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PubMed2004

[Effect of para-aminobenzonic acid (PABA) on cell-surface hydrophobicity of Streptococcus mutans].

OBJECTIVE: To study the effect of Para-aminobenzonic acid on cell-surface hydrophobicity of Streptococcus mutans. METHODS: Microbial adhesion to hydrocarbons (MATH) was used to measure the cell-surface hydrophobicity of Streptococcus mutans which grew in modified Carlsson medium with different dilutions of PABA. RESULTS: The cell-surface hydrophobicity of Streptococcus mutans increased when Carlsson medium contained low dilution of PABA. But following the increase of PABA, the cell-surface hydrophobicity decreased. CONCLUSION: Para-aminobenzonic acid could inhibit the adherence of Streptococcus mutans through changing its cell-surface hydrophobicity.

4-Aminobenzoic Acid↗

PubMed1999

The effect of nicotine on growth of Streptococcus mutans.

There is little information available concerning the effects of nicotine on oral bacteria; and in particular, Streptococcus mutans, an important microbe in the etiology of dental caries. To test the effects of nicotine, Streptococcus mutans were incubated in either 0 or 10(-1)-10(-7) M concentrations of nicotine and then plated onto mitis-salivarius-bacitracin agar. Colonies were counted and treatment groups compared. Both 10(-1) and 10(-2) M nicotine caused total inhibition of bacterial growth, while 10(-3) and 10(-4) M produced significantly more colonies than control. Also, 10(-6) and 10(-7) M nicotine produced a significant reduction in the mean number of colonies. These results suggest a biphasic, dosage-dependent effect of nicotine on the growth of Streptococcus mutans. Since 10(-3) M nicotine has been reported within the saliva of smokeless tobacco users, use of these products could stimulate growth of Streptococcus mutans and possibly place the user at increased risk for dental caries.

Dental Caries↗

PubMed1986

Isolation and characterization of a 60-kilodalton salivary glycoprotein with agglutinating activity against strains of Streptococcus mutans.

A bacterial agglutinin specific for strains of Streptococcus mutans was isolated from human saliva. Physiochemical analyses showed the agglutinin to be a glycoprotein with a molecular weight of 60,000. The agglutinin aggregated four of the eight strains of Streptococcus mutans tested but did not aggregate the strains of Streptococcus salivarius, Streptococcus sanguis, and Streptococcus mitis tested. Chemical modification of carbohydrate moieties of the agglutinin with sodium metaperiodate had no effect on aggregation, whereas modification of the polypeptide portion with trypsin abolished aggregating activity. A set of five murine hybridoma antibodies was employed to further analyze the agglutinin. Two carbohydrate-specific antibodies, directed against D-mannose and N-acetylgalactosamine moieties, respectively, failed to block agglutinin- or whole saliva-mediated aggregation of S. mutans cells. In contrast, two antibodies directed against pronase-sensitive antigenic sites blocked both agglutinin- and saliva-mediated aggregation of S. mutans cells. Western blot analysis with the agglutinin-specific hybridoma antibodies demonstrated the agglutinin in whole saliva and in artificial tooth pellicles formed on hydroxyapatite beads incubated with saliva. These results suggest that a 60-kilodalton glycoprotein of human saliva is a bacterial agglutinin with specificity for certain strains of S. mutans. They further suggest that aggregation is mediated by polypeptide rather than carbohydrate determinants of the glycoprotein.

Agglutination↗

PubMed2005

[Inhibition effect of methylene blue on the acids production of Streptococcus mutans].

OBJECTIVE: To study the effect of methylene blue on the growth and acid production of Streptococcus mutans, and the effect of methylene blue on acid production metabolism in plaque glycolysis model (i-PGM) in vitro, and investigate the practicability of methylene blue as a new kind of dental caries prevention agent. METHODS: Nephelometer method was used to measure OD value of Streptococcus mutans culture fluid in the different incubation conditions. The kinds and quantities of acid produced by Streptococcus mutans in the different incubation conditions were measured with gas chromatography. pH values of glycolysis buffer media of i-PGM in the different treatment conditions were measured by ORION electrode. RESULTS: (1) The OD value of Streptococcus mutans treated by methylene blue was lower than that by normal saline, and there was significant statistical difference between them. (2) The kinds of acid in three different culture fluid were same, but the total quantities of acid were significantly different among three different culture fluid, in which the total quantities of acid of culture fluids treated by glucose was the greatest, and treated by methylene blue was the lest. (3) The pH value of i-PGM treated by methylene blue was significantly different compared with negative control group, but was not significantly different compared with positive control group. CONCLUSION: Methylene blue can inhibit the growth and acid production metabolism of Streptococcus matans and acid production metabolism of i-PGM.

