• Biomolecules & Therapeutics
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• v.7 no.3
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• pp.257-262
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• 1999

Streptococcus pneumoniae (pneumococcus) is the most frequent causative agent of acute bacterial pneumonia. Outstanding characteristic of pneumococcus is an ample polysaccharide capsule that is highly anti-genic agent and is the major factor for classification of pneumococcus into more than 94 serotypes. In this study, production of capsular polysaccharide from Streptococcus pneumoniae type 23 was optimized by supplementation of metal ions or by modulation of culture conditions. When brain heart infusion (BHI) broth was supplemented with 1 mM concentration of $CaCl_2$, $CuSO_4$ and $MgSO_4$, growth of pneumococcus as well as polysaccharide yield were stimulated. Also slight aeration gave rise to better polysaccharide yield.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.2
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• pp.449-459
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• 1997

The main component of dental plaque is the mutan containing the a-1,3 bond. The following results were obtained by using a blue mutan to assess the factors affecting the mutan-digesting activity of Streptomyces exfoliatus isolated from soil. A clear zone was produced by mutanase-producing Streptomyces exfoliatus on the minimal essential agar containing blue mutan. Streptomyces exfoliatus digested more blue mutan in the minimal essential broth at pH 7.0 than at pH 5.5 or 8.5. Streptomyces exfoliatus digested more blue mutan at $37^{\circ}C$ than at $32^{\circ}C$ or $42^{\circ}C$ (P<0.05). When the concentration of $CaCl_2$ was increased in the minimal essential broth, the digestion of blue mutan was increased (P<0.05). The optimal concentration of KCl was 10mM to digest blue mutan, but a similar amount of blue mutan was digested at the range of 0.1mM to 6.4mM of $MgCl_2$. When the culture supernatant of Streptomyces exfoliatus was mixed with 2X brain heart infusion broth containing 0.5% yeast extract and 10% sucrose, less artificial plaque was formed by Streptococcus mutans on the orthodontic wire (P<0.05). These results indicated that the secretion of mutanase was identified in culture supernatant of mutan-digesting Streptomyces exfoliatus, suppressing the formation of artificial plaque by Streptococcus mutans.

• Archives of Pharmacal Research
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• v.28 no.6
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• pp.660-666
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• 2005

The intestinal microbiota are important to the host with regard to resistance they impart against bacterial infections and their involvement in mediating metabolic functions. Lactic acid producing bacteria such as Lactobacillus play an important physiological role in these matters. The aim of the present study was to isolate Lactobacillus sp. that inhibits enteric pathogens. Initially, 17 isolates from healthy Koreans were collected on Lactobacillus selective medium. Resistance of the isolates to antibiotics including rifampicin, streptomycin, clindamycin and vancomycin was measured. One of the isolate was identified as Lactobacillus ruminus on the basis of bacterial cell morphology, cultural characteristic and biochemical characteristics, 16S rRNA sequence analysis and PCR-RAPD. Antimicrobial activity of the bacterium against Vancomycin Intermediate Resistant Staphylococcus aureus (VISA) and Vancomycin-Resistant Enterococci (VRE) was measured. About $10^4$ cells of VISA or VRE were mixed with 1, 5, and 9 mL of L. ruminus SPM 0211 and the final volume was adjusted to 10 mL with brain heart infusion (BHI) broth. The cell suspension was incubated for 3, 6, 9, and 24 h, serially diluted and then plated on BHI agar plates. As numbers of L. ruminus SPM 0211 were increased, viable cell count of VISA and VRE decreased. The strongest antimicrobial activity of SPM 0211 was observed after 9 h incubation in any mixture, almost completely inhibiting the growth of these two bacteria. The results suggest that the freshly isolated L. ruminus SPM 0211 may be used as a pro-biotic microbe that prevents the colonization of enteric pathogens and can thereby promote good gastrointestinal health.

