Basic study in molecular noninvasive estimation of Clarithromycin resistant Helicobacter pylori: Set up of ASP-PCR in differentiation of infB, and PCR-sequencing to evaluate 23S rRNA, and rpl22 related mutations

Introduction:

Designation of the local profile of Clarithromycin resistant (CAM-R) in Helicobacter pylori (H. pylori) positive patients with phenotypic testes consequently evaluation of probable agreement between resistance phenotypes to genotypes is the necessity of accessing rapid molecular noninvasive tests. So, we designed ASP-PCR and PCR-sequencing methods to evaluate infB (G160A), 23S rRNA (A2142C/G, A2143C/G), and rpl22 (GTG deletion or TTCCATGTA insertion) nucleotide polymorphisms from the stool of patients with symptoms of gastritis. Urea tubes were used to transport 96 gastric biopsies to the laboratory.

The Agar dilution method was performed to assess CAM-R strains. Besides the phenotypical identification, stool samples were collected and stored at -80° C. Molecular identity w:as char:acterized by amplification of the 23S rRNA target gene. In the evaluation of non-invasive genotypical molecular tests in the detection of corresponding mutations, ASP-PCR was performed to isolate infB G160G wild-type strains and PCR-sequencing in determining 23S rRNA and rpl22 polymorphisms.

Molecular isolation of H. pylori positive-patients was reported to be 34/54(62%). Among 35/96 (36%) phenotypically characterized H. pylori-positive infected patients,16/35(45%) were considered for CAM-R strains. The distribution of point mutations between resistant isolates has been revealed to be (1/16) for A2143C, (4/16) for infB G160A (PCR negative patients), (2/16) rpl22 for 3bp deletion, and (16/16) for rpl22 9bp insertion.

Conclusion:

 We are honored to introduce rpl22-related point mutations as the potential marker in designing a noninvasive molecular method in Clarithromycin-resistant infected patients screening.