Dental Caries↗

PubMed1998

Intracellular alpha-amylase of Streptococcus mutans.

Sequencing upstream of the Streptococcus mutans gene for a CcpA gene homolog, regM, revealed an open reading frame, named amy, with homology to genes encoding alpha-amylases. The deduced amino acid sequence showed a strong similarity (60% amino acid identity) to the intracellular alpha-amylase of Streptococcus bovis and, in common with this enzyme, lacked a signal sequence. Amylase activity was found only in S. mutans cell extracts, with no activity detected in culture supernatants. Inactivation of amy by insertion of an antibiotic resistance marker confirmed that S. mutans has a single alpha-amylase activity. The amylase activity was induced by maltose but not by starch, and no acid was produced from starch. S. mutans can, however, transport limit dextrins and maltooligosaccharides generated by salivary amylase, but inactivation of amy did not affect growth on these substrates or acid production. The amylase digested the glycogen-like intracellular polysaccharide (IPS) purified from S. mutans, but the amy mutant was able to digest and produce acid from IPS; thus, amylase does not appear to be essential for IPS breakdown. However, when grown on excess maltose, the amy mutant produced nearly threefold the amount of IPS produced by the parent strain. The role of Amy has not been established, but Amy appears to be important in the accumulation of IPS in S. mutans grown on maltose.

Amino Acid Sequence↗

PubMed2006

[The study of salivary S-IgA antibody activity to clinical Streptococcus mutans in heat treated stress].

PURPOSE: The purpose of this study was to compare the salivary immunoglobulin A antibody response to Streptococcus mutans in normal with in heat treated stress. METHODS: Clinical Streptococcus mutans strains were isolated from 20 volunteers, serotyped by biochemical test and PCR, and genotyped by AP-PCR. Unstimulated secretions from submandibular glands and sublingual glands were collected from volunteers by modified collectors. Each identified genotype was cultured in two groups: control group was grown in BHI broth at 37 degrees C. for 3 hours; stress group was incubated in BHI broth at 42 degrees C. for 3 hours. Analysis of SIgA activity to clinical genotype strains and reference strains in different group was detected by Western blot. RESULTS: There was no significant difference between stress group and control group,in spite that some bands had strong or weak intensity. Different genotypes of S.mutans could have different immunoblotting profile as for an individual. SIgA from different volunteers could have different immonoblotting profiles as to the same genotype strain. CONCLUSIONS: Although Streptococcus mutans can express heat shock proteins in stress, this study suggests these new proteins have no significant effect on the reaction of SIgA to Streptococcus mutans. Different genotype strains may have different proteins, and different immunoreactivity to host. Different hosts may have different immunoreactivities to one genotypes of S.mutans.

Blotting, Western↗

PubMed1993

Identification of Streptococcus mutans from human dental plaque using the RapID STR System.

The identification of Streptococcus mutans from dental plaque samples with rapid systems, such as the RapID STR System, has not been recommended by the manufacturers. In this study, we evaluated the use of the above method for the identification of 34 human dental plaque Streptococcus mutans strains which had been identified previously by conventional procedures. The results obtained demonstrate that 88.2% of the Streptococcus mutans strains tested were identifiable by the rapid method.

Bacteriological Techniques↗

PubMedDate not supplied

[Incidence of Streptococcus mutans and changes in the concentration of serum immunoglobulins and SIgA in allergic children with caries].

The incidence of Streptococcus mutans in dental plaque and the relationship between dental caries and the levels of serum Igs and IgAS was investigated in allergic children. The relationship between IgAS mean levels and a) cariogenic diet, b) fluoride concentration in consumption water and c) different frequency in brush-washing was also studied. Direct examination of specimens obtained from either dental plaque or caries was performed. Cultures in tryptone soy agar and blood agar base were carried out. Catalase and nitrate reductase tests and biochemical tests for the identification of Streptococcus mutans were also done. Seric Igs and IgAS from saliva secretion were measured by radial immunodiffusion technique. Streptococcus mutans were found in 25/45 samples from allergic children, in 3/16 non allergic, in 25/43 children with caries and 3/18 children without caries. IgM reached higher levels in children with caries. Seric IgA average levels were lower in allergic children and were significantly increased in the non-allergic with caries. Most allergic children with caries showed very low IgAS values. Cariogenic diet, fluoride water ingestion and frequent brush-washing had no effect on IgAS concentration. Allergic children with caries showed low levels of seric IgA and Streptococcus mutans were frequently found in dental plaque. In these patients the specific class IgA response against the potentially cariogenic microorganisms was diminished. Allergic as well as non-allergic children with dental caries showed low IgAS levels suggesting that this may be an important factor in caries development.

