• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.4
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• pp.397-405
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• 2020

The aim of this study is to compare cariogenic characteristics of fluoride-sensitive Streptococcus mutans [fluoride-sensitive (FS) S. mutans ] and fluoride-resistant Streptococcus mutans [fluoride-resistant (FR) S. mutans] in the presence of sucrose, and to evaluate its effect on cariogenic biofilm formation. S. mutans ATCC 25175 was continuously cultured in trypticase soy broth (TSB) containing NaF (70 ppm) for 40 days to generate FR S. mutans. FS and FR S. mutans were inoculated in TSB with or without 2% sucrose, and optical density and pH were measured every hour. An oral biofilm was formed using saliva bacteria and analyzed through confocal laser scanning microscopy and CFU count. Finally, the expression of glucosyltransferases genes of both S. mutans was investigated through RT-PCR. FR S. mutans exhibited slower growth and lower acidogenicity in the presence of sucrose compared to FS S. mutans . Both cariogenic and single species biofilm formation was lower in the presence of FR S. mutans, along with reduced number of bacteria. FR S. mutans showed significantly low levels of gtfB, gtfC, and gtfD expression compared to FS S. mutans . On the basis of results, FR S. mutans may be less virulent in the induction of dental caries.

• Journal of Korean society of Dental Hygiene
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• v.12 no.6
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• pp.1158-1164
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• 2012

Objectives : The aim of the present study was to measure the level of Streptococcus mutans(S. mutans), the major causative agent in dental caries, and to examine the relationship between S. mutans level and dental caries experience. Methods : The present study was carried out in 41 university students. S.mutans plaque was detected in the saliva using Dentocult$^{(R)}$-SM and was measured in absorbance. The data were analyzed in the relevance for number of dental caries experience. Results : The group of S. mutans value has progressive caries, which was higher than that of non-suffering caries(p<0.05). More caries experience showed higher value of S. mutans(p>0.05). According to the relationship with DMFT, level of S. mutans and absorbance, correlation with the level of salivary S. mutans is shown statistically highly significant (p<0.01). The level of S. mutans in saliva and plaque and absorbance is statistically significant(p<0.05). Conclusions : The levels of S. mutans in both group of high caries experience and progressive caries was highly detected, continuous oral health management should be carried out to prevent the possible dental caries.

• Restorative Dentistry and Endodontics
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• v.29 no.5
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• pp.462-469
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• 2004

The aim of this study was to investigate the susceptibility of mutans streptococci (S. mutans and S. sobrinus) and Streptococcus anginosus, for seven antibiotics, penicillin G, amoxicillin, ciprofloxacin, cefuroxime, erythromycin, bacitracin, and vancomycin. The minimum inhibitory concentration (MIC) of seven antibiotics against 3 species (type strains) of mutans streptococci and S. anginosus, 10 strains (wild type) of S. mutans, 7 strains (wild type) of S. sobrinus, and 11 strains (wild type) of S. anginosus, were measured by broth dilution method. All of the type strains of mutans streptococci and S. anginosus had the same susceptibility for penicillin G, amoxicillin, cefuroxime and bacitracin. Type strain of S. anginosus was sensitive in ciprofloxacin, but those of mutans streptococci were not. All of the clinical isolates of mutans streptococci and S. anginosus had the same susceptibility for the seven antibiotics. Our data reveal that mutans streptococci and S. anginosus have similar antibiotic-resistant character. In addition. these results may offer the basic data to verify the antibiotic-resistant mechanism of mutans streptococci and S. anginosus.

