Production of glucosyltransferases by clinical mutans streptococcal isolates as determined by semiquantitative cross-dot assay

Tropical Oral Disease: Analysing Barriers, Burden, Nutrition, Economic Impact, and Inequalities

Traditionally, a healthy mouth is a good indicator of good general health. Poor oral hygiene reflects the health of the oral cavity and is a risk factor for overall health. Although oral diseases like dental decay and periodontitis are prevalent, awareness of oral diseases is still limited. Oral disorders include a wide range of diseases that may not be confined to the oral anatomical structures but may be manifestations of systemic diseases. Identification of the risk factors of dental and oral diseases, including socio-economic determinants, plays a major role in the type of oral health care, and in the promotion of dental health awareness. This article reviews oral diseases in the Caribbean and aims to raise awareness of this subject while suggesting a research agenda for the region.

Effect of sucrose concentration on sucrose-dependent adhesion and glucosyltransferase expression of S. mutans in children with severe early-childhood caries (S-ECC)

Sucrose, extracellular polysaccharide, and glucosyltransferases (GTFs) are key factors in sucrose-dependent adhesion and play important roles in the process of severe early-childhood caries (S-ECC). However, whether sucrose concentration regulates gtf expression, extracellular polysaccharide synthesis, and sucrose-dependent adhesion is related to the different genotypes of S. mutans isolated from ECC in children and still needs to be investigated. In this study, 52 strains of S. mutans were isolated from children with S-ECC and caries-free (CF) children. Water-insoluble glucan (WIG) synthesis was detected by the anthrone method, adhesion capacity by the turbidimetric method, and expression of gtf by RT-PCR in an in vitro model containing 1%–20% sucrose. The genotypes of S. mutans were analyzed by AP-PCR. The results showed that WIG synthesis, adhesion capacity, and gtf expression increased significantly when the sucrose concentration was from 1% to 10%. WIG synthesis and gtfB as well as gtfC expression of the 1% and 5% groups were significantly lower than those of the 10% and 20% groups (p < 0.05). There were no significant differences between the 10% and 20% groups. The fingerprints of S. mutans detected from individuals in the S-ECC group exhibited a significant difference in diversity compared with those from CF individuals (p < 0.05). Further, the expression of gtfB and gtfC in the S-ECC group was significantly different among the 1- to 5-genotype groups (p < 0.05). It can be concluded that sucrose-dependent adhesion might be related to the diversity of genotypes of S. mutans, and the 10% sucrose level can be seen as a “turning point” and essential factor for the prevention of S-ECC.

Genotypic diversity of Streptococcus mutans and Streptococcus sobrinus in 3-4-year-old children with severe caries or without caries

BACKGROUND.  The genotypic diversity of both Streptococcus mutans and Streptococcus sobrinus in children with different caries experience remains unclear. AIM.  To investigate the genotypic diversity of S. mutans and S. sobrinus in children with severe early childhood caries (SECC) and in caries-free (CF) children. METHODS.  Stimulated saliva of 87 SECC and 91 CF children aged 3-4 years was collected and submitted to cultivation, and MS colonies were enumerated. The genomic fingerprint analysis of S. mutans and S. sobrinus was carried out using AP-PCR. RESULTS.  One to five genotypes of S. mutans were colonized in an oral cavity of SECC and CF children; 85.5% SECC children and 57.9% CF children harboured more than one genotype of S. mutans. One to three genotypes of S. sobrinus were detected from each SECC child; 31.25% SECC children harboured more than one genotype of S. sobrinus. And one genotype was colonized in each CF child. S. mutans isolates from different individuals displayed distinctive DNA fingerprints. CONCLUSIONS.  DNA fingerprints of S. mutans and S. sobrinus isolates from 3- to 4-year-old children displayed genetic polymorphism, and S. mutans has greater genetic diversity than S. sobrinus. SECC children harboured more genotypes of S. mutans and S. sobrinus than CF children.

Tansmission, diversity and virulence factors of Sreptococcus mutans genotypes

Dental caries is an infectious and transmissible disease, in which many genetic, environmental and behavioral risk factors interact. The mutans streptococci (MS), mainly Streptococcus mutans and Streptococcus sobrinus are the microorganisms most strongly associated with this disease. The main virulence factors associated with MS cariogenicity include adhesion, acidogenicity and acid tolerance. These properties work together to modify the physico-chemical properties of the biofilm, resulting in ecological changes in the form of increased proportions of S. mutans and other acidogenic and aciduric species. In addition, reports of higher numbers of S. mutans genotypes with increased virulence in caries-active subjects suggest the importance of microenvironmental factors in increasing the risk of caries. This review focuses on the transmission and establishment of different genotypes of S. mutans and the role they play in the development of dental caries.

Genotypic diversity and virulence traits of Streptococcus mutans in caries-free and caries-active individuals

The present study evaluated the relationship between clonal diversity and some virulence traits of Streptococcus mutans isolated from eight caries-free and eight caries-active subjects. A total of 155 S. mutans isolates from caries-free subjects and 144 isolates from caries-active subjects were obtained from samples of saliva, dental plaque and tongue surface and identified by PCR. The isolates were submitted to arbitrarily primed (AP)-PCR (OPA-2 and OPA-13) and multilocus enzyme electrophoresis (MLEE) to establish the genotypic diversity. Production of water-insoluble glucan (WIG) (monitored by SDS-PAGE), final pH of cultures and the ability of bacterial cells to adhere to smooth glass in the presence of sucrose were measured. High and comparable abilities of MLEE and AP-PCR were found to distinguish S. mutans genotypes, using Simpson's index of discrimination (0.971 and 0.968, respectively). The results showed a significant difference (P < 0.01) in the number of genotypes when caries-free and caries-active groups were compared by both fingerprinting methods used. Final pH (P = 0.32) and the percentage of adherence to a glass surface (P = 0.62) did not show differences between the two groups; however, the intensities of WIG bands from the caries-active group were greater than those from the caries-free group (P < 0.01). In addition, WIG was positively correlated with the ability of S. mutans to adhere to a glass surface (r = 0.34, P = 0.02) from caries-active subjects. These data showed that AP-PCR analysis and MLEE are both effective methods for assessing the genetic relatedness of S. mutans. Using these techniques, it was found that there is a larger number of genotypes of S. mutans with increased ability to synthesize WIG in caries-active individuals.

Water-insoluble glucan synthesis by mutans streptococcal strains correlates with caries incidence in 12- to 30-month-old children

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.

Effects of surfactants on glucosyltransferase production and in vitro sucrose-dependent colonization by Streptococcus mutans

The presence of Tween 80 in media was associated with a significant increase in three glucosyltransferases(GTFs)(I, SI and S), especially GTF-I, produced by Streptococcus mutans strain PS14, indicating that the surfactant is a major cause of the enhanced GTF production observed in cultures in M4 medium. Lecithin and Tween 20 also enhanced GTF-I production, while Triton X-100 depressed it. At a lot concentration of 0.00125%, Tween 80 enhanced markedly only GTF-I production and its effect reached maximum at a concentration of 0.0025%. Water-insoluble glucan synthesis and artificial plaque formation (in vitro sucrose-dependent colonization) by PS14 were significantly enhanced by the addition of Tween 80 at concentrations over 0.00125%. These results suggest that surfactants might vary the cariogenic potential of Strep. mutans even at low concentrations.