Bacteriological Techniques↗

PubMed2000

[Evaluation of cariogenic potential of Streptococcus mutans isolated from caries-free and -active persons: adherence properties to saliva-coated hydroxyapatite].

OBJECTIVE: In this study, authors used saliva-coated hydroxyapatite to simulate tooth surface in oral cavity to evaluate adherence of different Streptococcus mutans isolated from caries-free and -active persons to saliva-coated hydroxyapatite. METHODS: Streptococcus mutans isolated from people with different carious experiences were divided into two groups: the caried-free group (DMFS = 0) including 19 persons and the caries-active group (DMFS > or = 6) including 40 persons. Totally 105 genotype Streptococcus mutans strains were obtains, including 22 strains from the caries-free group, and 83 strains from the caries-active group. The adhering properties of Streptococcus mutans (serotype c) strains were investigated, and different adhering properties were compared between the caries-free group and the caries-active group in order to find the correlationship between carious experiences and adhering properties of Streptococcus mutans. Saliva-coated hydroxyapatite was used to simulated tooth surface in oral cavity. Streptococci mutans were cultured in TPY liquid medium containing 3H-TDR in the same radioactive concentration. After being cultured in an anaerobic incubator for 18 hours, Streptococci mutans were radiolabelled by 3H-TDR. Saliva-coated hydroxyapatite and bacterial liquid(BSA = 0.52) were mixed for 90 minutes. Samples were assayed by using liquid scintillation counter, and binding abilities of strains were evaluated by the count per minute(cpm). RESULTS: Binding abilities of strains were significantly different in two groups, Caries-active people harbored more Streptococci mutans with high binding abilities(cpm > 2000) than caries-free people did(P < 0.05). The binding abilities to saliva-coated hydroxyapatite were different between strains of differing genotypes isolated from the same person. Each person always harbored one or two strains with high binding abilities(cpm > 2000) in the caries-active group. CONCLUSION: 1. Different genotypes have different adhering properties. 2. In caries-active group, different genotype strains have synergic effects, and adhesion of high binding ability strains cause caries susceptibility. 3. The differences in binding properties of isolates might relate to differences in carious experiences.

Bacterial Adhesion↗

PubMed1985

In vitro inhibition of adherence of Streptococcus mutans strains by nonadherent mutants of S. mutans 6715.

Four nonadherent mutants from Streptococcus mutans 6715 mutant UAB66 (serotype g) with similar phenotypes were shown to inhibit the adherence of adherence-proficient S. mutans serotypes c and g strains. One mutant, UAB108, was shown to inhibit adherence by wild-type strains representing serotypes a, d, and e as well. This inhibition of adherence was seen with pairs of strains grown in partially defined (PD) medium supplemented with 1% sucrose in both microtiter plates and glass tubes. The inhibiting factor was present in culture supernatant fluids of inhibiting strains grown in PD medium plus 1% sucrose and was heat stable. Ethanol precipitation of culture supernatant fluids of these strains yielded a water-soluble polymer which effectively inhibited the adherence of UAB66. This polymer, isolated from UAB108, was also shown to inhibit the adherence of UAB66 at lower concentrations than that needed to inhibit adherence with dextran T10. Partially purified glucosyltransferase, isolated from the culture supernatant fluids of glucose-grown UAB108, produced a water-soluble glucan which was shown to inhibit the adherence of UAB66 as well. The methods developed permit rapid screening for strains or mutants of strains or both that inhibit adherence or plaque formation or both by wild-type strains of S. mutans.

Adhesiveness↗

PubMed2001

[Relationship between Streptococcus mutans, Lactobacillus spp. and lactate-producing level and nursing bottle caries].

