• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3315-3322
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• 2015

Staphylococcus aureus is the major causative organism of nasocomial infection being the important pathogen in the clinic. Appearance of staphylococcus aureus resistant to methicillin (MRSA) is becoming a big problem in clinics and dynamics all over the world acquiring antibiotic resistance with virulence factors as its feature differentiated from other pathogenic bacteria fast. This research intended to compare and analyze the correlation of antibiotics resistance between strains with toxin genes and distribution of toxin genes of MRSA 101 strains acquired from clinical specimen in one general hospital (enterotoxin(se), toxic shock syndrome toxin-1(tst), exfoliative toxin(et), Panton Valentine leukocidin(pvl)). seg gene, isolated the most among toxin genes, was detected in 59 strains (58.4%) and more than two toxin genes were detected in 70 strains (69.3%). As a combination possessing toxin genes, it was detected in 19 strains (18.8%) as seb, sec, seg, sei, tst and the second frequent combination was sec, seg, sei shown in 11 strains (10.9%). 19 strains (18.8%) with combinations of toxin genes same with seb, sec, seg, sei, tst had 100% resistance Ampicillin, Benzylpenicillin, Ciprofloxacin, Clindamycin, Gentamicin, Erythromycin, Telithromycin, Tetracycline antibiotics. Strains with many toxin genes showed high correlation of antibiotic resistance. Afterwards, effective therapy and thorough infection management should be preceded not to spread the resistance of MRSA strain.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.50 no.1
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• pp.19-27
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• 2024

This study is to propose Lagerstroemia indica flower as an anti-acne cosmetic material, and confirmed the sebum control, anti-inflammatory, and antioxidant effects using Lagerstroemia indica flower extract (LIFE) . As a result of evaluating the sebum control effectiveness, it was confirmed that LIFE inhibited the production of sebum excessively induced with palmitic acid up to 65%. Subsequently, it was confirmed that LIFE has an antibacterial effect and the ability to inhibit lipase activity against Cutibacterium acnes (C. acnes), which mainly appears in acne lesions, and can also reduce the inflammatory response caused by virulence factors secreted by C. acnes. It was also confirmed that LIFE inhibited the secretion of nitrogen monoxide (NO) and prostaglandin E2 (PGE2), which are inflammatory mediators induced by LPS in macrophages, by 75% and 54%, respectively, and that it also had a high DPPH radical scavenging ability similar to that of ascorbic acid. These results suggest that LIFE, a natural extract, can be used as an anti-acne material to relieve and treat acne, a complex disease, by controlling sebum production and having antibacterial and lipase activity inhibiting against C. acnes, and anti-inflammatory, antioxidant properties.

• Journal of Food Hygiene and Safety
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• v.39 no.3
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• pp.181-190
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• 2024

Bovine mastitis-associated Escherichia coli (BMEC) is considered the main causative agent of significant financial losses in the dairy industry worldwide, as it alters both the quantity and quality of milk produced and increases the rate of culling. This creates a variety of challenges for researchers, veterinarians, and farmers in understanding and determining the most effective therapies and diagnostic techniques. Subclinical mastitis is particularly concerning, as infected bovines exhibit no obvious symptoms and continue to secrete apparently normal milk over an extended period, allowing the causative pathogen, E. coli, to spread within the herd. For effective prevention, understanding the pathogenesis of mastitis through three stages invasion, infection, and inflammation is essential. To date, no clear correlation has been found between virulence factors and pathogenicity contributing to the clinical severity of BMEC. Multidrug-resistant E. coli and the evolution of novel resistance mechanisms have become concerns owing to the extensive use of antibiotics to treat mastitis. Therefore, it is vital to explore alternative controls to enhance the efficacy of BMEC treatment. Over the past 30 years, various genetic typing techniques have been used to examine the subspecies-level epidemiology of bovine mastitis. These studies have advanced our understanding of the origin, transmission pathway, population structure, and evolutionary relatedness of BMEC strains. In this review we provide an overview of BMEC, including insights into its etiology, genetic relationship, pathogenesis, and management of the disease, as well as new therapy options.

• Journal of Periodontal and Implant Science
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• v.26 no.3
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• pp.641-654
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• 1996

