Clarithromycin-Susceptible But Virulent Helicobacter pylori Strains Infecting Iranian Patients’ Stomachs

Abstract

Introduction

Helicobacter pylori was discovered first in the stomachs of patients with gastritis and ulcers by Marshall and Warren in 1982. This discovery majorly affected many research areas of gastroenterology. Since then, the main aim has been to eradicate this microaerophilic bacterium from the stomachs of infected subjects.

Methods

We studied symptomatic cases by endoscopic surgery and examined the prevalence of cagA–vacA genotypes among the H. pylori isolates. H. pylori isolated from antral biopsies of patients with gastritis and duodenal ulcer were subjected to antimicrobial susceptibility testing and PCR genotyping by using routine bacterial cultures. Clarithromycin-susceptibility profiling was done by the E-test. DNA was extracted using standard manufacturer protocols with minor modifications and cagA and vacA genotyping was done PCR.

Results

In our study, all strains identified as H. pylori in culture (61/81) were confirmed by PCR by amplifying a fragment of the glmM gene. Totally, 61 patients were confirmed to be positive for H. pylori and they were included in the genotyping and antibiotic-susceptibility testing. Thirteen H. pylori strains were determined to be resistant to clarithromycin.

Discussion

Current accumulating data indicate that both clarithromycin-resistant and susceptible isolates of H. pylori need to be screened and tracked in populations.

Keywords:

• antibiotic susceptibility
• cagA
• clarithromycin
• E-test
• Helicobacter pylori
• genotypes
• PCR
• vacA

Acknowledgments

This study was financially supported by research deputy of Tarbiat Modares University, Tehran, Iran. We would like to thank Dr Farid Rahimi (The Australian National University) for constructive comments and help with English editing of this manuscript.

Ethics

Our study was conducted in accordance with the Declaration of Helsinki.

Author Contributions

All authors contributed to data analysis, drafting or revising the article, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

The authors declare no conflicts of interest in this work.