• 대한의생명과학회지
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• 제25권1호
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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.

• Natural Product Sciences
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• 제15권3호
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• pp.130-133
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• 2009

The crude extract of the mycelium of Cladosporium was found to exhibit antimicrobial activity against the Staphylococcus aureus, methicillin-resistant S. aureus, and multidrug-resistant S. aureus. Bioassayguided fractionation of an organic extract led to the isolation of an acetophenone derivative, clavatol (2',4'-dihydroxy-3',5'-dimethylacetophenone) (1), and a benzodiazepine alkaloid, circumdatin A (2). Compound 1 showed moderate antibacterial activity against S. aureus, methicillin-resistant S. aureus, and multidrug-resistant S. aureus with minimum inhibitory concentration (MIC) values of 62.5, 62.5, 31.0 $\mu$g/mL, respectively, but compound 2 was inactive. Compounds 1 and 2 exhibited UV-A protection activity with ED$_{50}$ values of 227.0 and 82.0 $\mu$M, respectively, indicating that they were more potent than the positive control, oxybenzone (ED$_{50}$ 350 $\mu$M), a common sunscreen agent.

• Restorative Dentistry and Endodontics
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• 제32권2호
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• pp.102-110
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• 2007

본 연구는 조선대학교 치과병원의 진료환경 및 진료요원으로부터 기회감염성 병원체로 알려진 methicillin 또는 vancomycin 저항성 황색포도상 구균 (methicillin-or vancomycin-resistant Staphylococcus aureus. MRSA or VRSA)의 존재 여부를 조사하여, 이를 광주지역 개원치과와 비교분석을 통해 현재 조선대학교 치과병원의 MRSA와 VRSA의 오염정도를 파악하고자 하였다. 이를 위해 진료실 환경 및 진료요원으로부터 분리한 S. aureus 균주들의 8종 항생제에 대한 감수성 조사를 시행하고, 기존에 알려진 항생제 내성 유전자 존재 여부를 PCR법을 이용하여 확인하였다. 그 결과, 조선대학교 치과병원의 진료요원에서 채취한 샘플 중 1개 (2.3%), 개원 치과에서는 2명 (10%)의 진료요원의 샘플에서 S. aureus가 분리되었으며, 진료환경에서는 두 곳 모두에서 S. aureus가 검출되지 않았다. 조선대학교 치과병원과 개원치과에서 분리된 S. aureus는 amoxicillin, penicillin G, ciprofloxacin clindamycin, vancomycin에 내성을 보이며 oxacillin, cefuroxime에는 균주에 따라 감수성 또는 내성을 보였다. 조선대학교 치과병원에서 분리된 S. aureus는 erythromycin과 clindamycin에 내성 유전자인 ermA가 존재하였으며, 개원치과에서 분리된 3개의 S. aureus 중 2개에서 penicillin과 oxacillin에 내성 유전자 mecA가 존재하는 것으로 나타났다. Vancomycin 내성 유전자인 vanA, vanB는 어떠한 샘플에서도 검출되지 않았다. 이상의 결과를 종합할 때, 본 연구는 조선대학교 치과병원과 개원치과의 S. aurues분포 및 MRSA 또는 VRSA의 존재여부를 조사하여 MRSA와 VRSA의 확산예방을 위한 치과진료 환경의 개선과 적절한 항생제 사용에 대한 기초 자료를 제공할 것으로 사료된다.

• 성인간호학회지
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• 제27권3호
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• pp.325-336
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• 2015

Purpose: This study was conducted to identify factors influencing compliance of multidrug-resistant organism infection control in intensive care units (ICU) nurses. Methods: Data were collected from 254 ICU nurses who were working at 6 general and advanced general hospitals in D city and G Province. Results: 77.2% and 84.4% of the subjects correctly answered to questions about Methicillin-Resistant Staphylococcus Aureus (MRSA) and Vancomycin-Resistant Enterococcus (VRE), respectively. The scores of MRSA infection control compliance and VRE infection control compliance were 3.41 and 3.43, respectively. The factors influencing MRSA infection control compliance were empowerment, environmental safety recognition, and education satisfaction, which explained 30% of MRSA infection control compliance. The factors significantly related to VRE infection control compliance were empowerment, hospital types, environmental safety recognition, number of education sessions, and neonatal ICU, which explained 37% of VRE infection control compliance. Conclusion: It is necessary to develop efficient educational programs for infection control including educational contents to improve empowerment and environmental safety recognition of nurses. Furthermore, administrative support for those infection control programs is also necessary.

