• Korean Journal of Clinical Laboratory Science
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• v.42 no.2
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• pp.86-91
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• 2010

We evaluated the performance of a novel screening test, PBP2a MRSA rapid kit (Dinona Inc., Iksan, Korea), for methicillin-resistant Staphylococcus aureus (MRSA) based on a immunochromatographic assay. The test is able to detect penicillin-binding protein 2a (PBP2a) using the nasal specimens from health care workers. The nasal specimens were obtained from 69 healthcare workers and were incubated in enrichment broth followed eight hours incubatin in BHI with cefoxitin $4{\mu}g/mL$. These broth were tested by PBP2a Rapid Kit. The enrichment broths were also directly tested for tube coagulase using the conventional identification method. 19 of 22 MRSA showed positive results by PBP2a rapid test and direct coagulase test (the sensitivity for detection of MRSA, 86.36%). While, 8 of 47 non-MRSA showed false positive results for the two tests. All of the 8 non-MRSA which showed false positive were co-colonizing isolates with MRCNS and MSSA. In addition, 46 of 49 methicillin-resistant staphylococci (MRS) showed positive results for PBP2a MRSA rapid kit (the sensitivity for detection of MRS, 93.8%), and all of 20 non-MRS showed negative results (specificity, 100%). The combination of PBP2a MRSA rapid kit and direct coagulase test showed the good sensitivity for detection of MRSA from anterior nares but frequently showed false positive results from the co-colonizing carrier with MRCNS and MSSA.

• Biomedical Science Letters
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• v.11 no.4
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• pp.447-453
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• 2005

A total of 108 strains of MRSA (Methicillin-resistant Staphylococcus aureus) clinical isolates was collected from $121^{st}$ general hospital (U.S. military hospital), Korean healthcare facility from January to March in 2005 and Wonju Christian hospital in 1999. Antimicrobial susceptibility test by Vitek System and MIC test using oxacillin and cephalothin stripes by E-test were executed. PCR based detection of mecA gene was performed on the all of MRSA clinical isolates, too. MRSA clinical isolates were characterized with antimicrobial resistance patterns, PCR based detection of mecA gene and validation of the multiplex PCR strategy of SCCmec among clinical isolates.

• Journal of Korean Medicine Rehabilitation
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• v.23 no.3
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• pp.15-26
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• 2013

Objectives The aim of this study was to investigate antimicrobial activity of Huanggeumjakyak- tang water extract against MRSA. Methods The antibacterial activities of Huanggeumjakyak-tang were evaluated against 3 strains of Methicillin-resistant Staphylococcus aureus (MRSA) and 1 standard Methicillinsusceptible 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 Huanggeumjakyak-tang water extract against S. aureus strains ranged from 1,000 to $2,000{\mu}g/ml$. So we confirmed that it has a strong antibacterial effect. Also the combinations of Huanggeumjakyak-tang water extract and conventional antibiotics exhibited improved inhibition of MRSA with synergy effect. Conclusions The results obtained in this study suggest that Huanggeumjakyak-tang water extract showed antibacterial effect against MRSA, and it also showed reducing effect on the side-effect problems that are the major weak points of traditional antibiotics.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.143-153
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• 2011

Purpose : It is known that carriage rates of Staphylococcus aureus (S. aureus) are highest in newborns and that the asymptomatic carriage of methicillin-resistant Staphylococcus aureus (MRSA) is associated with invasive MRSA infection with the colonizing strain. This study was carried out to investigate the carriage rates of MRSA in neonates with neonatal jaundice. Methods : We reviewed the medical records of 545 neonates admitted with neonatal jaundice to neonatal intensive care units between January 2006 and December 2010. Nasal and inguinal swab specimens had been taken from them and cultured for the isolation of S. aureus. Antimicrobial susceptibility tests had been done for such isolates to determine methicillinresistance. Results : Out of 545 neonates, 318 (58.3%) were colonized with S. aureus and 214 (39.3%) were colonized with MRSA. Results of the antibiogram analysis showed that 65.7% of MRSA isolates were likely to be community-associated (CA) MRSA. Conclusion : Based on the MRSA carriage rate of 39.3%, a surveillance program for MRSA colonization is considered necessary in neonates transferred from other clinics or hospitals. Out of MRSA isolates, 65.7% were likely to be CA-MRSA. This suggests that CA-MRSA strains were already present in obstetric clinic environments where the neonates were born. It is thought that MRSA surveillance programs in these environments are also necessary.

• The Korea Journal of Herbology
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• v.30 no.5
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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.