In infectious disease, invasion of host tissue by bacteria or their products frequently induces a wide variety of inflammatory and immunopathologic reaction. Evidence indicates that cytokines are involved in the initiation and progression of chronic inflammatory diseases, such as periodontitis. Interleukin-6, which is a multifunctional cytokine, has important roles in acute and chronic inflammation and may also be implicated in bone resorption. Periodontal diseases are characterized by chronic inflammation of the periodontium with alveolar bone resoption. A principal driving force behind this response appears to lie in the immune system's response to bacteria. Many of the cell components which have been shown to function as virulence factors in gram-negative bacteria are associated with the bacterial surface. Of these, lipopolysaccharide has been characterized as one that mediates a number of biological activities which can lead to the destruction of host tissue. Non-steroidal antiinflammatory drug is used for reduce inflammation, and most of NSAIDs inhibit prostaglandine $E_2$ production, but it is shown that $PGE_2$ production is stimulated by IL-1 in recent study. So, the influence of other cytokines except $PGE_2$ on periodontium can not be avoided. Therefore, new antiinflammatory drug is needed. Rhizoma coptidis is used in oriental medicine for anti-inflammation and antiseptics. In this present study, we examined the IL-6 release in periodontal ligament cells treated with the lipopolysaccharide, and also the effect of rhizoma coptidis on cellular activity and IL-6 production of periodontal ligament cells. To evaluate the effect of rhizoma coptidis on cellular activity, the cells were seeded at a cell density of $1{\times}10^4$ cells/well in 24-well culture plates. After one day incubation, 1-6, 10-9 and 10-12 g/ml of rhizoma coptidis and 5, $10{\mu}g/ml$ of LPS were added to the each well and incubated for 1 and 2 days, respectively. Then, MTT assay were carried out. To evaluate the effect of rhizoma coptidis on IL-6 production, the cells were seeded at a cell density of $1.5{\times}10^4$ cells/well in 24-well culture plates. After one day incubation, 10-9 g/ml of rhizoma coptidis and 5, $10{\mu}g/ml$ of LPS were added to the each well and incubated for 3, 6, 12 and 24 hours. Then, amounts of IL-6 production is measured by IL-6 ELISA kit used. The results were as follows : 1. Rhizoma coptidisrbelow to ($10^{-6}g/ml$) significantly increaed cellular activity of periodontal ligament cells than control. 2. Rhizoma coptidist ($10^{-9}g/ml$) significantly increased cellular activity of LPS($5{\mu}g/ml$)-treated periodontal ligament cells than control. 3. LPS(5 and $10{\mu}g/ml$) significantly increased IL-6 production of periodontal ligament cells than control. 4. Rhizoma coptidis($10^{-9}g/ml$) decreased IL-6 production of LPS ($5{\mu}g/ml$)-treated periodontal.ligarnent cells than LPS only tested group. These findings suggest that stimulation of the IL-6 release of periodontal ligament cells by LPS may have a role in the progression of inflammation and alveolar bone resoption in periodontal disease, and that inhibition of the IL-6 release of cells and stimulation of cellular activity by rhizoma coptidis may help the periodontal regeneration.

• Pediatric Infection and Vaccine
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• v.26 no.3
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• pp.148-160
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• 2019

Purpose: This study aimed to investigate the molecular epidemiology of a methicillin-resistant Staphylococcus aureus (MRSA) outbreak at a newborn nursery and neonatal intensive care unit (NICU). Methods: During the outbreak, from August to September 2017, MRSA isolates collected from neonates and medical staff underwent genotyping and screened for virulence factors. Antibiotic susceptibilities were tested. Results: During the study period, 41 neonates were admitted at the nursery (n=27) and NICU (n=14). Of these, 7 had MRSA infections (skin infection [n=6] and sepsis [n=1]) and 4 were colonized with MRSA. Associated medical staff (n=32) were screened; three were nasal MRSA carriers. Staphylococcal chromosomal cassette mec (SCCmec) type II, sequence type (ST) 89, spa type t375 was found to be the skin infection outbreak causing strain, with multi-drug resistance including low-level mupirocin resistance. SCCmec type IVa, ST 72, and a novel spa type designated t17879, was the cause of MRSA sepsis. Many different types of MRSA were colonized on the neonates; however, SCCmec type IVa, ST 72, spa type t664 was colonized in both neonates and a NICU nurse. All MRSA isolates from colonized infants were positive for the Panton-Valentine leukocidin (PVL) toxin gene. Conclusions: The strain causing an outbreak of skin infections had multi-drug resistance. Also, MRSA colonized in the neonates were found to carry the PVL toxin gene. Because different strains are present during an outbreak, molecular epidemiologic studies are important to identify the outbreak strain and colonized strains which aid in effective control and prevention of future MRSA outbreaks.

• Korean Journal of Microbiology
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• v.48 no.3
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• pp.180-186
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• 2012

