• International Journal of Oral Biology
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• v.38 no.4
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• pp.175-180
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• 2013

Xylitol is a five-carbon sugar alcohol that reduces the incidence of caries by inhibiting the growth of oral streptococci, including Streptococcus mutans. Since xylitol is transported via the fructose phosphotransferase system, we hypothesized that it could also affect the growth of other oral bacteria strains. We tested the effects of xylitol against non-periodontopathogenic oral bacteria frequently found in healthy subjects as well as periodontopathogens including Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. With 5% xylitol, Streptococcus vestibularis and Gemella morbillorum showed marked growth inhibition. With 10% xylitol, all of the tested periodontopathogens and Actinomyces naeslundii showed marked growth inhibition, whereas the growth inhibition of Neisseria mucosa, Neisseria sicca and Veillonella parvula was mild only. Xylitol is a widely used sweetener and the concentration used in our experiment is easily achieved in the oral cavity. If xylitol reduces the growth of periodontopathogens more preferentially, it could also reduce the prevalence of these pathogens and have clinical utility in the prevention or treatment of periodontal disease.

• Journal of Microbiology
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• v.44 no.4
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• pp.417-422
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• 2006

This study investigated the antibacterial effect of electrolyzed water on oral bacteria both in vitro and in vivo. Tap water was electrolyzed in a water vessel using platinum cell technology. The electrolyzed tap water (called Puri-water) was put in contact with five major periodontopathogens or toothbrushes contaminated with these bacteria for 30 sec. In addition, Puri-water was used as a mouthwash for 30 sec in 16 subjects and the antibacterial effect on salivary bacteria was evaluated. Puri-water significantly reduced the growth of all periodontopathogens in culture and on toothbrushes, and that of aerobic and anaerobic bacteria in saliva, when compared to the effect of tap water. It also significantly reduced mutans streptococci growing on mitis salivarius-bacitracin agar. Our results demonstrate that the electrolyzed tap water is effective as a mouthwash and for toothbrush disinfection.

• International Journal of Oral Biology
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• v.40 no.4
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• pp.189-196
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• 2015

Minimal inhibitory concentration (MIC) is the lowest antibiotic concentration that inhibits the visible growth of bacteria. Sub-minimal inhibitory concentration (Sub-MIC) is defined as the concentration of an antimicrobial agent that does not have an effect on bacterial growth but can alter bacterial biochemistry, thus reducing bacterial virulence. Many studies have confirmed that sub-MICs of antibiotics can inhibit bacterial virulence factors. However, most studies were focused on Gram-negative bacteria, while few studies on the effect of sub-MICs of antibiotics on Gram-positive bacteria. In this study, we examined the influence of sub-MICs of doxycycline, tetracycline, penicillin and amoxicillin on biofilm formation and coaggregation of Streptococcus gordonii, Streptococcus mutans, Actinomyces naeslundii, and Actinomyces odontolyticus. In this study, incubation with sub-MIC of antibiotics had no effect on the biofilm formation of S. gordonii and A. naeslundii. However, S. mutans showed increased biofilm formation after incubation with sub-MIC amoxicillin and penicillin. Also, the biofilm formation of A. odontolyticus was increased after incubating with sub-MIC penicillin. Coaggregation of A. naeslundii with S. gordonii and A. odontolyticus was diminished by sub-MIC amoxicillin. These observations indicated that sub-MICs of antibiotics could affect variable virulence properties such as biofilm formation and coaggregation in Gram-positive oral bacteria.

• International Journal of Oral Biology
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• v.38 no.2
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• pp.43-49
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• 2013

The objective of this study was to develop PCR primers that are specific for Streptococcus sanguinis, Streptococcus parasanguinis, and Streptococcus gordonii. We designed the S. sanguinis-, S. parasanguinis-, and S. gordonii-specific primers, Ssa21-F3/Ssa21-R2, Spa17-F/Spa17-R, and Sgo41-F1/Sgo41-R1 respectively, based on the nucleotide sequences of the Ssa21, Spa17, and Sgo41 DNA probes that were screened using inverted dot blot hybridization (IDBH). The species-specificity of these primers was assessed against 43 strains of mitis group streptococci, including clinical strains of S. sanguinis, S. parasanguinis, and S. gordonii. The resulting PCR data revealed that species-specific amplicons had been obtained from all strains of the target species tested, and that none of these amplicons occurred in any other strains from other species. These results suggest that the Ssa21-F3/Ssa21-R2, Spa17-F/Spa17-R, and Sgo41-F1/Sgo41-R1 primers may be useful in detecting S. sanguinis, S. parasanguinis, and S. gordonii at the species level, respectively.

• Korean Journal of Microbiology
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• v.53 no.3
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• pp.225-226
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• 2017

Streptococcus mitis is a Gram-positive, facultative anaerobic, alpha-hemolytic, and nonmotile cocci. S. mitis is a viridans streptococci and a normal commensal of throat, nasopharynx, and mouse and is associated with infective endocarditis, septicemia, and meningitis. S. mitis KCOM 1350 (= ChDC B183) was isolated from a human mandibular osteomyelitis lesion. Here, we present the complete genome sequence of S. mitis KCOM 1350.

