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PubMed1977

Subacute bacterial endocarditis due to Streptococcus mutans.

A case of subacute bacterial endocarditis due to Streptococcus mutans is presented. The case was successfully treated by intravenous and oral penicillin. Streptococcus mutans is a member of the viridans streptococcal group with properties similar to enterococcal streptococci. Since the enterococci are resistant to penicillin, and isolates of Streptococcus mutans are usually sensitive to penicillin, it is important that medical technologists and microbiologists accurately identify these organisms. The combination of the following characteristics: 1) lack of Group D antigen, 2) acid formation in mannitol broth, 3) failure to hydrolyze hippurate, and 4) formation in five per cent sucrose broth of gelatinous adherent deposits on walls and bottom of tube, distinguish Streptococcus mutans from enterococcal streptococci.

Adult↗
PubMed1987

Colonization of the human oral cavity by a Streptococcus mutans mutant producing increased bacteriocin.

Streptococcus mutans strain JH1005 is a mutant that produces levels of bacteriocin activity three-fold-elevated than those produced by its parent, JH1001. A single infection regimen with JH1005 was found to result in persistent colonization of the teeth of all three adult subjects tested. This is a significant improvement over JH1001, which required multiple exposures in order to colonize the teeth of humans reliably. The levels of total cultivable bacteria and indigenous S. sanguis were not affected by JH1005 colonization. In two of the three subjects, total (indigenous plus JH1005) S. mutans levels were significantly decreased. The results provide additional support for the role of bacteriocin production as an ecological determinant in colonization by S. mutans. They also indicate that a practical regimen for infection by an effector strain might be achieved for use in the replacement therapy of dental caries.

Adult↗
PubMed1984

Chemical analyses of membranes isolated from Streptococcus mutans BHT.

Cell membranes of Streptococcus mutans BHT (serotype b) were prepared following glass-bead disruption or mutanolysin digestion of whole cells. Major constituents of purified BHT membranes included: protein (60-65%), fatty acids (10%), glucose (3%), and phosphorus (0.5%). The principal amino acids measured were glutamate, aspartate, lysine, alanine, and leucine. The principal fatty acids measured were octadecenoic, palmitoleic, palmitic, and eicosenoic acids; smaller amounts of eicosanoic acid were also detected. Chemical analyses of membranes from cells grown to four different growth phases revealed no major shifts in composition during batch growth under our experimental conditions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of these four membrane preparations confirmed the apparent compositional stability of cell membranes during growth.

Amino Acids↗
PubMed1994

[3 different methods for evaluating Streptococcus mutans in the saliva].

Three different methods for detection and count of Streptococcus mutans in saliva have been compared with a microbiological method in order to estimate their efficacy and practicality. The study has been carried out on fifty children of six-eleven years old. The first method (stamp method) derives from that of Kohler and Bratthall, improved on the sampling, without saliva stimulation and, hence, more rapid. Furthermore, using a tongue depressor with a shovel-like extremity, we can either restrict the area where the grown colonies must be counted, avoiding any mistake, and stamp the spatula in the centre of the plate, not in the border, as the original method described, pressing it with the same force in every part, so that almost all the saliva collected can be plated on the Streptococcus mutans selective medium. As stated by this method, a tongue depressor is pressed first on the subject's tongue, then on a plate containing the medium. After incubation, the Streptococcus mutans colonies are counted on the plate's area limited by the stamp of the extremity of the spatula. According to Emilson we can also discriminate Streptococcus mutans and Streptococcus sobrinus colonies. The second method is a "strip mutans test" (Dentocult): saliva is stimulated making the subject chew a piece of paraffin and then it is collected passing a plastic spatula for ten times on the child's tongue. The spatula is introduced into a tube containing a liquid medium selective for Streptococcus mutans and then incubated.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteriological Techniques↗
PubMed1975

Isolation and purification of Flavobacterium alpha-1,3-glucanase-hydrolyzing, insoluble, sticky glucan of Streptococcus mutans.

