title: Genetic variability determinants of Helicobacter pylori: influence of clinical background and geographic origin of isolates.
abstract: Helicobacter pylori has an unusual pattern of genetic variation, which complicates research on this organism. To gain a better understanding of the forces behind this phenomenon, the extent to which recombination and single point mutations affect genetic variability in H. pylori was quantified and the influence of both geographical distance and clinical background were assessed. Site-directed restriction-endonuclease digestion of 2 gene fragments was performed on 168 isolates from Montreal and Berlin. Allelic diversity was found to be much higher for H. pylori than for other bacterial species. This finding is consistent with those of previous studies on H. pylori that were conducted using other techniques. However, nucleotide diversity was within the range reported for other bacterial species. Phylogenetic analysis found no grouping of strains with clinical background or geographical origin. Recombination at a rate that resulted in linkage equilibrium within genes can explain these observations.
authors.affiliation: Institute of Parasitology and Department of Internal Medicine, McGill University Health Centre, McGill University, Montreal, Canada.
authors.forename: M U
authors.initials: MU
authors.lastname: Göttke
authors.forename: C A
authors.initials: CA
authors.lastname: Fallone
authors.forename: A N
authors.initials: AN
authors.lastname: Barkun
authors.forename: K
authors.initials: K
authors.lastname: Vogt
authors.forename: V
authors.initials: V
authors.lastname: Loo
authors.forename: M
authors.initials: M
authors.lastname: Trautmann
authors.forename: J Z
authors.initials: JZ
authors.lastname: Tong
authors.forename: T N
authors.initials: TN
authors.lastname: Nguyen
authors.forename: T
authors.initials: T
authors.lastname: Fainsilber
authors.forename: H H
authors.initials: HH
authors.lastname: Hahn
authors.forename: J
authors.initials: J
authors.lastname: Körber
authors.forename: A
authors.initials: A
authors.lastname: Lowe
authors.forename: R N
authors.initials: RN
authors.lastname: Beech
mesh_terms: D000483:Alleles; D001426:Bacterial Proteins / Q000235:genetics; D001604:Berlin; D005408:Flagellin / Q000235:genetics; D005753:Gastric Mucosa / Q000382:microbiology*; D014644:Genetic Variation; D005843:Geography; D016480:Helicobacter pylori / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D006801:Humans; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011792:Quebec; D015183:Restriction Mapping
chemical_list: D001426:Bacterial Proteins; C074689:VacA protein, Helicobacter pylori; D005408:Flagellin; C067138:flaA protein, bacteria