title: Isogenic variation of Helicobacter pylori strain resulting in heteroresistant antibacterial phenotypes in a single host in vivo.
abstract: BACKGROUND
  Antibiotic-susceptible and -resistant Helicobacter pylori can be present simultaneously in the same host. The aim of this study was to evaluate the genomic diversity of H. pylori strains resulting in heteroresistant antibacterial phenotypes.
  
  
  METHODS
  Twenty-one pairs of H. pylori strains isolated from the antrum and body displaying heteroresistant antibacterial phenotypes were included. We compared the genotypes of paired-isolates by random arbitrarily primed polymerase chain reaction (PCR), flagella gene PCR-based restriction fragment length polymorphism, and flaA gene sequencing. In metronidazole-heteroresistant isolates, the sequence variation of rdxA and frxA genes was analyzed using phylogenetic analysis.
  
  
  RESULTS
  The DNA fingerprinting patterns of the paired isolates revealed that 12 pairs (57.1%) were identical, whereas one pair (3.8%) was different. The remaining eight pairs (38.1%) of isolates showed minor heterogenecity in fingerprinting patterns. In flaA gene sequencing, these identical and similar isolates showed close sequence similarity between the antrum and body, whereas different isolate showed 31 points of different nucleotide sequences. Phylogenetic analysis of the metronidazole-heteroresistant pairs showed consistent genetic relatedness of each paired isolates despite the sequence variation of the rdxA or frxA genes in five pairs (71.4%).
  
  
  CONCLUSIONS
  These results suggest that continuing genomic diversities in the same strain may play an important role in modulating the antibiotic-heteroresistant H. pylori in vivo.
authors.affiliation: Department of Internal Medicine and Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Yong Chan
authors.initials: YC
authors.lastname: Lee
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Lee
authors.forename: Jae Hee
authors.initials: JH
authors.lastname: Pyo
authors.forename: Dong H
authors.initials: DH
authors.lastname: Kwon
authors.forename: Jong Chul
authors.initials: JC
authors.lastname: Rhee
authors.forename: Jae J
authors.initials: JJ
authors.lastname: Kim
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D016172:DNA Fingerprinting; D024881:Drug Resistance, Bacterial; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000145:classification* / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D008297:Male; D008795:Metronidazole / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D008795:Metronidazole