PubMed Health⌕ Search

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 127 records · Page 7Linked to original sources
PubMed1994

Effects of subinhibitory concentrations of chemical agents on hydrophobicity and in vitro adherence of Streptococcus mutans and Streptococcus sanguis.

The aim of this investigation was to determine whether sublethal concentrations of chlorhexidine (Cx), hexetidine (Hx), cetylpyridinium chloride (Cc), sodium dodecyl sulfate (SDS), sanguinarine (Sg), sodium fluoride (NaF), and ammonium fluoride (NH4F) could affect hydrophobicity and adhesion of Streptococcus sanguis and Streptococcus mutans to saliva-coated hydroxyapatite (S-HA). Determination of the minimum inhibitory concentrations (MICs) showed that both species were susceptible to all agents tested. Growth in the presence of sub-MIC concentrations of Cx, SDS, Cc, NaF, or NH4F did not change significantly the hydrophobicity of S. sanguis cells when compared to the control which lacked any agent. However, growth in the presence of Hx or Sg resulted in a significant reduction in their hydrophobicity. Sub-MIC levels of SDS or Sg in the growth medium resulted in S. mutans cells with increased affinity for hexadecane compared with the control. The adherence of S. sanguis was changed significantly only by Hx or Sg, resulting in less cells adhering to S-HA. However, S. mutans cells previously incubated with NaF, NH4F, or Sg showed a higher adherence to S-HA than the control. The mechanisms of interference with adherence are at present not completely understood. Thus, antimicrobial agents at sub-MIC concentrations can interfere selectively with hydrophobicity and/or adhesion of oral streptococci.

Adsorption↗
PubMed1978

Effect of immunization on susceptibility to experimental Streptococcus mutans and Streptococcus sanguis endocarditis.

It has been asserted that humoral immunity is an important potentiating factor in pathogenesis of infective endocarditis, in that prior immunization to certain bacteria may predispose the host to endocarditis caused by those organisms. If so, possible future vaccination of humans with streptococcal antigens for the prevention of dental caries might increase the susceptibility of the population to streptococcal endocarditis. To examine this hypothesis further, we immunized rabbits with killed Streptococcus sanguis or Streptococcus mutans. After complement-fixing antibody had developed, the rabbits were tested for susceptibility to experimental infective endocarditis. Rabbits with high titers of complement-fixing antibody to the infecting organism developed streptococcal endocarditis less often (13%) than animals with lower titers (69%; P less than 0.0002). These findings do not support the hypothesis that pre-immunization predisposes to infective endocarditis and lend no credence to the concept that vaccination of human subjects against dental caries might increase their susceptibility to streptococcal endocarditis. On the contrary, the results of these experiments indicate that specific antibody can confer relative immunity to infective endocarditis.

Animals↗
PubMed1981

Ultrastructural location of Streptococcus mutans and Streptococcus sanguis antigens in carious human dentine.

The ultrastructural localization of bacterial antigens of Streptococcus sanguis and of the various serotypes a,b,c,d,e,f and g of Streptococcus mutans was studied in human carious dentine using the indirect peroxidase-antiperoxidase method with appropriate controls. No positive staining was seen in adjacent normal dentine. In the inner dentine underlying the cytoplasm of fibroblasts and Schwann cells of unmyelinated nerve fibrils. In sclerosed tubules, or on the plasmalemma of the odontoblast process or on both structures. Only in the odontoblast, facing the carious cone, were dense stainings noted in vacuoles of various sizes located in the Golgi apparatus in juxta-nuclear position and in their odontoblast processes. In pulpal regions, underlying the carious cone, dense vacuoles were also observed in the cytoplasm of fibroblasts and Schwann cells of unmyelinated nerve fibrils. In sclerosed tubules, electron dense deposits were noted in the lumen and the walls of the calcified tubules. In the outer carious dentine, invaded by micro-organisms, positive antigenic stainings were observed in the cell wall and capsular material of a great number of micro-organisms as well as in the interbacterial matrix.

Antigens, Bacterial↗
PubMed1987

Membrane-associated and solubilized ATPases of Streptococcus mutans and Streptococcus sanguis.