OBJECTIVE: The study aimed to investigate the levels of Streptococcus mutans and Lactobacillus spp. as well as the relationship between lactate-productive and aciduric organisms and nursing bottle caries. METHODS: Totally, 30 children of 2- to 2.5-year-old were divided into two groups, including the group of nursing bottle caries and the group of caries-free. Streptococcus mutans and Lactobacillus spp. were isolated from dental plaque of all the children. The amount of lactate produced was measured with a microlitre plate reader. RESULTS: The isolation frequency of Streptococcus mutans and Lactobacillus spp. were both 100 percent in the children with nursing bottle caries, and that the composition of these bacteria from nursing bottle caries lesions was higher than that of caries-free dental surface. Lactate-producing level was higher in the caries group than that of the caries-free group. CONCLUSION: This study suggests Streptococcus mutans and Lactobacillus spp. may be the major pathogenic bacteria leading to nursing bottle caries.

Bottle Feeding↗

PubMed1997

Effect of Cervitec varnish on the salivary Streptococcus mutans levels in the patients with fixed orthodontic appliances.

The aim of the present study was to assess the efficiency of a 1% chlorhexidine-containing varnish (Cervitec, Vivadent, Liechtenstein) on the levels of Streptococcus mutans in saliva of patients with fixed orthodontic appliances using the Dentocult-SM (Vivadent, Liechtenstein) technique for the microbiological investigation. Eighty subjects participated in the study and, divided randomly into two equal groups in which one group was treated with the placebo varnish (Vivadent, Liechtenstein) for negative controls. Streptococcus mutans in saliva of the subject was sampled and enumerated by using the Dentocult-SM dip-slide technique for periods of one, two four and twelve weeks after a single varnish application. The results were evaluated statistically. After the chlorhexidine containing varnish treatment the levels of Streptococcus mutans in saliva were significantly reduced after one week (p < 0.01) and continued reduction for one month (p < 0.05). After twelve weeks Streptococcus mutans levels in saliva were given a relative increase. No significant suppression was found in the placebo group (p > 0.05). The results suggested that Cervitec varnish reduces salivary Streptococcus mutans levels and that the application should be repeated every 3 months to get antibacterial effect.

Adolescent↗

PubMed1992

Effects of xylitol and fluoride on the response to glucose pulses of Streptococcus mutans T8 growing in continuous culture.

Streptococcus mutans T8 was grown glucose-limited at pH 7.0 in a chemostat and pulsed, under pH free-fall conditions, with glucose, xylitol or a mixture of the two. Experiments were conducted in the absence or continual presence of low levels (1 mmol.l-1) of fluoride. Culture filtrates of samples taken at frequent intervals were assayed for carbohydrate and fermentation end-products. Fluoride had little effect on the organism's response to glucose until the culture pH fell to ca. 5.0, at which point the rate of lactate production was reduced some 3-fold. Xylitol affected the response to glucose but its effect was most marked in the presence of fluoride. Under these conditions, the rate of lactate production was reduced at least 3-fold, the pH did not fall to 5.0 and only about 50% of the added glucose was consumed. This suggests that xylitol can augment the metabolic effects on S. mutans of low levels of fluoride.

Fluorides↗

PubMed1979

Serological properties of cellular and extracellular glycerol teichoic acid antigens of Streptococcus mutans.

Cell-free supernatant of Streptococcus mutans cultures was concentrated by 50% ammonium sulphate precipitation to 1/50 of the original culture volume. Most extracellular glucosyltransferase activity was detected in the supernatant. Furthermore, the supernatant reacted with serotype specific antiserum, showing immunological identities with the serotype specific polysaccharide antigen obtained from whole cells by hot saline or NaOH extraction in double diffusion tests. Immunoelectrophoretic analysis also revealed that the supernatant antigen possessed significant quantities of lipid-bound and free glycerol teichoic acid antigens. The lipoteichoic acid (LTA) was obtained from whole cells by phenol-water extraction. The lipid-teichoic acid linkage was easily split by mild acid or alkaline hydrolysis. The supernatant and phenol antigens spontaneously sensitized sheep red blood cells. These antigens were adsorbed to hydroxyapatite powder. The extracellular LTA and glucosyltransferase were found to be closely associated and difficult to separate chromatographically. In vivo significance of these properties of LTA and GTase is discussed in terms of the ecology of S. mutans and other oral streptococci.

Antigens, Bacterial↗

PubMed1989

Streptococcus mutans, not detected?

