title: PCR-RFLP detection of point mutations A2143G and A2142G in 23S rRNA gene conferring resistance to clarithromycin in Helicobacter pylori strains.
abstract: BACKGROUND
  The occurrence of clarithromycin resistance among Helicobacter pylori strains is a major cause of the treatment failure. Resistance to this drug is conferred by point mutations in 23S rRNA gene and the most prevalent mutations are A2143G and A2142G. The aim of the study was to evaluate the occurrence of A2143G and A2142G mutations in a group of H. pylori strains resistant to clarithromycin.
  
  
  METHODS
  The study included 21 clarithromycin-resistant H. pylori strains collected between 2006 and 2009 in southern Poland. Resistance to clarithromycin was quantitatively tested with the E-test to determine the minimal inhibitory concentration (MIC value). The point mutations of H. pylori isolates were detected by PCR followed by RFLP analysis.
  
  
  RESULTS
  The MIC values for clarithromycin for the analyzed strains ranged from 1.5 mg/L to 64 mg/L. Nine H. pylori strains exhibited A2143G mutation and A2142G mutation was found in 9 isolates as well. The results of RFLP analysis of 3 clarithromycin-resistant strains were negative for both mutations. The average MIC values for A2143G and A2142G mutants were 6 and 30 mg/L, respectively.
  
  
  CONCLUSIONS
  Frequencies of A2143G and A2142G mutations were the same in all isolates tested. Strains with A2143G mutation exhibited lower MIC values than A2142G mutants. Application of PCR-RFLP method for detection of clarithromycin resistance allows for better and more efficient management of H. pylori infections.
authors.affiliation: Department of Pharmaceutical Microbiology, Jagiellonian University Medical College, Kraków, Poland.
authors.forename: Karolina
authors.initials: K
authors.lastname: Klesiewicz
authors.affiliation: Department of Pharmaceutical Microbiology, Jagiellonian University Medical College, Kraków, Poland.
authors.forename: Paweł
authors.initials: P
authors.lastname: Nowak
authors.affiliation: Department of Pharmaceutical Microbiology, Jagiellonian University Medical College, Kraków, Poland.
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Karczewska
authors.affiliation: Department of Pharmaceutical Microbiology, Jagiellonian University Medical College, Kraków, Poland.
authors.forename: Iwona
authors.initials: I
authors.lastname: Skiba
authors.affiliation: Department of Pharmaceutical Microbiology, Jagiellonian University Medical College, Kraków, Poland.
authors.forename: Izabela
authors.initials: I
authors.lastname: Wojtas-Bonior
authors.affiliation: Falck Medycyna Outpatient Clinic of Gastroenterology, Kraków, Poland.
authors.forename: Edward
authors.initials: E
authors.lastname: Sito
authors.affiliation: Department of Pharmaceutical Microbiology, Jagiellonian University Medical College, Kraków, Poland.
authors.forename: Alicja
authors.initials: A
authors.lastname: Budak
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017291:Clarithromycin / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial / Q000187:drug effects / Q000235:genetics*; D005798:Genes, Bacterial; D016481:Helicobacter Infections / Q000188:drug therapy / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008826:Microbial Sensitivity Tests; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012338:RNA, Ribosomal, 23S / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D012338:RNA, Ribosomal, 23S; D017291:Clarithromycin