• Food Science of Animal Resources
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• v.27 no.4
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• pp.543-547
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• 2007

Bovine mastitis is costly infectious disease of dairy cattle, being responsible for significant economic losses all over the world. Also, mastitis has troubled about resistance to antibiotics. The purpose of this study was to screen a novel antimicrobial strain from various sources (raw milk and feeds (from farm of Paju, Dangjin, and Hwasung), commercial milk, Korean traditional fermented foods, and chicken feces). The isolate was screened using triple agar layer method and deferred method was used for confirmation of antimicrobial effect. Seventy six of isolates were screened using triple agar layer method. In these strain, 42 isolates were shown a broad spectrum of autimicrobial activity against mastitis pathogens. Especially, fourteen isolates were shown over 20 mm inhibition zone against S. aureous ATCC 25923. These results suggest that these novel antimicrobial strains could be used for the alternative of antibiotics.

• Pediatric Infection and Vaccine
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• v.22 no.3
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• pp.154-163
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• 2015

Purpose: Osteoarticular infections in children and adolescents are important because it can cause functional compromise if appropriate treatment is delayed. Therefore, this study was designed to describe the clinical presentations and causative organisms of osteoarticular infections in children and adolescents in order to propose early diagnosis method and an appropriate empiric antimicrobial therapy. Methods: Forty-two medical records were reviewed retrospectively, which were confirmed as osteomyelitis (OM) or septic arthritis (SA) at Department of Pediatrics or Orthopedic Surgery in patients under 18 years old of Ewha Womans University Mokdong Hospital from March 2008 to March 2015. Results: We identified 21 cases of OM, 13 cases of SA and 8 cases of OM with SA. There were 31 males and 11 females and mean age was 7.1 years old. The most common symptoms were pain and tenderness of involved site. Major involved bones were femur (10 cases, 34.5%), tibia (7 cases, 24.1%) and major involved joints were hip (9 cases, 42.9%), and knee (5 cases, 23.8%). Increased serum C-reactive protein and erythrocyte sedimentation rate were observed in 37 cases (88.1%) respectively. Magnetic resonance imaging was performed in 40 cases among 42 cases and was used to demonstrate osteoarticular infections and other adjacent infections. Nine cases (23.7%) among 38 cases and 20 cases (50.0%) among 40 cases were positive in blood culture and infected site culture respectively. The most common causative organism was Staphylococcus aureus, which was represented in 22 cases (75.9%), of which nine cases (40.9%) were resistant to methicillin. Conclusions: S. aureus was the most common causative organism of osteoarticular infections in children and adolescents and the proportion of MRSA was high in this study. Therefore, we recommend vancomycin as the first empiric antimicrobial therapy and suggest that further study is necessary to elucidate an appropriate guideline for treatment which takes into account MRSA proportion.

• Advances in Traditional Medicine
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• v.3 no.3
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• pp.157-162
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• 2003

Various extracts of higher plants have been used in traditional medicine systems for centuries. While tropical and sub-tropical plants have received considerable attention from the researchers for evaluation of their bioactivity, temeperate plants have always been neglected somewhat. Similarly, seeds of the plants have not been considered seriously compared to other plant parts, e.g. leaves, stems, roots, flowers, etc. as a potential source for biologically active compounds. As part of our on-going evaluation of the extracts of the seeds of temperate plants, especially from Scotland, for biological activity, Achillea millefolium, Angelica sylvestris and Phleum pratense have been chosen for the present study. Both A. millefolium and A. sylvestris are well known for their traditional medicinal uses in Europe and also in the orient, but there is no report on any medicinal properties of P. pratense available to date. Extracts of the seeds of these plants have been assessed for their antioxidant and antibacterial potential and also for general toxicity. Both DCM and MeOH extracts of A. millefolium showed the most significant broad spectrum antibacterial activity among the three plants and inhibited the growth of almost all test strains of bacteria. The DCM extracts of all three species were active against methicillin resistant Staphylococcus aureus (MRSA) and Citrobacter freundii $(MIC=6.25{\times}10^{-1}\;mg/mL)$. While the MeOH extracts of A. millefolium and P. pratense were active against C. freundii, that of P. pratense was also active against MRSA. The MeOH extract of A. sylvestris did not show any antibacterial activity against any of the eight bacterial strains at test concentrations. The MeOH extract of P. pratense showed the most prominent antioxidant activity $(IC_{50}=145\;{\mu}g/ml)$ and there was no antioxidant activity observed with the DCM extract of A. millefolium. The DCM extract of P. pratense was the most toxic $(LC_{50}=20\;{\mu}g/ml)$ among the extracts.

