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PubMed1986

Comparative recovery of Streptococcus mutans on five isolation media, including a new simple selective medium.

For the isolation of Streptococcus mutans, several selective media have been developed, of which Mitis-Salivarius Sucrose Bacitracin agar (MSB) is the most widely used (Gold et al., 1973). Recently, the Trypticase Yeast-Extract Cystine agar medium (TYC, de Stoppelaar et al., 1967) was modified into a selective medium for S. mutans, called Trypticase Yeast-Extract Cystine Sucrose Bacitracin (TYCSB, van Palenstein Helderman et al., 1983). The aim of this study was to compare the recovery of S. mutans from clinical samples on Mitis-Salivarius agar (MS), MSB, TYC, and TYCSB. Further, a new simple selective medium for S. mutans was introduced. This medium, called TSY20B, was supposed to have the same qualities as TYCSB, but its preparation is less laborious. One hundred eighty-five plaque and saliva samples from 37 subjects were plated on MS, MSB, TYC, and TYCSB, and 285 samples from 23 subjects were plated on TYCSB and TSY20B. All plates were incubated at 37 degrees C in a 91% N2, 5% CO2, 4% H2 atmosphere for five days. The S. mutans counts on TYC and TYCSB were significantly higher than on MS or MSB by almost a factor of 10. Seventy-seven percent of the samples gave higher S. mutans counts on TYCSB than on MSB. Especially, samples with high S. mutans d/g numbers gave lower S. mutans counts on MSB. These data clearly indicate that MSB agar is inhibitory for S. mutans and should not be used. An additional advantage of TYCSB over MSB agar is the possibility of distinguishing S. mutans serotypes d/g from other serotypes.(ABSTRACT TRUNCATED AT 250 WORDS)

Agar↗
PubMed2000

Influence of amalgam on the growth of mutans streptococcus: an in vivo study.

OBJECTIVE: To study the antibacterial activity of dental amalgam against mutans streptococcus. METHODS: Study volunteers included 14 patients, 21 to 35 years old, with aged amalgam fillings, with no antibiotic use during the previous 3 months, and 16 patients, 22 to 24 years of age, without aged amalgams, but with unfilled caries. Plaque samples were collected once from the subjects with aged amalgams. Subjects with fresh amalgams had plaque samples collected at 1 day, 1 week, 2 weeks, 4 weeks, and 8 weeks after amalgam restoration. As controls, plaque samples were collected from unrestored occlusal enamel surfaces on the same side, or on the opposite side of the same occlusion. Frequency of mutans streptococci from aged amalgams and fresh amalgams and the colony-forming units (CFU) were tested. RESULTS: The difference of CFU of mutans streptococci in the plaque samples between the amalgam restorations, the aged amalgams, and the controls was not significant within 8 weeks after amalgam filling. The difference of CFU of mutans streptococci in plaque samples from the amalgam restorations between all the timepoints was significant except between the fourth week and eighth week. For the control group, however, the difference in values between the first day and the timepoints afterward were significant, except between the first day and the first week. The difference between the first week and later timepoints was significant, but not between the second week and later, or between the fourth week and later. At the eighth week, the difference between the aged-amalgam and controls was not significant. CONCLUSION: Amalgam had some inhibitory effect on the in vivo growth of mutans streptococci.

Adult↗
PubMed2006

Colonization and vertical transmission of Streptococcus mutans in Turkish children.

The aim of the study was to establish the colonization of Streptococcus mutans and to determine the possibility of intra-familial transmission in a group of Turkish children and their parents. A total of 56 children participated in the study together with their parents (20 fathers and 49 mothers). Saliva samples were collected from the individuals and cultivated on S. mutans selective TYCSB agar. The typical isolates of S. mutans were identified by using classical microbiological methods, as well as molecular typing of S. mutans clones which was performed by using AP PCR with OPA5 primer for the detection of transmission. The vertical transmission of salivary S. mutans was detected among 14 mother-father-child, 35 mother-child (one twins) and 6 father-child combinations. The homologies of strain types were recorded as 24% and 16.6% for mother-child and father-child combinations, respectively. A significant positive correlation (p<0.001) was found between the infected children and their parents with high S. mutans counts.

Adult↗
PubMed1978

Evidence for a disseminated plasmid in Streptococcus mutans.