The proton-translocating, membrane ATPases of oral streptococci have been implicated in cytoplasmic pH regulation, acidurance, and cariogenicity. Membranes were isolated from Streptococcus mutans GS-5 and Streptococcus sanguis NCTC 10904 following salt-induced lysis of cells treated with lysozyme and mutanolysin. The ATPase activities of these membranes were 1.8 and 1.1 units per mg membrane protein, respectively. F1 ATPases were washed free from the membranes and purified by fast protein liquid chromatography (FPLC). Hydrolytic activities of the F1 ATPases were maximal at pH values between 6.0 and 6.6, whereas the membrane-bound enzymes had pH maxima of 7.5 (S. sanguis) and 6.0 (S. mutans). The F1 ATPases of the streptococci were similar to the well-characterized enzyme of Escherichia coli; they consisted of five different polypeptides and had apparent, aggregate molecular weights of from 335 to 350 Kd. The membrane-bound ATPases were characterized biochemically and found to be similar to those of proton-translocating ATPases of E. coli and Streptococcus faecalis. Km values for the membranes with respect to ATP were found to be 0.9 and 1.0 mmol/L for S. mutans and S. sanguis, respectively. Both enzymes had specificities for purine triphosphates and were active with a variety of divalent cations, although optimal activity occurred with ATP and Mg. The membrane-associated enzymes were sensitive to the inhibitors dicyclohexylcarbodiimide (DCCD) and azide, but insensitive to ouabain and vanadate.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Membrane↗
PubMed1980

Conservation of cell wall peptidoglycan by strains of Streptococcus mutans and Streptococcus sanguis.

Turnover of the cell wall peptidoglycan fraction of six different strains of Streptococcus mutans and eight different strains of Streptococcus sanguis was examined. Cells were grown in the presence of [3H]lysine and [14C]leucine for at least eight generations and then chased in growth medium lacking the two labels. At intervals during the chase, samples of cultures were removed, and the amounts of the two labeled precursors remaining in the peptidoglycan and protein fractions were quantitated. Similar experiments were done in which the pulse-labeling technique was used. In addition, cells were labeled in the presence of tetracycline or penicillin, chased with growth medium containing no inhibitor, and assayed at intervals during the chase for the amount of [3H]lysine present in peptidoglycan fractions. Studies of cultures of S. mutans strains FA-1, OMZ-61, OMZ-176, 6715, GS-5, and Ingbritt and of S. sanguis strains 10558, M-5, Wicky, DL-101, DL-1, 71X26, and 71X48 maintained in the exponential phase of growth in a chemically defined medium failed to show evidence of loss of insoluble peptidoglycan via turnover. Similarly, for the strains of S. mutans, insoluble peptidoglycan assembled during 2 h of benzylpenicillin or tetracycline treatment was also conserved during recovery from growth inhibition.

Lysine↗
PubMed1989

Characterisation of monoclonal antibodies to common protein epitopes on the cell surface of Streptococcus mutans and Streptococcus sobrinus.

Three monoclonal antibodies (MAb) were prepared against a cell surface antigen which cross-react between Streptococcus mutans (serotypes c, e and f) and Streptococcus sobrinus (serotypes d and g). Two of the MAb also recognise a determinant on the surface of Streptococcus cricetus (serotype a). The common antigen shared between S. mutans and S. sobrinus was demonstrated by Western blotting to be about 200 kD in size. This antigen is shared not only by the cell surfaces of serotypes a, c, d, e, f and g, but also by the major cell surface antigen of S. mutans of 185 kD and another of 150 kD. These MAb identify all but one mutans type of streptococci and can be utilised as analytical reagents.

Antibodies, Monoclonal↗
PubMed1977

Transfection of Streptococcus sanguis by phage deoxyribonucleic acid isolated from Streptococcus mutans.

Streptococcus sanguis ATCC 10556 cells were infected with free phage DNA of S, mutans strain PK 1. Two transformants were isolated which made colonies with large mucoid forms on mitis-salivarius agar. Both transformants had an increased ability to synthesize insoluble glucan and showed an adhesive nature on glass surfaces. These characteristics of the transformants bear a resemblance to S. mutans. These transformants had many physiological characteristics by which they could be recognized as S. sanguis. However, they resembled S. salivarius in forming a large amount of soluble fructan. Furthermore, the transformant cells did not produce ammonia from arginine, whereas their parent cells did.

Bacteriolysis↗
PubMed2002

Functional variation of the antigen I/II surface protein in Streptococcus mutans and Streptococcus intermedius.

