A novel RT-PCR for the detection of Helicobacter pylori and identification of clarithromycin resistance mediated by mutations in the 23S rRNA gene

In this study we evaluated the commercially available LightMix (R) RT-PCR assay for Helicobacter pylori detection and identification of clarithromycin (CLR) resistance in culture and clinical specimens (gastric biopsies and stool). The H. pylori LightMix (R) RT-PCR detects a 97 bp long fragment of the 23S rRNA gene and allows the identification of 3 distinct point mutations conferring CLR resistance via melting curve analysis. The performance of the H. pylori LightMix (R) RT-PCR was evaluated using a set of 60 H. pylori strains showing phenotypical CLR susceptibility or CLR resistance (Minimum inhibitory concentrations from 0.016 to 256 mg/L). We found high concordance (95%) between phenotypical CLR resistance screening by E-Test and the Lightmix (R) RT-PCR. Discrepant results were verified by sequencing of the 23S rRNA gene that always confirmed the results obtained by Lightmix (R) RT-PCR. Furthermore, H. pylori was detected in clinical biopsy and stool specimens by Lightmix (R) RT-PCR that identified the correct H. pylori genotype. The LightMix (R) RT-PCR is an accurate, sensitive and easy to use test for H. pylori and CLR resistance detection and can therefore be readily implemented in any diagnostic laboratory. (C) 2017 The Authors. Published by Elsevier Inc.