title: Bacterial flora concurrent with Helicobacter pylori in the stomach of patients with upper gastrointestinal diseases.
abstract: OBJECTIVE
  To investigate the non-Helicobacter pylori (H. pylori) bacterial flora concurrent with H. pylori infection.
  
  
  METHODS
  A total of 103 gastric biopsy specimens from H. pylori positive patients were selected for bacterial culture. All the non-H. pylori bacterial isolates were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS).
  
  
  RESULTS
  A total of 201 non-H. pylori bacterial isolates were cultivated from 67 (65.0%) of the 103 gastric samples, including 153 isolates identified successfully at species level and 48 at genus level by MALDI-TOF MS. The dominant species were Streptococcus, Neisseria, Rothia and Staphylococcus, which differed from the predominantly acid resistant species reported previously in healthy volunteers. The prevalence of non-H. pylori bacteria was higher in non-ulcer dyspepsia group than in gastric ulcer group (100% vs 42.9%, P < 0.001). Six bacterial species with urease activity (Staphylococcus epidermidis, Staphylococcus warneri, Staphylococcus capitis, Staphylococcus aureus, Brevibacterium spp. and Klebsiella pneumoniae) were also isolated.
  
  
  CONCLUSIONS
  There is a high prevalence of the non-H. pylori bacteria concurrent with H. pylori infection, and the non-H. pylori bacteria may also play important as-yet-undiscovered roles in the pathogenesis of stomach disorders.
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Hu
authors.forename: Li-Hua
authors.initials: LH
authors.lastname: He
authors.forename: Di
authors.initials: D
authors.lastname: Xiao
authors.forename: Guo-Dong
authors.initials: GD
authors.lastname: Liu
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: Gu
authors.forename: Xiao-Xia
authors.initials: XX
authors.lastname: Tao
authors.forename: Jian-Zhong
authors.initials: JZ
authors.lastname: Zhang
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D001706:Biopsy; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006801:Humans; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013270:Stomach / Q000382:microbiology*; D013272:Stomach Diseases / Q000382:microbiology*; D014510:Urease / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D014510:Urease