Virulence Genes and Neutral DNA Markers ofHelicobacter pyloriIsolates from Different Ethnic Communities of West Bengal, India

Abstract

Virulence-associated genes and neutral DNA markers of Helicobacter pylori strains from the Santhal and Oroan ethnic minorities of West Bengal, India, were studied. These people have traditionally been quite separate from other Indians and differ culturally, genetically, and linguistically from mainstream Bengalis, whose H. pylori strains have been characterized previously. H. pylori was found in each of 49 study participants, although none had peptic ulcer disease, and was cultured from 31 of them. All strains carried the cag pathogenicity island and potentially toxigenic s1 alleles of vacuolating cytotoxin gene (vacA) and were resistant to at least 8 g of metronidazole per ml. DNA sequence motifs in vacA mid-region m1 alleles, cagA, and an informative insertion or deletion motif next to cagA from these strains were similar to those of strains from ethnic Bengalis. Three mobile elements, IS605, IS607, and ISHp608, were present in 29, 19, and 10%, respectively, of Santhal and Oroan strains, which is similar to their prevalence in Bengali H. pylori. Thus, there is no evidence that the gene pools of H. pylori of these ethnic minorities differ from those of Bengalis from the same region. This relatedness of strains from persons of different ethnicities bears on our understanding of H. pylori transmission between communities and genome evolution.

Indistinguishable cellular changes in gastric mucosa between Helicobacter pylori infected asymptomatic tribal and duodenal ulcer patients

“…H pylori in the biopsy specimens was looked for carefully and then the bacterial density was measured as it may have an impact on disease association and epidemiologic importance. [7] VA1-R 5'-CTGCTTGAATGCGCCAAAC vacA m1 or vacA m2 VAG-F 5'-CAATCTGTCCAATCAAGCGAG [28] VAG-R 5'-GCGTCAAAATAATTCCAAGG cagA (5' end) cag5c-F 5'-GTTGATAACGCTGTCGCTTC [28] cag3c-R 5'-GGGTTGTATGATATTTTCCATAA cag-PAI empty site Luni 1 5'-ACATTTTGGCTAAATAAACGCTG [7] R5280 5'-GGTTGCACGCATTTTCCCTTAATC iceA1 IceA1F 5'-TATTTCTGGAACTTGCGCAACCTGAT [7] M.Hpy1R 5'-GGCCTACAACCGCATGGATAT IceA2 cycSF 5'-CGGCTGTAGGCACTAAAGCTA [7] IceA2R 5'-TCAATCCTATGTGAAACAATGATCGTT Saha DR et al . Cellularity of H pylori infected tribal and DU patients H pylori was measured in the modified Giemsa stained sections by counting the H pylori like organisms on the mucosal surface and in the foveolae [13] .…”

“…On the other hand, DNA sequence motifs of an informative middle region of vacA gene from Indian H pylori strains are distinct both from European and East Asian strains. So, there are strong indications of significant geographic differences among strains [6,7] . Moreover, gastric cancer is more prevalent in Japan and China than any other parts of the world and duodenal ulcer is more common in India as compared to gastric ulcer.…”

“…Their separation from mainstream Bengalis and other Indians during much of human history is reflected in genetic differences in autosomal and mitochondrial DNA markers. Our previous study [7] showed that the majority of these tribal communities are infected with H pylori; but, interestingly, none of them shows any symptoms. On the other hand, duodenal ulcer, which is H pyloriassociated, is of particular importance in ethnic Bengali populations and is far more common than in most other geographic regions [9] .…”

“…Santhals and Oroans are two distinct ethnic tribal groups that had settled in the Birbhum district of West Bengal centuries ago [7] . They constitute less than 5% of the overall population of West Bengal (Census of India, 2001).…”

Molecular characterization and antibiotic susceptibility profiles of Helicobacter pylori isolated from patients with Gastrodeudenal diseases in Jordan

“…Among the H. pylori virulence factors, cytotoxin A (CagA) and vacuolating cytotoxin A (VacA) are the most studied since the production of these toxins increases the risk for gastric atrophy, intestinal metaplasia and gastric carcinoma [7,8]. However, genetic variation within the genes encoding these virulence factors contributes to differences in the pathogenicity of strains [9]. It has been reported that a round 70% of the H. pylori strains isolated in the western countries possess the cagA gene while higher prevalence of cagA-positive strains is Results: Among 72 symptomatic patients, 13(23%) patients showed positive H. pylori infection by both rapid urease test and culture.…”