title: Viability determination of Helicobacter pylori using propidium monoazide quantitative PCR.
abstract: BACKGROUND
  While Helicobacter pylori exists in a bacillary form in both the natural habitat and the human host, detrimental environmental circumstances have been observed to lead to the conversion of H. pylori from the bacillary to the coccoid form. However, the viability or nonviability of coccoid forms remains to be established in H. pylori. The aim of this study was to determine whether the quantitative PCR combined with propidium monoazide could be an alternative and good technique to determine H. pylori viability in environmental samples and, to contribute to understanding of the role of the H. pylori forms.
  
  
  METHODS
  Viability, morphological distribution, and the number of live H. pylori cells were determined using a propidium monoazide-based quantitative PCR method, at various time points.
  
  
  RESULTS
  Under adverse environmental conditions was observed the conversion of H. pylori from the bacillary to the coccoid form, and the decrease in amplification signal, in samples that were treated with propidium monoazide, over the time.
  
  
  CONCLUSIONS
  Incorporation of propidium monoazide indicates that there is an increase in H. pylori cells with the damaged membrane over the study, leading to the manifestation of cellular degeneration and death. Consequently, quantitative PCR combined with propidium monoazide contributes to our understanding of the role of H. pylori cells, under adverse environmental conditions.
authors.affiliation: Laboratori de Microbiologia Sanitària i Mediambiental (MSM Lab)-Aquasost, UNESCO Chair in Sustainability, Universitat Politècnica de Catalunya, 08222 Terrassa, Barcelona, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Agustí
authors.forename: Francesc
authors.initials: F
authors.lastname: Codony
authors.forename: Mariana
authors.initials: M
authors.lastname: Fittipaldi
authors.forename: Bárbara
authors.initials: B
authors.lastname: Adrados
authors.forename: Jordi
authors.initials: J
authors.lastname: Morató
mesh_terms: D001386:Azides / Q000378:metabolism*; D001431:Bacteriological Techniques / Q000379:methods*; D004783:Environmental Microbiology; D004791:Enzyme Inhibitors / Q000378:metabolism; D016480:Helicobacter pylori / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D006801:Humans; D050296:Microbial Viability; D008853:Microscopy; D016133:Polymerase Chain Reaction / Q000379:methods*; D011419:Propidium / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D001386:Azides; D004791:Enzyme Inhibitors; C533957:propidium monoazide; D011419:Propidium