• Food Science of Animal Resources
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• v.42 no.6
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• pp.1020-1030
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• 2022

The aim of the study was to investigate the effect of bacteriocin-like inhibitory substance (BLIS) from Enterococcus faecium DB1 on cariogenic Streptococcus mutans biofilm. Crystal violet staining, fluorescence, and scanning electron microscopy analyses demonstrated that the BLIS from Enterococcus faecium DB1 (DB1 BLIS) inhibited S. mutans biofilm. When DB1 BLIS was co-incubated with S. mutans, biofilm formation by S. mutans was significantly reduced (p<0.05). DB1 BLIS also destroyed the preformed biofilm of S. mutans. In addition, DB1 BLIS decreased the viability of S. mutans biofilm cells during the development of biofilm formation and in the preformed biofilm. DB1 BLIS significantly decreased the growth of S. mutans planktonic cells. Furthermore, S. mutans biofilm on the surface of saliva-coated hydroxyapatite discs was reduced by DB1 BLIS. Taken together, DB1 BLIS might be useful as a preventive and therapeutic agent against dental caries caused by S. mutans.

• The Journal of the Korean Society for Microbiology
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• v.17 no.1
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• pp.75-85
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• 1982

In order to demonstrate the effect of specific serum IgG antibody on the adherence of Streptococcus mutans to smooth surface and the mechanism of effective adherence inhibition by IgG antibody, in the present study authors obtained purified IgG from different immunogen preparations of S. mutans NCTC 10449(serotype c) and observed the effect of each IgG preparation on the adherence of each S. mutans strain cultured in different conditions. In addition, the present study was undertaken to observe the cross-reactivity of IgG and the effect of sucrose concentration on the adherence of S. mutans in vitro non-growth condition. The adherence of S. mutans to glass surface was effectively inhibited by serum IgG antibody. At the same IgG concentrations, anti-2% fructose grown/1N NaCl washed S. mutans NCTC 10449 cell showed greater adherence inhibitory effect to S. mutans strains than anti-2% sucrose grown and anti-S. mutans NCTC 10449 cell wall, and the greater inhibitory effects of IgG preparations were observed in assay using 2% fructose grown S. mutans cell preparations than using 0.1% sucrose grown cell preparations. These results suggest that the more effective adherence inhibition by serum IgG antibody is due to the reaction with S. mutans cell surface antigens rather than glucan and cell-associated glucosyltransferase. The greatest adherence inhibitory effect of IgG to S. mutans strains was observed on homologous NCTC 10449 strain and the inhibition cross-reactivities were observed between serotype c, e, and f strains. More pronounced cross-reactivity of adherence inhibition of IgG to S. mutans was observed in assay using anti-2% fructose grown/1N NaCl washed cell than using other IgG preparations, and observed in assay using 2% fructose grown S. mutans cell preparations than 0.1% sucrose grown cell preparations. It was interested that low, but adequate concentration of reactive IgG antibody significantly increased the adherence ability of S. mutans. This result may be due to the formation of small cell aggregates resulted in a increase in the numbers of organisms which adhered to glass surface. The adherence of S. mutans to glass surface was possible in the absence of glucan-synthetic activity. Low level of sucrose significantly increased the adherence ability of S. mutans to glass surface, but excessive amount of sucrose induced large cell aggregates resulted in a decrease in the numbers of organism which adhered.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.5
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• pp.854-858
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• 2010

Streptococcus mutans (S. mutans) plays an important role in the information of dental plaque and it is being noticed as major causative bacteria of dental caries. In the present study, inhibitory effects of the ethanol extract of Dianthus superbus Linne (D. superbus) on the growth, acid production, adhesion and water-insoluble glucan synthesis of S. mutans were examined. The ethanol extract of D. superbus (0.5 - 4 mg/ml) significantly lowered the growth of S. mutans in a dose dependent manner. The acid production of S. mutans were inhibited by the presence of ethanol extract of D. superbus(1 - 4 mg/ml) significantly. The ethanol extract of D. superbus (0.25 - 4 mg/ml) also significantly lowered the adherence of S. mutans in a dose dependent manner. In water-insoluble glucan synthesis assay, 0.25 - 4 mg/ml of the ethanol extract of D. superbus significantly inhibited the formation of water-insoluble glucan. These results suggest that D. superbus may inhibit the caries-inducing properties of S. mutans. Further studies are necessary to clarify the active constituents of D. superbus responsible for such biomolecular activities.

