title: Effect of culture media and nutrients on biofilm growth kinetics of laboratory and clinical strains of Enterococcus faecalis.
abstract: OBJECTIVE
  Enterococcus faecalis is a bacterial pathogen that is often associated with endodontic infections. Biofilm formation is a key virulence attribute in the pathogenicity of E. faecalis. In the present study, we comprehensively examined the effect of various culture media and nutrients on the development of E. faecalis biofilms.
  
  
  METHODS
  A reference strain and a clinical isolate of E. faecalis were used in all experiments for comparison. Commonly used liquid culture media with different nutrient compositions were used to support the development of E. faecalis biofilms in a time-dependent assay. E. faecalis biofilms were quantified by colony forming unit (CFU) and crystal violet (CV) assays. Biofilm architecture and cellular viability were evaluated by scanning electron microscopy and confocal laser scanning microscopy.
  
  
  RESULTS
  Growth kinetics evaluated by CFU and CV assays and by microscopy showed that E. faecalis biofilms reached maturity at 72h. "Pg broth" (Tryptic Soy Broth with yeast extract, hemen and vitamin K) promoted E. faecalis biofilm formation more than Brain Heart Infusion broth or Tryptic Soy Broth. Addition of 2% glucose enhanced biofilm formation. Thus, it seems that nutrients such as hemen, vitamin K and glucose are important for E. faecalis for the formation of biofilms.
  
  
  CONCLUSIONS
  The present study demonstrated that nutrient-rich media containing glucose enhances the formation of E. faecalis biofilms, which exhibit maturation at 72h.
authors.affiliation: Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore. jaya@nus.edu.sg
authors.forename: C J
authors.initials: CJ
authors.lastname: Seneviratne
authors.forename: J W Y
authors.initials: JW
authors.lastname: Yip
authors.forename: J W W
authors.initials: JW
authors.lastname: Chang
authors.forename: C F
authors.initials: CF
authors.lastname: Zhang
authors.forename: L P
authors.initials: LP
authors.lastname: Samaranayake
mesh_terms: D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development*; D003470:Culture Media / Q000494:pharmacology*; D013293:Enterococcus faecalis / Q000187:drug effects* / Q000254:growth & development* / Q000472:pathogenicity / Q000648:ultrastructure; D006801:Humans; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D014774:Virulence
chemical_list: D003470:Culture Media
keywords: Biofilms; Enterococcus faecalis