• 미생물학회지
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• 제41권3호
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• pp.183-187
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• 2005

본 연구는 PC방의 세균 오염 실태를 조사하기 위한 목적으로 2004년 7월${\~}$12월까지 서울시내에 있는 PC방(Internet Cafe)들 중에서 34곳을 표본으로 선정하여 연구를 수행하였다. 총 세균수를 측정한 결과, 키보드에서는 $9.0{\times}10^4$ CFU/ml, 마우스에서는 $2{\times}10$ CFU/ml, 그리고 화장실 손잡이에서는 $5{\times}10^3$ CFU/ml의 세균이 검출되었다. 이는 화장실 손잡이보다 키보드와 마우스에서 세균에 대한 오염정도가 더 심한 것을 의미한다. PC방에서 항생제에 대한 내성을 지닌 7개의 균주를 분리해 내었는데, 2개의 균주는 methicillin과 erythromycin에 대한 내성을 나타내었고, 5개의 균주는 gentamicin, ampicllin, cefotaxim, chloramphenicol에 대해서 내성을 나타내었다. 이들 균주들을 동정한 결과, 2 균주는 Staphylococcus aureus로 동정되었고, 4 균주는 Actinobacillus ureae로 동정되었으며. 나머지 1개의 균주는 Pasteurella multocida로 동정되었다. Pasteurella multocida와 Actinobacillus ureae는 잠재적인 병원균으로 이전에 Pasteurella ureae로 알려졌던 Actinobacillus ureae는 인간의 상부 호흡기에 드물게 공생하는 것으로 알려졌으며, Pasteurella multocida는 많은 가축의 비인두강 안에 존재하는 평범한 정상 균총을 구성하는 세균인 것으로 알려졌다. 항생제 내성에 대한 연구 결과 Staphylococcus aureus는 erythromycin과 methicillin의 혼합제에 대해서 $100\;{\mu}g/ml$ 이상의 높은 항생제 내성을 나타내었고, Pasteurella multocida와 Actinobacillus ureae는 gentamicin, ampicillin 에 대하여 $100\;{\mu}g/ml$ 이상의 높은 항생제 내성이 있음을 알 수 있었다.

• 대한의생명과학회지
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• 제26권3호
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• pp.230-237
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• 2020

Staphylococcus aureus (S. aureus) is known as a bacterium that can cause skin infections, respiratory system infections, and sinusitis; however, it can exist as a normal flora rather than a pathogen. Recently, methicillin-resistant S. aureus (MRSA) infections have emerged in the community as a new variant of community-associated (CA)-MRSA. In the present study, S. aureus and MRSA were isolated and cultured by collecting samples from facilities and environments where students and educational personnel have multiple contacts on university campuses; specifically, the nostrils and hands of college students were tested from July to September of 2019. The molecular properties of the isolated MRSA were analyzed, and the one MRSA strain was isolated from the university campuses. One MRSA that was isolated and cultured on campus was the mec complex group A and staphylococcal cassette chromosome (SCC) mec type II, which is a characteristic of healthcare-associated (HA)-MRSA, and SCCmec type V, which is a characteristic of CA-MRSA. This result was similar to other studies wherein the SCCmec type II was detected in SCCmec typing analysis in CA-MRSA. To confirm whether there is a new variant of CA-MRSA in the Republic of Korea, additional follow-up studies on the analysis of virulence factors of MRSA are needed by additionally separating CA-MRSA from the body parts of university students and educational personnel.

• Tuberculosis and Respiratory Diseases
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• 제80권2호
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• pp.201-209
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• 2017

Background: Methicillin-resistant Staphylococcus aureus (MRSA) infection is a severe and life-threatening disease in patients with community-onset (CO) pneumonia. However, the current guidelines lack specificity for a screening test for MRSA infection. Methods: This study was retrospectively conducted in elderly patients aged ${\geq}65years$, who had contracted CO-pneumonia during hospitalization at the Jeju National University Hospital, between January 2012 and December 2014. We analyzed the risk factors of MRSA in these patients and developed a scoring system to predict MRSA infection. Results: A total of 762 patients were enrolled in this study, including 19 (2.4%) with MRSA infection. Healthcare-associated pneumonia (HCAP) showed more frequent MRSA infection compared to community-acquired pneumonia (4.4% vs. 1.5%, respectively; p=0.016). In a multivariate logistic regression analysis, admissions during the influenza season (odds ratio [OR], 2.896; 95% confidence interval [CI], 1.022-8.202; p=0.045), chronic kidney disease (OR, 3.555; 95% CI, 1.157-10.926; p=0.027), and intensive care unit admission (OR, 3.385; 95% CI, 1.035-11.075; p=0.044) were identified as predictive factors for MRSA infection. However, the presence of HCAP was not significantly associated with MRSA infection (OR, 1.991; 95% CI, 0.720-5.505; p=0.185). The scoring system consisted of three variables based on the multivariate analysis, and showed moderately accurate diagnostic prediction (area under curve, 0.790; 95% CI, 0.680-0.899; p<0.001). Conclusion: MRSA infection would be considered in elderly CO-pneumonia patients, with three risk factors identified herein. When managing elderly patients with pneumonia, clinicians might keep in mind that these risk factors are associated with MRSA infection, which may help in selecting appropriate antibiotics.