• International Journal of Oral Biology
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• v.40 no.4
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• pp.217-221
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• 2015

Cariogenic Streptococcus mutans encounters a variety of host defense factors produced in oral cavity. Nitric oxide (NO) and NO-mediated reactive nitrogen species are potential antimicrobials of innate immunity that can threaten the fitness of S. mutans in their ecological niches. Streptococcal strategies to detoxify cytotoxic NO, which allow S. mutans to persist in caries or other environments of the oral cavity, remain unknown. In this study, we directly measured NO consumption rates of S. mutans isolated in Korea. Surprisingly, all S. mutans strains were unable to consume exogenous NO efficiently, while an intracellular parasite Salmonella enterica serovar Typhimurium expressing the NO-metabolizing enzyme flavohemoglobin consumed most of the NO. This result suggested that S. mutans has alternative detoxification systems for tolerating NO-induced nitrosative stresses.

• Korean Journal of Microbiology
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• v.42 no.1
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• pp.19-25
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• 2006

This study was undertaken to develop PCR primers for the identification and detection of Streptococcus mutans (by)using species-specific forward and universal reverse primers. These primers targeted the variable regions of the 16S ribosomal RNA coding gene (rDNA). The primer specificity was tested against 11S. mutans strains and 10 different species (22 strains) of oral bacteria. The primer sensitivity was determined by testing serial dilutions of the purified genomic DNA of S. mutans ATCC $25175^T$. The data showed that species-specific amplicons were obtained from all the S. mutans strains tested, which was not observed in the other species. The direct and nested PCR could detect as little as 2 pg and 2 fg of the chromosomal DNA from S. mutans ATCC $25175^T$, respectively. This shows that the PCR primers are highly sensitive and applicable to the detection and identification of S. mutans.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.439-447
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• 2004

The aim of this study is to survey the frequency of mutans streptococci species and biotypes isolated from dental plaque in Korean children and the relationship between species and biotypes of mutans streptococci and dft index. Dental plaques were collected from the anterior and molar teeth of upper and lower jaws in the subjects, aged below 12 years old. A dental examination was performed for dft (decayed, filled, total) with the WHO caries diagnostic criteria. The mutans streptococci from the sample were cultured selectively on mitis salivarius-bacitracine (MSB) agar plate. For biotyping of mutans streptococci, biochemical test was performed. From the culture, bacterial genomic DNA was prepared for using of PCR template for the identification of mutans streptococci at the species-level. Forty strains of mutans streptococci were isolated from dental plagues of 40 patients. The biotype I (45%) and biotype IV (32.5%) were most frequently detected. The prevalence of S. mutans and S. sobrinus was 69% and 31%, respectively. There was no positive relationship between species and biotypes of mutans streptococci and dft index. Our results revealed that biotype I and S. mutans were frequently detected in Korean children and support that dental caries incidents by many causative factors not only bacterial factor.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.357-369
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• 2005

Streptococci are Gram-positive, facultative anaerobes and have no catalase activities. Among mutans streptococci containing ${\alpha}-type$ hemolytic activity, S. mutans is a causative agent for dental caries. As well as acid production yielding the demineralization of tooth enamel, adherence and colonization of S. mutans to the teeth are also important for its virulence. These early colonization are accomplished by the bacterial fibrillar protein, Antigen I/II (Ag I/II) and glucosyltransferase (GTF). Therefore, Ag I/II and GTF are reasonable targets for the development of vaccine against S. mutans GS-5. The ag I/II and gtfD genes from S. mutans GS-5 were cloned and sequenced. Sequence analyses showed the nucleotides sequence of cloned genes had high homology to the sequences previously reported. The sequence alignment of 280 nucleotides between the cloned Ag I/II and the available sequence of the corresponding S. mutans GS-5 showed the perfect match. Comparing with the sequence of gtfD from S. mutans UA159, the corresponding nucleotide sequence of S. mutans GS-5 showed some mismatches and the mismatches introduced changes in four residues out of 105 amino acids, yielding four missense mutations.