Role of an autoinducer-2-like molecule from Veillonella tobetsuensis in Streptococcus gordonii biofilm formation

Abstract

ObjectivesDental plaque is a multispecies biofilm that causes dental caries and periodontal diseases. In particular, Streptococcus spp. and Veillonella spp. have been identified as early colonizers of oral biofilms. Coaggregation of bacterial species and/or autoinducers using the quorum sensing system has been suggested to plan an important role in biofilm formation. In our previous study, we showed that Veillonella tobetsuensis clearly promoted the development of Streptococcus gordonii biofilms. To clarify the mechanism, coaggregation between S. gordonii and V. tobetsuensis and the effect of an autoinducer-like molecule were investigated in this study. MethodsThe coaggregation assay was performed according to a previously reported method. AI-2-like molecule was detected by a Vibrio harveyi BB170 reporter assay. After partial purification, the effect of the AI-2-like molecule on S. gordonii biofilm formation was examined using the wire method. ResultsNo coaggregation between S. gordonii and V. tobetsuensis was observed. An AI-2-like molecule was detected in large amounts in the culture supernatant of V. tobetsuensis in the mid-exponential growth phase. In addition, the AI-2-like molecule produced by V. tobetsuensis significantly inhibited S. gordonii biofilm formation. ConclusionsThese results suggest that an AI-2-like molecule from V. tobetsuensis is a potential inhibitor of the development of S. gordonii biofilms and could be used for the prevention of early-stage oral biofilm formation. However, the V. tobetsuensis factors that promote the development of S. gordonii biofilms will need to be explored in future studies.