• Title/Summary/Keyword: 독력인자

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EFFECTS OF SUBINHIBITORY CONCENTRATIONS OF ANTIMICROBIAL AGENTS ON CELL SURFACE PROPERTIES AND VIRULENCE FACTORS OF MUTANS STREPTOCOCCI (아저해농도(亞沮害濃度)의 항균물질이 mutans streptococci의 세포표면성질과 독력인자에 미치는 영향)

  • Kim, Young-Jae;Hahn, Se-Hyun;Lee, Sang-Hoon;Jang, Ki-Taeg;Kim, Chol-Chul
    • Journal of the korean academy of Pediatric Dentistry
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    • v.31 no.4
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    • pp.605-616
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    • 2004
  • Subinhibitory concentrations (sub-MICs) refer to concentrations below minimum inhibitory concentrations (MICs). The antimicrobial agents may be present at relatively high concentration, at least higher than bacterial MIC and thereafter be deserted off a surface and function at sub-MICs, perhaps by interfering with bacterial metabolism. Consequently, the aim of this study was to determine the effects of growth, in the presence of sub-MICs of antimicrobial agents, on the cell surface properties and virulence factors of mutans streptococci and to investigate the efficacy of a chemical approach in vitro. Streptococcus mutans Ingbritt and Streptococcus sobrinus 6715-7 were used. Eight antimicrobial agents (Sanguinaria extract;SG, Chlorhexidine digluconate;CHX, Fluoride;F, Propolis;PP, Hydrogen peroxide;HP, Triclosan;TC, Sodium dodecyl sulfate;SDS Cetylpyridinium chloride; CC) were diluted serially in broth to determine MICs and to compare the growth rate, acid production, hydrophobicity, adhesion activity to saliva coated hydroxyapatite, glucan synthesis and cellular aggregation of experiment groups (in the presence of sub-MICs) with those of control (in the absence of antimicrobial agents). Sub-MICs of antimicrobial agents affected the growth of cells, hydrophobicity, and adhesion of bacteria to saliva coated hydroxyapatite and glucan synthesis. They also resulted in a significant reduction in pH after 12 hours (p<0.05). By cells pretreated with proteinase K, either the aggregation induced by antimicrobial agents was completely inhibited or the aggregation titers were markedly increased. According to the results of the present study, each antimicrobial agent at sub-MICs could affect similar as its known action mechanism and could continually inhibit cariogenic bacteria at such concentrations. Thus, the use of these antimicrobial agents would be one of the effective methods to prevent dental caries.

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Study on Convergence Technique Using the Antimicrobial Resistance and Virulence Genes Analysis in Escherichia coli (대장균의 항균제 내성과 독력 유전자의 분석을 활용한 융합기술연구)

  • Han, Jae-Il;Sung, Hyun-Ho;Park, Chang-Eun
    • Journal of the Korea Convergence Society
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    • v.6 no.5
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    • pp.77-84
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    • 2015
  • This study was conducted to investigate the characteristics of antibiotic resistant E. coli. its antibiotic susceptibility and pathogenicity were analyzed via molecular convergence technique, for the relationship of antibiotic susceptibility and pathogenicity. The 60 isolated strains consisted of ESBL(+)(8) and ESBL(-)(52) strains. The ESBL(+)(8) strains consisted of 2 strains without a pathogenic gene, stb(3), flich7(1), and flich7-eae(2). The ESBL(-)(52) strains consisted of 26 strains without a pathogenic gene, stx1(3), stb(10), flich7(2), eae(2), stx1-flich7(2), stx1-stb(4), flich7-stb(2), and flich7-stb-eae(1). In conclusion, antibiotic resistance is increasingly, Focused on molecular convergence, showed the correlation of pathogenicity with antibiotic resistance was poor. However, It will be able to find the exact pathogenic factor in the future through convergence technique including the analysis of virulence genes.

A STUDY ON THE HEMOLYTIC PROPERTIES OF PREVOTELLA NIGRESCENS (Prevotella nigrescens의 용혈특성에 관한 연구)

  • Kwak, Ju-Seok;Jang, Hoon-Sang;Jang, Seok-Woo;Lee, Su-Jong;Yu, Yong-Wook;Min, Kyung-San
    • Restorative Dentistry and Endodontics
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    • v.30 no.4
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    • pp.335-343
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    • 2005
  • Hemolytic property is a specific feature of bacteria to obtain iron which is essential for its survival in host tissues. Therefore, it is thought to be one of several factors of virulence. The purpose of this study was to investigate the hemolytic properties of Prevotella nigrescens isolated from the teeth diagnosed as pulp necrosis and apical periodontitis under the presence of hemolysin inhibitors such as $NaN_3$ and dithiothreitol. heat, various pH and cultural conditions. The results were as follows; 1. Clinically isolated P. nigrescens strains and standard P. nigrscens ATCC 33563 showed hemolytic activity. 2. P. nigrescens showed higher hemolytic activity against human erythrocytes than sheep or horse erythrocytes. 3. $NaN_3$ and dithiothreitol (DTT) reduced the hemolytic activity of P. nigrescens in a dose dependent manner (p<0.05). 4. Optimal pH for the maximum hemolytic activity of P. nigrescens was 4.0 and the hemolysin was stable under the $50^{\circ}C$, but the hemolytic activity was significantly decreased at $95^{\circ}C$. 5. P. nigrescens cultured in $10\%\;CO_2$ condition showed higher hemolytic activity than the bacteria cultured in the anaerobic condition.

