• Korean Journal of Pharmacognosy
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• v.47 no.2
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• pp.122-127
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• 2016

Methicillin-Resistant Staphylococcus aureus(MRSA) is a multidrug-resistant(MDR) strain. (+)-Usnic acid(UA) is uniquely found in lichens, and is especially abundant in genera such as Usnea and Cladonia. UA has antimicrobial activity against human and plant pathogens. Therefore, UA may be a good antibacterial drug candidate for clinical development. In search of a natural products capable of inhibiting this multidrug-resistant bacteria, we have investigated the antimicrobial activity of UA against 17 different strains of the bacterium. In this study, the effects of a combination of UA and permeable agents against MRSA were investigated. For the measurement of cell wall permeability, UA with concentration of Ethylenediaminetetraacetic acid(EDTA) was used. In the other hand, Sodium azide($NaN_3$) was used as inhibitors of ATPase. Against the 17 strains, the minimum inhibitory concentrations(MICs) of UA were in the range of $7.81-31.25{\mu}g/ml$. EDTA or $NaN_3$ cooperation against MRSA showed synergistic activity on cell wall. UA and in combination with EDTA and $NaN_3$ could lead to the development of new combination antibiotics against MRSA infection.

• Pediatric Infection and Vaccine
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• v.26 no.1
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• pp.42-50
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• 2019

Purpose: We investigated the clinical features and epidemiology of staphylococcal scalded skin syndrome (SSSS) from year 2006 to 2015 in Changwon city, Korea. Methods: We reviewed medical records of 69 patients diagnosed with SSSS from year 2006 to 2015. Antibiotic susceptibility testing was performed by agar dilution method. Methicillinresistant Staphylococcus aureus (MRSA) was phenotypically identified by oxacillin susceptibility testing and genotypically confirmed by the existence of the mecA gene. Results: The median age of patients was 2.0 years (range 0.2-6 years). Three (4.3%), 53 (76.8%), and 13 (18.9%) patients showed the generalized type, the intermediate type, and the abortive type, respectively. Patients occurred throughout the year, but most patients occurred between July and October. MRSA was isolated from 54 of the 60 patients regardless of the clinical types. All patients recovered without any complications. Conclusions: There was a constant occurrence of SSSS patients caused by MRSA in Changwon area during 2006 and 2015. It is needed to constantly monitor the occurrence of patients with SSSS.

• Natural Product Sciences
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• v.24 no.4
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• pp.225-228
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• 2018

By activity-guided fractionation, gliotoxin was isolated as an antibacterial metabolite of the fungus Penicillium decumbens which was derived from the jellyfish Nemopilema nomurai. Gliotoxin was further evaluated for antibacterial activity against several piscine and human MDR (multidrug resistance) pathogens. Gliotoxin showed significant antibacterial activity against Gram-positive piscine pathogens such as Streptococcus iniae FP5228, Streptococcus iniae FP3187, Streptococcus parauberis FP3287, Streptococcus parauberis SPOF3K, S. parauberis KSP28, and Lactococcus garvieae FP5245. Gliotoxin showed strong activity especially against S. parauberis SPOF3K and S. iniae FP5228, which are resistant to oxytetracycline. It is noteworthy that gliotoxin effectively suppressed streptococci which are the major pathogens for piscine infection and mortality in aquaculture industry. Gliotoxin also showed strong antibacterial activity against multidrug- resistant human pathogens (MDR) including Enterococcus faecium 5270 and MRSA (methicillin-resistant Staphylococcus aureus) 3089.

• Child Health Nursing Research
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• v.22 no.4
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• pp.379-389
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• 2016

Purpose: A longitudinal study was conducted to explore flora colonization and oral glucose high-risk newborns during the first 7 days after birth. Methods: Oral secretions of hospitalized newborns were obtained for microbial cultures and glucose test at days 1-7 after birth. Results: Among the total 112 newborns, 40% were girls and 73% were premature. Mean gestational age was $34.4{\pm}3.2$ weeks and weight was $2,266{\pm}697.5$ grams. The most common flora included Streptococcus (28.2%), Methicillin-resistant Staphylococcus aureus (MRSA, 10.9%), Staphylococcus (6.0%) and Coagulase-Negative Staphylococcus (CNS, 4.0%). The average oral glucose level was $29.2{\pm}23.0mg/dL{\sim}58.2{\pm}39.5mg/dL$. Newborns with higher oral glucose than serum (crude odds ratio [ORc] =1.75; 95% confidence interval [CI] =1.03-2.97), phototherapy (ORc=3.30; 95% CI=2.29-4.76) and prone position (ORc= 2.04; 95% CI=1.13-3.69) were more likely to be colonized. Having oral tubes (ORc=0.42; 95% CI=0.29-0.59), parental nutrition (ORc=0.21; 95% CI=0.13-0.32) and antibiotics (ORc=0.51; 95% CI=0.36-0.73) had protective effects. For oral glucose statistical significances existed on time effect among newborns with Streptococcus (F=9.78, p=.024), MRSA (F=7.60, p=.037) or CNS (F=11.15, p=.019) and interaction between time and colonization among newborns with all of four flora (F=2.73, p=.029) or colonization with only Staphylococcus (F=2.91, p=.034). Conclusion: High-risk newborns develop flora colonization at an early period of life. Their clinical features were associated with types and time of oral flora colonization. They need close monitoring and multifaceted intervention to improve oral environment and infection control.