Although Streptococcus intermedius and Streptococcus mutans are regarded as members of the commensal microflora of the body, S. intermedius is often associated with deep-seated purulent infections, whereas S. mutans is frequently associated with dental caries. In this study, we investigated the roles of the S. mutans and S. intermedius antigen I/II proteins in adhesion and modulation of cell surface characteristics. By using isogenic mutants, we show that the antigen I/II in S. mutans, but not in S. intermedius, was involved in adhesion to a salivary film under flowing conditions, as well as in binding to rat collagen type I. Binding to human fibronectin was a common function associated with the S. mutans and S. intermedius antigen I/II. Adhesion of S. mutans or S. intermedius to human collagen types I or IV was negligible. Hydrophobicity, as measured by water contact angles, and zeta potentials were unaltered in the S. intermedius mutant. The S. mutans isogenic mutants, on the other hand, exhibited more positive zeta potentials at physiological pH values than did the wild type. The results indicate common and species-specific roles for the antigen I/II in mediating the attachment of S. mutans and S. intermedius to host components and in determining cell surface properties.

Adhesins, Bacterial↗
PubMed1974

Calcification of selected strains of Streptococcus mutans and Streptococcus sanguis.

Nine strains of cariogenic Streptococcus mutans and two strains of Streptococcus sanguis were tested for their ability to form hydroxyapatite. The cells were examined by X-ray diffraction and electron microscopy for apatite crystals after growth in a synthetic calcification medium. Each of the test isolates, except for one strain of S. sanguis, produced intracellular mineral. Two strains of S. mutans formed both intra- and extracellular crystals. There was no apparent relationship between calcifiability and serotype.

Apatites↗
PubMed1987

Effect of growth conditions on levels of components of the phosphoenolpyruvate:sugar phosphotransferase system in Streptococcus mutans and Streptococcus sobrinus grown in continuous culture.

The membrane-bound, sugar-specific enzyme II (EII) component of the phosphoenolpyruvate:sugar phosphotransferase system (PTS) in Streptococcus mutans Ingbritt is repressed by growth on glucose under various conditions in continuous culture. Compared with optimal PTS conditions (i.e., glucose limitation, dilution rate [D] of 0.1 h-1, and pH 7.0), EII activity for glucose (EIIGlc) and mannose (EIIMan) in cells grown at a D of 0.4 h-1 and pH 5.5 with the same glucose concentration was reduced 24- to 27-fold. EII activity with methyl alpha-glucoside and 2-deoxyglucose was reduced 6- and 26-fold, respectively. Growth with excess glucose (i.e., nitrogen limitation) resulted in 26- to 88-fold repression of EII activity with these substrates. The above conditions of low pH, high dilution rate, and excess glucose also repressed EII activity for fructose (EIIFru), but to a lesser extent (two- to fivefold). Conversely, growth of S. mutans DR0001 at a D of 0.2 h-1 and pH 5.5 resulted in increased EIIGlc and EIIMan activity. Unlike the EII component, the HPr concentration in S. mutans Ingbritt varied only twofold (5.5 to 11.4 nmol/mg of protein) despite growth at pH 5.5 with limiting and excess glucose. The HPr concentrations in S. mutans DR0001 and the glucose-PTS-defective mutant DR0001/6 were similar. In a companion study, the soluble components of the PTS (i.e., HPr, EI, and EIIILac) in Streptococcus sobrinus grown on limiting lactose in a chemostat were not influenced significantly by growth at various pHs (7.0 and 5.0) and growth rates (D of 0.1, 0.54, and 0.8 h-1). However, growth on lactose resulted in repression of both EIIGlc and EIIFru, confirming earlier results with batch-grown cells. Thus, the glucose-PTS in some strains of S. mutans is regulated at the level of EII synthesis by certain environmental conditions.

Glucose↗
PubMed1981

Inactivation of D-glucosyltransferases from oral Streptococcus mutans and Streptococcus sanguis by photochemical oxidation.

Cell-free D-glucosyltransferase of D-glucose-grown Streptococcus mutans AHT was completely inactivated in the presence of 0.002% of Methylene Blue at 25 degrees and pH 7.0 after illumination with a 150-W incandescent lamp. The rate of inactivation was decreased at pH values less than 7.0. Histidine was the only amino acid residue modified to a significant extent, and the rates of oxidation of histidine residues and loss of enzyme activity closely agreed. Production of both water-insoluble and -soluble D-glucan fractions from sucrose by the oxidized D-glucosyltransferase preparations was significantly inhibited. Photooxidation with 0.002% of Rose Bengal at pH 7.0 or higher also induced complete inactivation of the D-glucosyltransferase. These results strongly suggest that the imidazole portion of histidine may function as part of the active sites of both D-glucosyltransferase isozymes of S. mutans AHT, which are responsible for the synthesis of (1 goes to 3)- and (1 goes to 6)-alpha-D-glucosidic linkages. The D-glucosyltransferases from S. mutans 6715 and AHT-mutant M1, and Streptococcus sanguis ATCC 10558 were also almost completely inactivated by Methylene Blue-sensitized photooxidation.

