• 한국축산식품학회지
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• 제40권3호
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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.

• Journal of Microbiology and Biotechnology
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• 제24권8호
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• pp.1059-1064
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• 2014

Staphylococcus aureus is a major human pathogen, implicated in both community and hospital acquired infections. The therapy for methicillin-resistant Staphylococcus aureus (MRSA) infections is becoming more difficult because of multidrug resistance and strong biofilm-forming properties. Schiff bases have attracted attention as promising antibacterial agents. In this study, we investigated the in vitro activity of taurine-5-bromosalicylaldehyde Schiff base (TBSSB) against MRSA. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) were determined using a microtiter broth dilution method. TBSSB effectively inhibited planktonic MRSA, with an MIC of $32{\mu}g/ml$. The time-kill curve confirmed that TBSSB exhibited bactericidal activity against MRSA. TBSSB was also found to significantly inhibit MRSA biofilm formation at 24 h, especially at $1{\times}MIC$ and sub-MIC levels. Furthermore, scanning electron microscopy and transmission electron microscopy showed remarkable morphological and ultrastructural changes on the MRSA cell surface, due to exposure to TBSSB. This study indicated that TBSSB may be an effective bactericidal agent against MRSA.

• 한국자원식물학회지
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• 제29권6호
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• pp.699-703
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• 2016

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious clinical and an urgent problem worldwide. Few new drugs are available against MRSA, because MRSA has the ability to acquire resistance to most antibiotics, which consequently increases the cost of medication. In the present study, the antibacterial activity of Hydnocarpi Semen was investigated. The most effective method is to develop antibiotics from the natural products without having any toxic or side effects. Therefore, there is a need to develop alternative antibacterial drugs for the treatment of infectious diseases. Five Clinical isolates (MRSA) were obtained from five different patients at Wonkwang University Hospital (Iksan, South Korea). The Other 2 strains were ATCC 33591 (Methicillin-resistant strain) and ATCC 25923 (Methicillin-susceptible strain). Antibacterial activity (Minimal Inhibitory Concentrations, MICs) was determined by broth dilution method, disk diffusion method, MTT test, and checkerboard dilution test. Antibacterial activity of n-hexane fraction was remarkable, and had a MICs ranging from $31.25-125{\mu}g/m{\ell}$. FICI values for HFH+AM and HFH+OX were 0.13-0.19 and 0.04-0.29, showing the increase of synergistic effect. When combined together, these antibacterial effects were dramatically increased.

• 미생물학회지
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• 제42권1호
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• pp.54-58
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• 2006

항생제 내성균에 대처 할 수 있는 새로운 항생제의 개발에는 많은 시간과 인력 및 개발비가마 필요하며 새로운 항생제들이 생산되어도 균들은 빠르면 수개월내에 내성을 획득한다. 이 문제의 해결방법의 하나로 전통적으로 감염질환의 치료에 사용되어온 백작약 추출물의 methicillin-resistant Staphylococcus aureus(MRSA)에 대한 항균활성 보유여부를 조사한 결과 백작약의 dichloromethane 추출물이 MRSA에 대하여 높은 항균활성을 나타내어 앞으로 새로운 항균재로서의 개발 및 사용 가능성이 있을 것으로 판단된다.

• 대한임상검사과학회지
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• 제44권3호
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• pp.118-123
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• 2012

Nosocomial infection and community-acquired infection with Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), has become a strong concern in human body sites and related effects. The aim of this study is investigate the isolation rate of MRSA from nasal cavity inferior regions and cellular phones to assess the risk factor of nosocomial infection and community-acquired infection. 34.7% and 37.2% isolates were MRSA from the nasal cavity inferior regions and cellular phones according to a Mannitol salt agar (added oxacillin $6{\mu}g/mL$) culture and PCR according to S. aureus specific 16S rRNA and mecA primers. Thus, the distribution of S. aureus and the isolation rate of MRSA represent a very high risk factor regards nosocomial infection and community-acquired infection.