Studies were made on the physical and chemical properties of polysaccharides synthesized by cell-free extracts of Streptococcus mutans, Streptococcus sanguis, and Streptococcus sp. and their susceptibilities to dextranases. Among the polysaccharides examined, insoluble glucans were rather resistant to available dextranase preparations, and the insoluble, sticky glucan produced by S. mutans OMZ 176, which could be important in formation of dental plaques, was the most resistant. By enrichment culture of soil specimens, using OMZ 176 glucans as the sole carbon source, an organism was isolated that produced colonies surrounded by a clear lytic zone on opaque agar plates containing the OMZ 176 glucan. The organism was identified as a strain of Flavobacterium and named the Ek-14 bacterium. EK-14 bacterium was grown in Trypticase soy broth, and an enzyme capable of hydrolyzing the OMZ 176 glucan was concentrated from the culture supernatant and purified by negative adsorption on a diethylaminoethyl-cellulose (DE-32) column and gradient elution chromatography with a carboxymethyl-cellulose (CM-32) column. The enzyme was a basic protein with an isoelectric point of pH 8.5 and molecular weight of 65,000. Its optimum pH was 6.3 and its optimal temperature was 42 C. The purified enzyme released 11% of the total glucose residues of the OMZ 176 glucan as reducing sugars and solubilized about half of the substrate glucan. The products were found to be isomaltose, nigerose, and nigerotriose, with some oligosaccharides. The purified enzyme split the alpha-1,3-glucan endolytically and was inactive toward glucans containing alpha-1,6, alpha-1,4, beta-1,3, beta-1,4, and/or beta-1,6 bonds as the main linkages.

Cell-Free System↗
PubMed2000

[Evaluation of cariogenic potential of Streptococcus mutans isolated from caries-free and -active persons: abilities to synthesize water-soluble and -insoluble glucans].

OBJECTIVE: In this study, authors investigated abilities of Streptococcus mutans (serotype c) strains to synthesize water-soluble and water-insoluble glucans. METHODS: Streptococcus mutans strains were isolated from people with different carious experiences, which were divided into two groups: caries-free (DMFS = 0) group including 19 persons and caries-active group(DMFS > or = 6) including 40 persons. Totally 105 genotypes of Streptococcus mutans strains were obtained, including 22 strains from the caries-free group and 83 strains from the caries-active group. The differences of abilities to synthesize water-soluble and water-insoluble glucans between these two groups were compared in order to find the correlationship between the synthesis of glucans and caries experience. Then, Streptococcus mutans were cultured in TPY liquid medium containing 1% sucrose in an anaerobic incubator at 37 degrees C for 24 hours. Glucans synthesized by Streptococcus mutans was qualified by using infrared spectrophotometry. The amounts of water-soluble and water-insoluble glucans were measured by using the anthron method. RESULTS: According to the same absorption tops position analysed by infrared spectrophotometry, glucans samples were certified. The amounts of glucans synthesized by Streptococcus mutans strains were different between strains of different genotypes even isolated from the same person. Mostly, the amount of water-insoluble glucans was higher than that of water-soluble glucans between different genotype Streptococcus mutans strains. The oral environments of patients in the caries-active group harbored more Streptococcus mutans strains with higher water-soluble glucans producing ability than those of the caries-free group did (P < 0.05), and patients of the caries-active group also harbored more Streptococcus mutans strains with higher water-insoluble glucans producing ability than those of the caries-free group did(P < 0.01). CONCLUSION: 1. Glucosyltranferases of different genotype strains are different in glucans production, and different genotype strains relate to different cariogenic abilities. 2. Glucans was one of cariogenic factors, and water-insoluble glucans was more important than water-soluble glucans in cariogenic ability of Streptococcus mutans. 3. The differences in glucans production of isolated strains might relate to differences in carious experiences.

Dental Caries↗
PubMed2006

Isolation and characterization of Streptococcus mutans in heart valve and dental plaque specimens from a patient with infective endocarditis.

