• International Journal of Oral Biology
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• v.38 no.2
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• pp.51-54
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• 2013

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the important causative microbes for nosocomial infection and has been isolated from the dental environment. The purpose of this study was to investigate the antimicrobial activity of linalool and ${\alpha}$-terpineol against MRSA isolates from a Korean population. In the experiments, we determined the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of these two compounds against 18 strains of MRSA. The data revealed that the $MIC_{90}/MBC_{90}$ values of linalool and ${\alpha}$-terpineol against MRSA were >12.8 mg/ml and 6.4 mg/ml, respectively. These results indicate that ${\alpha}$-terpineol has more potent antimicrobial activity against MRSA than linalool and may have utility as an anti-MRSA cleansing agent for dental instruments and dental unit chairs.

• International Journal of Oral Biology
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• v.38 no.1
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• pp.1-4
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• 2013

Staphylococcus species are one of prevalent pathogens found in hospitals. Microbes that are a primary cause of nosocomial infection were isolated from a dental and medical environment it may assist the reader to explain what this is and how it differs from the 'dental health care providers and ward health care providers'. To investigate the distribution of staphylococcus species in this environment, we used vitek II to measure drug sensitivity, and further performed biochemical testing. The isolation rate of staphylococcus species from the dental and medical environment was 100% but from dental health care providers and ward health care providers were 44.4% and 33.3%, respectively. In the analyses, staphylococcus species showed resistance to diffusion of cefoxitin and oxacillin discs. These staphylococci may be sufficiently positive for the mecA gene. Our results suggest that staphylococci might be an important cause of nosocomial infection in the dental clinic.

• International Journal of Oral Biology
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• v.39 no.4
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• pp.169-176
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• 2014

A positional scanning synthetic peptide combinatorial library (PS-SCL) was screened in order to identify antimicrobial peptides against the cariogenic oral bacteria, Streptococcus mutans. Activity against Streptococcus gordonii and Aggregatibacter actinomycetemcomitans was also examined. The library was comprised of six sub-libraries with the format $O_{(1-6)}XXXXX-NH_2$, where O represents one of 19 amino acids (excluding cysteine) and X represents equimolar mixture of these. Each sub-library was tested for antimicrobial activity against S. mutans and evaluated for antimicrobial activity against S. gordonii and A. actinomycetemcomitans. The effect of peptides was observed using transmission electron microscopy (TEM). Two semi-mixture peptides, RXXXXN-$NH_2$ (pep-1) and WXXXXN-$NH_2$ (pep-2), and one positioned peptide, RRRWRN-$NH_2$ (pep-3), were identified. Pep-1 and pep-2 showed significant antimicrobial activity against Gram positive bacteria (S. mutans and S. gordonii), but not against Gram negative bacteria (A. actinomycetemcomitans). However, pep-3 showed very low antimicrobial activity against all three bacteria. Pep-3 did not form an amphiphilic ${\alpha}$-helix, which is a required structure for most antimicrobial peptides. Pep-1 and pep-2 were able to disrupt the membrane of S. mutans. Small libraries of biochemically-constrained peptides can be used to generate antimicrobial peptides against S. mutans and other oral microbes. Peptides derived from such libraries may be candidate antimicrobial agents for the treatment of oral microorganisms.

• International Journal of Oral Biology
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• v.46 no.3
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• pp.146-153
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• 2021

Accurate identification of microbes facilitates the prediction, prevention, and treatment of human diseases. To increase the accuracy of microbiome data analysis, a long region of the 16S rRNA is commonly sequenced via paired-end sequencing. In paired-end sequencing, a sufficient length of overlapping region is required for effective joining of the reads, and high-quality sequencing reads are needed at the overlapping region. Trimming sequences at the reads distal to a point where sequencing quality drops below a specific threshold enhance the joining process. In this study, we examined the effect of trimming conditions on the number of reads that remained after quality control and chimera removal in the Illumina paired-end reads of the V3-V4 hypervariable region. We also examined the alpha diversity and taxa assigned by each trimming condition. Optimum quality trimming increased the number of good reads and assigned more number of operational taxonomy units. The pre-analysis trimming step has a great influence on further microbiome analysis, and optimized trimming conditions should be applied for Divisive Amplicon Denoising Algorithm 2 analysis in QIIME2 platform.

• Journal of Periodontal and Implant Science
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• v.43 no.1
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• pp.3-11
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• 2013

Periodontitis is a chronic inflammation of periodontal tissue caused by subgingival plaque-associated bacteria. Periodontitis has long been understood to be the result of an excessive host response to plaque bacteria. In addition, periodontal pathogens have been regarded as the causative agents that induce a hyperinflammatory response from the host. In this brief review, host-microbe interaction of nonperiodontopathic versus periodontopathic bacteria with innate immune components encountered in the gingival sulcus will be described. In particular, we will describe the susceptibility of these microbes to antimicrobial peptides (AMPs) and phagocytosis by neutrophils, the induction of tissue-destructive mediators from neutrophils, the induction of AMPs and interleukin (IL)-8 from gingival epithelial cells, and the pattern recognition receptors that mediate the regulation of AMPs and IL-8 in gingival epithelial cells. This review indicates that true periodontal pathogens are poor activators/suppressors of a host immune response, and they evade host defense mechanisms.

