• The Korean Journal of Food And Nutrition
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• v.11 no.3
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• pp.340-346
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• 1998

The strain YSK-681 has been selected for antibiotic-producing strain against methicillin resistant Staphylococcus aureus(MRSA) form 1,000 strains of actinomycetes which had been isolated from soil. The strain YSK-681 has been identified on the point of morphological, cultural, physiological and chemical characteristics. Forty-one taxonomic unit characters were tested and the data were analysed numerically using the TAXON program. The isolate was classified into the major cluster 29 of Streptomyces and best-matched to Streptomyces lydicus. Therefore, it was concluded that the isolate was identified to be Streptomyces lydicus.

• The Journal of the Korean Society for Microbiology
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• v.35 no.3
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• pp.215-224
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• 2000

In this study, the distribution of the mec regulator genes and the presence of the mutation in mecI gene and mec promoter region among 50 MRSA clinical isolates derived from a single university hospital in Korea were analyzed. Among 50 MRSA strains, 13 strains had a deletion of mecI gene, and 37 strains were found to have mutations in mecI gene or mecA promoter region corresponding to a presumptive operator of mecA, i.e., the binding site of the repressor protein. Furthermore, in order to track the evolution of methicillin-resistant Staphylococcus aureus (MRSA) distributed in Korea, we determined the MRSA clonotype by combined use of genetic organization patterns of mec regulator genes, ribotype, and coagulase type. As the result, 48 of 50 MRSA strains could be classified into four distinct clones. Clonotype I is characterized by the coagulase type 3, deletion of mecI gene, and ribotype 1 shared by NCTC10442, the first reported MRSA isolate in England (9 strains). Clonotype II is characterized by the coagulase type 4, C to T substitution at position 202 of mecI gene, and ribotypes 2, 3 and 4 shared by 85/3619 strain isolated in Austria (10 strains). Clonotype III is characterized by the coagulase type 2, mutations of mecA promoter region and/or mecI, and ribotypes 4, 5, and 6 shared by N315 strain isolated in Japan (25 strains). Clonotype IV is characterized by the coagulase type 4, deletion of mecI gene, and ribotype 7 (4 strains). The clonality of two strains could not be determined due to their undefined ribotype.

• Journal of Environmental Science International
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• v.33 no.3
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• pp.205-215
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• 2024

Antibiotics are substances produced by microorganisms that kill or inhibit and are essential for infectious diseases management. This study aimed to provide basic data for overcoming antibiotic resistance in the marine bacterium LJ-18. The API 20NE and API 50CH kits were used to identify this microorganism. Morphological, physiological, and biochemical properties were investigated using MacFaddin's manuals. Subsequently, isolated LJ-18 was found to belong to a genus of Streptomyces that forms mycelia. LJ-18 also grew well at 28-32℃ on modified Bennett's agar. To isolate and purify the antibacterial compound, LJ-18 culture was divided into ethyl acetate and distilled water fractions. Considerable antimicrobial activity against various pathogenic microorganisms, including methicillin-resistant Staphylococcus aureus (MRSA), was confirmed in the C₁₈ ODS open column fractions. Peak 2 compound was obtained using reversed-phase HPLC. As a result, this compound had a significant antimicrobial activity against various pathogenic microorganisms. In particular, it showed strong activity against MRSA, Mycobacterium smegmatis, Bacillus subtilis, Bacillus cereus, and Staphylococcus aureus.

• Neonatal Medicine
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• v.18 no.2
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• pp.288-292
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• 2011

Purpose: The incidence of methicillin-resistant Staphylococcus aureus (MRSA) infection has increased in children and in neonates, and is particularly associated with frequent use of central venous catheter in very low birth weight (VLBW) infants. It is known that the morbidity and mortality of MRSA infection are low in neonates, as compared with adults. The objective of this study was to examine the difference in clinical characteristics between VLBW infants that survived and those that did not, a catheter-related bloodstream infection (CRBSI) of MRSA. Methods: Thirty-four VLBW infants had laboratory-confirmed bloodstream infection with S. aureus. We examined the incidence, mortality and morbidity of CRBSI, and predictive factors associated with mortality. Results: Twenty-six infants had same pathogen (24 MRSA, 2 Methicillin-sensitive Staphylococcus aureus) in the blood and in the catheter tip. Eight infants (25.8%) died in the CRBSI and they all had MRSA blood infections. Sex ratio, gestational age, duration between blood collection and identification of pathogens, and WBC and platelet count were not significantly different between patients that died from and patients that survived CRBSI of MRSA. C-reactive protein (CRP) was significantly higher in VLBW infants that died. Mean age of onset and hospital day was earlier (9.1${\pm}$6.6 vs. 26.9${\pm}$20.2; P=0.005) and shorter for patients that died (10.1${\pm}$7.0 vs. 73.0${\pm}$32.4; P=0.000). Two survivors had complications of pyogenic arthritis of the lower extremities and soft tissue infection, respectively. Conclusion: Mortality of CRBSI was likely to be high in VLBW infants and might be anticipated by CRP and early onset of disease.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.19 no.3 s.31
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• pp.55-59
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• 2006