Streptococcus mutans, known to be an aetiologic agent of dental caries, also causes infective endocarditis (IE), although a comparison of isolates from the oral cavity and infected heart valve of the same patient has not been reported. In the present study, infected heart valve and dental plaque samples from a patient with IE were analysed. Broad-range PCR with DNA sequencing revealed that 50 clones from the dental plaque isolates were composed of oral streptococci and periodontopathic bacteria, whereas only Streptococcus mutans was detected in 50 clones from the heart valve. Eighteen strains of Streptococcus mutans were isolated from dental plaque and seven from the heart valve, and the biochemical properties of each were in accordance with those of Streptococcus mutans. DNA fingerprinting analysis revealed that all the oral isolates of Streptococcus mutans had similar patterns, which were different from those of the isolates from the infected heart valve. Western blotting using glucosyltransferase (GTF)-specific antiserum showed that the seven strains from the heart valve lacked the three types of intact GTF. In addition, the sucrose-dependent adhesion rates of these isolates were significantly lower than those of the oral isolates (P<0.001). Furthermore, the isolates from the heart valve were less susceptible to erythromycin and kanamycin. These results indicate that the properties of the Streptococcus mutans strains isolated from the infected valve were different from those of typical oral strains, which may be related to the effects of IE.

Anti-Bacterial Agents↗
PubMed1998

Relationship between caries status, colony forming units (cfu) of Streptococcus mutans and Snyder caries activity test.

It is a well established fact that dental caries is caused by streptococcus mutans. For qualitative and quantitative analysis of streptococcus mutans, saliva samples are often preferred and are processed according to Kohler and Brathall method. In the present study an attempt is made to relate caries status (caries free, average caries, and rampant caries group) with cfu counts of streptococcus mutans and Snyder test. The streptococcus mutans were isolated using MSB agar and cfu were determined of each individual from different caries groups. The saliva of the same individual was drooled into a culture bottle containing Snyder test agar and extent of colour change was observed after 24, 48, and 72 hours incubated at 37 degrees C. The time and extent of colour change determined the conduciveness of diet. It has been observed that caries free individuals have low cfu count and their diet was mild or moderately conducive, while the individuals having average caries had medium cfu count and their diet was moderately-high conducive. In rampant caries, individuals however the cfu count were high and the diet was highly conducive. In caries free, average caries and rampant caries group 40, 60, and 80 per cent samples showed colour change, in Snyder test up to full length in 72 hours respectively. Thus a definite correlation exists between caries status, cfu count of streptococcus mutans and Snyder caries activity test.

Child↗
PubMed2006

[Experimental study of the inhibitory effects of Chelidonium majus L. extractive on Streptococcus mutans in vitro].

PURPOSE: To study the inhibitory effects of Chelidonium majus L. extractive on the growth of Streptococcus mutans in vitro, and to explore its mechanism in caries prevention. METHODS: Streptococcus mutans 25175 was chosen as the experimental bacterium. The Chelidonium majus L. extractives chelidonine and chelerythrine were double diluted to different concentrations by two-fold dilution. The inhibitory effect of Streptococcus mutans was measured by slip diffusion method. The minimal inhibitory concentration(MIC) was also determined. 0.16% liquor hibitane was used as positive control. Spearman correlation was used for statistical analysis. RESULTS: Inhibition zone of Streptococcus mutans appeared in some concentration of chelerythrine, but no inhibition zone in each concentration of chelidonine. The MIC of chelerythrine was 0.78 mg/ml which determined by liquid culture medium. The concentration of chelerythrine was highly related to the inhibitory zone of Streptococcus mutans (r=0.99, P<0.01). CONCLUSION: The antibacterial activity of Chelidonium majus L. extractive chelerythrine on Streptococcus mutans was significant,and the antibacterial activity of the concentration 100 mg/ml was higher than that of 0.16% liquor hibitane (19.4 mm), indicating that chelerythrine can be used as an agent for prevention of dental caries.

Anti-Bacterial Agents↗
PubMed2001

[Preliminary study on the rules of streptococcus mutans reactive oxygen species metabolism].

