title: Genetic variation of Helicobacter pylori in the oral cavity and stomach detected using thymine adenine cloning in children with chronic gastritis.
abstract: OBJECTIVE
  To investigate the DNA sequence variations of Helicobacter pylori in the oral cavities and stomachs of children with chronic gastritis.
  
  
  METHODS
  Dental plaques and gargle on 235 patients were obtained before gastroscopy. Gastric H. pylori infection was diagnosed using rapid urease test or Giemsa staining. H. pylori 16S rDNA and CagA gene were analyzed using PCR methods. Thymine adenine cloning-based sequencing was performed in patients with CagA gene positive from oral cavities. The sequence alignments and V1 variable region were evaluated by comparison with the sequence of the standard H. pylori 26695 strain.
  
  
  RESULTS
  Totally, 46 out of the 235 patients were positive for gastric H. pylori infection. Of the 46 patients, 26 cases had amplified H. pylori 16S rDNA in both oral (plaque and gargle) and gastric samples. Of the 26 cases, 12 patients (46.1%) were positive for the H. pylori CagA gene in the oral samples, which was significantly lower than that in the gastric mucosa (80.8%; P = 0.010). The homology of the complete sequence alignment ranged from 74.0% to 92.1% in the oral and gastric samples. The V1 region alleles (positions 75-99) had 7-22 polymorphisms (homology from 12.0% to 72.0%) in 11 patients between the oral and gastric samples, but had 100% homology in 1 patient.
  
  
  CONCLUSIONS
  Our study found that distinct H. pylori strains exist in the oral cavities of children, but we would not support the hypothesis that H. pylori in the oral cavities is an important reservoir of gastric H. pylori infections in children.
authors.affiliation: Department of Gastroenterology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China. Haifang Cai, MD, is currently at the Lishui Central Hospital of Zhejiang Province, Lishui 323000, China Wei Li is currently at the Department of Pediatrics, Jiaxing Maternity and Child Health Care Hospital of Zhejiang Province, Jiaxing, 314050, China.
authors.forename: Haifang
authors.initials: H
authors.lastname: Cai
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Shu
authors.forename: Kerong
authors.initials: K
authors.lastname: Peng
authors.forename: Yanyi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Mizu
authors.initials: M
authors.lastname: Jiang
mesh_terms: D000293:Adolescent; D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D003001:Cloning, Molecular; D015331:Cohort Studies; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D005753:Gastric Mucosa / Q000382:microbiology*; D005756:Gastritis / Q000382:microbiology*; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009055:Mouth / Q000382:microbiology*; D011110:Polymorphism, Genetic; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; C080866:cagA protein, Helicobacter pylori