Genetic adaptation of Streptococcus mutans during biofilm formation on different types of surfaces

Moshe Shemesh,Avshalom Tam,Doron Steinberg,Reuven Aharoni

doi:10.1186/1471-2180-10-51

Moshe Shemesh, Avshalom Tam + Show 2 more

Open Access

https://doi.org/10.1186/1471-2180-10-51

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Abstract

BackgroundAdhesion and successful colonization of bacteria onto solid surfaces play a key role in biofilm formation. The initial adhesion and the colonization of bacteria may differ between the various types of surfaces found in oral cavity. Therefore, it is conceivable that diverse biofilms are developed on those various surfaces. The aim of the study was to investigate the molecular modifications occurring during in vitro biofilm development of Streptococcus mutans UA159 on several different dental surfaces.ResultsGrowth analysis of the immobilized bacterial populations generated on the different surfaces shows that the bacteria constructed a more confluent and thick biofilms on a hydroxyapatite surface compared to the other tested surfaces. Using DNA-microarray technology we identified the differentially expressed genes of S. mutans, reflecting the physiological state of biofilms formed on the different biomaterials tested. Eight selected genes were further analyzed by real time RT-PCR. To further determine the impact of the tested material surfaces on the physiology of the bacteria, we tested the secretion of AI-2 signal by S. mutans embedded on those biofilms. Comparative transcriptome analyses indicated on changes in the S. mutans genome in biofilms formed onto different types of surfaces and enabled us to identify genes most differentially expressed on those surfaces. In addition, the levels of autoinducer-2 in biofilms from the various tested surfaces were different.ConclusionsOur results demonstrate that gene expression of S. mutans differs in biofilms formed on tested surfaces, which manifest the physiological state of bacteria influenced by the type of surface material they accumulate onto. Moreover, the stressful circumstances of adjustment to the surface may persist in the bacteria enhancing intercellular signaling and surface dependent biofilm formation.

Highlights

Adhesion and successful colonization of bacteria onto solid surfaces play a key role in biofilm formation
The initial adhesion and the successful colonization of bacteria onto solid surfaces play a key role in biofilm formation and the pathogenesis of infections related to biomaterials [1,2,3,4]
Using DNA-microarray technology we identified the differentially expressed genes of S. mutans (Figure 1), reflecting the physiological state of biofilms formed on the different biomaterials tested

Summary

Introduction

Adhesion and successful colonization of bacteria onto solid surfaces play a key role in biofilm formation. The initial adhesion and the colonization of bacteria may differ between the various types of surfaces found in oral cavity. The initial adhesion and the successful colonization of bacteria onto solid surfaces play a key role in biofilm formation and the pathogenesis of infections related to biomaterials [1,2,3,4]. The oral cavity is a unique environment, as different types of surfaces (hard, soft, natural and artificial) share the same ecological niche. Among the artificial surfaces in the mouth one can find various types of restorative materials, which differ in chemical and physical properties These surfaces occur in the same ecological niche, the attached biofilms are probably substantially different from one another, and each of these biofilms represents a unique micro-environment [9]

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