• Biomedical Science Letters
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• v.13 no.3
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• pp.189-195
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• 2007

This study was carried out to examine antimicrobial substances from medicinal plants, the ethanol extracts of 38 medicinal plants were tested for the antimicrobial activity against Staphylococcus aureus ATCC 25923 and methicillin-resistant Staphylococcus aureus ATCC 43300. The extracts of Glycyrrhiza uralensis, Sophora flavescens, Dryopteris crassirhizoma, and Pinas densiflora showed significant antimicrobial activities against both S. aureus ATCC 25923 and methicillin-resistant S. aureus ATCC 43300. The extract of Dryopteris crassirhizoma among these medical plants showed the highest antimicrobial activity. These results suggested that the extracts from Dryopteris crassirhizoma, Sophora flavescens, Pinas densiflora, and Glycyrrhiza uralensis could be the potential source of antimicrobial agents against methicillin-resistant S. aureus and S. aureus.

• Biomedical Science Letters
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• v.5 no.2
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• pp.135-145
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• 1999

A total of 45 Staphylococcus aureus strains from clinical samples were tested for the biochemical test and antibiotic susceptibility test. Forty-five S. aureus strains were subjected to the molecular epidemiological study by susceptiblity test, antibiogram, bacteriophage typing, polymerase chain reaction and mec-associated hypervariable region gene in order to detect of mecA gene which was one of the structural gene related to antibiotic resistant expression factors. Three of 15 mecA-negative S. aureus isolates were classified as oxacillin resistant despite borderline minimal inhibitory concentration values. Methicillin susceptiblities were completely consistent with PCR results for these strains. On the other hand, 4 of 30 mecA-positive isolates yielded results in the oxacillin and methicillin susceptibility tests which were discrepant from those of PCR analysis. Except for SA6, the methicillin resistant S. aureus strains tested were highly resistant to penicillin, oxacillin, gentamicin, and chloramphenicol. In the phage typing, 27 strains were typable. The Iytic group III was as many as 12 strains, and 7 of 12 were 75/83A/84 type. In the PCR of specific mecA gene probe with chromosomal DNA of 30 methicillin resistant S. aureus, the amplified DNA band of 533 bp was confirmed in 30 strains and not in methicillin sensitive S. aureus. The single amplified band of hypervariable region related to mec was investigated in all of 30 methicillin resistant S. aureus, but in methicillin sensitive S. aureus it was amplified. The size of PCR products was between 200 bp and 600 Up. Four units was directly repeated.

• The Journal of Korean Medicine
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• v.23 no.3
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• pp.223-232
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• 2002

Objectives : Methicillin-resistant Staphylococcus aureus (MRSA) CCARM 3251 and S. aureusKCTC 1928 have been known to be resistant to many kinds of antibiotics. The extract of Glycyrrhizae Radix showed antibacterial activity against MRSA and antibiotics-resistant S. aureus. Methods : We examined the effects of the water-soluble extract and the methanol-soluble extract of Glycyrrhizae Radix on MRSA and antibiotic-resistant S. aureus. The methanolic extract was further fractionated with organic solvents such as hexane, chloroform, and ethyl acetate in that order. Results and Conclusions : The methanol-soluble extract of Glycyrrhizae Radix showed relatively high antibacterial activity against MRSA and antibiotic-resistant S. aureus. However, the water-soluble extract of Glycyrrhizae Radix showed no antibacterial activity against MRSA and antibiotic-resistant S. aureus. Among the fractions tested, the chloroform fraction showed the highest antibacterial activity against MRSA and antibiotic-resistant S. aureus. The methanol-soluble extract of Glycyrrhizae Radix minimal inhibitory concentrations (MICs) against MRSA and antibiotics-resistant S. aureus were $5{\;}mg/m{\ell}$ in both. The methanol-soluble extract of Glycyrrhizae Radix was separated using thin-layer chromatography and detected with UV -detector. Further study should be carried out to identify which effects cell growth inhibition of MRSA and antibiotics-resistant S. aureus.