• Clinics in Orthopedic Surgery
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• v.10 no.4
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• pp.427-432
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• 2018

Background: The purpose of this study was to evaluate the usefulness of sonication technique for microbiological diagnosis and the sterility of the recycled autoclaved femoral components from infected total knee arthroplasty (TKA) using a sonication method. Methods: Nineteen femoral implants explanted from patients with infected TKA were sterilized with a standard autoclave method. Standard culture of the fluid before and after sonication of the sterilized implants was performed to detect pathogenic microorganisms. Additional experiments were performed to evaluate the sterility of the recycled implant by inducing artificial biofilm formation. Methicillin-resistant Staphylococcus aureus (MRSA) was inoculated into 10 implants and sterilization in a standard autoclave was performed, and then the fluid was cultured before and after sonication. Results: Two of the 19 sterilized implants were positive for growth of bacteria after sonication, whereas no growth was detected in the cultured fluid from the sterilized implants before sonication. The bacteria were Staphylococcus species in all two cases. In one of 10 implants inoculated with MRSA, the culture was positive for growth of bacteria both before and after sonication. However, Staphylococcus epidermidis was cultured from both occasions and thus this implant was thought to be contaminated. Conclusions: We found sonication for identification of pathogens could be helpful, but this finding should be interpreted carefully because of the possibility of contamination. Sterilization of an infected femoral implant with an autoclave method could be a good method for using the temporary articulating antibiotic spacer in two-stage revision arthroplasty.

• Archives of Plastic Surgery
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• v.40 no.5
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• pp.536-541
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• 2013

Background Pathogens in the nasal cavity during nasal surgery could lead to a systemic infectious condition, such as bacteremia, nosocomial infection, or toxic shock syndrome. However, there is no research about the prevalence of nasal carriage in patients with nasal bone fracture. Methods This was a prospective, double-blind, randomized study about the rate of nasal carriage in 200 patients with nasal bone fracture in Korea. Nasal secretions were taken from both the middle nasal meatus and colonized. All analyses were carried out using SPSS software. Results Pathogens were identified in 178 of the 200 cases. Coagulase-negative staphylococci (CNS) were the most cultured bacteria in 127 (66.84%) of the 190 total patients after excluding 10 cases of contaminated samples, and methicillin-resistant coagulase-negative staphylococci (MRCNS) were found in 48 (25.26%). Staphylococcus aureus was the second most identified pathogen, found in 36 (18.95%), followed by 7 cases (3.68%) of methicillin-resistant Staphylococcus aureus (MRSA). The prevalence rate of MRSA in the females was higher than that in the males (RR=4.70; 95% CI, 1.09-20.18), but other demographic factors had no effect on the prevalence rate of MRSA and MRCNS. Conclusions The prevalence rate of these pathogens in patients with nasal bone fracture in Korea was similar to other reports. However, few studies have addressed the prevalence rate of CNS and MRCNS in accordance with risk factors or the change in prevalence according to specific prophylaxis against infectious complications. Additional research is needed on the potential connections between clinical factors and microbiological data.

• Journal of Microbiology and Biotechnology
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• v.32 no.10
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• pp.1284-1291
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• 2022

The rise of methicillin-resistant Staphylococcus aureus (MRSA) has resulted in significant morbidity and mortality, and clinical treatment of MRSA infections has become extremely difficult. Sortase A (SrtA), a virulence determinant that anchors numerous virulence-related proteins to the cell wall, is a prime druggable target against S. aureus infection due to its crucial role in the pathogenicity of S. aureus. Here, we demonstrate that isovitexin, an active ingredient derived from a variety of traditional Chinese medicines, can reversibly inhibit SrtA activity in vitrowith a low dose (IC₅₀=24.72 ㎍/ml). Fluorescence quenching and molecular simulations proved the interaction between isovitexin and SrtA. Subsequent point mutation experiments further confirmed that the critical amino acid positions for SrtA binding to isovitexin were Ala-92, Ile-182, and Trp-197. In addition, isovitexin treatment dramatically reduced S. aureus invasion of A549 cells. This study shows that treatment with isovitexin could alleviate pathological injury and prolong the life span of mice in an S. aureus pneumonia model. According to our research, isovitexin represents a promising lead molecule for the creation of anti-S. aureus medicines or adjuncts.

