title: Differences between single- and dual-species biofilms of Streptococcus mutans and Veillonella parvula in growth, acidogenicity and susceptibility to chlorhexidine.
abstract: Streptococcus mutans, considered a primary pathogen in dental caries, thrives in dental plaque, which is a multispecies biofilm. Metabolic interactions between S. mutans and Veillonella parvula have been suggested. In this study we developed a biofilm model to quantify single-species (S. mutans or V. parvula) and dual-species (S. mutans and V. parvula) biofilm formation, and we identified the differences between the respective biofilms in terms of growth, acid formation, and response to chlorhexidine. Polystyrene 96-well microtiter plates were used for biofilm formation. These biofilms were exposed to various chlorhexidine concentrations (0.025-0.4 mg ml(-1)) and treatment conditions. Growth of the biofilms and the effects of chlorhexidine were evaluated by viable counts. Viability of the two species in all biofilm types was similar ( approximately 10(8) colony-forming units per well) after 72 h. Lactic acid accumulation of dual-species biofilms was significantly lower at 48 and 72 h than single-species biofilms of S. mutans. Dual-species biofilms were less susceptible to chlorhexidine than single-species biofilms when a neutralization step was included. These results indicate that bacteria in dual-species biofilms have different properties from bacteria in single-species biofilms.
authors.affiliation: Academic Center for Dentistry Amsterdam, Department of Cariology, Endodontology and Pedodontology, Amsterdam, the Netherlands. d.kara@acta.nl
authors.forename: Duygu
authors.initials: D
authors.lastname: Kara
authors.forename: Suzanne B I
authors.initials: SB
authors.lastname: Luppens
authors.forename: Jacob M
authors.initials: JM
authors.lastname: Cate
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D000890:Anti-Infective Agents / Q000008:administration & dosage* / Q000494:pharmacology; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D002710:Chlorhexidine / Q000008:administration & dosage* / Q000494:pharmacology; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D017753:Ecosystem; D019344:Lactic Acid / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D011422:Propionates / Q000378:metabolism; D013295:Streptococcus mutans / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D014678:Veillonella / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D000890:Anti-Infective Agents; D011422:Propionates; D019344:Lactic Acid; D019342:Acetic Acid; D002710:Chlorhexidine