SEARCH · PubMed Health

Results for “Streptococcus mutans”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,441 records · Page 80Linked to original sources

PubMed1990

Inhibition of Streptococcus mutans adherence by means of surface hydrophilization.

Derivatives of polyalkylene oxide (PAO) were examined for their ability to inhibit adherence of 3H-labeled cells of Streptococcus mutans to hydroxyapatite (HA) and to plastic surfaces treated with buffer or parotid saliva from two individuals. Pellicles formed on HA with saliva from the two subjects were distinct in their binding capacity. One saliva promoted and the other saliva reduced adherence, as compared with the buffer control (BHA). Three of the PAO compounds effectively hindered binding of bacteria to BHA. However, on saliva-treated HA (SHA) the inhibition was not as effective. One compound, a phosphated polypropylene glycol, was potent in inhibiting adherence both to BHA and to the plastic surfaces treated with either buffer or saliva. However, treatment of HA with this compound followed by saliva incubation only gave a limited reduction in the number of bacteria binding. Evidently, salivary constituents are capable of interacting also with the PAO-treated surface. When 14C-labeled hydrophilizing agent was used, it was shown that the PAO was not replaced by salivary molecules. Instead, the components of the saliva that mediate the binding of bacteria seemed capable of adhering directly to the PAO layer.

Bacterial Adhesion↗

PubMed1983

A plaque assay for assessment of immune responses to Streptococcus mutans cell wall carbohydrate.

A plaque-forming cell (PFC) assay has been developed for measurement of single cell responses to the serotype carbohydrate antigen of the Streptococcus mutans cell wall. Serotype g carbohydrate was purified from a mutanolysin (M1) enzyme digest (and designated M1g) of S. mutans 6715 cell walls by ion exchange and gel filtration chromatography. M1g carbohydrate was esterified by stearoylization (sM1g), and subsequently coated to sheep erythrocytes (sM1g-SRBC). This coating antigen was then used for enumeration of IgM anti-M1g PFC responses from spleens of either mice or rats immunized with S. mutans 6715 antigen. Good splenic IgM anti-M1g PFC responses were seen in either mice or rats given S. mutans whole cells or cell walls, while cell wall lysates or M1g were lowly immunogenic. Of interest was the finding that sM1g induced good IgM anti-M1g PFC responses in mice and in murine spleen cell cultures, in vitro. This study describes a method for assessment of individual antibody-producing cells to a major S. mutans cell wall determinant which should facilitate studies directed to determine mechanisms involved in the induction of immune responses to this important bacterium.

Animals↗

PubMed1978

Some immunohistochemical experiments aiming at the electron-microscopic in situ identification of a dental plaque microorganism--Streptococcus mutans.

The aim of the present investigation was to test a procedure useful for the electron-microscopic in situ identification of the presumptive cariogenic microorganism Streptococcus mutans (serotype d) growing in the human dental plaque. For this purpose, different parameters of an indirect immunohistochemical method were tested in three sets of experiments. In experiment set I, all serological and histochemical procedures were performed en bloc on specimens fixed only with glutaraldehyde before embedding in Vestopal W. Different marking substances, such as ferritin, alkaline phosphatase and horseradish peroxidase (HRP) were tested. The en bloc method using HRP-labelled antibodies was found useful for staining of in vitro-grown bacteria but failed when applied to dental plaque. In experiment set II, ultrathin sections of glutaraldehyde-fixed and glycol methacrylate-embedded in vitro-grown bacteria were section-stained. The bacteria became outlined with a highly electron-dense HRP reaction product which accumulated on top of the cell envelope. The same type of HRP reaction product was found on some bacteria in the 2-day-old dental plaque after section-staining. This system was further tested in a series of controls also using consecutive serial sections. In exp. set III, a number of different stationary and transient oral bacteria were immunohistochemically section-stained. A cross-reaction with bacteria belonging to S.salivarius was discovered and removed by absorbing the anti-S.mutans serotype d serum with S.salivarius (NCTC 8618).

Antibodies, Bacterial↗

PubMed2003

A longitudinal study of Streptococcus mutans colonization in infants after tooth eruption.

