Gene mutations of 23S rRNA and rdxA deletion associated with clarithromycin& metronidazole resistance in Helicobacter pylori strains isolated from UAE patients

Abstract number: P1255

Alfaresi M., Altayyari W., Elkouch A.

Objective: To determine the prevalence of antibiotic resistance genes (mutation in 23S rRNA gene in clarithromycin, and deletion in RdxA gene in metronidazole) among H. pylori strains isolated from U.A.E patients by using molecular methods PCR and Sequencing.

Methods: DNA was extraxted from antral gastric biopsy samples from 90 dyspeptic patients. Primary screening for H. pylori were done by Clo test at endoscopy department in Zayed Military Hospital (ZMH). All samples were confirmed for positive H. pylori by PCR. Mutations of the corresponding gene were studied by PCR and sequencing technique. DNA sequence editing and analysis were performed by ClustalX, version 2.

Results: Out of 90 biopsy samples 26 were positive for H. pylori by PCR were as 22 by clotest. Resistance to clarithromycin and metronidazole was detected in 9 (34.6%) and 3 (11.5%) of strains, respectively. Of the clarithromycin resistant strains, 22.22% had the A2142G mutation in the 23S rRNA gene, 55.56% A2143G, and 11.11% A2143C and 11.11% of highly changed in sequence. Of the metronidazole resistant strains, deletion in rdxA gene was detected in 3 strains which were negative for Clo test.

Conclusion: A significant proportion of gastric mucosal biopsies obtained in the UAE is positive for Genes associated with Clarithromycin and Metronidazole resistance(mainly in Clarithromycin). A2143G remains the most prevalent point mutation involved, thus suggesting that new therapeutic strategies are needed.