• 대한본초학회지
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• 제30권5호
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• pp.15-21
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• 2015

Objectives : Methicillin-resistantStaphylococcus aureus(MRSA) is a human pathogen. New antibacterial agents are needed to treat MRSA-related infections. This study investigated the antibacterial activity of EtOH 70% extracts ofTonghyeonipal-dan(THD) which prescription is composed of oriental medicine against MRSA.Methods : The antibacterial activity of THD was evaluated against MRSA strains by using the Disc diffusion method, broth microdilution method, Checkerboard dilution test, and Time-kill test; its mechanism of action was investigated by bacteriolysis, detergent or ATPase inhibitors were used.Results : The minimum inhibitory concentration (MIC) of THD is 1,000~2,000 μg/mL against MRSA. In the checkerboard dilution test, fractional inhibitory concentration index (FICI) of THD in combination with antibiotics indicated synergy or partial synergism againstS. aureus. Furthermore, a time-kill assay showed that the growth of the tasted bacteria was considerably inhibited after 24 h of treatment with the combination of THD with selected antibiotics. For measurement of cell membrane permeability, THD 500 μg/mL along with concentration of Triton X-100 (TX) and Tris-(hydroxymethyl) aminomethane (TRIS) were used. In the other hand, N,N-dicyclohexylcarbodimide (DCCD) and Sodium azide (NaN3) were used as an inhibitor of ATPase. TX, TRIS, DCCD and NaN3 cooperation againstS. aureusshowed synergistic action.Conclusions : Accordingly, antimicrobial activity of THD was affected by cell membrane and inhibitor of ATPase were assessed. These results suggest that THD has antibacterial activity, and that THD extract offers great potential as a natural antibiotic against MRSA.

• Journal of Microbiology and Biotechnology
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• 제19권12호
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• pp.1576-1581
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• 2009

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has led to an urgent need for the discovery and development of new antibacterial agents. As part of an ongoing investigation into the antibacterial properties of natural products, 20-hydroxyecdysone (20E), isolated from the roots of Achyranthes japonica Nakai, was found to be active against MRSA, either alone or in combination with ampicillin (AM) or gentamicin (GM), via checkerboard assay. This study investigated the antibacterial activity of 20E, which exhibited poor antibacterial activity ($MIC=250-500\;{\mu}g/ml$) against MRSA tested. The combined activity of AM or GE plus 20E against MRSA resulted in fractional inhibitory concentractions (FICs) ranging from 4.00 to $0.031\;{\mu}g/ml$, respectively. Meanwhile, the FIC index ranged from 0.16-4.50, indicating a marked synergistic relationship between AM, GE, and 20E against MRSA. Time-kill assays also showed a remarkable decrease between the combination and the more active compound. Therefore, this study demonstrated that AM, GE, and 20E can act synergistically in inhibiting MRSA in vitro.

• Journal of Microbiology and Biotechnology
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• 제26권4호
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• pp.784-789
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• 2016

We evaluated the synergistic antibacterial effect in combination with the chitosan-ferulic acid conjugate (CFA) and β-lactam antibiotics, such as ampicillin, penicillin, and oxacillin, against methicillin-resistant Staphylococcus aureus (MRSA) using fractional inhibitory concentration (FIC) indices. CFA clearly reversed the antibacterial activity of ampicillin, penicillin, and oxacillin against MRSA in the combination mode. Among these antibiotics, the combination of oxacillin-CFA resulted in a ΣFIC_min range of 0.250 and ΣFIC_max of 0.563, suggesting that the oxacillin-CFA combination resulted in an antibacterial synergy effect against MRSA. In addition, we determined that CFA inhibited the mRNA expression of gene mecA and the production of PBP2a, which is a key determinant for β-lactam antibiotic resistance, in a dose-dependent manner. Thus, the results obtained in this study supported the idea on the antibacterial action mechanism that oxacillin will restore the antibacterial activity against MRSA through the suppression of PBP2a production by CFA.