We previously reported that, before tooth eruption, over one-half of infants aged 6 mos were already infected with Streptococcus mutans. The aim of this investigation was to determine the colonization of S. mutans after tooth eruption in the same cohort of 111 infants (35 pre-term, 76 full-term). Our results showed that S. mutans colonization increased with increasing age, so that by 24 mos of age, 84% harbored the bacteria (p < 0.01). The mean and median ages of S. mutans colonization in dentate infants were 15.7 mos and 16.0 mos, respectively. Factors associated with S. mutans colonization were sweetened fluids taken to bed (p < 0.01), frequent sugar exposure (p < 0.03) and snacking (p < 0.03), sharing of foods with adults (p < 0.03), and maternal S. mutans levels of > 10(5) CFU/mL (p < 0.02). In contrast, non-colonization of S. mutans was associated with toothbrushing (p < 0.03) and multiple courses of antibiotics (p < 0.001). Analysis of our data establishes the timing of S. mutans colonization in children from birth to 24 mos of age.

Age Factors↗

PubMed1995

Sequence analysis of the Streptococcus mutans Ingbritt dexA gene encoding extracellular dextranase.

The complete nucleotide sequence (3,747 bp) of the dextranase gene (dexA) and flanking regions of the chromosome of Streptococcus mutans Ingbritt (serotype c) were determined. The open reading frame for dexA was 2,550 bp, ending with a stop codon TGA. A putative ribosome-binding site, promoter preceding the start codon, and potential stem-loop structure were identified. The presumed dextranase protein (DexA) consisting of 850 amino acids was estimated to have a molecular size of 94,536 Da and a pI of 4.79. The nucleotide sequence and the deduced amino acid sequences of S. mutans dexA exhibited homologies of 57.8% and 47.0%, respectively, to those of Streptococcus sobrinus dex. The homologous region of dex of S. sobrinus was in the N-terminal half. The C terminus of DexA consisted of a hexapeptide LPQTGD, followed by 7 charged amino acids, 21 amino acids with a strongly hydrophobic character, and a charged hexapeptide tail, which have been reported as a common structure of C termini of not only the surface-associated proteins of Gram-positive cocci but also the extracellular enzymes such as beta-fructosidase of S. mutans and dextranase of S. sobrinus. The DexA protein had no significant homology with the glucosyltransferases, the glucan-binding protein, or the dextranase inhibitor of mutans streptococci.

Amino Acid Sequence↗

PubMed1986

Streptococcus mutans and dental caries in urban and rural schoolchildren in Thailand.

Two groups of Thai schoolchildren aged 11-13 yr were examined for dental caries, dental fluorosis and Streptococcus mutans. One hundred children lived in an urban district, Bangkok, and 71 children in a rural district, Petchaboon. Saliva samples were analyzed for S. mutans by the spatula method. The fluoride content of the drinking waters was also determined. The prevalence of caries, diagnosed according to WHO, was 89% in Bangkok and 18% in the rural district. Mean DMFT was 3.46 and 0.38 respectively. S. mutans was found in 98% of the urban children and in 82% of the rural. The differences in distribution between S. mutans and DMFT classes were statistically significant for the total sample. Mild fluorosis was present in some of the rural children.

Adolescent↗

PubMed2005

[Construction of a dual-promoter DNA expression plasmid pCN-SSIE harboring gene encoding SBR of Streptococcus mutans and verification of its immunogenicity as DNA vaccine].

PURPOSE: To construct a dual-promoter expression plasmid that harbors the target gene encoding SBR of Streptococcus mutans and can be applied as DNA vaccine especially suitable for using attenuated Salmonella as delivery vector to elicit effective mucosal immune responses because of its advantage of possessing dual-promoter. METHODS: Genes encoding SBR and green fluorescence protein gene (EGFP) were amplified by PCR and inserted to the proper sites of vector pCMVnir. Then IRES sequence was inserted between the genes coding for SBR and EGFP. Furthermore, a DNA fragment encoding tissue-type plasminogen activator (tPA) signal peptide was fused to the 5' end of target gene. Thereby, construction of the dual-promoter expression plasmid pCN-SSIE was completed and then the plasmid was analyzed with DNA sequencing and endonuclearase digestion mapping. The expressions of SBR protein by attenuated Salmonella SL3261 and CHO cell transformed or transfected by the plasmid were tested respectively. Finally, BALB/c mice were immunized through injecting intramuscularly with plasmid pCN-SSIE and anti-SBR specific IgG in serum was tested. RESULTS: Both DNA sequencing and endonuclearase digestion mapping showed that the construction of pCN-SSIE was successful with its open reading frame being correct. The expressions of SBR protein in transformed attenuated Salmonella SL3261 and transfected CHO were detected, and anti-SBR specific IgG levels in serum of immunized mice were markedly higher than the control. CONCLUSION: The construction of the dual-promoter expression plasmid pCN-SSIE was successful and the plasmid can express in prokaryocyte and eukaryocyte and elicit dramatic immune response when applied as DNA vaccine in experimental animal.