• Journal of Life Science
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• v.22 no.5
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• pp.692-696
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• 2012

$Listeria$ $monocytogenes$, a fatal food-borne pathogenic bacteria, can form a biofilm on many different supports. The biofilm gives $L.$ $monocytogenes$ more viability and resistance to disinfectants and sterilization procedures.$L.$ $monocytogenes$ formed biofilms on various culture vessels tested in this experiment and showed the maximum amount of biofilm when it was cultured for 4 days at $30^{\circ}C$ in BHI broth. In this study, biofilm formation was stimulated or inhibited by addition of different Kimchi samples. That was not in accordance with the effect of Kimchi on the growth of $L.$ $monocytogenes$.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.304-313
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• 2004

Xylitol, a five-carbon natural sugar alcohol, is widely used non-cariogenic sugar substitute. In present study, the effects of xylitol on the expression of mRNA for glucosyltransferase which synthesizes glucan from sucrose were detected by Fluorescent in situ hybridization (FISH) and flow cytometry. FITC fluorescences for mRNA of gtfB, gtfC and gtfD were decreased further with increasing concentration of xylitol from 1% to 10% when detected by FISH. Flow cytometric analysis also showed that the expression of gtfB, gtfC and gtfD was increased by the addition of sucrose and decreased by the addition of xylitol to BHI broth containing 1% sucrose. In conclusion, the expression of gtfB, gtfC and gtfD mRNA was decreased by the addition of xylitol.

• Restorative Dentistry and Endodontics
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• v.28 no.6
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• pp.435-448
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• 2003

This study was performed to observe the antibacterial effect of polyphosphate (polyP) with various chain lengths (P3~P75) on virulent. invasive strains of P. gingivalis A7A1-28 and W50, and multidrug resistant E. faecalis ATCC29212. P. gingivalis strains were grown in brain-heart infusion broth (BHI) containing hemin and vitamin K with or without polyP. PolyP was added at the very beginning of the culture or during the exponential growth phase of the culture. Inhibition of the growth of P. gingivalis was determined by measuring the absorbancy at 540nm of the grown cells. Viable cell counts of the culture and release of intracellular nucleotide from P. gingivalis were measured. E. faecalis was grown in plain BHI with antibiotics alone or in combination with polyP(calgon: 0.1~1.0%) and the bacterial absorbancy was measured. The overall results suggest that polyP has a strong antibacterial effect on the growth of the virulent strains of P. gingivalis and the antibacterial activity of polyP seems largely bactericidal. accompanying bacteriolysis in which chelation phenomenon is not involved. Although polyP does not exert antibacterial activity against E. faecalis, it appears to increase antibacterial effect of erythromycin and tetracycline on the bacterium. Therefore, polyP alone or in combination with antibiotics may be developed as a candidate for the agent controlling oral infections including endodontic infection.

• Restorative Dentistry and Endodontics
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• v.42 no.1
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• pp.54-59
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• 2017

Objectives: The purpose of this study was to compare the antibacterial activity of urushiol against Enterococcus faecalis (E. faecalis) to that of NaOCl. Materials and Methods: The canals of thirty two single rooted human teeth were instrumented with Ni-Ti files (ProTaper Next X1, X2, X3, Dentsply). A pure culture of E. faecalis ATCC 19433 was prepared in sterile brain heart infusion (BHI) broth. The teeth were submerged in the suspension of E. faecalis and were incubated at $37^{\circ}C$ for 7 days to allow biofilm formation. The teeth were randomly divided into three experimental groups according to the irrigant used, and a negative control group where no irrigant was used (n = 8). Group 1 used physiologic normal saline, group 2 used 6% NaOCl, and group 3 used 10 wt% urushiol solution. After canal irrigation, each sample was collected by the sequential placement of 2 sterile paper points (ProTaper NEXT paper points, size X3, Dentsply). Ten-fold serial dilutions on each vials, and 100 µL were cultured on a BHI agar plate for 8 hours, and colony forming unit (CFU) analysis was done. The data were statistically analyzed using Kruskal-Wallis and Mann-whitney U tests. Results: Saline group exhibited no difference in the CFU counts with control group, while NaOCl and urushiol groups showed significantly less CFU counts than saline and control groups (p < 0.05). Conclusions: The result of this study suggests 10% urushiol and 6% NaOCl solution had powerful antibacterial activity against E. faecalis when they were used as root canal irrigants.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.684-695
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• 2003

