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

作者：Eghbali Zahra; Mojtahedi Ali^*; Ansar Malek Moien; Asl Saba Fakhrieh; Aminian Keyvan

来源：Jundishapur Journal of Microbiology, 2016, 9(2): e29694.

DOI：10.5812/jjm.29694

• Clarithromycin Resistance
• PCR-RFLP
• Helicobacter pylori

Background: Ilelicobacter 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 23.5rRNA 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 IL 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 II. 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 FL pylori DNA was confirmed by amplifying the ureC (gImM) gene by PCR. Also, point mutation on 23SrRNA gene (A2142G and A2143G) was detected by PCR-RFLP using Mboll and Bsal restriction endonucleases in all extracted DNA.
Results: Of the 89 II. pylori isolates, eighty-four were susceptible to clarithromycin, while five (5.6%) were resistant. All DNA samples of resistant strains, which were treated with Bsal had A2143G mutation.There was no point mutation in the sensitive strains of fl. 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.

• 出版日期2016-2