Based on a survey of 86 isolates, approximately 5% of all naturally occurring strains of Streptococcus mutans contains a 3.6 X 10(6)-dalton (3.6-megadalton) multicopy plasmid of unknown function. The amount of plasmid deoxyribonucleic acid per chromosome varies from 2 to 6% depending on the host strain. About 13% of the total covalently closed circular deoxyribonucleic acid in each of the four plasmid-containing strains consists of dimeric molecules, with interlocked circular forms predominating. Site-specific restriction endonucleases have been identified that cleave this 3.6-megadalton plasmid at single and at multiple sites. Each of the four plasmids is cleaved once by the HindIII and BamHI restriction enzymes. The HpaI, TaqI, and HhaI enzymes generate two, five, and six components, respectively, and the digestion products of each of the four plasmids are identical. Because the four plasmid-containing S. mutans strains are physiologically unique with respect to one another, we conclude this plasmid to be a disseminated extrachromosomal element in S. mutans.

DNA, Bacterial↗
PubMed1982

Streptococcus mutans genes that code for extracellular proteins in Escherichia coli K-12.

Chromosomal DNA from Streptococcus mutans 6715 (serotype g) was cloned into Escherichia coli K-12 by using the cosmid pJC74 cloning vector and a bacteriophage lambda in vitro packaging system. Rabbit antiserum against S. mutans extracellular proteins was used for immunological screening of the clone bank. Twenty-one clones produced weak to strong precipitin bands around the colonies, but only after the lambda c1857 prophage was induced by being heated to lyse the E. coli cells. None of the clones expressed enzyme activity for several known S. mutans extracellular enzymes. One of these clones contained a 45-kilobase recombinant plasmid designated pYA721. An 8.5-kilobase fragment of S. mutans DNA from pYA721 was isolated and recloned into the BamHI restriction site of the plasmid vector pACYC184 to construct pYA726. pYA726 contained all, or nearly all, of the gene for a surface protein antigen (the spaA protein) of S. mutans 6715. This was deduced from immunological studies in which extracts of cells harboring pYA726 reacted with antisera against both purified 6715 spaA protein (about 210,000 daltons) and the immunologically similar antigen I/II of serotype c strains of S. mutans. In addition, the S. mutans spaA protein was found to possess at least one antigenic determinant not present on the protein specified by pYA726. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of E. coli clone extracts revealed that pYA726 produced a polypeptide with a molecular mass of about 180,000 daltons which was predominantly found in the periplasmic space of E. coli cells. Antisera to the spaA protein of S. mutans reacted with extracellular protein from representative strains of S. mutans serotypes a, c, d, e, f, and g, but not b.

Antigens, Bacterial↗
PubMed2000

Identification of a fibronectin binding protein from Streptococcus mutans.

The interaction of viridans streptococci with components of the extracellular matrix (ECM) plays an important role in the pathogenesis of infective endocarditis. We have identified a surface protein of Streptococcus mutans which binds the ECM constituent fibronectin (Fn). Initially, we found that S. mutans could adsorb soluble Fn in plasma, but with lower efficiency than Streptococcus pyogenes. In addition, S. mutans could bind immobilized Fn in a dose-dependent manner when tested using an enzyme-linked immunosorbent assay. Crude extracts of cell wall-associated proteins or extracellular proteins from S. mutans MT8148 specifically bound Fn through a protein with the molecular mass of ca. 130 kDa, as detected by far-Western immunoblotting. The candidate Fn binding protein (FBP-130) was purified to near homogeneity by using Fn coupled Sepharose 4B affinity column chromatography. A rabbit polyclonal antibody against FBP-130 reacted specifically with a protein of molecular mass of ca. 130 kDa in both cell wall and extracellular fractions, and the abundance of FBP was higher in the former than in the latter fractions. The purified FBP bound specifically to immobilized Fn, whereas the binding of soluble Fn to coated FBP could only be detected in the presence of high concentrations of Fn. The purified FBP, as well as anti-FBP immunoglobulin G, inhibited the adherence of S. mutans to immobilized Fn and endothelial cells (ECV304) in a dose-dependent manner. These results demonstrated that FBP-130 mediated the adherence of S. mutans specifically to Fn and endothelial cells in vitro. The characteristics of S. mutans and FBP-130 in binding Fn confirmed that viridans streptococci adopt different strategies in their interaction with ECM.

Adhesins, Bacterial↗
PubMed1983

An enzyme from Streptococcus mutans forms branches on dextran in the absence of sucrose.

An enzyme in glucosyltransferase preparations from Streptococcus mutans catalyzed the transfer of [14C]glucopyranoside from purified isomaltosaccharides, each containing [14C]glucopyranoside at its non-reducing terminus, to acceptor dextran, in the absence of sucrose. Half of the radioactivity present in the resulting [14C]dextrans was resistant to hydrolysis by amylo-1,6-glucosidase. Treatment of the [14C]dextrans with endodextranase resulted in extensive hydrolysis and produced [14C]-labeled limit oligosaccharides containing branch sites. Acetolysis of the [14C]-labeled limit oligosaccharides yielded [14C]nigerose, thus indicating the formation of branch sites on dextran in the absence of sucrose. The enzyme catalyzing this reaction has not been identified but appears to be independent of the major extracellular glucosyltransferases of S. mutans.

