Detection of 23SrRNA Mutations Strongly Related to Clarithromycin Resistance in Helicobacter pylori Strains Isolated From Patients in the North of Iran

Abstract

Background:Helicobacter pylori is curved Gram negative and microaerophilic bacilli that have infected half of the world’s population. It is recognized as the causative agent of duodenal ulcer, gastritis peptic ulcer, mucosa-associated lymphoid tissue (MALT) lymphoma and is associated with gastric adenocarcinoma. Resistance to clarithromycin is related to point mutations in 23SrRNA gene on nt 2143 and 2144, when A turns to G, and A2143G is the most important type. These mutations lead to reduced affinity of antibiotics to their ribosomal target and are considered as the main cause of treatment failure.Objectives:The aim of this study was to determine the frequency of A2143G point mutation in 23SrRNA of H. pylori strains isolated from gastric biopsies of patients in Rasht, north of Iran, by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).Patients and Methods:A descriptive study was performed on 89 H. pylori strains, which were isolated from gastric biopsies of patients with gastric disorders such as gastritis, peptic ulcer, duodenal ulcer, non-ulcer dyspepsia and gastric adenocarcinoma. Isolated strains were tested for clarithromycin resistance using as breakpoint a minimum inhibitory concentration (MIC) of ≥ 1 mg/L by the E-test. The presence of H. pylori DNA was confirmed by amplifying the ureC (glmM) gene by PCR. Also, point mutation on 23SrRNA gene (A2142G and A2143G) was detected by PCR-RFLP using MboII and BsaI restriction endonucleases in all extracted DNA.Results:Of the 89 H. pylori isolates, eighty-four were susceptible to clarithromycin, while five (5.6%) were resistant. All DNA samples of resistant strains, which were treated with BsaI had A2143G mutation. There was no point mutation in the sensitive strains of H. pylori. Also, we detected no mutation on nt A2142G of resistant strains.Conclusions:In the present study, the frequency of clarithromycin resistance was lower than the other studies conducted in Iran. Resistance frequency in samples isolated from gastric ulcer was higher than other gastric disorders. Women and patients aged more than 60 years old showed the most resistance frequency in this study. All resistant strains had the A2143G genotype.

Molecular Assessment of Resistance to Clarithromycin in Helicobacter pylori Strains Isolated from Patients with Dyspepsia by Fluorescent In Situ Hybridization in the Center of Iran

“…A high relative frequency of resistance was seen in CAG patients; however, there was no significant relationship between various diseases and clarithromycin resistance status. These findings are in agreement with Eghbali et al [32].…”

“…In this study, although the relative frequency of clarithromycin resistance was higher in females than males, the difference was not significant. This is consistent with the findings of others [12,32]. The consumption of new macrolides, which are commonly prescribed in the elderly, can lead to more mutations.…”

GenoType® HelicoDR test in comparison with histology and culture for Helicobacter pylori detection and identification of resistance mutations to clarithromycin and fluoroquinolones

“…In general, in our study, the most frequent mutation responsible for resistance to clarithromycin was found in the rrl gene in the A2147G allele in accordance with other reports . Mutations responsible for fluoroquinolones resistance with highest frequency were found in the N87K allele on the gyr 87 gene and in the D91N allele on the gyr91 gene in accordance with other reports .…”

A systematic review and meta‐analysis of genotypic methods for detecting antibiotic resistance in Helicobacter pylori

“…Subgroup analysis based on PCR methods Several PCR-based methods were applied in these 22 studies. Including PCR-RFLP, 34,35,37,[41][42][43][44][45][46] PCR-based sequencing, 40,47-52 fluorescent in situ hybridization (FISH), 36,50,52 scorpion PCR assay, 43,53 GenoType HelicoDR, 51 PCR-line probe assay, 24 LightCycler PCR, 54 denaturing HPLC (DHPLC) assay, 23 and primer-mismatch PCR. 46,55 The pooled sensitivity and specificity for any of these assays were greater than 0.95, except for GenoType HelicoDR, which had a sensitivity of 89.6%.…”