Title: 1726 - Role of A. naeslundii in Virulence Factors of Dual-species Biofilms


Rosa Virgínia de Oliveira, Universidade Estadual Paulista - UNESP
Denise Madalena Spolidorio, Universidade Estadual Paulista - UNESP
Cristiane Yumi Koga-Ito, Universidade Estadual Paulista - UNESP
Aline de Farias, Universidade Estadual Paulista - UNESP
Fernanda Brighenti (Presenter)
Universidade Estadual Paulista - UNESP


Objectives: The interaction between different species in dental biofilm influences community behavior and may contribute to dental caries development. To date, the role of Actinomyces naeslundii on virulence factors of dual-species biofilms has not been yet studied. The aim of this study was to evaluate how the interaction between Streptococcus mutans and Actinomyces naeslundii affects virulence factors of dual species biofilms.

Methods: Single- and dual-species biofilms of Streptococcus mutans UA159 or Actinomyces naeslundii ATCC 12104 were formed in hydroxyapatite discs (n=18) using an active attachment model and BHI broth supplemented with 0.2% sucrose. Initial inoculation of biofilms was made with bacterial species containing 104 CFU/mL S. mutans and 108 CFU/mL A. naeslundii. After incubation at 5% CO2 / 37 °C for 24 h, the following virulence factors were evaluated: cell viability, lactic acid production XTT reduction, total proteins concentration in the extracellular matrix and biomass formation. Data were analyzed by one-way ANOVA and Tukey test at 5% significance level.

Results: A. naeslundii viability was not affected by the presence of S. mutans in dual-species biofilms. However, S. mutans viability in dual-species biofilms was significantly reduced. Lactic acid production in dual-species biofilms was reduced in 50% in comparison to single-species biofilms. For the other virulence factors tested in the present study (total protein, biomass and XTT reduction) there were no statistically significant differences between the growth conditions.

Conclusions: In conclusion, the presence of A. naeslundii at early stages of biofilm development reduced dual-species cariogenicity by decreasing S. mutans viability and lactic acid production in dual-species biofilms.

This abstract is based on research that was funded entirely or partially by an outside source:
grants 2012/17236-4, 2013/12326-8 and 2014/02397-8, São Paulo Research Foundation (FAPESP)

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: The authors declare no conflict of interest.