract

Introduction:  Helicobacter pylori is a major cause of more than 80% of chronic active gastritis and other gastrodeudonal diseases worldwide. Successful treatment of H. pylori routinely requires the use of multiple agents with different mechanisms including compounds inhibiting acid secretion in conjunction with antibiotics. However, recent data showed the emergence of resistant clinical strains particularly against metronidazole and clarithromycin. The aim of this study is to determine the prevalence of and the susceptibility of H. pylori isolates recovered from patients with gastrodeudonal diseases to several antimicrobial agents. Materials and Methods: A prospective study has been conducting on Jordanian patients attended the gastrointestinal unit of the Jordan university hospital starting from 2014-2015 with gastroduodenal diseases. Antral and corpus mucosal biopsies from the stomach of each patient were used for the isolation of H. pylori on selective culture media. Presumptive H. pylori colonies were subsequently confirmed by biochemical tests and standard 16S rDNA PCR assay. The antimicrobial susceptibility testing was performed by standard agar diffusion methods according to CLSI. Subsequently, MICs were determined by E test and standard agar dilution method. Molecular typing of the clinical strains was performed using multiplex PCR for the detection of vacA and cagA genotypes. Metronidazole resistance was characterized by molecular methods for the detection of rdxA gene mutations. Results: Among 72 symptomatic patients, 13 (23%) patients showed positive H. pylori infection by both rapid urease test and culture. The antibiotic susceptibility profile showed that all of the isolates were sensitive to amoxicillin.  Resistance to, clarithromycin, ciprofloxacin and levofloxacin were observed in 15%, 23% and 8% of the isolates respectively while 92% of the strains were resistant to metronidazole (MIC ≥ 32 ug/ml). Metronidazole resistance due to mutations in rdxA gene was only observed in one strain (8%) suggesting other resistance mechanisms. Correlation between antibiotic resistance and virulence factors was statistically not significant (p > 0.05). Conclusion: The present study showed that the prevalence of metronidazole resistance among clinical isolates of H. pylori is very high. Lower resistance to other antibiotics are reported. Concern should be taken into consideration when triple therapy is used for the treatment of H. pylori in our region.