• 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.

• Archives of Aesthetic Plastic Surgery
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• v.23 no.3
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• pp.143-145
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• 2017

Medical leech therapy is a treatment for the venous congestion of tissue flaps, grafts, and replants. We report a case of methicillin-resistant Staphylococcus aureus (MRSA) following leech application at a congested flap after mastectomy. A 45-year-old woman had an invasive ductal carcinoma. Modified radical mastectomy was performed. The chest wall defect was reconstructed with a local rotation flap. On postoperative day (POD) 1, congestion and color change were observed, and 10 medical leeches were applied to the congested area. On POD 4, another 10 medical leeches were applied. On POD 12, wound necrosis progressed and a pus-like discharge appeared. A wound swab culture revealed MRSA. Debridement was carried out on POD 15. From POD 16, vancomycin and piperacillin/tazobactam were injected for 18 days. The wound culture on POD 18 also revealed MRSA. A split-thickness skin graft was performed on POD 28. MRSA has not been clearly identified in the literature as a leech enteric bacterium. Although MRSA may have come from another source, the present case raises the possibility of MRSA infections following leech application at congested flaps. When medical leeches are applied at the congestion site of a flap, an aseptic cradle will be helpful. Vancomycin irrigation may be needed if infection occurs.

• 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.

• Journal of Microbiology and Biotechnology
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• v.34 no.6
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• pp.1322-1327
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• 2024

The accurate and rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) holds significant clinical importance. This work presents a new method for detecting methicillin-resistant Staphylococcus aureus (S. aureus) in clinical samples. The method uses an aptamer-based colorimetric assay that combines a recognizing probe to identify the target and split DNAzyme to amplify the signal, resulting in a highly sensitive and direct analysis of methicillin-resistance. The identification of the PBP2a protein on the membrane of S. aureus in clinical samples leads to the allosterism of the recognizing probe, and thus provides a template for the proximity ligation of split DNAzyme. The proximity ligation of split DNAzyme forms an intact DNAzyme to identify the loop section in the L probe and generates a nicking site to release the loop sequence ("3" and "4" fragments). The "3" and "4" fragments forms an intact sequence to induce the catalytic hairpin assembly, exposing the G-rich section. The released the G-rich sequence of LR probe induces the formation of G-quadruplex-hemin DNAzyme as a colorimetric signal readout. The absorption intensity demonstrated a strong linear association with the logarithm of the S. aureus concentration across a wide range of 5 orders of magnitude dynamic range under the optimized experimental parameters. The limit of detection was calculated to be 23 CFU/ml and the method showed high selectivity for MRSA.

• Journal of Korean Biological Nursing Science
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• v.21 no.4
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• pp.283-291
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• 2019

Purpose: The aim of this study was to identify awareness and competency for Multi-Drug Resistant Organisms (MDRO) infection control in nursing students with experience of clinical practice. Methods: This cross-sectional descriptive study was conducted from March 2019 to May 2019 by including 231 nursing students in four nursing schools located in Seoul, Gyeonggi-do and Chungcheongnam-do. The data were collected using self-report questionnaires. Results: The awareness and the competency for Carbapenem-Resistant Enterobacteriaceae (CRE) infection control were lower than that of Methicillin-Resistant Staphylococcus aureus (MRSA). The agreement between the awareness and the competency of MDRO infection control in participants was low with regard to isolation, contact precautions, and disinfection for MRSA. Also, it was low with respect to disinfection, isolation, contact precautions, and carrier identification for CRE. The awareness and the competency of MDRO infection control exhibited significant positive correlation. Conclusion: The infection control competency is required to prevent MDRO infection. In order to enhance the infection control competency, it is important to raise awareness about MDRO infection control by providing education based on the guidelines and the principles of infection control.

• Journal of the Korea Fashion and Costume Design Association
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• v.23 no.4
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• pp.95-103
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• 2021

This study aims to examine the antibacterial effects of cotton and silk fabrics naturally dyed with Artemisia princeps extract on antibiotic-resistant strains of bacteria. The concentrated natural dye of the Artemisia princeps extract was made at the liquor ratio of 1:10 at 40-60℃ for 60 minutes. The concentration of FeSO4·7H2O, Al2(SO4)3, and CuSO4 5H2O mordant was 3% (owf), and the liquor ratio was 1:20. In order to experiment on the antimicrobial activity of the naturally dyed fabrics, Methicillin-resistant Staphylococcus aureus (MRSA) ATCC 33591, was used by breeding it in Brain Heart Infusion Agar (BHA) containing Oxacillin (2㎍/ml), Fungizone (2.5㎍/ml), and Brain Heart Infusion broth (BHI; Detroit, MI, USA). As a result of examining the bacterial growth reduction rate on dyed cotton and silk fabrics against antibiotic-resistant strains, it was found that the copper mordant in cotton fabric shows the highest antibacterial activity with a bacterial growth reduction rate of 99.9%, and the non-mordant cotton fabric shows the lowest antibacterial activity with a reduction rate of 18.6%. In the case of the naturally dyed silk fabric, it indicates the highest reduction rate of strains in the Al mordanting (94.9%), and Cu mordanting (99.9%).

