title: Comparison of Gastric Microbiota Between Gastric Juice and Mucosa by Next Generation Sequencing Method.
abstract: BACKGROUND
  Not much is known about the role of gastric microbiota except for Helicobacter pylori in human health and disease. In this study, we aimed to detect human gastric microbiota in both gastric mucosa and gastric juice by barcoded 454-pyrosequencing of the 16S rRNA gene and to compare the results from mucosa and juice.
  
  
  METHODS
  Gastric biopsies and stomach juices were collected from 4 subjects who underwent standard endoscopy at Seoul National University Bundang Hospital. Gastric microbiota of antral mucosa, corpus mucosa samples, and gastric fluids were analyzed by barcoded 454-pyrosequencing of the 16S rRNA gene. The analysis focused on bacteria, such as H. pylori and nitrosating or nitrate-reducing bacteria.
  
  
  RESULTS
  Gastric fluid samples showed higher diversity compared to that of gastric mucosa samples. The mean of operational taxonomic units was higher in gastric fluid than in gastric mucosa. The samples of gastric fluid and gastric mucosa showed different composition of phyla. The composition of H. pylori and Proteobacteria was higher in mucosa samples compared to gastric fluid samples (H. pylori, 66.5% vs. 3.3%, P = 0.033; Proteobacteria, 75.4% vs. 26.3%, P = 0.041), while Actinobacteria, Bacteroidetes, and Firmicutes were proportioned relatively less in mucosa samples than gastric fluid. However there was no significant difference. (Actinobacteria, 3.5% vs. 20.2%, P = 0.312; Bacteroidetes, 6.0% vs. 14.8%, P = 0.329; Firmicutes, 12.8% vs. 33.4%, P = 0.246).
  
  
  CONCLUSIONS
  Even though these samples were small, gastric mucosa could be more effective than gastric fluid in the detection of meaningful gastric microbiota by pyrosequencing.
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam.
authors.forename: Jihee
authors.initials: J
authors.lastname: Sung
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam; Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Nayoung
authors.initials: N
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Jaeyeon
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam.
authors.forename: Hyun Jin
authors.initials: HJ
authors.lastname: Jo
authors.affiliation: Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam.
authors.forename: Ryoung Hee
authors.initials: RH
authors.lastname: Nam
authors.affiliation: Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, Korea.
authors.forename: Yeong-Jae
authors.initials: YJ
authors.lastname: Seok
authors.affiliation: Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, Korea.
authors.forename: Yeon-Ran
authors.initials: YR
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam; Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Dong Ho
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam.
authors.forename: Hyun Chae
authors.initials: HC
authors.lastname: Jung
keywords: Gastric juice; Gastric mucosa; Helicobacter pylori; Microbiota