Rapid detection of Clarithromycin-resistant Helicobacter pylori in dyspeptic patients by fluorescent in situ hybridization (FISH) compared with E-test

Background: Rapid detection of H. pylori is important for determining of resistant are susceptible strains to clarithromycin and recovery of patients will be acelerated, if clarithromycin is added to therapeutic protocol. Objective: Rapid detection of susceptible or resistant strains of Helicobacter pylori to clarithromycin in patients with dyspeptic ulcers by FISH technique and also comparison of FISH results with E-test technique. Methods: Frozen sections of gastric biopsies from 50 patients with dyspeptic ulcers were hybridized in situ with 5 fluorescent oligonucleotide probes (FISH). Following staining with DAPI, the slides were examined using fluorescent microscopy. Also, susceptibility and resistance of isolated strains of H. pylori to clarithromycin was determined by E-test. The results obtained from both E-test and FISH techniques were compared. Findings: Twenty five out of 50 examined gastric biopsy samples were positive for H. pylori by FISH. Out of 25 H. pylori strains, 17 strains (68%) were susceptible, 6 strains (24%) resistant and 2 strains (8%) showed intermediate response to clarithromycin. This study showed that there was no significant difference between FISH and E-test results in terms of the number of susceptible or resistance strains. Conclusion: Regarding the results of this study, it sems that the FISH technique to be a suitable method to determine the susceptibility are H. pylori to clarithromycin, especially when a quickly decision is necessary for treating of dyspeptic patients