title: Clarithromycin resistance and point mutations in the 23S rRNA gene in Helicobacter pylori isolates from Malaysia.
abstract: OBJECTIVE
  To determine the prevalence of primary clarithromycin resistance amongst Helicobacter pylori (H. pylori) strains in Malaysian patients with gastroduodenal diseases, by using restriction fragment length polymorphism (RFLP) in domain V of 23S rRNA.
  
  
  METHODS
  Gastric biopsies were obtained from H. pylori positive patients undergoing gastroscopy. DNA extraction was followed by PCR amplification using the primers Hp23-1 and Hp23-2 flanking a region of 425bp within the bacterial 23S rRNA peptidyltranferase (Hp23S fragment). Analysis of the 23S rRNA gene mutations is based on the generation of restriction sites for two restriction enzymes: BbsI and BsaI, which correspond to the base substitutions characteristic of clarithromycin resistance from A to G at positions 2142 and 2143, respectively.
  
  
  RESULTS
  Gastric biopsy samples were obtained from 107 patients. A fragment of size 425bp corresponding to that expected from amplification of domain V of 23S rRNA was PCR-amplified from only 105 samples. The amplicon was subsequently subjected to restriction by BbsI and BsaI. Only 1 sample (0.95%) had the BbsI mutation (base substitution at A2142G) and 2 samples (1.90%) the BsaI mutation (base substitution at A2143G). Thus 3 of 105 (2.9%) samples harbored clarithromycin resistant strains.
  
  
  CONCLUSIONS
  In our experience, PCR-RFLP is a rapid and precise method to detect the resistance of H. pylori to clarithromycin. Using this method, a low prevalence of clarithromycin resistance was detected in our local Malaysian strains. This augurs well for the continued use of clarithromycin as a first line drug in the treatment and eradication of H. pylori infection.
authors.affiliation: Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Sin-Loong
authors.initials: SL
authors.lastname: Ho
authors.forename: Eng Lai
authors.initials: EL
authors.lastname: Tan
authors.forename: Chook Koon
authors.initials: CK
authors.lastname: Sam
authors.forename: Khean-Lee
authors.initials: KL
authors.lastname: Goh
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001706:Biopsy; D017291:Clarithromycin / Q000627:therapeutic use*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005260:Female; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics*; D006801:Humans; D008296:Malaysia / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D017354:Point Mutation / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D015995:Prevalence; D012338:RNA, Ribosomal, 23S / Q000235:genetics*; D012189:Retrospective Studies; D013270:Stomach / Q000382:microbiology / Q000473:pathology
chemical_list: D000900:Anti-Bacterial Agents; D012338:RNA, Ribosomal, 23S; D017291:Clarithromycin