Phylogenetic analysis of 3’ region of Helicobacter pylori cagA gene of Lombok isolates and the association with gastric pathology

Lombok island is a transitional region beetwen Asian and Australian faunal biodiversity. There has been no previous report on the genotype of Helicobacter pylori in the population. The cagA gene is one of the important virulence factors of H. pylori. The diversity of cagA 3′ regions reflect the phylogenetic relationships among the different H. pylori isolates and their association with clinical outcomes and significant geographical differences among isolates have been reported. The purpose of this study was to analyse the variability of 3’region of cagA H. pylori Lombok isolates and determine the genotype based on EPIYA(Glu-Pro-Ile-Tyr-Ala) motif of CagA and its relationship with pathological of the stomach. Total of 36 isolates of H. pylori Lombok origins were studied. Gastric antral biopsies collected from 36 Lomboknese patients (chronic gastritis = 13, gastric/duodenal ulcer =12, and gastric cancer =10) were used to amplify the 3’ regions of cagA containing EPIYA motifs by PCR then followed by DNA sequencing. We have found that 34/36 of the H. pylori Lombok isolates were clustered alone while 1/36 was clustered together with other East Asian strains. The findings of the study suggested that Lombok H. pylori strains share a common ancestry with East Asians but with their own unique sequences. No association of specific sequences with the outcome of disease was revealed through additional phylogenetic analysis based on amino acid sequences.