Infection and Drug Resistance (Nov 2019)
Clarithromycin-Susceptible But Virulent Helicobacter pylori Strains Infecting Iranian Patients’ Stomachs
Abstract
Shadiyeh Khani, Amin Talebi Bezmin Abadi, Ashraf Mohabati Mobarez Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, IranCorrespondence: Amin Talebi Bezmin AbadiDepartment of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran 14115-111, IranTel +98 21 8288 4883Email [email protected]: 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
