Mutations in the Helicobacter pylori 23S rRNA gene associated with clarithromycin resistance in patients at an endoscopy unit in Medellin, Colombia

Introduction: Clarithromycin is the first-line antibiotic for the treatment of Helicobacter pylori infection. Bacterial resistance is mainly due to the presence of point mutations in the 23S ribosomal RNA (rRNA) gene. Objective: To determine the frequency of A2143G and A2142G point mutations in the 23S rRNA gene associated with clarithromycin resistance of H. pylori in samples from patients with dyspeptic manifestations in Medellin, North West, Colombia. Materials and methods: DNA extraction was performed from gastric biopsy samples obtained from patients with dyspeptic manifestations attending at endoscopy unit from 2016 to 2017. PCR was performed to amplify the bacterial s and m vacA regions and 23S rRNA gene. The presence of the A2142G and A2143G mutations was determined by restriction fragment length polymorphism (RFLP) technique with the Bbsl and Bsal enzymes, respectively. Results: The prevalence of infection was 44.2% (175/396), according to the histopathology report. The positive samples were analyzed and amplification of the three regions of the bacterial genome was obtained in 143/175. The A2143G and A2142G mutations were identified in 27 samples (18.8%, 27/143). The most frequent mutation was A2143G (81.5%, (22/27)). Conclusions: We found a high prevalence of H. pylori mutations associated with clarithromycin resistance in the study population. Further studies are required to determine the bacterial resistance in Colombian population and thus define first line and rescue therapies.