Amino Acids, Branched-Chain↗
PubMed1978

Dental caries induction in experimental animals by clinical strains of Streptococcus mutans isolated from Japanese children.

Oral implantation and the cariogenic activity of clinical strains of Streptococcus mutans which had been isolated from Japanese children and labeled with streptomycin-resistance were examined in specific pathogen-free Sprague-Dawley rats. All the seven strains tested were easily implanted and persisted during the experimental period. Extensive carious lesions were produced in rats inoculated with clinical strains of S. mutans belonging to serotypes c, d, e, and f, and maintained on caries-inducing diet no. 2000. Noninfected rats did not develop dental caries when fed diet no. 2000. Type d S. mutans preferentially induced smooth surface caries in the rats. Strains of other serotypes primarily developed caries of pit and fissure origin. Caries also developed in rats inoculated with reference S. mutans strains BHTR and FAIR (type b) that had been maintained in the laboratories for many years. However, the cariogenicity of the laboratory strains was found to have decreased markedly. All three S. sanguis strains could be implanted, but only one strain induced definite fissure caries. Two S. salivarius strains could not be implanted well in the rats and therefore they were not cariogenic. Four different species of lactobacilli also failed to induce dental caries in rats subjected to similar caries test regimen on diet no. 200. S. mutans strain MT6R (type c) also induce caries in golden hamsters and ICR mice, but of variable degrees.

Animals↗
PubMed1995

Effect of sucrose monolaurate on acid production, levels of glycolytic intermediates, and enzyme activities of Streptococcus mutans NCTC 10449.

We studied the mechanism by which the antimicrobial compound sucrose monolaurate inhibits Streptococcus mutans NCTC 10449 by determining its effect on the rate of acid production from glucose and sucrose and the intracellular and extracellular levels of glycolytic intermediates. Sucrose monolaurate was more effective than either sodium laurate or sodium fluoride in inhibiting acid production at pH 7.0 from glucose. Inhibition of acid production was the same when either glucose or sucrose was the carbon source and in the presence or absence of oxygen. Quantitative analysis of various glycolytic intermediates revealed that the steps inhibited by sucrose monolaurate were the reactions catalyzed by phosphofructokinase and glyceraldehyde 3-phosphate dehydrogenase and/or phosphoglycerate kinase. Since the activities of these enzymes in cell-free extracts were not decreased by the addition of sucrose monolaurate, the inhibition of acid production could not be ascribed to direct effects on the enzymes. A decrease in the rate of acid production with corresponding elevations in the extracellular levels of glycolytic intermediates indicates that sucrose monolaurate inhibits S. mutans by altering the permeability of the cell membrane, which causes a loss of important metabolites.

Anti-Infective Agents, Local↗
PubMed1984

Lactose transport in Streptococcus mutans: isolation and characterization of factor IIIlac, a specific protein component of the phosphoenolpyruvate-lactose phosphotransferase system.

The transport of lactose in Streptococcus mutans is mediated via an inducible phosphoenolpyruvate-lactose phosphotransferase system. This system requires for catalytic activity a membrane fraction (enzyme II), two general proteins called enzyme I and HPr, and a soluble specific protein termed factor IIIlac. This protein factor was purified from S. mutans ATCC 27352 by chromatographies on DEAE-cellulose, hydroxylapatite, Ultrogel AcA 34, and phosphocellulose. The purified protein migrated as a single band with a molecular weight of 10,000 on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and urea. The molecular weight calculated from the amino acid composition was 10,541. Gel filtration of the native protein gave a molecular weight of 41,500. Its isoelectric point was ca. 4.70. A specific antiserum was prepared against purified factor IIIlac. Immunodiffusion experiments revealed that only cellular extracts from lactose-grown cells contained factor IIIlac. A cross-reaction was observed with all of the S. mutans strains tested as well as with Streptococcus sanguis 10556, Streptococcus lactis 11454, and Staphylococcus aureus 6538. No precipitin band was observed with extracts of Streptococcus salivarius, Streptococcus faecalis, Lactobacillus casei, and Bacillus subtilis.

Amino Acids↗
PubMedDate not supplied

Continuous culture studies on the growth and physiology of Streptococcus mutans.