Animals↗

PubMed1999

Streptococcus mutans ffh, a gene encoding a homologue of the 54 kDa subunit of the signal recognition particle, is involved in resistance to acid stress.

The ability of Streptococcus mutans, a bacterial pathogen associated with dental caries, to tolerate rapid drops in plaque pH (acidurance), is considered an important virulence factor. To study this trait, Tn917 mutants of S. mutans strain JH1005 which display acid sensitivity have been isolated and partially characterized. In this paper, the characterization of one of these mutants, AS17, is reported. Preliminary sequence analysis revealed that the transposon insertion in AS17 occurred in the intergenic region of a two-gene locus which has been named sat for secretion and acid tolerance. This locus displays a high degree of homology to the ylxM-ffh operon of Bacillus subtilis. The sat+ locus was cloned by complementation of a conditional Escherichia coli ffh mutant with an S. mutans genomic library. Sequencing of the complementing clone identified the intact ylxM and ffh genes as well as a partial ORF with homology to the proUlopuAC gene of B. subtilis which encodes the binding protein of the ProU/OpuA osmoregulated glycine betaine transport system. RNA dot blot experiments indicated steady-state levels of ffh mRNA in the mutant that were approximately eightfold lower compared to parental levels. This suggests a partial polar effect of the sat-1::Tn917 mutation on ffh expression. Upon acid shock (pH 5), wild-type ffh mRNA levels were found to increase approximately four- to eightfold compared to unstressed (pH 7.5) levels. Mutant levels remained unaltered under the same conditions. Experiments designed to investigate the origins of the acid-sensitivity of the mutant revealed a lack of an acid-adaptive/tolerance response. Assays of proton-extruding ATPase (H+/ATPase) specific activity measured with purified membranes derived from acid-shocked AS17 showed twofold lower levels compared to the parent strain. Also, AS17 was found to be unable to ferment sorbitol although it was able to grow in glucose and a variety of other sugar substrates. These findings suggest that Ffh may be involved in the maintenance of a functional membrane protein composition during adaptation of S. mutans to changing environmental conditions.

Bacterial Proteins↗

PubMed1991

Binding of a Streptococcus mutans cationic protein to kidney in vitro.

An 8-kDa protein, with binding activity for heparin and heparan sulfate of basal laminae of animal tissues, was isolated from Streptococcus mutans MT703 and purified to homogeneity. Binding of radioiodinated 8-kDa protein to rabbit kidney tissue in vitro showed a high degree of specificity, as indicated by saturation kinetics, time dependence, and competitive inhibition by unlabeled protein. Binding activity for kidney tissue was competitively inhibited by selected glycosaminoglycans and polyanions in the following order: heparin greater than dextran sulfate greater than heparan sulfate greater than chondroitin sulfate greater than lipoteichoic acid greater than keratan sulfate greater than hyaluronic acid. Binding of the streptococcal protein to rabbit kidney tissue was also strongly inhibited by protamine sulfate, polylysine, and a random copolymer of lysine and alanine. Among the monosaccharides tested at 50 mM, glucosamine 2,3- or 2,6-disulfate, glucuronic acid, glucose 6-phosphate, and glucose 6-sulfate inhibited 50% or more of the binding activity, whereas N-acetylglucosamine 3-sulfate, glucosamine 6-sulfate, N-acetyl-glucosamine, N-acetylgalactosamine, N-acetylneuraminic acid, and a selection of neutral sugars were not inhibitory. The heparin-binding protein was detected on the cell wall of S. mutans and in the culture medium following growth. Several other species of streptococci produce an immunologically related protein of similar size.

Animals↗

PubMed1983

Acid sensitivity of glycolysis in normal and proton-permeable cells of Streptococcus mutans GS-5.

Gramicidin, an ionophoric antibiotic which enhances proton permeability of cell membranes, was found to increase the acid sensitivity of glycolysis by intact cells of Streptococcus mutans GS-5, to inhibit uptake of 2-deoxyglucose at pH values of 5.5 or less, and to cause a decrease in the intracellular levels of early intermediates of glycolysis. The inhibitory effects of the antibiotic on glycolysis at low pH values were related to inhibition of sugar uptake via the phosphotransferase system.