The aim of this study was to investigate the effect of composite resin components on proliferation and glucan synthesis by cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus. Light curing pit and fissure sealant was chosen for evluation. Specimens were eluted in deionized water for 10 minutes, 1, 12, and 24 hours. Extracts of specimens were diluted into 1/2, 1/4, and 1/8 with addition of BHI broth and BHI-YS. Bacteria were cultured in media included eluted components, and measured optical density($A_{600}$). The following results were obtained 1. 1/4 concentration of elutes for 10 minutes significantly inhibited the proliferation of S. mutans, whereas 1/2, 1/8 concentration of elutes stimulated it. Also, exacts, especially 1/2, 1/4 concentration, for 1 hours stimulated it. But exacts for 12, 24 hours had not effects on the proliferation of S. mutans. 2. 1/4 concentration of elutes for 10 minutes inhibited growth of S. sobrinus, whereas extracts for 1, 12, 24 hours had not effects on the proliferation of S. sobrinuss. 3. Extracts from composite resin stimulated total growth of S. mutans more than growth control group, where as inhibited it of S. sobrinus. 4. Extracts from composite resin, especially 1/4 concentration of it for 10 minutes increased the formation of water insoluble glucan of S. mutans. But elutes for 1, 12, 24 hours, and 1/8 concentration of it for 10 minutes inhibited it. 5. Except 1/4 concentration of elutes for 10 minutes, extracts decreased the formation of water insoluble glucan of S. sobrinus. 6. Total amount of formated glucan was 3-fold higher in S. mutans than in S. sobrinus.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.2
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• pp.135-138
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• 2019

The aim of this study was to investigate the susceptibility of Mutans streptococci in both planktonic and biofilm states to erythrosine. S. mutans was cultured in brain-heart infusion (BHI) broth. Erythrosine was diluted in BHI broth and prepared at a concentration range of $0.02-10000{\mu}g/L$. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were measured using the microdilution method. After forming biofilms on 96-well plates, the minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC) were measured. S. mutans was susceptible to erythrosine in both planktonic and biofilm states. MIC and MBC values were both $19.5{\mu}g/L$ for the planktonic state, while MBIC and MBEC values were $313{\mu}g/L$ and $2500{\mu}g/L$, respectively, for the biofilm state. Erythrosine ($19.5{\mu}g/L$) exhibited a bactericidal effect on S. mutans (killing 99.9%) in the planktonic state. For biofilms, erythrosine inhibited biofilm growth and eradicated 99.9% of biofilm bacteria at higher concentrations than MIC and MBC. These MBIC and MBEC concentrations are much lower than known noxious doses, and the MIC, MBC, and MBIC values were even lower than clinical concentrations.

• Restorative Dentistry and Endodontics
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• v.34 no.5
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• pp.390-396
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• 2009

The aim of this study was to evaluate endodontic irrigation methods with $EndoVac^{(R)}$ and $EndoActivator^{(R)}$ in the elimination of Enterococcus faecalis from the root canals. Extracted 70 human single-rooted teeth were used. The canals were instrumented by a crown-down technique with .04 taper ProFile to ISO size 40. After the teeth were autoclaved, the canals were inoculated with E. faecalis and incubated for 48 h. The teeth were randomly divided into three experimental groups of 20 teeth each according to canal irrigation methods and two control groups as follows: group 1 - $EndoVac^{(R)}$; group 2 - $EndoActivator^{(R)}$; group 3-Conventional needle irrigation method. After canal irrigation using 2.5% NaOCl. first samples (S1) were taken using sterile paper point. And the canals were filled with sterile brain heart infusion (BHI) broth and incubated for 24 h, then second samples (S2) were taken. The samples were cultured on BHI agar plate to determine the numbers of colony forming units (CFU). In first sampling (S1), only one canal of conventional method among the all experimental groups was positive cultured. In second sampling (S2), $EndoVac^{(R)}$ group showed the least positive culture numbers of E. faecalis. There was statistically significant difference between the $EndoVac^{(R)}$ and conventional needle irrigation methods in the mean value of Log CFU. According to the results of this study, $EndoVac^{(R)}$ showed better efficacy than conventional needle irrigation method in the elimination of E. faecalis from the root canal.