OBJECTIVE: To study the rules of Streptococcus mutans reactive oxygen species metabolism and its enzymatic basis, and to investigate its significance intermediate to plaque microbial ecology. METHODS: Electron spin trapping method was used to measure reactive oxygen species produced by Streptococcus mutans in the different incubation conditions, and evaluate the efficicay of NADH to hypoxanthine-xanthine oxidase and Fe(2+)-H2O2 system. RESULTS: Electron spin resonance (ESR) spectrum of DMPO-O2- and DMPO-OH. and superoxide dismutase were obtained in Streptococcus mutans culture fluid, these spectrum were strengthened by exogenous sugar, and disappeared when methylene blue was added to culture fluid, but that spectrum was not significantly changed by NADH. ESR spectrum of hypoxanthine-xanthine oxidase and Fe(2+)-H2O2 system were significantly reduced or disappeared by NADH. CONCLUSION: These results suggest that there are O2- and OH in Streptococcus mutans metabolism, and they may come mainly from the reaction catalyzed by NADH oxidase.

Electron Spin Resonance Spectroscopy↗
PubMedDate not supplied

Inhibitory effects of MoAbs against a surface protein antigen in real-time adherence in vitro and recolonization in vivo of Streptococcus mutans.

A surface protein antigen (PAc) of Streptococcus mutans, particularly the A-region of the molecule, has been reported to interact with salivary components on the tooth surface. It might be a candidate antigen inducing the production of antibodies against the adherence of S. mutans to the tooth surface. We investigated the effects of monoclonal antibodies (MoAbs) obtained by immunization of synthetic PAc peptides that completely correspond to the amino acid sequence of part of the A-region. These MoAbs recognize several core B-cell epitopes in the sequence. Two (KH5 and SH2) of these antibodies reacted with both S. mutans and Streptococcus sobrinus, but not with Streptococcus sanguis, Streptococcus salivarius, Porphyromonas gingivalis or Lactobacillus casei. They clearly inhibited the real-time adherence of S. mutans to salivary components in a biosensor. KH5, which showed a real-time inhibition (71%), also significantly prevented the recolonization of S. mutans on the tooth surface in rats. These results suggested that the core B-cell epitope (-Y---L--Y----) recognized by KH5 was the essential sequence in the antigenic epitopes of PAc protein recognized specifically by the inhibitory antibody. Therefore, the amino acid residues were found to be important in the initial attachment of S. mutans to the tooth surface. These results provide for the mechanism of PAc molecule in the initial attachment of S. mutans on the tooth surface and more effective designs for the removal of S. mutans and S. sobrinus from the oral cavity.

Adhesins, Bacterial↗
PubMed2003

[The study on specific anti-Streptococcus mutans IgY against dental caries in rats].

OBJECTIVE: To investigate the effect of specific anti-streptococcus mutans IgY against streptococcus mutans on dental caries development in rats. METHODS: 35 wistar rats were divided into 5 groups: group A received IgY gargle; group B received IgY lyophilized powder; group C received sterilized water as control; group D and E received egg yolk food with or without specific IgY individually. They were all fed with caries-inducing diet 2000#. The number of caries scores was counted by the procedure of Keyes'. RESULTS: There was a significant lower mean of caries scores in groups treated with IgY lyophilized powder and gargle. By treating with egg-yolk food contained specific IgY, the mean of caries scores decreased comparing with no treatment group. CONCLUSION: Local passive immunization with specific anti-streptococcus mutans IgY may be an effective way to prevent the development of dental caries.

Animals↗
PubMed1989

[Characterization of fatty acid composition in the cytoplasmic membrane of Streptococcus mutans].

The present study was performed to investigate the role of the fatty acid composition of cytoplasmic membranes in bacterial differentiation and the appearance of cariogenic properties of Streptococcus mutans. Bacterial fatty acid composition was effective for differentiation of Streptococcus mutans from the other oral streptococci. The composition obtained from the reference strains and the clinical isolates involved five groups and was useful as a rapid screening index for Streptococcus mutans. Compositional changes in membrane lipids played important roles in synthesis and secretion of extracellular glucosyltransferase for Streptococcus mutans. A characteristic property of Streptococcus mutans, resistance to 40% sucrose in the medium, is ascribable to compositional changes in membrane lipids, especially the glycolipids, of Streptococcus mutans.

Cell Membrane↗
PubMed1998

Combined inhibitory effect of bovine immune whey and peroxidase-generated hypothiocyanite against glucose uptake by Streptococcus mutans.

