Prevalence of A2143G and A2144G Point Mutations Responsible for Clarithromycin Resistance among Helicobacter pylori Strains in Bushehr, Iran

Abstract

Background: Resistance to clarithromycin in Helicobacter pylori has become one of the most important reasons for failure of antibiotic eradication therapies. This resistance is predominantly caused by point mutations in the peptidyl transferase region of 23S rRNA. Objectives: The aim of this study was to determine the prevalence of the A2143G, A2144G, and A2143C point mutations among H. pylori strains from gastric biopsy specimens in Bushehr, in the southwest of Iran. Patients and Methods: Gastric biopsy specimens were obtained from patients with upper gastrointestinal symptoms during endoscopy. Fluorescent in situ hybridization (FISH) using oligonucleotide probes was applied to detect the point mutations responsible for clarithromycin resistance in H. pylori. Results: Of the 135 H. pylori-positive specimens, two harbored strains with the A2143G mutation and nine contained strains with the A2144G mutation. Thus, the prevalences of the A2143G and A2144G point mutations were 1.5% and 6.7%, respectively. The A2143C point mutation was not found. Conclusions:The prevalences of the point mutations A2143G and A2144G were low in our geographic area. Based on the findings of this study, clarithromycin still seems to be a useful antibiotic for initial treatment regimens in Bushehr, Iran.

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

“…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.…”

“…To deparaffinize the tissue sections, the slides were subsequently immersed in hexane and absolute ethanol (Merck, Germany) twice, each time for 30 minutes. After air-drying of the slides, they were then ready for checking by FISH [12].…”

“…However, several other mutations have been detected in A2144G, A2143C, and T2182C positions. Given the heterogeneous distribution of antibiotic resistance across different geographical areas, determining regional patterns of antibiotic resistance can help the physicians choose a valuable and specific treatment [11,12].…”

Punctual mutations in23S rRNAgene of clarithromycin-resistantHelicobacter pyloriin Colombian populations

“…It was found that the frequency in the sampled population in this study, is in line with the frequencies reported in other regions, 0.01 (1/73)[ 21 ] and 0.81(9/11)[ 20 - 23 ]. This mutation was first reported in H. pylori isolates resistant to clarithromycin in Colombia, which indicates that it may be associated with the inclusion of strains from high frequency countries such as South Korea (frequency of 0.57)[ 15 ]; Japan (frequency of 0.7)[ 24 ] and Turkey (frequency between 0.29 and 0.81[ 20 , 22 ].…”

“…The mutations associated with clarithromycin resistance in the H. pylori isolates described in this study (A2144G, C2196T, and T2183C), are located in 23S rRNA gene V domain, as reported in the current literature[ 3 ]. Inhibition of the action of the macrolide may be due to spatial alterations in the V domain of 23S rRNA gene, which inhibit the target, as seen in transversion mutations A2143G, A2142G, A2142C[ 3 ], A2144G[ 18 , 19 , 22 ], where a nitrogenous base with two H groups (Adenine) is changed for another with three H groups (Guanine and Cytosine), with the inherent spatial alteration of the molecular structure, a phenomenon similar in transitions C2196T and T2183C[ 17 ].…”