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Comparative genomics of Helicobacter pylori isolates recovered from ulcer disease patients in England

Pathogen Evolution Group, Laboratory of Molecular and Cell Biology, Centre for DNA Fingerprinting and Diagnostics (CDFD), Hyderabad, India.
BMC Microbiology (Impact Factor: 3.1). 03/2005; 5(32):1-10. DOI: 10.1186/1471-2180-5-32
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ABSTRACT Background . Genomic diversity of H. pylori from many different human populations is largely unknown. We compared genomes of 65 H. pylori strains from Nottingham, England. Molecular analysis was carried out to identify rearrangements within and outside the cag -pathogenicity-island ( cag PAI) and DNA sequence divergence in candidate genes. Phylogenetic analysis was carried out based on various high-resolution genotyping techniques.

Results . Analyses of virulence genes ( cag T, cag E, cag A, vac A, ice A, oip A and bab B) revealed that H. pylori strains from England are genetically distinct from strains obtained from other countries. The toxigenic vac A s1m1 genotype was found to be less common and the plasticity region cluster was found to be disrupted in all the isolates. English isolates showed a predominance of ice A1 alleles and a functional proinflammatory oip A gene. The English H. pylori gene pool revealed several Asian/oriental features. This included the predominance of cag A – glr ( cag A right junction) motif types III and II (up to 42%), presence of vac A m1c alleles and phylogenetic affinity towards East Asian / Amerindian gene pools based on fluorescent amplified fragment length polymorphism (FAFLP) analysis and glm M sequence analysis.

Conclusion . Overall, our results demonstrated genetic affinities of H. pylori in England with both European and the Asian gene pools and some distinctive genetic features of virulence genes that may have evolved in this important European population.

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