Pseudomonas aeruginosa, a Gram-negative bacterium, is an ubiquitous and opportunistic human pathogen, which expresses many virulence factors through quorum sensing (QS) regulation. QscR, one of the QS signal receptors of P. aeruginosa, has unique features that make it possible to distinguish QscR from other QS receptors. In the present study, we focused on amino acid residues responsible for such a broad signal specificity of QscR. Thus we constructed mutant QscRs: $QscR_{T72I}$, $QscR_{R132M}$, and $QscR_{T140I}$ by substituting $72^{nd}$ threonine, $132^{nd}$ arginine, and $140^{th}$ threonine residues with isoleucine, methionine, and isoleucine, respectively by site-directed mutagenesis. When we examined the activity of these mutant QscRs, $QscR_{R132M}$ failed to respond to N-3-oxododecanoyl homoserine lactone (3OC12-HSL), but $QscR_{T72I}$ and $QscR_{T140I}$ remained the ability to respond to 3OC12-HSL despite much reduction of the sensitivity. When we treated a variety of acyl-HSLs with different structure, $QscR_{T72I}$ and $QscR_{T140I}$ showed better responsiveness to N-decanoyl HSL (C10-HSL) or N-dodecanoyl HSL (C12-HSL) that has no oxo-moiety at $3^{rd}$ carbon of acyl group than to 3OC12-HSL, and $QscR_{R132M}$ showed no responsiveness to any acyl-HSLs tested here. In addition, $QscR_{T72I}$ and $QscR_{T140I}$ were inhibited by 5f, a QscR inhibitor as similarly as wild type QscR was. These results suggest that while the $130^{th}$ arginine is crucial in both activity and acyl-HSL binding of QscR, the $72^{nd}$ and $140^{th}$ threonines are important in the activity, but they are little responsible for the discrimination of acyl-HSLs or competitive inhibitor.

• Tuberculosis and Respiratory Diseases
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• v.44 no.3
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• pp.470-478
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• 1997

Background : Phagocytosis is probably the first step for mycobacteria to be virulent in host because virulent strains are more readily phagocytosed by macrophage than attenuated strains. According to the traditional concept, multi-drug resistant strains have been regarded as less virulent. However, this concept has been challenged, since recent studies(reported) showed that the degree of virulence and drug-resistance is not related. The purpose of this study is to evaluate whether the phagocytic activity of M.tuberculosis by peripheral blood mononuclear cells(PBMC) is different according to drug-resistance or host factor. To evaluate this, we estimated the difference of phagocytic activity of drug-resistant and drug-sensitive M.tuberculosis and also estimated the phagocytic activity of PBMC from intractable tuberculosis patients and healthy controls. Methods : PBMC from ten intractable tuberculosis patients and twelve healthy control, and three different strains of heat-killed M.tuberculosis, ie, ADS(all drug sensitive), MDR(multi-drug resistant), and ADR(all drug resistant) were used. After incubation of various strains of M.tuberculosis with PBMC, the phagocytic activity was evaluated by estimating proportion of PBMC which have phagocytosed M.tuberculosis. Results : Drug-resistant strains of M.tuberculosis were phagocytosed easily than drug sensitive strains(Percentage of PBMC phagocytosed M.tuberculosis in healthy control : ADS : $32.3{\pm}2.9%$, ADR : $49.6{\pm}3.4%$, p = 0.0022, Percentage of PBMC phagocytosed M.tuberculosis in intractable tuberculosis patients : ADS : $34.9{\pm}3.6%$, ADR : $50.7{\pm}4.5%$, p = 0.0069). However, there was no difference in phagocytic activity of PBMC from healthy control and intractable tuberculosis patients. Conclusion : Drug-resistant strains of M.tuberculosis were phagocytosed easily than drug sensitive strains and host factors does not seems to influence the phagocytosis of M.tuberculosis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.12
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• pp.1895-1904
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• 2015

Foodborne illness associated with food service establishments is an important food safety issue in Korea. In this study, foodborne pathogens (Bacillus cereus, Clostridium perfringens, Escherichia coli, pathogenic Escherichia coli, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus, and Vibrio parahaemolyticus) and hygiene indicator organisms [total viable cell counts (TVC), coliforms] were analyzed for food and environmental samples from foodservice establishments at schools in Gyeonggi province. Virulence factors and antimicrobial resistance of detected foodborne pathogens were also characterized. A total of 179 samples, including food (n=66), utensil (n=68), and environmental samples (n=45), were collected from eight food service establishments at schools in Gyeonggi province. Average contamination levels of TVC for foods (including raw materials) and environmental samples were 4.7 and 4.0 log CFU/g, respectively. Average contamination levels of coliforms were 2.7 and 4.0 log CFU/g for foods and environmental swab samples, respectively. B. cereus contamination was detected in food samples with an average of 2.1 log CFU/g. E. coli was detected only in raw materials, and S. aureus was positive in raw materials as well as environmental swab samples. Other foodborne pathogens were not detected in all samples. The entire B. cereus isolates possessed at least one of the diarrheal toxin genes (hblACD, nheABC, entFM, and cytK enterotoxin gene). However, ces gene encoding emetic toxin was not detected in B. cereus isolates. S. aureus isolates (n=16) contained at least one or more of the tested enterotoxin genes, except for tst gene. For E. coli and S. aureus, 92.7% and 37.5% of the isolates were susceptible against 16 and 19 antimicrobials, respectively. The analyzed microbial hazards could provide useful information for quantitative microbial risk assessment and food safety management system to control foodborne illness outbreaks in food service establishments.