Objective : This experimental study was performed to investigate the contents of glucan from mycellium and its activity against methicillin-resistant Staphylococcus(MRSA). Methods : A gel permeation chromatography method was develped for the determination and isolation of glucan in mycellium. Their structures were elucidated using ^1H-NMR$, ^{13}C-NMR$. Also, The antibacterial activity of the glucan against MRSA was estimathed by determining the minimum inhibitory concentration(MIC). Results : The contents of glucan in mycellium was $766{\pm}0.19$ mg/g. Glucan exhibited activity against MRSA, with an MIC values of 4 to 9 mg/mL. Conclusions : These findings suggested that glucan might be useful in controlling MRSA infections.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.4
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• pp.420-426
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• 2017

Methicillin-resistant Staphylococcus (MRS) can be colonized in various body sites and is more frequently isolated in healthcare associated persons. This study aimed to evaluate the contamination rate of MRS in a high school environment, those living with closed life style. Staphylococcus aureus was isolated from only the hands of 2 students among a sample of 28 students, and S. aureus were susceptible to methicillin antibiotics. Coagulase negative Staphylococci (CoNS) were isolated from the hands of 26 students (26/28, 92.9%), and among them, 14 (53.8%) isolates were methicillin-resistant CoNS (MRCoNS). Among the 14 MRCoNS, S. warneri was the most common (8/14, 57%) and susceptible to most $non-{\beta}-lactam$ antibiotics, such as clindamycin, erythromycin, ciprofloxacin, tetracycline, gentamicin, and vancomycin. In a culture of 31 desks, S. aureus was not isolated but CoNS were isolated from 26 desks (26/31, 83.6%), which did not harbor the mecA gene. The other bacteria isolated from the hands and desks were Micrococcus and Bacillus spp. In conclusion, methicillin-resistant S. aureus was not isolated from the hands and desks of high school students. However, the frequency of MRCoNS harboring mecA gene were high in the hands of high school students. Therefore, to prevent and to control the transfer of infection, intensifying preventive education, such as hand washing, and active surveillance systems, such as an investigation of contamination or carrier rate of resistant bacteria are necessary.

• Safe Food
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• v.5 no.1
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• pp.26-35
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• 2010

• 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%).

• Journal of Microbiology and Biotechnology
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• v.31 no.8
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• pp.1060-1068
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• 2021

Community-associated Methicillin-Resistant Staphylococcus aureus (CA-MRSA) is notorious as a leading cause of soft tissue infections. Despite several studies on the Agr regulator, the mechanisms of action of Agr on the virulence factors in different strains are still unknown. To reveal the role of Agr in different CA-MRSA, we investigated the LACΔagr mutant and the MW2Δagr mutant by comparing LAC (USA300), MW2 (USA400), and Δagr mutants. The changes of Δagr mutants in sensitivity to oxacillin and several virulence factors such as biofilm formation, pigmentation, motility, and membrane properties were monitored. LACΔagr and MW2Δagr mutants showed different oxacillin sensitivity and biofilm formation compared to the LAC and MW2 strains. Regardless of the strain, the motility was reduced in Δagr mutants. And there was an increase in the long chain fatty acid in phospholipid fatty acid composition of Δagr mutants. Other properties such as biofilm formation, pigmentation, motility, and membrane properties were different in both Δagr mutants. The Agr regulator may have a common role like the control of motility and straindependent roles such as antibiotic resistance, biofilm formation, change of membrane, and pigment production. It does not seem easy to control all MRSA by targeting the Agr regulator only as it showed strain-dependent behaviors.

• Korean Journal of Microbiology
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• v.40 no.1
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• pp.17-22
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• 2004

Scutellaria baicalensis and Phellodendron amurense, which have been used traditionally in treatment of many kinds of illness including infectious diseases, were extracted with hexane, dichloromethane, methanol and water, respectively and serially. Antimicrobial activities of the extracts were examined by disk diffusion method. Methanol extract from Scutellaria baicalensis revealed high antimicrobial activities against MRSA, Gm-bacteria and Candida albicans, dichloromethnane extract from Phellodendron amurense showed lower activity than the extract of Scutellaria baicalensis. Results suggest that methanol extract from Scutellaria baicalensis could be one of the candidates for new antimicrobial agent against the antibiotic-resistant microorganisms by further steps for the purification, determination of structure and synthesis.