Acids↗

PubMed1974

Purification and properties of dextransucrase from Streptococcus mutans.

The dextransucrase (EC 2.4.1.5) activity from cell-free culture supernatants of Streptococcus mutans strain 6715 has been purified approximately 1,500-fold by ammonium sulfate precipitation, hydroxylapatite chromatography, and isoelectric focusing. The enzyme was eluted as a single peak of activity from hydroxylapatite, and isoelectric focusing of the resulting preparation gave a single band of dextransucrase activity which focused at a pH of 4.0. The final enzyme preparation contained two distinct, enzymatically active proteins as judged by assay in situ after polyacrylamide gel electrophoresis. One of the proteins represented 90% of the total dextransucrase activity and 53% of the total protein. The molecular weight of the enzyme was estimated by gel filtration to be 94,000. The temperature optimum of the enzyme was broad (34 to 42 C) and its pH range was rather narrow, with optimal activity at pH 5.5. The K(m) for sucrose was 3 mM, and fructose competitively inhibited the enzyme reaction with a K(i) of 27 mM.

Ammonium Sulfate↗

PubMed2005

Susceptibility of Streptococcus mutans and Actinobacillus actinomycetemcomitans to bactericidal activity of human beta-defensin 3 in biological fluids.

Bactericidal activity of human beta-defensin 3 (hBD-3) against Streptococcus mutans and Actinobacillus actinomycetemcomitans was inhibited in a dose-dependent manner by the presence of saliva and/or serum. Increasing the concentration of hBD-3 partially overcame this inhibition. A fast bactericidal effect was observed against both bacterial strains, suggesting a potential therapeutic use for hBD-3 in the local treatment of oral infections.

Aggregatibacter actinomycetemcomitans↗

PubMed1989

Immunolocalization of Streptococcus mutans sr gene product in recombinant Escherichia coli.

A direct post-embedding immunogold method was used to determine the subcellular localization of the expression product of Streptococcus mutans sr gene in Escherichia coli cells. Immunolabelling was principally localized in the cytoplasm and was absent in the periplasmic space and extracellular compartment. We observed no difference in the localization of the labelling between bacteria originated from solid or liquid cultures. No difference in saliva binding could be observed between recombinant E. coli or control E. coli cells. These results showed that the cloned SR protein was not accessible at the surface of the host cell.

Bacterial Proteins↗

PubMed1977

[Extracellular polysaccharides from Streptococcus mutans of various biotypes--chemical characterization and enzymatic hydrolysis].

The composition and proportions of different types of compound were established in extracellular polysaccharides synthesized in virto by streptococcus mutans strains of various biotypes. The polysaccharides were further enzymatically hydrolysed with dextranase and the degree of hydrolysis as well as the character and amount of the products of decomposition were determined. Under the conditions employed the strains synthesized solely glucanes. The water insoluble polysaccharides of strains of various biotypes show significant differences with regard to the proportions of alpha 1,3 and alpha 1,3,6-compounds. There is a significant correlation between the proportions of these compounds and the degree of hydrolysis by dextranase.

Dental Plaque↗

PubMed1996

Molecular and genetic analysis of multiple changes in the levels of production of virulence factors in a subcultured variant of Streptococcus mutans.

We previously isolated a variant strain, Xc100L, which shows decreased production of a surface protein antigen with a molecular mass of 190 kDa (PAc), after repeated subculturing of Streptococcus mutans strain Xc [Koga, T. et al. (1989) J.Gen. Microbiol. 135, 3199-3202]. In the present study, the levels of expression of the gtfB, gtfC, gtfD and ftf genes coding for polysaccharide-synthesizing enzymes in strain Xc100L were compared with those in strain Xc. Western blot analysis revealed multiple differences in the levels of production of these enzymes between these two strains. The amounts of the gtfB and gtfC gene products responsible for water-insoluble glucan synthesis in strain Xc100L were lower than those in strain Xc, whereas the amounts of the gtfD and ftf gene products responsible for water soluble glucan synthesis and fructan synthesis, respectively, in strain Xc100L were higher than those in strain Xc. Northern blot analysis revealed that the amounts of the four enzymes and PAc produced by strain Xc100L reflected the relative amounts of mRNAs from the genes. The chloramphenicol acetyltransferase gene was fused with each of these five genes, and the transcriptional activity of each gene in strain Xc100L was quantitatively compared with that in strain Xc. The chloramphenicol acetyltransferase assay also indicated that the phenotypic differences between strain Xc and strain Xc100L were due to differences in the transcriptional activities of the virulence genes. No differences in the nucleotide sequences of the promoter regions of the gtfB, gtfC, gtfD, ftf and pac genes were found between strain Xc and strain Xc100L. It is possible that a factor(s) affecting the levels of transcription of the multiple virulence genes exists in S. mutans.

