title: Usefulness of Housekeeping Genes for the Diagnosis of Helicobacter pylori Infection, Strain Discrimination and Detection of Multiple Infection.
abstract: BACKGROUND
  Helicobacter pylori infects human stomachs of over half the world's population, evades the immune response and establishes a chronic infection. Although most people remains asymptomatic, duodenal and gastric ulcers, MALT lymphoma and progression to gastric cancer could be developed. Several virulence factors such as flagella, lipopolysaccharide, adhesins and especially the vacuolating cytotoxin VacA and the oncoprotein CagA have been described for H. pylori. Despite the extensive published data on H. pylori, more research is needed to determine new virulence markers, the exact mode of transmission or the role of multiple infection.
  
  
  METHODS
  Amplification and sequencing of six housekeeping genes (amiA, cgt, cpn60, cpn70, dnaJ, and luxS) related to H. pylori pathogenesis have been performed in order to evaluate their usefulness for the specific detection of H. pylori, the genetic discrimination at strain level and the detection of multiple infection. A total of 52 H. pylori clones, isolated from 14 gastric biopsies from 11 patients, were analyzed for this purpose.
  
  
  RESULTS
  All genes were specifically amplified for H. pylori and all clones isolated from different patients were discriminated, with gene distances ranged from 0.9 to 7.8%. Although most clones isolated from the same patient showed identical gene sequences, an event of multiple infection was detected in all the genes and microevolution events were showed for amiA and cpn60 genes.
  
  
  CONCLUSIONS
  These results suggested that housekeeping genes could be useful for H. pylori detection and to elucidate the mode of transmission and the relevance of the multiple infection.
authors.affiliation: Departament de Microbiologia i Parasitologia Sanitàries, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Catalonia, Spain.
authors.forename: Montserrat
authors.initials: M
authors.lastname: Palau
authors.affiliation: Departament de Microbiologia i Parasitologia Sanitàries, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Catalonia, Spain.
authors.forename: Marcos
authors.initials: M
authors.lastname: Kulmann
authors.affiliation: Digestive Diseases Service, Hospital de Sabadell, Institut Universitari Parc Taulí, Departament de Medicina, Universitat Autònoma de Barcelona, Sabadell, Barcelona, Spain.|Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: María José
authors.initials: MJ
authors.lastname: Ramírez-Lázaro
authors.affiliation: Digestive Diseases Service, Hospital de Sabadell, Institut Universitari Parc Taulí, Departament de Medicina, Universitat Autònoma de Barcelona, Sabadell, Barcelona, Spain.|Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Lario
authors.affiliation: Digestive Diseases Service, Hospital de Sabadell, Institut Universitari Parc Taulí, Departament de Medicina, Universitat Autònoma de Barcelona, Sabadell, Barcelona, Spain.|Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: María Elisa
authors.initials: ME
authors.lastname: Quilez
authors.affiliation: Digestive Diseases Service, Hospital de Sabadell, Institut Universitari Parc Taulí, Departament de Medicina, Universitat Autònoma de Barcelona, Sabadell, Barcelona, Spain.|Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Campo
authors.affiliation: Departament de Microbiologia i Parasitologia Sanitàries, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Catalonia, Spain.
authors.forename: Núria
authors.initials: N
authors.lastname: Piqué
authors.affiliation: Digestive Diseases Service, Hospital de Sabadell, Institut Universitari Parc Taulí, Departament de Medicina, Universitat Autònoma de Barcelona, Sabadell, Barcelona, Spain.|Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Calvet
authors.affiliation: Departament de Microbiologia i Parasitologia Sanitàries, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Catalonia, Spain.
authors.forename: David
authors.identifier: http://orcid.org/0000-0003-2281-0402
authors.initials: D
authors.lastname: Miñana-Galbis
mesh_terms: D005798:Genes, Bacterial; D020043:Genes, Essential; D060005:Genotyping Techniques / Q000379:methods*; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000382:microbiology* / Q000635:transmission; D016480:Helicobacter pylori / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D017720:Molecular Epidemiology / Q000379:methods
keywords: 
  Helicobacter pylori
  ; detection; genotyping; housekeeping genes; multiple infection