Amino Acids↗
PubMed1997

Generation of bovine immune colostrum against Streptococcus mutans and Streptococcus sobrinus and its effect on glucose uptake and extracellular polysaccharide formation by mutans streptococci.

Due to potential side-effects of active immunization by cariogenic mutans streptococci, oral administration of passively-derived antibodies could be a more acceptable way to reduce colonization and virulence of these microorganisms in human dentition. The aim of this study was to produce antistreptococcal immunoglobulins into bovine colostrum and explore the possible antibacterial mechanisms of these immunoglobulins against mutans streptococci. Specific serum IgG antibodies to whole cell antigens of both Streptococcus mutans and Streptococcus sobrinus increased rapidly in cows during immunization and were high also in the final whey-product. Low concentration (0.5% w/v) of bovine immune preparation inhibited significantly the incorporation of [14C]glucose by both S. mutans and S. sobrinus. Higher concentration (> 1%) was needed to inhibit the glucosyltransferase or fructosyltransferase activities of these bacteria. No such inhibitory effects were observed with the control preparation from the non-immunized cows. Our results indicate that bovine immune colostrum has a significant inhibitory potential against mutans streptococci, apparently dependent on the presence of specific IgG antibodies against S. mutans and S. sobrinus.

Animals↗
PubMed1995

Effects of sugar restriction on Streptococcus mutans and Streptococcus sobrinus in saliva and dental plaque.

The effect of sugar restriction on the oral levels of mutans streptococci was studied in 20 subjects fulfilling three criteria: (1) having more than 300,000 CFU mutans streptococci/ml saliva, (2) harbouring both Streptococcus mutans and Streptococcus sobrinus in saliva, and (3) eating sugar frequently. The subjects were randomly divided into a test group (n = 12), who were asked to refrain from using sugar-containing foods between meals and to reduce sugar in main meals for 6 weeks, and a control group (n = 8), who did not receive any dietary advice. Saliva and plaque samples were collected at baseline and at 3, 6 and 12 weeks. The results showed that the levels of S. mutans and S. sobrinus decreased in saliva and plaque during the 6-week sugar restriction period. The decrese in mutans streptococci was more pronounced on buccal than on approximal tooth surfaces. Both species seemed to react in a similar way to the sugar restriction in saliva as well as in dental plaque. At the follow-up examination at 12 weeks, i.e. 6 weeks after completing the sugar restriction period, the numbers of S. mutans and S. sobrinus had increased again, but were still lower when compared to the baseline values.

Adult↗
PubMed1995

Simultaneous monitoring of intracellular pH and proton excretion during glycolysis by Streptococcus mutans and Streptococcus sanguis: effect of low pH and fluoride.

A system was developed by which 2',7'-bis(carboxyethyl)-4 or 5-carboxyfluorescein could be used to monitor intracellular pH at the same time that proton excretion was being measured. Streptococcal cells were loaded with the dye, and after the addition of glucose protons were excreted and the intracellular pH increased quickly and remained higher than the extracellular pH of 7.0. The excretion of protons stopped and the intracellular pH returned to the original level when glucose was depleted. The intracellular level of ATP remained high during glucose metabolism and decreased with the depletion of glucose. At extracellular pH of 5.5, and 5.0, the intracellular pH of fasting cells was higher than the extracellular pH value. After addition of glucose there were initial lags of proton excretion and of increases in intracellular pH at the acidic extracellular pH values. In the presence of fluoride, a lag in proton excretion and a simultaneous decrease in intracellular pH were observed, indicating a partial and transient inhibition of proton-ATPase activity.

Adenosine Triphosphate↗
PubMedDate not supplied

Investigation of possible solvents for extracellular polysaccharides from Streptococcus mutans and Streptococcus sanguis.

The solubilities of extracellular polysaccharide fractions produced by 14 oral streptococcal strains were compared in water, aqueous lithium and guanidine salt solutions, dimethyl sulfoxide (DMSO), and a 9:1 DMSO-water mixture. The best results for solubilizing the fractions were obtained with the DMSO-water mixture procedure, which used the water and DMSO in sequence. By this method all fo the fractions were solubilized.

Dimethyl Sulfoxide↗