Antigens, Bacterial↗

PubMed1989

In vitro induced fluoride resistance of Streptococcus mutans and dental caries in rats.

The aim of this investigation was to study the effect of an in vitro acquired, stable, fluoride-resistant strain of Streptococcus mutans on dental caries in rats. Three groups (P0, P5 and P10) of SPF Osborne-Mendel rats were inoculated with the fluoride-sensitive S. mutans C180-2. Three other groups (FR0, FR5 and FR10) were inoculated with cultures of the fluoride-resistant S. mutans C180-2FR. Diet SSP 20/5 and tap water (less than 0.2 ppm fluoride) were available ad libitum to all groups. The drinking water of groups P5 and FR5 was supplemented with 5 mg F-/1 and the drinking water of groups P10 and FR10 with 10 mg F-/1. At the end of the caries experiment (days 58/59) there were no significant differences in the percentages and in the numbers of S. mutans in the total maxillary plaques of groups P0 to P10 and of groups FR0 to FR10, respectively. The fluoride tolerance of S. mutans cells re-isolated from rats, inoculated with the fluoride-sensitive strain, showed an unstable decrease compared to before inoculation. S. mutans cells re-isolated from rats, inoculated with the fluoride-resistant strain, showed both unstable and stable adaptation towards fluoride sensitivity. The animals superinfected with the fluoride-resistant strain developed less dentinal/fissure caries. Fluoride given in the drinking water at concentrations of 5 and 10 mg/l was effective in reducing caries irrespective of whether the animals were superinfected with the fluoride-sensitive or the fluoride-resistant strain.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Antibacterial effect of composite incorporating Triclosan against Streptococcus mutans.

It has been shown that composite incorporating the antibacterial agent Triclosan (Irgasan DP 300, which is sparingly soluble in water, inhibited in vitro plaque formation by Streptococcus mutans, although the release of the agent was much less than the minimum inhibitory concentration for the bacterium. In this study, the inhibitory effect of the composite incorporating 1% Triclosan against growth and adherence of S. mutans was investigated. S. mutans was inoculated on the surface of a specimen made of control or Triclosan-incorporated composite and the number of bacteria was compared after 3, 6, 12 and 24 hr of incubation. The adherence of S. mutans to the control and experimental composite, with or without saliva treatment, was also examined by scanning electron microscopy. The composite incorporating Triclosan demonstrated significant inhibition of growth of S. mutans after 6, 12 and 24 hr of incubation. Adherence of S. mutans to the Triclosan-incorporated composite was less compared with control for both non-treated and saliva-treated specimens. It is concluded that the antiplaque effect of composite incorporating Triclosan depends upon its ability to inhibit bacterial growth and adherence, and Triclosan-incorporated composite is able to exhibit the antibacterial activity even after being treated with saliva.

Anti-Infective Agents, Local↗

PubMed2003

Analysis of loci required for determination of serotype antigenicity in Streptococcus mutans and its clinical utilization.

We recently identified the genes responsible for the serotype c-specific glucose side chain formation of rhamnose-glucose polysaccharide (RGP) in Streptococcus mutans. These genes were located downstream from the rgpA through rgpF locus that is involved in the synthesis of RGP. In the present study, the corresponding chromosomal regions were isolated from serotype e and f strains and characterized. The rgpA through rgpF homologs were well conserved among the three serotypes. By contrast, the regions downstream from the rgpF homolog differed considerably among the three serotypes. Replacement of these regions in the different serotype strains converted their serotypic phenotypes, suggesting that these regions participated in serotype-specific glucose side chain formation in each serotype strain. Based on the differences among the DNA sequences of these regions, a PCR method was developed to determine serotypes. S. mutans was isolated from 198 of 432 preschool children (3 to 4 years old). The serotypes of all but one S. mutans isolate were identified by serotyping PCR. Serotype c predominated (84.8%), serotype e was the next most common (13.3%), and serotype f occured rarely (1.9%) in Japanese preschool children. Caries experience in the group with a mixed infection by multiple serotypes of S. mutans was significantly higher than that in the group with a monoinfection by a single serotype.

Child, Preschool↗