EFFECT OF ROASTED BARLEY TEA ON THE ADHESIVE PROPERTIES ON SALIVA-COATED HYDROXYAPATITE BEADS OF CARIOGENIC MUTANS STREPTOCOCCI (보리차(Hordeum vulgare var, hexastichon)가 수산화인회석에 대한 우식유발성 세균의 부착에 미치는 영향)

  • Kim, Young-Jae;Kim, Chong-Chul;Kim, Kack-Kyun
    • Journal of the korean academy of Pediatric Dentistry
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    • v.29 no.4
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    • pp.618-624
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    • 2002
  • Effect of the roasted barley tea in commercial markets on the adherence to the saliva-coated hydroxyapatite(HA) beads and the cell surface hydrophobicity of Streptococcus mutans and Streptococcus sobrinus as cariogenic microorganism was examined in vitro. Adherence activity and hydrophobicity in bacteria tested in all the barley tea samples decreased and the values were different according to the type of tea and the type of treatment. The inhibition of bacterial adsorption to HA beads suggest that barley tea active molecules as catechins and melanoidins may adsorb to a host surface, preventing the tooth receptor from interacting with any bacterial adhesions. The obtained results showed that the barley tea may inhibit bacterial adherence, the first step of the pathogenesis of dental caries in which these microorganism are involved.

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Comparison of characteristics of xylitol-sensitive and xylitol-resistant Streptococcus mutans by use of various carbohydrates (다양한 탄수화물 분해에 따른 xylitol-sensitive Streptococcus mutans와 xylitol-resistant Streptococcus mutans의 특성 비교)

  • Kim, Ji-Hye;Lee, Young-Eun;Ahn, Sang-Hun;Choi, Youn-Hee;Song, Keun-Bae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.10
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    • pp.4450-4458
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    • 2011
  • The aim of this study was to investigate the capacity of the xylitol-sensitive(Xs) and xylitol-resistant(Xr) S. mutans to induce dental caries in the presence of various carbohydrate. S. mutans KCTC3065 was cultured with 0.4% glucose and 1% xylitol in TYE medium for 30 days at $37^{\circ}C$, 10% $CO_2$ to form Xr S. mutans. Both Xs and Xr strains were cultured in four different carbohydrate environments; 0.5% glucose containing basal culture TYE medium(G-TYE), G-TYE plus 0.5% sucorse, G-TYE plus 0.5% fructose, G-TYE plus 0.5% maltose. Then cell growth, acid production, and extracellular polysaccharides synthesis were analyzed. The final growth level and extracellular polysaccharides contents in the Xr strain were significantly lower than in the Xs strain in all carbohydrates except fructose. While, acid production was no significantly difference between Xs and Xr strain. These results indicate that the virulence of Xr strains is significantly lower than that of Xs strains, which supports Xr strains may be less cariogenic than Xs strains.

Augmented Osteoclastogenesis from Committed Osteoclast Precursors by Periodontopathic Bacteria Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis (치주염 유발 세균 Aggregatibacter actinomycetemcomitans와 Porphyromonas gingivalis에 의한 committed osteoclast precursor 분화 증가)

  • Park, Ok-Jin;Kwon, Yeongkag;Yun, Cheol-Heui;Han, Seung Hyun
    • Microbiology and Biotechnology Letters
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    • v.44 no.4
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    • pp.557-562
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    • 2016
  • Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis are gram-negative bacteria frequently found in lesions from patients with periodontitis manifesting alveolar bone loss. Lipopolysaccharides are a major virulence factor of gram-negative bacteria. Bone resorption is known to be regulated by bacteria and their virulence factors. In the present study, we investigated the effects of A. actinomycetemcomitans and P. gingivalis on bone resorption. Heat-killed A. actinomycetemcomitans (HKAa) and heatkilled P. gingivalis (HKPg) induced bone loss in the femurs of mice after intraperitoneal administration. HKAa and HKPg augmented the differentiation of committed osteoclast precursors into osteoclasts, while they inhibited the differentiation of bone marrow-derived macrophages into osteoclasts. Concordant with the effects of the heat-killed whole cells, LPS purified from A. actinomycetemcomitans and P. gingivalis also augmented osteoclast differentiation from committed osteoclast precursors but attenuated it from bone marrow-derived macrophages. Taken together, these results suggest that the whole cells and lipopolysaccharides of A. actinomycetemcomitans and P. gingivalis induce the differentiation of committed osteoclast precursors into osteoclasts, potentially contributing to bone resorption in vivo.