• Journal of Microbiology and Biotechnology
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• v.33 no.5
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• pp.698-705
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• 2023

Rapid diagnosis of methicillin-resistant Staphylococcus aureus (MRSA) is essential for guiding clinical treatment and preventing the spread of MRSA infections. Herein, we present a simple and rapid MRSA screening test based on the aggregation effect of mannose-binding lectin (MBL)-conjugated gold nanoparticles (AuNP), called the MRSA probe. Recombinant MBL protein is a member of the lectin family and part of the innate immune system. It can recognize wall teichoic acid (WTA) on the membrane of MRSA more specifically than that of methicillin-sensitive Staphylococcus aureus (MSSA) under optimized salt conditions. Thus, the MRSA probe can selectively bind to MRSA, and the aggregation of the probes on the surface of the target bacteria can be detected and analyzed by the naked eye within 5 min. To demonstrate the suitability of the method for real-world application, we tested 40 clinical S. aureus isolates (including 20 MRSA specimens) and recorded a sensitivity of 100%. In conclusion, the MRSA probe-based screening test with its excellent sensitivity has the potential for successful application in the microbiology laboratory.

• Journal of Environmental Health Sciences
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• v.39 no.5
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• pp.447-455
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• 2013

Objectives: This study aims to understand the concentration, diversity, and antibiotic characteristics of staphylococci present in the indoor air of child-care facilities. Methods: Air sampling was performed from October 2012 to January 2013 in 120 child-care facilities in Seoul, Korea. Methicillin-resistant bacteria were selected from the total obtained airborne bacteria and subjected to 16S rRNA analysis for methicillin-resistant staphylococcal species determination. Identified staphylococcal strains were tested for resistance to a range of antibiotics. Results: Average total airborne bacterial concentration was $508.9{\pm}246.3CFU/m^3$. Indoor concentration of total airborne bacteria had a significant positive correlation with the $CO_2$ concentration in the child-care facilities. Methicillin-resistant staphylococci were present in 13.3% of the child-care facilities studied. A total of four species (S. epidermidis, S. cohnii, S. saprophyticus, S. sp.) and 55 strains were identified from the indoor air of the child-care facilities. Staphylococcus cohnii was the most common species (54.5%), followed by S. epidermidis (38.2%). All of the isolated staphylococcal strains exhibited high resistance to oxacillin, erythromycin, mupirocin, and ceftizoxime. Especially, S. saprophyticus strains showed more multidrug resistance to oxacillin, vancomycin, clindamycin, erythromycin, lincomycin, ceftizoxime, mupirocin, and tetracycline than did other species. Conclusion: The results of this study showed that a monitoring system for multidrug-resistant bacteria is needed in facilities for children, as the community-associated infections of these bacteria are increasing.

• Food Science of Animal Resources
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• v.40 no.3
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• pp.401-414
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• 2020

The emergence and persistence of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in livestock animals have been reported as a potential risk factor for transmission to humans. In this study, we investigated the nationwide prevalence and characteristics of MRSA and MSSA in the Korean beef production system, including retail markets, slaughterhouses, and cattle farms. From a total of 1,285 samples, only 5 MRSA strains were isolated: from a farmer (1 ST72 MRSA), a carcass sample from a slaughterhouse (1 ST72 MRSA), and beef cattle (3 ST5 MRSA). In addition, 11 MSSA strains were isolated from beef cattle (n=3), humans (1 farmer, 1 slaughterhouse worker, and 4 retail market workers), and carcass samples (n=1) and slaughterhouse environment (n=1). Although the prevalence of MRSA and MSSA in beef cattle was much lower than that reported in pigs, 5/5 MRSA and 2/11 MSSA strains displayed multiple drug resistance (MDR) phenotypes. Unlike the swine-associated MRSA, no correlation was found between tetracycline/zinc resistance and MDR phenotype. However, MRSA strains had an identical set of staphylococcal enterotoxins and exhibited enhanced levels of resistance to antimicrobial peptides (PMAP-36 and LL-37) compared to the MSSA strains. In conclusion, continued and systemic surveillance of livestock, meat products, and humans in close contact with livestock/meat products is necessary to prevent the transmission of MRSA and MSSA to humans.

• The Journal of Internal Korean Medicine
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• v.34 no.3
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• pp.278-288
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• 2013

Objectives : Methicillin-resistant Staphylococcus aureus (MRSA) has a cephalosporin and beta-lactam antibiotic-resistant strains. MRSA is one of the major pathogens causing hospital infection and the isolation ratio of MRSA has gradually increased. Consequently, 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 infectious diseases. Methods : The antibacterial activities of Ipyo-san were evaluated against 2 strains of MRSA and 1 standard Methicillin-susceptible staphylococcus aureus (MSSA) strain by using the disc diffusion method, minimal inhibitory concentrations (MIC) assay, colorimetric assay using MTT test, checkerboard dilution test and time-kill assay performed under dark. Results : The MIC of Ipyo-san water extract against S. aureus strains ranged from 1000 to $2,000{\mu}g/ml$, so we confirmed that it had a strong antibacterial effect. Also, the combinations of Ipyo-san water extract and conventional antibiotics exhibited improved inhibition of MRSA with synergy effect. We suggest that Ipyo-san water extract against MRSA has antibacterial activity so it has potential as alternatives to antibiotic agents. For the combination test, we used Triton X-100 (TX) and DCCD for measurement of membrane permeability and inhibitor of ATPase. As a result, antimicrobial activity of Ipyo-san water extract was affected by the cell membrane. Conclusions : We suggest that the Ipyo-san 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.