We examined the effects of nutritional limitations on the production of lactic acid by Streptococcus mutans grown at low growth rates in continuous culture. Lactic acid production was greater in nitrogen- and phosphate-limited continuous cultures than in glucose-limited conditions. These results are correlated with the release of calcium from enamel in cellfree broths from various fermentations.

Cells, Cultured↗
PubMed1974

Bacteriocin production and susceptibility among strains of Streptococcus mutans grown in the presence of sucrose.

Whereas the bacteriocin activity of eight strains of Streptococcus mutans was unaffected by growth in the presence of sucrose, such a medium rendered five S. mutans and one S. salivarius indicator strains unsusceptible to the bacteriocins. In contrast, the susceptibility of three S. faecalis and one S. pyogenes strains was unaltered when these indicators were grown in the presence of sucrose. Since the S. mutans and S. salivarius strains produced extracellular polysaccharides from sucrose whereas the S. faecalis and S. pyogenes strains did not, it was concluded that a coating of extracellular polysaccharides rendered normally susceptible organisms unsusceptible to bacteriocin action. This supports previous suggestions that such bacteriocins are not active in vivo and therefore play no role in regulating the microbial ecology in dental plaque.

Bacteriocins↗
PubMed1986

Monoclonal antibody to Streptococcus mutans type e cell wall polysaccharide antigen.

A monoclonal antibody against the polysaccharide antigen of Streptococcus mutans serotype e was prepared. It was found that beta-methyl-D-glucopyranoside and cellobiose markedly inhibited the precipitin reaction, whereas maltose showed no inhibition. The beta-glucosyl moiety of the type e polysaccharide seems to be the predominant antigenic determinant of the antigen.

Animals↗
PubMed2000

Streptococcus mutans H2O2-forming NADH oxidase is an alkyl hydroperoxide reductase protein.

Nox-1 from Streptococcus mutans, the bacteria which cause dental caries, was previously identified as an H2O2-forming reduced nicotinamide adenine dinucleotide (NADH) oxidase. Nox-1 is homologous with the flavoprotein component, AhpF, of Salmonella typhimurium alkyl hydroperoxide reductase. A partial open reading frame upstream of nox1, homologous with the other (peroxidase) component, ahpC, from the S. typhimurium system, was also identified. We report here the complete sequence of S. mutans ahpC. Analyses of purified AhpC together with Nox-1 have verified that these proteins act as a cysteine-based peroxidase system in S. mutans, catalyzing the NADH-dependent reduction of organic hydroperoxides or H2O2 to their respective alcohols and/or H2O. These proteins also catalyze the four-electron reduction of O2 to H2O2, clarifying the role of Nox-1 as a protective protein against oxygen toxicity. Major differences between Nox-1 and AhpF include: (i) the absolute specificity of Nox-1 for NADH; (ii) lower amounts of flavin semiquinone and a more prominent FADH2 to NAD+ charge transfer absorbance band stabilized by Nox-1; and (iii) even higher redox potentials of disulfide centers relative to flavin for Nox-1. Although Nox-1 and AhpC from S. mutans were shown to play a protective role against oxidative stress in vitro and in vivo in Escherichia coli, the lack of a significant effect on deletion of these genes from S. mutans suggests the presence of additional antioxidant proteins in these bacteria.

Amino Acid Sequence↗
PubMed2005

The putative autolysin regulator LytR in Streptococcus mutans plays a role in cell division and is growth-phase regulated.

Streptococcus mutans is the primary odontopathogen present in supragingival plaque and causes the oral disease known as dental caries. Colonization of the oral cavity by S. mutans requires the bacteria to adhere to the tooth surface and occurs by both sucrose-dependent and -independent mechanisms. Sucrose-independent adhesion of S. mutans in vitro has been shown to involve an ORF (ORF0317) encoding a homologue (39 %) to LytR, a regulator of autolysin activity in Bacillus subtilis. The protein encoded by ORF0317, LytR, belongs to the LytR/CpsA/Psr protein family. This family has a putative role in cell-wall structural maintenance, possibly through autolysin regulation. Autolysins have also been shown to be important in surface adhesion in Lactococcus lactis and in the pathogenic properties of Streptococcus pneumoniae. To investigate the role of autolysins in the adhesion and pathogenesis of S. mutans, a LytR mutant was constructed. The mutant grows in long chains, which may indicate a defect in cell division. Further experiments with the mutant strain show increased autolytic activity, indicating that LytR attenuates S. mutans autolytic activity, possibly through regulation of the expression of autolytic enzymes. No defect in cell-to-surface adherence or biofilm growth was seen in the LytR mutant. However, a connection between cell growth phase and transcription of lytR was found.

Amino Acid Sequence↗