Water-insoluble Glucan Synthesis by Mutans Streptococcal Strains Correlates with Caries Incidence in 12- to 30-month-old Children

Abstract

Early mutans streptococci (MS) infection has been associated with higher caries activity in childhood. Since colonization with MS does not always lead to caries activity, additional factors may be involved in MS cariogenicity. For example, MS may differ in virulence traits such as the potential to synthesize glucan polymers from sucrose. In the present study, we tested the hypothesis that caries activity can be associated with variations in virulence factor expression of MS-infecting strains. At baseline, levels of MS obtained by the tongue-blade sampling method, and the presence of visible plaque on upper incisors, were measured in 101 12- to 30-month-old children. Dental caries lesions were diagnosed at baseline and after one year. Caries incidence data were then used to select ten caries-free and nine caries-active children from whom a total of 20 MS fresh isolates was studied. Water-insoluble glucan (WIG) synthesis, final pH, and sucrose-dependent adherence on glass surfaces were measured in these MS isolates. Concentrated culture supernatants were separated in duplicate SDS-PAGE gels, which were then either stained for protein or incubated with 5% sucrose. The intensities of the WIG bands developed in the 5% sucrose PAGE gels and the corresponding protein-stained GTF bands were measured by scanning densitometry. High MS levels (> or = 100 CFU) were associated with high caries incidence (p < 0.01). The presence of visible plaque did not correlate with caries incidence. The intensities of WIG bands were positively correlated with caries incidence (p < 0.05) and with the ability of MS to adhere to glass surfaces (p < 0.05). Analysis of our data suggests that the ability to synthesize WIG is an important virulence factor in initial caries development by increasing MS adherence and accumulation in the plaque of young children.

Comparison of biofilm formation and migration of Streptococcus mutans on tooth roots and titanium miniscrews

“…S . mutans mainly create water‐insoluble glucan that will form a semisolid solid polysaccharide to cover the bacteria cell (Koo et al, 2010; Mattos‐Graner et al, 2000); which corresponds to the result from SEM images, in which bacteria cells can be hardly seen (Figure 3a–d). The extracellular polysaccharide forms the gelatinous bulk structure of the biofilm and protects the bacteria from harmful environmental conditions (Bowen & Koo, 2011; Krzyściak, Jurczak, Kościelniak, Bystrowska, & Skalniak, 2014; Welin‐Neilands & Svensäter, 2007).…”

“…As the biofilm matures, the proportion of S . mutans decreases and the microbiota shifts to late colonizer bacterial assemblages (Koo et al, 2010; Mattos‐Graner, Smith, King, & Mayer, 2000). …”

Two-component signal transduction systems in oral bacteria

“…Some of these gene functions are also associated with the ability of S. mutans to avoid host immune functions in systemic infections [95]. However, expression of these genes is not constitutive, and expression under different conditions varies between strains [95–97]. Increased expression of virulence functions was observed in strains associated with cariogenicity and systemic diseases (e.g.…”

“…Increased expression of virulence functions was observed in strains associated with cariogenicity and systemic diseases (e.g. bacteraemia and infectious endocarditis) compared with strains isolated under healthy conditions [95,97]. Therefore, it is necessary to define the TCS regulatory circuits in S. mutans , as well as in other streptococcal species in oral biofilms in order to understand the environmental signals that trigger expression of virulence phenotypes.…”

Antimicrobial effects of the combination of chlorhexidine and xylitol

“…1 The biofilm produced by this pathogen accounts for S. mutans adhesion, and is therefore considered to be cariogenic as well. 2 Chlorhexidine (CHX) 3,4 and xylitol (XYL) 5 have been used as strategies to prevent and reduce carious lesions. 6,7 Aims To assess the effect of combining 1% chlorhexidine varnish (CHX) with xylitol chewing gum (XYL) on Streptococcus mutans and biofilm levels in 6-8-year-old children.…”