• Journal of Oral Medicine and Pain
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• v.45 no.1
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• pp.17-21
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• 2020

Osteomyelitis of the jaw infected with Coagulase-Negative Staphylococci (CNS) is rarely reported in the Oral and Maxillofacial Region. Staphylococcus is a part of the normal body flora, but it may be cause severe infections and CNS are often described as the important pathogens in nosocomial infections. Although many studies on prevalence and antibiotics of Staphylococcus aureus have been done, but many of these studies focus only on Methicillin-resistant S. aureus and not on methicillin-resistant coagulase-negative Staphylococci (MRCNS). There was a less study about CNS or MRCNS infections in the Oral and Maxillofacial Region. This report describes a case of a 41-year-old male patient who developed osteomyelitis caused by MRCNS on condyle after open reduction and internal fixation and suggests guideline for the prevention of postoperative infection and appropriate recommendation for treatment and control.

• Journal of Life Science
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• v.9 no.4
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• pp.358-367
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• 1999

Thirty strains of methicillin resistant Staphylococcus aureus were obtained from the clinical isolates. In order to investigate the pursuit of the pathogens of nosocomial infection, these strains were studied for antibiotic sensitivity as well as its resistant pattern. Among the methods of hybridization which directly confirm the specific antibiotic resistant genes by means of the recently developed specific probe DNA, dot blot hybridization and southern blot hybridization were performed and these two methods were compared in their sensitivity and specificity. Strains that is sensitive to cephalothin to the subject of methicillin resistant Staphylococcus aureus were in 43%. Those that are sensitive to cefoperazone and cefuroxime were 26% and 23%, respectively. In case of MIC, MIC50 of cefoperazone was 8 $\mu\textrm{g}$/$m\ell$, and MIC90 was 128 $\mu\textrm{g}$/$m\ell$ to be the lowest. As the results of plasmid DNA electrophoresis, most of methicillin resistant Staphylococcus aureus strains had more than 4 plasmids. These plasmids digested by BamHI, methicillin resistant Staphylococcus aureus is distributed as 10 fragments with the size of 65 kb to 1.5 kb. Dot blot hybridization were performed to examine the existence of mecA gene to show the detection rate of 50%. Southern blot hybridization were done to see if DNA bands which amplify the activity of digoxigenium-labeled probe by PCR were actually PCR products of mecA gene and it showed the detection rate of 53%. It can be concluded that the southern blot hybridization seemed to be better in sensitivity and specificity when it is compared with the results of dot blot hybridization.

• Fashion & Textile Research Journal
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• v.19 no.3
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• pp.331-336
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• 2017

Bacteria exist everywhere and continuously come into contact with daily surroundings and humans. Super bacterium methicillin-resistant Staphylococcus aureus, resistant to methicillin, has recently appeared. The morbidity and rate of death associated with super bacteria infection has increased. This study investigated the antibacterial activity of fabrics naturally dyed with Chamaecyparis obtusa leaves extract against methicillin-resistant Staphylococcus aureus. Fabrics were left for 15 min in a natural dyeing solution prepared by extraction from C. obtusa leaves using 11.3% (o.w.f) with a fixed liquor ratio of 1:22 at $40^{\circ}C$. The dyeing process was conducted using three different mordants; subsequently, the K/S value of the dyed fabrics increased in the order of None < Cu < Fe < Al. The color fastness property of the fabrics to washing, dry-cleaning, and rubbing was found to be excellent and ranked in the 4-5 grade. The color fastness to light of natural dyeing is low in most cases and has the problem that the dye color soon becomes bleached. Yet, in most cases cloth dyed with retinispora leaves, the color fastnezz to light was good with a third to fourth grade. Non-mordant fabrics, aluminum mordants, and copper mordants also showed better antibacterial properties (99.9% reduction) against methicillin-resistant Staphylococcus aureus, compared to the control fabrics. The dyed fabrics showed the same antibacterial activity even after three washes. The results highlight the strong potential of fabrics naturally dyed with C. obtusa-extract as a medicinal material with excellent antibacterial function against methicillin-resistant Staphylococcus aureus.

• Journal of Marine Bioscience and Biotechnology
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• v.9 no.2
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• pp.49-57
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• 2017

We isolated marine bacterium, isolate DG-2 which produces the antibiotics against MRSA (methicillin-resistant Staphylococcus aureus). This isolate DG-2 was examined by its morphological, biochemical properties, and 16S rRNA sequencing analysis. And then, isolate DG-2 was identified to the genus Streptomyces. Therefore, this isolate was designated as Streptomyces sp. DG-2. Streptomyces sp. DG-2 grew relatively well at $25^{\circ}C$, pH 7.0, and NaCl 1.0%. For the pre-purification of the bioactive compounds, DG-2 was fermented in 30 L PPES-II medium, and the culture filtrates of DG-2 was extracted by ethyl acetate. The ethyl acetate extract of DG-2 showed the significant anti-MRSA and antibacterial activities.

