title: Effect of Veillonella parvula on the antimicrobial resistance and gene expression of Streptococcus mutans grown in a dual-species biofilm.
abstract: BACKGROUND
  Our previous studies showed that Streptococcus mutans and Veillonella parvula dual-species biofilms have a different acid production profile and a higher resistance to chlorhexidine than their single-species counterparts. The aim of the current study was to test whether the susceptibility of S. mutans grown in the presence of V. parvula is also decreased when it is exposed to various other antimicrobials. Furthermore, the aim was to identify other changes in the physiology of S. mutans when V. parvula was present using transcriptomics.
  
  
  METHODS
  Susceptibility to antimicrobials was assessed in killing experiments. Transcript levels in S. mutans were measured with the help of S. mutans microarrays.
  
  
  RESULTS
  When V. parvula was present, S. mutans showed an increase in survival after exposure to various antimicrobials. Furthermore, this co-existence altered the physiology of S. mutans. The expression of genes coding for proteins involved in amino acid synthesis, the signal recognition particle-translocation pathway, purine metabolism, intracellular polysaccharide synthesis, and protein synthesis all changed.
  
  
  CONCLUSIONS
  Growing in a biofilm together with a non-pathogenic bacterium like V. parvula changes the physiology of S. mutans, and gives this bacterium an advantage in surviving antimicrobial treatment. Thus, the study of pathogens implicated in polymicrobial diseases, such as caries and periodontitis, should be focused more on multispecies biofilms. In addition, the testing of susceptibility to currently used and new antimicrobials should be performed on a multispecies microbial community rather than with single pathogens.
authors.affiliation: Department of Cariology Endodontology Pedodontology, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, The Netherlands. s.luppens@acta.nl
authors.forename: S B I
authors.initials: SB
authors.lastname: Luppens
authors.forename: D
authors.initials: D
authors.lastname: Kara
authors.forename: L
authors.initials: L
authors.lastname: Bandounas
authors.forename: M J
authors.initials: MJ
authors.lastname: Jonker
authors.forename: F R A
authors.initials: FR
authors.lastname: Wittink
authors.forename: O
authors.initials: O
authors.lastname: Bruning
authors.forename: T M
authors.initials: TM
authors.lastname: Breit
authors.forename: J M
authors.initials: JM
authors.lastname: Ten Cate
authors.forename: W
authors.initials: W
authors.lastname: Crielaard
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000494:pharmacology*; D000891:Anti-Infective Agents, Local / Q000494:pharmacology; D018441:Biofilms / Q000254:growth & development; D002327:Cariostatic Agents / Q000494:pharmacology; D002594:Cetylpyridinium / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D003959:Diamines / Q000494:pharmacology; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004917:Erythromycin / Q000494:pharmacology; D005459:Fluorides; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D020411:Oligonucleotide Array Sequence Analysis; D016877:Oxidants / Q000494:pharmacology; D011135:Polysaccharides, Bacterial / Q000235:genetics; D012329:RNA, Bacterial / Q000235:genetics; D013295:Streptococcus mutans / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic / Q000235:genetics; D014678:Veillonella / Q000187:drug effects / Q000502:physiology*; D017967:Zinc Compounds / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D000891:Anti-Infective Agents, Local; D002327:Cariostatic Agents; D002712:Chlorides; D003959:Diamines; D016877:Oxidants; D011135:Polysaccharides, Bacterial; D012329:RNA, Bacterial; D017967:Zinc Compounds; D004917:Erythromycin; C016837:zinc chloride; C495399:Olaflur; D006861:Hydrogen Peroxide; D002594:Cetylpyridinium; D005459:Fluorides