Immune whey product was obtained from Streptococcus mutans- and Streptococcus sobrinus-immunized cows. Hypothiocyanite (HOSCN/OSCN-) was generated in VMG-buffer, pH 5.5 or 6.5, by bovine milk lactoperoxidase, KSCN and hydrogen peroxide. The glucose incorporation by late-log cells of S. mutans 10449, serotype c, was followed by measuring the uptake of 14C-glucose at 37 degrees C. At pH 5.5 and 6.5 both immune whey product and HOSCN/OSCN- dose-dependently inhibited glucose uptake. The inhibition by their combination was additive if bacterial cells were treated with HOSCN/OSCN- before exposed to immune whey product. In contrast to immune whey product, the control product from sham-immunized cows increased the glucose uptake even when added simultaneously with HOSCN/OSCN-. However, when bacterial cells were pretreated with HOSCN/OSCN- an enhanced inhibitory effect was observed also with control product. The results indicate that colostral proteins from S. mutants- or S. sobrinus-immunized cows inhibit glucose uptake and that the effect is enhanced by pretreatment with lactoperoxidase-generated HOSCN/OSCN-.

Adjuvants, Immunologic↗
PubMed1989

[Lysis of oral streptococci by an extracellular enzyme from the bacterium Streptococcus mutans].

The ability of crude extracellular enzyme produced by the bacterium Streptococcus mutans AL-7 to lysis the cells of five species, sixteen strains, of oral streptococci was examined. This enzyme showed lytic activity of living cells of only Streptococcus sanguis ATCC 10558 strain, and of heated cells of Streptococcus sanguis ATCC 10558 and ST-7 strains. The long chains of Streptococcus sanguis ATCC 10558 was severed at random by this enzyme. Early log phase cells of this strain were more sensitive to this enzyme than late log phase cells. No bacteriocins or bacteriocin-like substances were produced by Streptococcus mutans AL-7 strain in chemically defined medium. In view of these results, the relationship between this lytic enzyme from Streptococcus mutans and a decrease in the number of serotype III strains of Streptococcus sanguis in dental plaque is suggested.

Bacteriolysis↗
PubMed1994

Amphiphilic property of chlorhexidine and its toxicity against Streptococcus mutans GS-5.

The toxicity of chlorhexidine digluconate against Streptococcus mutans GS-5 was comparatively determined by measuring its bactericidal activity, and its inhibitory effect on microbial dehydrogenases was studied by the resazurin reduction method. Both methods indicated that chlorhexidine within the range 0.75-5.00 mg/l was highly toxic to Streptococcus mutans, probably due to inhibition of dehydrogenase activity, and the extent of toxicity was closely associated with concentration. In an attempt to better understand the relationship between the amphiphilic nature of chlorhexidine and its toxicity against Streptococcus mutans, the effect of solvent polarity on dehydrogenase inhibition was investigated. A decrease in solvent polarity, induced by inclusion of 5% acetone in the reaction mixture, did not enhance the toxicity of chlorhexidine. This implies that the antimicrobial action of chlorhexidine is mainly attributable to its hydrophilicity, and that the nature of the lipophilic groups is only of secondary importance.

Acetone↗
PubMed2002

An essential amino acid residue for catalytic activity of the dextranase of Streptococcus mutans.

Dextranase (Dex) is an enzyme that hydrolyzes glucan, a polymer of glucose synthesized from sucrose by glucosyltransferases (GTFs). By comparing amino acid sequences of Dexs and GTFs, we found that the Dex enzymes of Streptococcus mutans, Streptococcus sobrinus, Streptococcus downei and Streptococcus salivarius had similar amino acid sequences to those of the catalytic sites of GTFs of mutans streptococci. We therefore examined the amino acid essential in Dex catalysis by molecular genetic approaches in this study. Site-directed mutagenesis was used to convert the Asp-385 of the Dex molecule of S. mutans Ingbritt to Glu, Asn, Thr or Val. Replacement of Asp-385 with any of the amino acids resulted in complete disappearance of Dex activity. However, replacement of other Asp residues did not affect the enzyme activity. The inactive enzymes still retained dextran-binding ability. These results suggest that Asp-385 of the Dex of S. mutans Ingbritt was essential for enzyme activity and the catalytic and substrate-binding sites were located at different sites within the Dex molecule.

Amino Acid Sequence↗