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.109-115
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• 2019

This study was conducted to identify the relationship among the cognitive function of the elderly with dementia in the nursing home and the oral health condition and pathogenic microorganisms in the mouth. Data was collected for a month in February 2019 for 30 people through a non-probable sampling method due to the special nature of dementia elderly people aged 70 years or older, living in nursing homes in Daegu. Technical statistics, ANOVA, and Pearson's correlation coefficient were analyzed using the SPSS window ver. 21.0 program. According to the study, the lower the rating of long - term care classification in nursing homes, the more the number of high-risk oral pathogens, and the more the number of existing permanent teeth, the more the number of microbes in the mouth. However, there was no significant difference in cognitive function. Therefore, it is suggested that oral health care, an elderly dementia people in nursing homes, should have different management methods depending on the oral environment, and also professional managers should be able to manage oral health condition for actual care.

• Journal of Environmental Health Sciences
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• v.33 no.2 s.95
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• pp.137-144
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• 2007

Yam, Prunella was stepwise extracted with hexane, chloroform, ethyl acetate, butanol, and water. Anti-microbial activity of each extract was investigated. Hexane extract was tested for anti-microbial effect on Streptocaccus mutans, one of causative factor of dental caries. Methanol extracts of 7 plants were investigated to anti-microbial effects on S. mutans KCTC 5316, P. gingivalis KCTC 5352, S. aureus KCTC 1927 by means of agar diffusion method. Methanol extract of Yam and Prunella revealed anti-microbial activity against S. mutans, P. gingivalis, and S. aureus. Also, hexane fraction of Yam revealed anti-microbial activity against S. mutans. In sequence of hexane, chloroform, ethylacetate, butanol fraction by Prunelia acted as potent anti-microbial agent on P. gingivalis. The measured MIC of hexane fraction of Yam and Prunella on S. mutans KCTC 5316 strain was 0.25 mg/ml and 0.5 mg/ml and the MIC of hexane fraction of Prunella on S. aureus was 0.5 mg/ml. The hexane fraction of Yam and Prunella suppressed viable ceil counts(VCC) of S. mutans, especially after 24 hrs. The Prunella hexane fraction suppressed VCC of S. aureus, after 12 and 24 hrs. Tested concentrations were 0.1, 0.25 and 0.5 mg/ml. the results were compared with control (0 mg/ml). The pH of S. mutans media and GTase activity were determined to evaluate the anticariogenic activity of Yam, Prunella hexane fraction. The pH were increased from 5.6 to 7.0-7.2 in concentration of 2.0 mg/ml. Yam hexane extraction revealed 35% inhibition to GTase activity and Punella inhibited 25% of GTase. These results suggest that the hexane extracts of Yam and prunella have Antibacterial activities against S. mutans, P. gingivalis, S. aureus and have preventive effect on dental caries.

• 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.

• International Journal of Oral Biology
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• v.35 no.4
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• pp.185-190
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• 2010

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most prevalent pathogens in hospitals. To investigate cross contamination by this bacterium in both dental and medical settings, the pathogens that cause acute pyogenic infection and one of the major microbes responsible for nosocomial infection were isolated from health care providers, nurses and patients. We used VITEK II to measure drug sensitivity, and we further performed biochemical testing, coagulase serotype testing and pulse-field gel electrophoresis (PFGE) for isolated MRSA colonies. The isolation rate of Staphylococcus aureus from nasal swabs was 75.0% from dental health care providers and 18.8% from the medical health care providers. A total of 10 MRSA strains were isolated from 40 health care providers and 2 patients and the prevalent coagulase serotype from patients and health care providers was VII. The antimicrobial drug resistance and partial PFGE types of the isolated MRSA strains showed a similar pattern. These results suggest that MRSA may be one of the principal causes of nosocomial infection in dental and medical hospitals.

• The Korean Journal of Pesticide Science
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• v.17 no.3
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• pp.193-199
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• 2013

Burkholderia pyrrocinia CAB08106-4 has an anti-bacterial effect on Garlic White Rot caused by Sclereotium cepivorum and Sclereotium sp.. It is an environmentally friendly microbial product that prevents and controls a variety of phytopathogens involving Garlic White Rot caused by Sclereotium cepivorum and Sclereotium sp.. The aim of this study was to assess and to compare the pathogenicity of Burkholderia pyrrocinia CAB08106-4 by single exposure of rats through several routes such as oral, intranasal and intravenous. For the acute toxicity / pathogenicity study, the animals were sacrificed on days 3, 7, 14 and 21, and macroscopically observed their organs to examine the numbers of internally-retained pesticidal microbes. Clinical examinations were performed daily during administration period, and body weight gain was evaluated. In the study, no clinical sign, weight gain and mortality were observed in relation to the administration of test article. The significant changes of internal/external microbes by test article were not detected. The pathological findings in relation to the administration of the test article in the necropsy were not observed. It could be concluded that the microorganism was not toxic or pathogenic in rats via oral, intranasal and intravenous route.