• The korean journal of orthodontics
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• v.42 no.2
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• pp.87-93
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• 2012

Objective: The purpose of this study was to investigate the antimicrobial effect of silverized elastomers on mutans streptococci in dental plaque. Methods: Forty patients undergoing orthodontic treatment were randomly placed into 1 of 2 groups. We examined the maxillary right and left central incisors and premolars, and the mandibular right and left canines of all participants. We ligated the right maxillary and left mandibular teeth of the participants in group 1 with silverized elastomers and ligated their contralateral teeth with conventional elastomers. We ligated the left maxillary teeth and right mandibular teeth of group 2 participants with silverized elastomers. Each participant visited the clinic 4 times at 3-week intervals. We applied the elastomers to the teeth on one side of each patient's mouth during their first visit. During the second visit, the elastomers were removed for microbiological analysis and replaced with steel ligatures. During the third visit, we used silverized elastomers to ligate the teeth contralateral to those treated on the first visit. The elastomers were removed during the fourth visit, and microbiological analyses were performed. We compared the quantity of bacteria on silverized and conventional elastomers at the 0.05 level of significance. Results: The percentage of mutans streptococci was not significantly different in cultures of dental plaque from the silverized and the conventional elastomers (p > 0.05). Conclusions: There was no significant difference between the antimicrobial effect of the silverized elastomers and that of the conventional elastomers.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.4
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• pp.587-596
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• 2006

Most of oral streptococci express the Antigen I/II (AgI/II) proteins, cell wall anchored adhesions. AgI/II protein binds to salivary agglutinin glycoprotein, a component of tooth pellicle and to ligands in other bacteria. These associations play important roles in bacterial colonization. Recently, it was reported that diverse host molecules also interact with AgI/II protein and that these interactions induce inflammatory responses from host cells. Among mutans streptococci containing -type hemolytic activity, Streptococcus mutans is a causative agent for dental caries. Compared with many other strains of S. mutans, GS-5 strain is unique in that this bacterium expresses truncated secretory AgI/II protein due to the nonsense mutation in the agI/II gene. This indicates that S. mutans GS-5 has a different clinical role and a recent report supported this idea based on the results from clinically isolated S. mutans strains. Previously, we had cloned agI/II gene from S. mutans GS-5 and generated recombinant N-terminal AgI/II protein. In this study, we further produced a hybridoma line expressing anti-AgI/II monoclonal antibodies named as 1C11A. This antibody showed high sensitivity to AgI/II protein in Western blot and ELISA. This new reagent will provide a basis for investigating the mechanisms of AgI/II-related diseases.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.73-82
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• 2008

Dental caries is an infectious disease caused by mutans streptococci, and is a primary etiologic agent of dental caries in humans. The molecular pathogenesis of mutans streptococcal-associated dental caries occurs in three phases. Firstly, S. mutans attaches to tooth surface via a cell surface adhesion termed antigen I/II. In the second phase, the glucosyltransferase(GTFs) synthesize polymers like glucans in the presence of sucrose. In the third phase, the multivalent glucans interacts with glucan binding proteins (GBPs) and they make dental plaque and accumulation of microorganisms. Many studies and clinical trials have indicated that a mucosal immune response to these antigens(Ag I/II, GTFs, GBPs) of S. mutans can influence the pathogenesis of dental caries. So these antigens can be important vaccine candidates for immunologic intervention against dental caries. In this study, we cloned the genes for GTFb, GTFc, GTFd from S. mutans GS-5 and did the nucleotide sequence analysis. And the recombinant proteins of GTFd and N-terminus of GTFd were expressed. Intact GTF which we get from this experiment can be used for antibody production specific for any GTF activity domain through animal experiment.

• The Journal of the Korean dental association
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• v.9 no.12
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• pp.819-822
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• 1971

For this investigation, author isolated Streptococcus mitis strain SD-9 from the bacterial flora in the human dental plaque, which was incubated in brain-heart infusion media containing 5% sucrose at 37℃ for 24 hours. For the cytochemical demonstration of polysaccharide produced by this strain, a modified thiosemicarbazide osmium method (Critchley et al., 1967) was used. After fixation with this reagent, the harvested cells was suspended in 1% agar for the higher concentration of cells(Kellenberger et al., 1964). And they were dehydrated in the various concentration of ethanol, and embedded in Epon 812(Luft, 1961). Sectioning was done with the Sorvall MT-2 Porter Blum ultramicrotome by means of a glass knife, and the sections were stained with saturated uranyl acetate and lead citrate (Raynolds, 1963). All preparations were examined in a electron microscope, Hitachi HU-ll E-1 type. The morphological features of extracellular polysaccharide produced by Streptococcus mitis strain SD-9 were appeared in 3 structurally different forms, those are, electron dense fibrillar material linearly arranged adjacent to the outer surface of cell wall, highly electron dense globular material adjacent to the outer surface of cell wall, and strutureless fluffy meshwork of possible very fine filament.

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.212-218
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• 2000

The recruitment of leukocytes to a site of inflammation is dependent on a complex interplay of a number of cytokines. Monocyte chemoattractant protein-1 (MCP-1) is a potent chemoattractant for monocytes, whereas interleukin-8 (IL-8) has chemotactic activity for neutrophils, lymphocytes, and basophils. The purpose of this study was to determine the effects of several microbes found in infected root canal systems on the production of inflammatoy cytokines, interleukin 8 and monocyte chemoattractant protein-1 from human peripheral blood mononuclear cells (PBMC). Monocytes isolated from peripheral blood were stimulated by group A streptococci (GAS, ATCC 19615), Enterococcus faecalis (ATCC 29212), Streptococcus mutans (ATCC 10449), Streptococcus sanguis (clinical isolate), and Candida albicans (ATCC 90029) respectively. Each of these bacteria induced dose-dependent induction in IL-8 and MCP-1 determined by ELISA. IL-8 production by each bacteria was decreased in the range of the microbe-to-PBMC ratios of 0.1-1.0. Group A streptococci was the week inducer of MCP-1 production. These results suggest that different oral pathogens induce specific dose-dependent patterns of cytokine release. Such patterns may provide a means of control of the type of immune celles particularly with regard to inflammatory leukocyte recruitment.