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Copyright ©2009 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Jul 7, 2009; 15(25): 3161-3165
Published online Jul 7, 2009. doi: 10.3748/wjg.15.3161
Characterization of clarithromycin resistance in Malaysian isolates of Helicobacter pylori
Norazah Ahmad, Wan Rasinah Zakaria, Sheikh Anwar Abdullah, Ramelah Mohamed
Norazah Ahmad, Wan Rasinah Zakaria, Bacteriology Unit, Institute for Medical Research, Jalan Pahang, 50588 Kuala Lumpur, Malaysia
Sheikh Anwar Abdullah, Department of Internal Medicine, Universiti Kebangsaan Malaysia Medical Centre, 56000 Kuala Lumpur, Malaysia
Ramelah Mohamed, Universiti Kebangsaan Malaysia Molecular Biological Institute, Universiti Kebangsaan Malaysia Medical Centre, 56000 Kuala Lumpur, Malaysia
Author contributions: All the authors have contributed equally in this study.
Correspondence to: Dr. Norazah Ahmad, Bacteriology Unit, Institute for Medical Research, Jalan Pahang, 50588 Kuala Lumpur, Malaysia. norazah@imr.gov.my
Telephone: +60-3-26162658
Fax: +60-3-26924949
Received: January 6, 2009
Revised: May 27, 2009
Accepted: June 3, 2009
Published online: July 7, 2009
Abstract

AIM: To characterize the types of mutations present in the 23S rRNA genes of Malaysian isolates of clarithromycin-resistant Helicobacter pylori (H pylori).

METHODS: Clarithromycin susceptibility of H pylori isolates was determined by E test. Analyses for point mutations in the domain V of 23S rRNA genes in clarithromycin-resistant and -sensitive strains were performed by sequence analysis of amplified polymerase chain reaction products. Restriction fragment length polymorphism was performed using BsaI and MboII enzymes to detect restriction sites that correspond to the mutations in the clarithromycin-resistant strains.

RESULTS: Of 187 isolates from 120 patients, four were resistant to clarithromycin, while 183 were sensitive. The MIC of the resistant strains ranged from 1.5 to 24 &mgr;g/mL. Two isolates had an A2142G mutation and another two had A2143G mutations. A T2182C mutation was detected in two out of four clarithromycin-resistant isolates and in 13 of 14 clarithromycin-sensitive isolates. Restriction enzyme analyses with BsaI and MboII were able to detect the mutations.

CONCLUSION: Clarithromycin resistance is an uncommon occurrence among Malaysian isolates of H pylori strains and the mutations A2142G and A2143G detected were associated with low-level resistance.

Keywords: Clarithromycin resistance, Helicobacter pylori, 23S rRNA mutation, Restriction fragment length polymorphism