title: Comparison of FISH, RFLP and agar dilution methods for testing clarithromycin resistance of Helicobacter pylori.
abstract: OBJECTIVE
  Clarithromycin resistance is an important factor of Helicobacter pylori (H. pylori) eradication failure in adults and children. There are some tests to determine resistance such as restriction fragment length polimorphism (RFLP), fluorescence in situ hibridisation (FISH), PCR and (culture) agar dilution. Clarithromycin resistance is reported between 16.8%-48.2% in Turkey using PCR, 18% in Japan using RFLP. The aim of the study is to compare the efficacy of FISH, RFLP and culture.
  
  
  METHODS
  Patients with gastric complaint underwent endoscopic examination. H. pylori status of all patients was tested with urea breath test. Gastric biopsy samples obtained from adult patients and children were studied. Each tissue was analised with FISH, PCR-RFLP anda gar dilution.
  
  
  RESULTS
  A total 100 patients were positive by UBT and histology for H. pylori. Tissues from 89 adults and 11 children were evaluated. According to FISH and RFLP clarithromycin resistance was 26% and 16% respectively. Among 100 patients H. pylori was cultured in 52 tissue samples, among these samples 7 were resistant to clarithromycin. There was strong correlation between the results of FISH and RFLP; RFLP and culture; and FISH and culture.
  
  
  CONCLUSIONS
  There is a high ratio of clarithromycin resistance in the studied population. All 3 tests are valuable, but FISH seems to be more sensitive among these tests. We suggest FISH should be used for detecting clarithromycin resistance among H. pylori infected patients before eradication therapy.
authors.affiliation: Department of Microbiology, Sakarya University Faculty of Medicine, Sakarya, Turkey. meltemkorkut@yahoo.com.
authors.forename: İhsan Hakkı
authors.initials: İH
authors.lastname: Çiftci
authors.forename: Meltem
authors.initials: M
authors.lastname: Uğraş
authors.forename: Gürsel
authors.initials: G
authors.lastname: Acartürk
authors.forename: Gülşah
authors.initials: G
authors.lastname: Aşık
authors.forename: Birol
authors.initials: B
authors.lastname: Şafak
authors.forename: Fatma Hüsniye
authors.initials: FH
authors.lastname: Dilek
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002648:Child; D017291:Clarithromycin / Q000494:pharmacology*; D015169:Colony Count, Microbial; D024881:Drug Resistance, Bacterial; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008826:Microbial Sensitivity Tests / Q000379:methods*; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D017291:Clarithromycin