• Biomedical Science Letters
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• v.25 no.1
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• pp.75-82
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• 2019

We developed the multiplex LAMP assay using 16S rRNA, femA and mecA genes for direct detection of the methicillin resistance in Staphylococci from positive blood culture. To simultaneously recognize Staphylococci genus, S. aureus and methicillin resistance, three sets of six primers for 16S rRNA, femA and mecA were designed, respectively. The performance of LAMP assay was affirmed using VITEK system for the phenotypic methods of identification and for oxacillin and cefoxitin antimicrobial susceptibility. The optimal condition for LAMP assay was obtained under $64^{\circ}C$ for 50 min. The detection limit was determined to be of 20 copies and CFU/reaction ($10^4CFU/mL$). For clinical application of comparison with phenotypic methods, the sensitivity and specificity of the LAMP with femA gene for detecting S. aureus was 95.31% and 100%, respectively. The sensitivity and specificity of the LAMP with mecA gene for detecting methicillin resistance was 98.46% and 100%, respectively. The multiplex LAMP assay with femA and mecA gene successfully detected all of MRSA (38 isolates) isolates from 103 Staphylococci in blood cultures. The LAMP assay developed in this study is sensitive, specific, and of excellent agreement with the phenotypic methods.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.2
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• pp.180-184
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• 2001

MRSI is the staphylococcal infection having resistance to the methicillin which is semisynthetic penicillinase-resistant agents against penicillinase. These infections are very difficult to treat because they have resistance to almost every antibiotics except for vancomycin. We experienced MRSE(methicilline-resistant staphylococcal epidermis) infected 56 years old man who developed 2 months after arthroplasty for TMJ ankylosis and MRSA(methicilline-resistant staphylococcal aureus) infected 59 years old man who was performed arthroplasty far traumatic TMJ disc displacement.

• Fisheries and Aquatic Sciences
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• v.11 no.1
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• pp.1-6
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• 2008

In an effort to discover an alternative therapeutic agent against methicillin-resistant Staphylococcus aureus (MRSA), several medicinal plants and seaweeds were evaluated for its antibacterial activity against MRSA. A methanolic extract of the Phaeophyta Ecklonia stolonifera exhibited significant antibacterial activity against MRSA. To perform more detailed investigation on antibacterial activity, the methanol extract of E. stolonifera was further fractionated with organic solvents such as hexane, dimethylchloride, ethyl acetate, and n-butanol. Among them, the hexane fraction showed the strongest antibacterial activity against MRSA strains with MIC from 500 to $600 {\mu}g/mL$. The fraction also exhibited a bactericidal activity against MRSA, indicating that E. stolonifera contains a bactericidal substance against MRSA.

• Korean Journal of Microbiology
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• v.42 no.1
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• pp.54-58
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• 2006

Dried roots of Paeonia japonica were extracted with dichloromethane, methanol and water aerially. Silica gel column chromatography and thin layer chromatography were used to separate the fractions with antimicrobial activities, and mass spectrometry was used to determine the mass. Dichloromethane extract showed the highest antimicrobial activity. Dichloromethane extract from Paeonia japonica could be a candidate for a new antimicrobial agent against MRSA.

• Biomedical Science Letters
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• v.10 no.4
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• pp.473-477
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• 2004

Methicillin-Resistant Staphylococcus aureus (MRSA) strains are resistant to a wide range of antibiotics and are a major cause of nosocomial infections. Accurate and rapid typing of MRSA is needed to implement effective infection control measures. Arbitrarily Primed PCR (AP-PCR) is a very useful method in rapid typing. AP-PCR is not necessary information about target DNA sequence because this is basically DNA amplification and could be useful in epidemiological typing by classified band pattern. In this study, MRSA were isolated and identified from ICU, Neu, IM and Ped environments and investigated molecular typing by AP-PCR. Ped, the MRSA pattern determines the la, IIa type, 1M is Ib type, Neu is IIa type and ICU determines the IIa, lIb types. All MRSA in this study were typeable by AP-PCR, which was easy to perform and reproduce with evidence of MRSA for purposes of nosocomial infection control.

• Biomedical Science Letters
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• v.16 no.4
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• pp.331-339
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• 2010

This study aims to evaluate the effect of Photodynamic Therapy (PDT) against methicillin-resistant Staphylococcus aureus with high-level mupirocin resistance (Hi-Mup MRSA). To examine the antimicrobial effect of photogem-mediated PDT against Hi-Mup MRSA, CFU quantifications, bacteria cell viability tests, and disk diffusion antimicrobial susceptibility tests were evaluated. In addition, one of PDT mechanisms was investigated by accumulating photogem ($10\;{\mu}g/ml$) in Hi-Mup MRSA. Photogem-mediated PDT properly inhibited the colony formation of Hi-Mup MRSA. Viable bacteria decreased greatly after a PDT application with photogem $10\;{\mu}g/ml$ at energy density $15\;J/cm^2$. The diameter of the inhibition zone around susceptible disks increased after PDT. In addition, we confirmed the accumulation of photogem in bacteria through fluorescent images. These results demonstrated that excellent photosensitization of Hi-Mup MRSA can be achieved using photogem with 630 nm LED irradiation. Thus, PDT may make survival Hi-Mup MRSA inactive.