title: Clinical role and importance of fluorescence in situ hybridization method in diagnosis of H pylori infection and determination of clarithromycin resistance in H pylori eradication therapy.
abstract: H pylori is etiologically associated with gastritis, gastric and duodenal ulcers, gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. Eradicating H pylori may convert rapidly the outcome of related diseases with the use of more accurate diagnostic molecular tests. Indeed some of the tests cannot give the evidence of current infection; H pylori can be detected by noninvasive and invasive methods, the latter requiring an endoscopy. Eradication failure is a big problem in H pylori infection. Recently, clarithromycin resistance in H pylori strains is increasing and eradication therapy of this bacterium is becoming more difficult. Molecular methods have frequently been applied besides phenotypic methods for susceptibility testing to detect clarithromycin resistance due to mutations in the 2143 and 2144 positions of 23S rRNA gene. Fluorescence in situ hybridization (FISH) method on paraffin embedded tissue is a rapid, accurate and cost-effective method for the detection of H pylori infection and to determine clarithromycin resistance within three hours according to the gold standards as a non-culture method. This method can also be applied to fresh biopsy samples and the isolated colonies from a culture of H pylori, detecting both the culturable bacillary forms and the coccoid forms of H pylori, besides the paraffin embedded tissue sections. This technique is helpful for determining the bacterial density and the results of treatment where clarithromycin has been widely used in populations to increase the efficacy of the treatment and to clarify the treatment failure in vitro.
authors.affiliation: Department of Microbiology and Clinical Microbiology, Faculty of Medicine, Dokuz Eylül University, Inciralti 35340, Izmir, Turkey. ozlem.yilmaz@deu.edu.tr
authors.forename: Ozlem
authors.initials: O
authors.lastname: Yilmaz
authors.forename: Ebru
authors.initials: E
authors.lastname: Demiray
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D017291:Clarithromycin / Q000627:therapeutic use*; D024881:Drug Resistance, Bacterial; D005756:Gastritis / Q000175:diagnosis / Q000188:drug therapy; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000188:drug therapy*; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods
chemical_list: D000900:Anti-Bacterial Agents; D017291:Clarithromycin