• Korean Journal of Head & Neck Oncology
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• v.38 no.1
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• pp.59-63
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• 2022

The latissimus dorsi flap has high vascularity and is helpful for the reconstruction of infected areas. Herein, we present a patient with recurrent infections and soft-tissue defects who underwent cranial reconstruction using a free latissimus dorsi flap. The patient had undergone craniectomy and reconstruction using alloplastic bone 18 years previously. A scalp defect accompanied by infection occurred five years ago, and patient underwent reconstruction using a free flap at another hospital; however, the problem persisted. After debridement and bone flap removal, the right latissimus dorsi musculocutaneous flap was elevated, and the thoracodorsal artery and vein were anastomosed end-to-end to the right superficial temporal artery and vein. Methicillin-resistant Staphylococcus aureus was eradicated, and the flap survived. Cranioplasty was performed eight months later, and one year follow-up proceeded without complications. Effective reconstruction and cranioplasty are possible using the free latissimus dorsi musculocutaneous flap, even on scalp with persistent infections and soft-tissue defects.

• Journal of Microbiology and Biotechnology
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• v.25 no.1
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• pp.98-108
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• 2015

Staphylococcus aureus is an important foodborne pathogen that causes diverse diseases ranging from minor infections to life-threatening conditions in humans and animals. To further understand its pathogenesis, the genome of the strain S. aureus FORC_001 was isolated from a contaminated food. Its genome consists of 2,886,017 bp double-stranded DNA with a GC content of 32.8%. It is predicted to contain 2,728 open reading frames, 57 tRNAs, and 6 rRNA operons, including 1 additional 5S rRNA gene. Comparative phylogenetic tree analysis of 40 complete S. aureus genome sequences using average nucleotide identity (ANI) revealed that strain FORC_001 belonged to Group I. The closest phylogenetic match was S. aureus MRSA252, according to a whole-genome ANI (99.87%), suggesting that they might share a common ancestor. Comparative genome analysis of FORC_001 and MRSA252 revealed two non-homologous regions: Regions I and II. The presence of various antibiotic resistance genes, including the SCCmec cluster in Region I of MRSA252, suggests that this strain might have acquired the SCCmec cluster to adapt to specific environments containing methicillin. Region II of both genomes contains prophage regions but their DNA sequence identity is very low, suggesting that the prophages might differ. This is the first report of the complete genome sequence of S. aureus isolated from a real foodborne outbreak in South Korea. This report would be helpful to extend our understanding about the genome, general characteristics, and virulence factors of S. aureus for further studies of pathogenesis, rapid detection, and epidemiological investigation in foodborne outbreak.

• Journal of radiological science and technology
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• v.31 no.3
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• pp.229-237
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• 2008

Purpose : For the number of microbes and the pollution level of bacteriology of IP Cassette and Table by laboratories, after identifying the bacteria before and after using alcohol and tissue including disinfectant and statistically testing, this research was intended to provide the basic data for the prevention and the right disinfection guideline for infection management of hospitals in diagnostic radiology. Subject and Method : The subject of this research was the general room of diagnostic radiology of a university hospital in Daejeon City. The research was conducted from Apr 5 to Apr 12, 2007. The number of microbes and the pollution level of bacteriology of IP Cassette and Table by laboratories were tested before and after using alcohol and tissue for disinfection including disinfectant. In order to collect specimens exactly, they were collected with the nurse who specialized in infection management of the hospital, and statistical processing was done with SPSS V13.0. To compare the results before and after using alcohol and tissue, T-test was implemented, and post-hoc test was conducted. Results : Bacteria were detected in 19 cases of 24 subjects(79.2%), however, they were not detected in 5 cases(20.8%). 7kinds of bacteria were detected as isolated bacteria, of which Methicillin Resistant coagulase-negative Staphylococci(MRCNS) were detected in 15 cases(62.5%), which was most, Methicillin Resistant Staphylococcus Aureus(MRSA) in 6 cases(16.7%), Enterococcus Faecium(EFM) in 5 cases(20.8%), Acinetobacter baumannii(ABA) in 2 cases(8.3%), and Bacillus sp, Coagulase-negative Staphylococci(CNS), and Enterococcus sp(ENT) in 1 case, respectively(4.2%). In all bacteria except ABA, Gram positive bacillia were detected in 30 cases(97%), and Gram negative bacilli were detected only in 1 case(3%). As for the kinds of bacteria and the number of groups before and after using 70% Alcohol by Groups, when the bacteria were identified after disinfecting IP Cassette and Table with 70% Alcohol, all the bacteria became extinct in both IP Cassette and Table Group(100%). As for the kinds and number of bacteria before and after using Tissue Cleaner by Groups, the bacteria in Tissue Cleaner Group became completely extinct only in 10 Groups(71.2%), and in 4 Groups, there was much decrease in bacteria, however, they were still detected. The extinction rate of all the bacteria was 91.5%. That is, though the other bacteria became extinct(100%), that of MRCNS bacteria was lowest(83.6%), followed by MRSA(95%). Conclusion : As a result of comparing the mean of the bacteria which were detected before and after using 70% Alcohol and Tissue Cleaner, there was statistically significant in the significant level of 5% in both of them.