[Antibiotic resistance rates of Helicobacter pylori isolates and the comparison of E-test and fluorescent in situ hybridization methods for the detection of clarithromycin resistant strains].

Helicobacter pylori which is one of the commonly seen chronic bacterial infections in the world, has been demonstrated to have a relationship with chronic gastritis, peptic ulcer disease and gastric cancer. Current management of H. pylori infection involves the use of a proton pump inhibitor (PPI) and any two of amoxicillin, clarithromycin and metronidazole in combination. Antibiotic resistance which is in an increasing trend in H. pylori since the recent years, is the main cause of treatment failure. This study was conducted to determine the susceptibility of 31 H. pylori strains to several antibiotics by using E-test method (AB Biodisk, Sweden) and also to detect clarithromycin resistance by fluorescent in situ hybridization (FISH; SeaFAST, Hungary). The strains were isolated from the gastric biopsy specimens of patients who were admitted to Uludağ University Hospital, Bursa, Turkey with dyspeptic complaints. Clarithromycin, amoxycillin, metronidazole, tetracycline and ciprofloxacin resistance rates were as 41.9%, 3.2%, 41.9%, 3.2% and 45.2%, respectively. Resistance to single antibiotic was detected in 32.2% of the isolates whereas multiresistance was seen in 45.2%. For the hybridization process one probe specific for 16S rRNA and labeled with a fluorescein dye and the other probe specific for the mutations in 23S rRNA and labeled with Cy3 stain were used. Green signalling denoted presence of H. pylori in the specimen and red signalling was associated with clarithromycin resistance. All of the isolates yielded green signalling and the 13 isolates found to be resistant to clarithromycin by E-test, gave red signalling. No difference was detected between the two methods in terms of clarithromycin resistance determination. This was a preliminary study reporting the H. pylori resistance rates in our region, however, further larger scale studies are required for obtaining countrywide data.