• Pediatric Infection and Vaccine
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• v.3 no.2
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• pp.133-138
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• 1996

Purpose : In the treatment of MRSA infection, rapid detection of MRSA is extremely important. The mecA gene codes the new drug resistant polypeptides called PBP2' which mediates the clinically relevant resistance to all beta-lactam antibiotics. The identical mecA gene has been found in coagulase-negative staphylococcus with the methicillin-resistant phenotype. On the other hand, the femA gene was absent from coagulase negative staphylococcus strains with the methicillin resistant phenotype. This study is aimed at early detection and definite diagnosis of MRSA. Methods : A total of 24 MRSA strains were studied. All strains were tested for antimicrobial susceptibility and purified DNA. We amplified both mecA and femA genes by PCR in 24 strains. Results : In MRSA all the 16 strains (100%) carried femA gene and 11 strains (68.7%) carried mecA gene. In contrast, in methicillin sensitive staphylococcus all the 8 strains (100%) carried femA and only 3 strains (37.5%) were detected mecA. Conclusions : As results, there are difference in the phenotype and genotype of methicillin resistance by PCR of mecA and femA. Such disparities between methicillin resistance and the presence of mecA gene suggest the presence of control gene of the mecA.

• 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.

• Korean Journal of Veterinary Research
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• v.48 no.1
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• pp.75-81
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• 2008

The rapid evolution of antibiotic resistance in Staphylococcus (S.) aureus is of considerable concern. Methicillin-resistant S. aureus (MRSA) strains are especially one of the greatest public concerns since the treatment of infections is more difficult when encountering resistance. In this study, we conducted a nationwide survey on the antimicrobial resistance of S. aureus isolated from raw meat samples collected from 16 countries, including Korea, and investigated the prevalence of MRSA as a possible source of human infection. Of 1,984 meat samples, S. aureus was isolated from 218 (11.0%) samples consisting of 23 (12.1%) from domestic meat and 195 (10.9%) from imported meat. The isolation rates of poultry meat, pork and beef were 12.8%, 7.0% and 10.0%, respectively. With regard to imported meat, the incidence varied from 4.8% to 16.6% from 13 countries, with the exception of Austria and Poland. In a resistance test to 20 antimicrobial agents, one hundred and eighty-four isolates (84.4%) were resistant to one or more antimicrobial agents tested. Especially, 17 (7.8%), 124 (56.9%) and 28 (12.8%) isolates showed a resistance to 3, 2 and 1 drugs, respectively. One isolate originating from domestic beef was resistant to 7 drugs. Another isolate originating from imported poultry meat showed resistance to oxacillin and methicillin by the disk diffusion test and minimal inhibition concentration methods, but showed negative for detection of the mecA gene.

• Journal of Korean society of Dental Hygiene
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• v.11 no.1
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• pp.29-38
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• 2011

Objectives : The purpose of this study was to survey the awareness of methicillin -resistant Staphylococcus aureus(MRSA) among dental hygiene students in Yeungnam South Korea. Also the knowledge of infection control and infection diseases was surveyed. Methods : The subjects in this study were 213 dental hygiene students in three different colleges in Yeungnam. This study was conducted by using the self-reported questionnaire. Results : In the first, most of the students(86.9%) did not know about MRSA and 85.7% of them got the information in the college. Secondly, the awareness of infectious disease according to infection control education didn't have statistically significant difference(p>0.05). In the third, the infection control attitude level that the gowns should be changed after the treatment of infectious patients was scored lower than the others questions. on the other hand, the level of 'The use of high vacuum suction', 'The change of wet mask', 'The history taking of infectious disease' was scored higher. Finally, the attitude level according to grade and clinical training had statistically significant difference(p<0.05). But the infection control education had not affected significantly(p>0.05). Conclusions : Despite the infection control education and clinical training, the awareness was found insufficient in infectious diseases and MRSA. Therefore, it should be strengthen that the dental hygiene students were more educated about infection control at college course before clinical training, and especially the danger of MRSA was more.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.3
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• pp.202-209
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• 2016

This study is aimed to determine the correlation between the toxin gene types and antibiotic resistance from MRSA (methicillin-resistant Staphylococcus aureus). Fifty-two strains of MRSA, between January 2014, and December 2014, were isolated from clinical specimens obtained from 2,664 cases in the intensive care unit of a hospital in Suncheon, Jeonnam, Korea. Genes encoding mecA, enterotoxin (SE), toxic shock syndrome toxin-1 (TSST-1), exfoliative toxin (ET), and Panton-Valentine leukocidin (PVL) were detected by multiplex PCR-mediated amplification using specific primers. Toxin genes (seg and sei) were present in 40 strains (76.9%), followed by tst in 34 strains (65.4%). Other genes (eta, etb, sea, sed, see, seh, sej, and pvl) were not detected. Forty strains (76.9%) of MRSA had 2 or more toxin genes simultaneously; 5 coexistent toxin-genes (seb, sec, seg, sei, tst) were the most common in 28 strains (53.8%), and 6 strains (11.5%) had seg and sei genes. The coexistence of genes were 72.5~100%, showing a high correlation among genes (seb, sec, seg, sei and tst). As strains (seb, sec, tst) that had particular toxin genes (seb, sec, seg, sei, tst) in multiple showed 100% resistance to ciprofloxacin, clindamycin, erythromycin, we were able to find that seb, sec, and tst genes have a close relationship to the aforementioned antibiotics. It showed a higher resistance to ciprofloxacin, clindamycin, erythromycin, and tetracycline compared with strains that had toxin genes independent from multiple toxin genes.