• Korean Journal of Plant Resources
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• v.31 no.6
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• pp.719-724
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• 2018

Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterium responsible for a number of infections in humans that are difficult to treat, and as a result, is a substantial contributor to morbidity and mortality. In the present study, in search of natural products capable of inhibiting this multidrug-resistant bacterium, we investigated the antimicrobial activity of Lysimachia clethroides Duby root. The antibacterial activities of EtOH extract of Lysimachia clethroides Duby root and its n-hexane, EtOAc, n-BuOH and water fractions were evaluated against 15 strains of methicillin-resistant staphylococcus aureus (MRSA) and 1 standard methicillin-susceptible S. aureus (MSSA) strain by using the minimal inhibitory concentrations (MICs) assay, colorimetric assay using MTT test, checkerboard dilution test. Antimicrobial activity of n-hexane fraction of Lysimachia clethroides Duby root was remarkable. Against the 16 strains, the minimum inhibitory concentrations (MICs) were in the range of $31.25-62.5{\mu}g/ml$ and FICI values for n-hexane fraction of Lysimachia clethroides Duby root+AM and n-hexane fraction of Lysimachia clethroides Duby root+OX were checkerboard method performed using the MRSA, MSSA and one clinical isolate strains via MICI 0.12-1 and 0.25-0.75, showing the increase of synergistic effect. When combined together, these antibiotic effects were dramatically increased. These effective combinations could be new promising agents in the management of MRSA.

• Microbiology and Biotechnology Letters
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• v.50 no.2
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• pp.193-201
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• 2022

Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) are major causes of hospital- and community-acquired infections. The treatment of biofilm-related infections caused by these bacteria is a global healthcare challenge. Therefore, the development of alternative therapeutics is required. An essential oil extracted from Curcuma zedoaria (CZ) Rosc, also known as white turmeric, has been reported to possess various antimicrobial activities. In the present study, we evaluated the antibiofilm activities of an ethanolic extract of the CZ rhizome against MRSA and MSSA. The results showed that the CZ extract with the highest sub-minimum inhibitory concentration (sub-MIC), 1/2 MIC (0.312 mg/ml), significantly inhibited biofilm production by up to 80-90% in both tested strains. Subsequently, we evaluated the ability of the CZ extract to prevent cell-surface attachment to a 96-well plate and extracellular DNA (eDNA) release from the biofilm. The CZ extract demonstrated an inhibitory effect on bacterial attachment and eDNA release from the biofilm biomass. The CZ extract may inhibit biofilm formation by preventing eDNA release and cell-surface attachment. Therefore, this CZ extract is a potential candidate for the development of alternative treatments for biofilm-associated MRSA and MSSA infections.

• Journal of Microbiology and Biotechnology
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• v.32 no.10
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• pp.1284-1291
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• 2022

The rise of methicillin-resistant Staphylococcus aureus (MRSA) has resulted in significant morbidity and mortality, and clinical treatment of MRSA infections has become extremely difficult. Sortase A (SrtA), a virulence determinant that anchors numerous virulence-related proteins to the cell wall, is a prime druggable target against S. aureus infection due to its crucial role in the pathogenicity of S. aureus. Here, we demonstrate that isovitexin, an active ingredient derived from a variety of traditional Chinese medicines, can reversibly inhibit SrtA activity in vitrowith a low dose (IC₅₀=24.72 ㎍/ml). Fluorescence quenching and molecular simulations proved the interaction between isovitexin and SrtA. Subsequent point mutation experiments further confirmed that the critical amino acid positions for SrtA binding to isovitexin were Ala-92, Ile-182, and Trp-197. In addition, isovitexin treatment dramatically reduced S. aureus invasion of A549 cells. This study shows that treatment with isovitexin could alleviate pathological injury and prolong the life span of mice in an S. aureus pneumonia model. According to our research, isovitexin represents a promising lead molecule for the creation of anti-S. aureus medicines or adjuncts.