Mutations in the 23S rRNA genes of Helicobacter pylori mediate resistance to clarithromycin (A preliminary study)

Background: Background Helicobacter pylori(H.pylori) is a bacterium that can colonize in the gastric mucosa. Different antibiotic regimens have been developed in the treatment of H.pylori infections. In recent years it has been suggested that resistance is responsible for reducing the rate of resistant H.pylori eradication caused by mutations developed in different gene regions against antibiotics such as clarithromycin, metronidazole. In this study, we aimed to determine the resistance of clarithromycin in H.pylori strains isolated from gastric biopsy specimens by phenotypic tests and molecular methods and to determine the mutations responsible for resistance. Methods & Materials: Methods & Materials Antrum and corpus biopsy specimens from 48 patients with dyspeptic complaints were cultured at Heliocobacter agar(microaerophilic, 3-10 days, at 37 °C). Colonies were identified as H.pylori by testing for Gram stain, urease, catalase and oxidase. Minimum inhibitory concentrations were determined using clarithromycin E-tests(MIC S≤0.25-R≥0.5 mg/L). To investigate the resistance of clarithromycin, 23S rRNA gene region of H.pylori was amplified by PCR. A2143G and A2144G point mutations which are most frequently responsible in addition with less frequent point mutations A2115G, G2141A, A2142G/C, T2182C, T2190C and C2195T for clarithromycin resistance were investigated by sequencing to the obtained products. Results: Results Phenotypic resistance to the clarithromycin was detected in 18/48(37.5%) strains(MIC ≥0.5 mg/L). According to the results of the sequencing, 18(37.5%) resistant strains were detected. Point mutations were detected in all of the 18 isolates. These mutations were identified as A2142G/C(8.3%) in 4 samples, A2143G(16.6%) in 8 samples, T2182C(8.3%) in 4 samples, A2144G(2.1%) in 1 sample and G2141A, A2142G/C, A2144G, A2115G(2.1%) multiple mutation in 1 sample. T2190C and C2195T were not detected. Conclusion: Conclusion The resistance development problem during the treatment regimens and the search for solutions with the recommended treatment regimens continues increasingly. It was observed that the resistance rate of 37.5% for clarithromycin is slightly higher than that of 36.7%, which we have previously(year2014) identified in our region. Therefore, we suggest that the eradication problem will continue as new treatment alternatives are not developed in our country and in the world due to these resistance rates, which do not decrease in our country yet.