• Microbiology and Biotechnology Letters
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• v.41 no.3
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• pp.335-340
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• 2013

The antimicrobial effect of the methanol extract of Inula britannica flowers against methicillin resistant Staphylococcus aureus (MRSA) was investigated. It was confirmed that the methanol extract is mainly composed of quercetin, which has antimicrobial properties. The antimicrobial effect of the methanol extract against 3 MRSA strains was determined by the disc diffusion method. The minimal inhibitory concentrations were ranged from 0.625 mg/ml to 1.25 mg/ml, and the minimum bactericidal concentrations were 2.5 mg/ml. Time kill kinetics revealed bactericidal activities, and the morphological alterations in S. aureus ATCC 33591 treated with the extract were observed using a scanning electron microscope. The methanol extract affected the expression of the resistant genes, mecA, mecI, and mecRI in mRNA. Therefore, the methanol extract of I. britannica flowers clearly demonstrated an antimicrobial effect against MRSA and these results suggest a potential for application as a natural antimicrobial agent.

• The Korea Journal of Herbology
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• v.28 no.1
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• pp.59-64
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• 2013

Objectives : Methicillin-Resistant Staphylococcus aureus (MRSA) is a cephalosporin and beta-lactam antibiotic-resistant strains. In most cases, that is spread from infected patients and infection rates are growing increasingly. Thus, accordingly, increased resistance to antibiotics is causing serious problems in the world. Therefore, there is a need to develop alternative antimicrobial drugs for the treatment of infections diseases. Methods : The antibacterial activities of Sinhyowoldosan were evaluated against 3 strains of Methicillin-resistant staphylococcus aureus(MRSA) and 1 standard Methicillin-susceptible S. aureus (MSSA) strain by using the disc diffusion method, minimal inhibitory concentrations (MICs) assay, colorimetric assay using MTT test, checkerboard dilution test and time-kill assay was performed under dark. Results : The MIC (minimum inhibitory concentration) of Sinhyowoldosan water extract against S. aureus strains ranged from 500 to 2,000 ${\mu}g/mL$, so we have confirmed it on a strong antibacterial effect. Also, the combinations of Sinhyowoldosan water extract and conventional antibiotics exhibited improved inhibition of MRSA with synergy effect. We suggest that Sinhyowoldosan water extract against MRSA have antibacterial activity, it has potential as alternatives to antibiotic agent. the combination test was used, Triton X-100 (TX) and DCCD for measurement of membrane permeability and inhibitor of ATPase. As a result, antimicrobial activity of SH is affected by the cell membrane were assessed. Conclusion : We suggest that the Sinhyowoldosan water extract lead the treatment of bacterial infection to solve the resistance and remaining side-effect problems that are the major weak points of traditional antibiotics.

• Microbiology and Biotechnology Letters
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• v.52 no.1
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• pp.97-98
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• 2024

Methicillin-resistant Staphylococcus aureus (MRSA) represents antimicrobial-resistant bacteria that can cause a wide range of illnesses both in humans and animals. Multidrug resistance phenotype is common, especially in healthcare-associated (HA) MRSA strains. Currently, one of the most prevalent HA-MRSA clonal lineages in Korean hospitals is sequence type (ST) 5 carrying staphylococcal cassette chromosome mec type II (ST5-SCCmec II). Here, we report the complete genome sequence of an ST5 HA-MRSA strain (SA492) originated from a patient in Korea.

• Biomedical Science Letters
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• v.11 no.4
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• pp.525-531
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• 2005

Staphylococcus aureus is a major cause of nosocomial infections and is one of the most commonly isolated bacterial species in the hospital and continues to be an important pathogen in both community and hospital-acquired infection. Methicillin resistant S. aureus (MRSA), which is associated with hospitals is now being isolated in the community. The purpose of this study is to investigate the carrier rate of S. aureus in the community, antibiotic resistance patterns of the organism, detection of MRSA and mecA gene in MRSA. Ninety strains $(46.4\%)$ of S. aureus were isolated from the nasal specimens of 194 elementary school students. Eighty-nine strains $(98.9\%)$ of 90 S. aureus were resistant to penicilin, 36 strains $(40.0\%)$ to erythromycin, 14 strains $(15.6\%)$ to fusidic acid, 11 strains $(12.2\%)$ to gentamycin, 9 strains $(10.0\%)$ to tobramycin, 5 strains $(5.6\%)$ to oxacillin, 4 strains $(4.4\%)$ to clindamycin, 2 strains $(2.2\%)$ to tetracycline, 1 strains $(1.1\%)$ to fosfomycin. None of $90(0\%)$ S. aureus isolates was resistant to ciprpfloxacin, trimethoprim/sulfamethoxazole, levofloxacin, linezolid, moxifloxacin, nitrofurantoin, norfloxacin, rifampicin, quinupristin/dalfopristin, teicoplanin, and vancomycin. Five strains $(5.6\%)$ of 90 S. aureus isolates were MRSA. The mecA gene was detected from five MRSA strains by PCR.