The growth of Streptococcus mutans was followed for three years in 24 healthy 12-17 year-old children, who were selected for the study on the basis of undetectable levels of salivary S. mutans. The saliva samples were cultured by a dip-slide method based on mitis-salivarius agar supplemented with sucrose and bacitracin. At the final occasion, additional examination of plaque and saliva of 10 children using TSY20B agar was performed. During the 3-year study period, S. mutans was found in saliva samples from 15 children on one or more of the 4 test occasions, suggesting that most 'S. mutans negative individuals' were those in whom S. mutans could not be temporarily detected. The additional examination of plaque did not increase the number of 'S. mutans-positive individuals'.

Adolescent↗

PubMed2002

Intracellular and extracellular pHs of Streptococcus mutans after addition of acids: loading and efflux of a fluorescent pH indicator in streptococcal cells.

A pH-sensitive fluorescent dye, 2', 7'-bis-(2-carboxyethyl)-5 and 6-carboxyfluorescein (BCECF), was used to determine intracellular pH (pH(in)). The efflux of BCECF loaded into oral streptococcal cells was determined after incubation of the cells at 35 degrees C for 20 min in the presence and absence of glucose. In the absence of glucose, the fluorescence of intracellular BCECF in Streptococcus mutans, Streptococcus sanguis, Streptococcus salivarius and Streptococcus sobrinus decreased only very slightly, indicating that the dye could be useful for pH(in) determination. In the presence of glucose, however, the fluorescence decreased by 57%. Thus, the pH(in) of S. mutans cells was measured by the BCECF method in the absence of glucose at various acidic pH levels by adding lactic, acetic and hydrochloric acids to the cell suspensions. The pH(in) was almost equal to the extracellular pH (pH(out)) for pH(out) values of between 8 and 5, indicating that protons permeated easily across the S. mutans cell membrane. For pH(out) between 5 and 4, pH(in) was constant at around 5, suggesting that the cell membrane was impermeable to protons, or that a cytoplasmic buffering system functioned. pH(in) decreased at pH(out) values of < 4. The constant pH(in) at acidic pH(out) levels could protect intracellular components, such as proteins, against acidification by sugar fermentation.

Acetic Acid↗

PubMed1975

Antigenic variation of Streptococcus mutans colonizing gnotobiotic rats.

Strains of Streptococcus mutans representative of serotypes b and d exhibited antigenic variation in both the oral cavity and in the intestinal canal of gnotobiotic rats. Laboratory-maintained cultures did not vary. The antigenic alterations observed were: (i) loss of detectable levels of both weakly reacting "strain" antigens and the type antigen; (ii) decreased production of the type antigen; (ii) production of altered type antigen; and (iv) production of an antigen not possessed by the parent strain. Immunization of animals before monoinfection with S. mutans strain Bob-1 (serotype d) appeared to increase the rate of emergence of antigenically altered mutants in the intestinal canal, and more diversely altered isolates were obtained. Antigenic variation may account in part for the variation noted by several investigators in attempting to immunize animals against S. mutans-induced dental caries.

Animals↗

PubMed1984

Characterization and expression of a cloned tetracycline resistance determinant from the chromosome of Streptococcus mutans.

A chromosomal tetracycline resistance (Tcr) determinant previously cloned from Streptococcus mutans into Streptococcus sanguis (Tobian and Macrina, J. Bacteriol. 152:215-222, 1982) was characterized by using restriction endonuclease mapping, deletion analysis, and Southern blot hybridization. Deletion analysis allowed localization of the Tcr determinant to a 2.8-kilobase region of the originally cloned 10.4-kilobase sequence. This cloned determinant hybridized to a representative of the tetM class of streptococcal Tcr determinants but not to representatives of the tetL and tetN classes and, like other tetM determinants, mediated high-level resistance to tetracycline and low-level resistance to minocycline. A portion (approximately 3 kilobases) of the isolated streptococcal fragment was subcloned into Escherichia coli, where it conferred resistance to tetracycline and minocycline. Two proteins with apparent molecular weights of 33,000 and 35,000, encoded by the S. mutans DNA, were synthesized in E. coli minicells. Insertion of DNA into a unique SstI site of the cloned S. mutans fragment resulted in inactivation of Tcr expression in E. coli and S. sanguis, as well as loss of production of both the 33,000- and 35,000-dalton proteins in E. coli minicells. Incubation of minicells in subinhibitory concentrations of tetracycline did not result in changes in the levels of synthesis of either protein. Our data suggest that at least one of these proteins is involved in the expression of Tcr.

Chromosome Deletion↗