title: Development of a multispecies biofilm community by four root canal bacteria.
abstract: BACKGROUND
  The development of multispecies biofilm models are needed to explain the interactions that take place in root canal biofilms during apical periodontitis. The aim of this study was to investigate the ability of 4 root canal bacteria to establish a multispecies biofilm community and to characterize the main structural, compositional, and physiological features of this community.
  
  
  METHODS
  Four clinical isolates isolated from infected root canals, Actinomyces naeslundii, Lactobacillus salivarius, Streptococcus gordonii, and Enterococcus faecalis, were grown together in a miniflow cell system. Simultaneous detection of the 4 species in the biofilm communities was achieved by fluorescence in situ hybridization in combination with confocal microscopy at different time points. The LIVE/DEAD BacLight technique (Molecular Probes, Carlsbad, CA) was used to assess cell viability and to calculate 3-dimensional architectural parameters such as biovolume (μm(3)). Redox fluorescence dye 5-cyano-2,3-ditolyl tetrazolium chloride was used to assess the metabolic activity of biofilm bacteria.
  
  
  RESULTS
  The 4 species tested were able to form stable and reproducible biofilm communities. The biofilms formed in rich medium generally showed continuous growth over time, however, in the absence of glucose biofilms showed significantly smaller biovolumes. A high proportion of viable cells (>90%) were generally observed, and biofilm growth was correlated with high metabolic activity of cells. The community structure of biofilms formed in rich medium did not change considerably over the 120-hour period, during which E. faecalis, L. salivarius, and S. gordonii were most abundant.
  
  
  CONCLUSIONS
  The ability of 4 root canal bacteria to form multispecies biofilm communities shown in this study give insights into assessing the community lifestyle of these microorganisms in vivo. This multispecies model could be useful for further research simulating stresses representative of in vivo conditions.
authors.affiliation: Department of Oral Biology, Faculty of Odontology, Malmö University, Malmö, Sweden. ChavezdePaz@gde.uchc.edu
authors.forename: Luis E
authors.initials: LE
authors.lastname: Chávez de Paz
mesh_terms: D000190:Actinomyces / Q000378:metabolism / Q000502:physiology*; D001431:Bacteriological Techniques; D018441:Biofilms / Q000145:classification* / Q000254:growth & development; D018533:Biomass; D002462:Cell Membrane / Q000502:physiology; D003786:Dental Pulp Cavity / Q000382:microbiology; D013293:Enterococcus faecalis / Q000378:metabolism / Q000502:physiology*; D005456:Fluorescent Dyes; D005947:Glucose / Q000378:metabolism; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007778:Lactobacillus / Q000378:metabolism / Q000502:physiology*; D059013:Microbial Consortia / Q000502:physiology*; D050296:Microbial Viability; D018613:Microscopy, Confocal; D010485:Periapical Periodontitis / Q000382:microbiology*; D054773:Streptococcus gordonii / Q000378:metabolism / Q000502:physiology*; D013778:Tetrazolium Salts; D013997:Time Factors
chemical_list: D005456:Fluorescent Dyes; D013778:Tetrazolium Salts; C075453:5-cyano-2,3-ditolyltetrazolium; D005947:Glucose