• 한국축산식품학회지
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• 제40권5호
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• pp.758-771
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• 2020

This study was to investigate the prevalence and characteristics of antimicrobial-resistant Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) from 4,264 retail meat samples including beef, pork, and chicken in Korea between 2013 and 2018. A broth microdilution antimicrobial susceptibility testing was performed for S. aureus. Molecular typing by multilocus sequence typing (MLST), spa typing, and pulsed-field gel electrophoresis (PFGE), was performed on mecA-positive S. aureus strain. S. aureus was isolated at a rate of 18.2% (777/4,264), of which MRSA comprised 0.7% (29 strains). MLST analysis showed that 11 out of the 29 MRSA isolates were predominantly sequence type (ST) 398 (37.9%). In addition, ST72, ST692, ST188, ST9, and ST630 were identified in the MRSA isolates. The spa typing results were classified into 11 types and showed a high correlation with MLST. The antimicrobial resistance assays revealed that MRSA showed 100% resistance to cefoxitin and penicillin. In addition, resistance to tetracycline (62.1%), clindamycin (55.2%), and erythromycin (55.2%) was relatively high; 27 of the 29 MRSA isolates exhibited multidrug resistance. PFGE analysis of the 18 strains excluding the 11 ST398 strains exhibited a maximum of 100% homology and a minimum of 64.0% homology. Among these, three pairs of isolates showed 100% homology in PFGE; these results were consistent with the MLST and spa typing results. Identification of MRSA at the final consumption stage has potential risks, suggesting that continuous monitoring of retail meat products is required.

• 동의생리병리학회지
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• 제26권6호
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• pp.886-893
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• 2012

Methicillin-Resistant Staphylococcus aureus (MRSA) is a cephalosporin and beta-lactam antibiotic-resistant strain. In most cases, MRSA is spread from infected patients and infection rates are growing increasingly. Furthermore, increased resistance to antibiotics is causing serious problems in the world. Staphylococcus aureus is responsible for both nosocomial and community-based infections that range from relatively minor skin and soft tissue infections to life-threatening systemic infections. Therefore, there is a need to develop alternative antimicrobial drugs for the treatment of infectious diseases. In this study, we investigated antimicrobial activity of oriental medicine prescription against MRSA. The minimum inhibitory concentration (MIC) of Sohamhyung-tang water extract against S. aureus strains ranged from 500 to 2,000 ${\mu}g/mL$, so we have it confirmed that a strong antibacterial effect. Also, the combinations of Sohamhyung-tang water extract and conventional antibiotics exhibited improved inhibition of MRSA with synergy effect. We suggest that Sohamhyung-tang water extract against MRSA have antibacterial activity, it has potential as alternatives to antibiotic agent. We suggest that the Sohamhyung-tang 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.

• 대한의생명과학회지
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• 제13권3호
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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.

• 한국미생물·생명공학회지
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• 제50권2호
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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.

• 한국식품영양과학회지
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• 제38권5호
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• pp.541-547
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• 2009

42가지의 천연물 시료 중 세신, 호두(열수), 골쇄보, 뽕잎, 로즈마리에서 S. aureus ATCC 25923 및 MRSA KCCM 40511에 대해 우수한 항균활성을 나타냈다. 이들 시료 중 가장 우수한 항균활성을 가지는 로즈마리를 순차 분획하여 각 분획물을 이용한 MRSA에 대한 항균활성을 알아본 결과 hexane, chloroform 분획물에서 항균활성을 나타냈으며, 각 분획물 중 hexane 분획물이 가장 높은 저해활성을 나타내었다. 또한 SEM을 통한 형태학적 관찰을 통해 분획물 처리 시 MRSA의 세포벽이 파괴되는 것을 확인할 수 있었다. 로즈마리 메탄올추출물 및 hexane 분획물은 MRSA KCCM 40511의 내성 단백질인 MecA와 MecA에 의해 합성되는 세포벽 단백질 penicillinase의 발현을 억제시킴으로써 고도 내성균의 내성을 억제시키는 것으로 나타났다.