title: Helicobacter pylori free-living and biofilm modes of growth: behavior in response to different culture media.
abstract: The physiological behavior of Helicobacter pylori in different growth conditions was investigated to approach its growth standardization. H. pylori free-living and biofilm modes of growth were assessed in four different liquid culture media (Brucella broth, brain heart infusion broth and Ham's F-12 supplemented with 2% fetal calf serum and Ham's F-12 without serum). Free-living growth was monitored during 72 h in each medium and characterized for bacterial density, culturability, viability and morphology. The biofilm formation in the same media was evaluated for biomass production, colony forming unit (CFU) counts and microscopic visualization. Afterward, using Ham's F-12, the effect of amoxicillin and clarithromycin at sub- minimum inhibitory concentrations (sub-MICs) was evaluated on H. pylori biofilm formation and luxS gene expression. Differences in the free-living growth were observed between the media supplemented with serum and Ham's F-12 without serum. Biofilm formation was significantly dependent on the growth media used. Ham's F-12 seems to be a good medium to support both growth phenotypes of H. pylori. Moreover, sub-MICs of antibiotics increased the biofilm formation and affected the luxS gene expression. Optimizing the growth conditions of H. pylori, especially in the biofilm mode, will be helpful to perform more accurate in-depth studies that will allow increasing the knowledge about H. pylori biofilm, which should be a target to eradicate resistant infection.
authors.affiliation: Department of Biomedical Sciences, University G. d'Annunzio - Chieti-Pescara, Italy.
authors.forename: Lucinda J
authors.initials: LJ
authors.lastname: Bessa
authors.forename: Rossella
authors.initials: R
authors.lastname: Grande
authors.forename: Donato
authors.initials: D
authors.lastname: Di Iorio
authors.forename: Mara
authors.initials: M
authors.lastname: Di Giulio
authors.forename: Emanuela
authors.initials: E
authors.lastname: Di Campli
authors.forename: Luigina
authors.initials: L
authors.lastname: Cellini
mesh_terms: D000658:Amoxicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D058491:Bacterial Load; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms / Q000187:drug effects*; D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000378:metabolism; D017291:Clarithromycin / Q000494:pharmacology; D015169:Colony Count, Microbial; D003470:Culture Media / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D016481:Helicobacter Infections / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability; D010641:Phenotype
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D003470:Culture Media; D000658:Amoxicillin; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria; D017291:Clarithromycin