title: Three Tests Used to Identify Non-Culturable Form of Helicobacter pylori in Water Samples.
abstract: BACKGROUND
  Helicobacter pylori, causing the most common chronic bacterial infection, exist in two forms; bacilli and coccoid. The coccoid form is identified as viable but non-culturable bacteria.
  
  
  OBJECTIVE
  The current study aimed to conduct culture, polymerase chain reaction (PCR), and loop-mediated isothermal amplification (LAMP) tests to identify coccoid forms of H. pylori.
  
  
  METHODS
  The PCR and LAMP tests were optimized using specific primers for glmM gene. The sensitivity and specificity of the tests were determined. The current experimental study was conducted on 10 different strains isolated from clinical cases (H1-H10). The isolates were added to tap water and incubated at three different temperatures for one and two months intervals. After pure-culturing of the bacteria, DNAs were extracted and PCR and LAMP were performed.
  
  
  RESULTS
  Ten copies of targeted DNA were required for PCR detection whereas only five copies gave a positive reaction by LAMP assay, with 100% specificity. Of the 10 isolates inoculated in water for one and two months at three different temperatures 4, 22, and 37°C, only three cases (5%) were found positive in the first month; 13 (21.6%) and 29 cases (48.3%) were also positive by PCR and LAMP tests in the first and second months.
  
  
  CONCLUSIONS
  Results of the current study confirmed that molecular methods such as PCR and LAMP were much more sensitive, rapid, and specific than culturing to identify non-culturable coccoid forms of H. pylori in water.
authors.affiliation: Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, IR Iran.
authors.forename: Parastoo
authors.initials: P
authors.lastname: Chamanrokh
authors.affiliation: Department of Microbiology, Shahre Qods Branch, Islamic Azad University, Shahre Qods, IR Iran ; Iranian Gene Fanavar Institute (IGF), Tehran, IR Iran.
authors.forename: Mohammad Hassan
authors.initials: MH
authors.lastname: Shahhosseiny
authors.affiliation: Department of Biotechnology, Iranian Research Organization for Science and Technology, Tehran, IR Iran.
authors.forename: Mahnaz
authors.initials: M
authors.lastname: Mazaheri Assadi
authors.affiliation: Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, IR Iran.
authors.forename: Taher
authors.initials: T
authors.lastname: Nejadsattari
authors.affiliation: Department of Microbiology, Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, IR Iran.
authors.forename: Davood
authors.initials: D
authors.lastname: Esmaili
keywords: Coccoid; Culture; Helicobacter pylori; LAMP; Polymerase Chain Reaction