Sulfated vizantin causes detachment of biofilms composed mainly of the genus Streptococcus without affecting bacterial growth and viability

Taisuke Hasegawa,Takumi Hiyoshi,Hisanori Domon,Naoki Hayashi,Yuichiro Noiri,Hirofumi Yamamoto,Masataka Oda,Yutaka Terao,Tatsuya Ohsumi,Karin Sasagawa,Hayato Ohshima,Yasuko Okamoto,Shoji Takenaka

doi:10.1186/s12866-020-02033-w

Taisuke Hasegawa, Takumi Hiyoshi + Show 11 more

Open Access

https://doi.org/10.1186/s12866-020-02033-w

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Abstract

BackgroundSulfated vizantin, a recently developed immunostimulant, has also been found to exert antibiofilm properties. It acts not as a bactericide, but as a detachment-promoting agent by reducing the biofilm structural stability. This study aimed to investigate the mechanism underlying this activity and its species specificity using two distinct ex vivo oral biofilm models derived from human saliva.ResultsThe biofilm, composed mainly of the genus Streptococcus and containing 50 μM of sulfated vizantin, detached significantly from its basal surface with rotation at 500 rpm for only 15 s, even when 0.2% sucrose was supplied. Expression analyses for genes associated with biofilm formation and bacterial adhesion following identification of the Streptococcus species, revealed that a variety of Streptococcus species in a cariogenic biofilm showed downregulation of genes encoding glucosyltransferases involved in the biosynthesis of water-soluble glucan. The expression of some genes encoding surface proteins was also downregulated. Of the two quorum sensing systems involved in the genus Streptococcus, the expression of luxS in three species, Streptococcus oralis, Streptococcus gordonii, and Streptococcus mutans, was significantly downregulated in the presence of 50 μM sulfated vizantin. Biofilm detachment may be facilitated by the reduced structural stability due to these modulations. As a non-specific reaction, 50 μM sulfated vizantin decreased cell surface hydrophobicity by binding to the cell surface, resulting in reduced bacterial adherence.ConclusionSulfated vizantin may be a candidate for a new antibiofilm strategy targeting the biofilm matrix while preserving the resident microflora.

Highlights

Sulfated vizantin, a recently developed immunostimulant, has been found to exert antibiofilm properties
Influence of Sulfated vizantin (Viz-S) on cytotoxicity and bacterial growth The cytotoxicity assays showed that Viz-S at concentrations less than 50 μM did not affect the human gingival epithelial cells (HGECs) and human gingival fibroblasts (HGFs) (Fig. 1a and b)
In this study, we demonstrated that Viz-S at a concentration of 50 μM caused detachment of the biofilm composed mainly of the genus Streptococcus despite supplementation with sucrose as a nutrient source

Summary

Introduction

A recently developed immunostimulant, has been found to exert antibiofilm properties. It acts not as a bactericide, but as a detachment-promoting agent by reducing the biofilm structural stability. Numerous and diverse microorganisms reside in the intraoral environment, creating multispecies microbial communities that form an oral biofilm [1]. Within such a biofilm population, cells demonstrate genetic and physiological heterogeneity as they adapt to the local environmental conditions [2]. The ideal antibiofilm strategy is to control oral biofilms to levels compatible with oral health while preserving the natural and beneficial properties of the resident oral microflora [7]

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