• Pediatric Infection and Vaccine
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• v.12 no.1
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• pp.67-74
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• 2005

Purpose : The incidence of mortality associated with respiratory difficulties is decreasing nowadays contributed to the development of neonatology. However, complications associated with mechanical ventilator are increasing. This study is to determine clinical manifestations, diagnositc availability of the endotracheal tip culture in patients with Ventilator-Associated Pneumonia(VAP) in neonatal intensive care unit(NICU). Methods : A retrospective analysis of 50 neonates who were admitted to the NICU of Kangnam Sacred Heart Hospital and had given mechanical ventilator from 1 January 2000 to 30 June 2003. VAP group defined as neonates who had pneumonia with mechanical ventilation longer than 48 hours. They were classified into VAP group(n=13) and control group (n=37) and the prevalence, microorganisms cultured from the endotracheal tube tip and risk factors were investigated. Results : The prevalence of VAP was 26.0%(n=13) and the most dominant microorganism cultured in our NICU was methicillin-resistant coagulase negative staphylococcus(MR-CNS) in 4 cases. Other microorganisms were Pseudomonas, Enterobacter, methicillin-resistant Staphylococcus aureus(MRSA) and Klebsiella. Gestational age, birth weight, Apgar score, respiratory distress syndrome, retinopathy of prematurity, bronchopulmonary dysplasia, sepsis, renal failure, pulmonary hemorrhage, pneumothorax were not different significantly between two groups except intraventricular hemorrhage(P<0.001) and patent ductus arteriosus(P<0.05). Duration of hospital stay and mortality rate were also not different significantly. Conclusion : VAP occurred at a significant rate among mechanically ventilated NICU patients. Despite of limitation of encotracheal tip culture, the most common microorganism was MR-CNS. We should be aware of occurrence of VAP in NICU neonate who were with mechanical ventilator and should treat with great care.

• Journal of Microbiology and Biotechnology
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• v.27 no.7
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• pp.1249-1256
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• 2017

In our search for new sources of bioactive secondary metabolites from Streptomyces sp., the ethyl acetate extracts from endophytic Streptomyces SUK 25 afforded five active diketopiperazine (DKP) compounds. The aim of this study was to characterize the bioactive compounds isolated from endophytic Streptomyces SUK 25 and evaluate their bioactivity against multiple drug resistance (MDR) bacteria such as Enterococcus raffinosus, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter spp., and their cytotoxic activities against the human hepatoma (HepaRG) cell line. The production of secondary metabolites by this strain was optimized through Thornton's medium. Isolation, purification, and identification of the bioactive compounds were carried out using high-performance liquid chromatography, high-resolution mass liquid chromatography-mass spectrometry, Fourier transform infrared spectroscopy, and nuclear magnetic resonance, and cryopreserved HepaRG cells were selected to test the cytotoxicity. The results showed that endophytic Streptomyces SUK 25 produces four active DKP compounds and an acetamide derivative, which were elucidated as $cyclo-({\text\tiny{L}}-Val-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Leu-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Phe-{\text\tiny{L}}-Pro)$, $cyclo-({\text\tiny{L}}-Val-{\text\tiny{L}}-Phe)$, and N-(7-hydroxy-6-methyl-octyl)-acetamide. These active compounds exhibited activity against methicillin-resistant S. aureus ATCC 43300 and Enterococcus raffinosus, with low toxicity against human hepatoma HepaRG cells. Endophytic Streptomyces SUK 25 has the ability to produce DKP derivatives biologically active against some MDR bacteria with relatively low toxicity against HepaRG cells line.

• Tuberculosis and Respiratory Diseases
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• v.52 no.3
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• pp.207-218
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• 2002

Background : Intensive care units (ICUs) are generally considered epicenters of antibiotic resistance and the principal sources of multi-resistant bacteria outbreaks. The antibiotic resistance in newly opened intensive care unit that has no microbial colonization on and around the devices was investigated. Materials and Methods : The authors analyzed the antibiotic resistance patterns for common hospital acquired-pneumonia pathogens in the ICUs(Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter spp.) at the newly opened ICU of Hanyang University Medical Center, Kuri Hospital during 6 years(1995-2000). Results : 1) Regarding Staphylococcus aureus, the resistance rate to methicillin was 15% at 1995, 21% at 1996, 20% at 1997, 23% at 1998, 22% at 1999, 55% at 2000. 2) Regarding Pseudomonas aeruginosa, the resistance rate to $3^{rd}$ cephalosporin was 50% at 1995, 50% at 1996, 78% at 1997, 40% at 1998, 77% at 1999, 39% at 2000. Imipenam was 0% at 1995, 27% at 1996, 65% at 1997, 12% at 1998, 16% at 1999, 12% at 2000. Ciprofloxacin was 0% at 1996, 56% at 1997, 36% at 1998, 57% at 1999, 58% at 2000. Tobramycin was 7% at 1995, 10% at 1996, 67% at 1997, 36% at 1998, 65% at 1999, 12% at 2000. Gentamycin was 14% at 1995, 36% at 1996, 67% at 1997, 36% at 1998, 65% at 1999, 12% at 2000. Amikacin was 14% at 1995, 30% at 1996, 61% at 1997, 16% at 1998, 39% at 1999, 18% at 2000. 3) Regarding Acinetobacter spp., the resistance rate to $3^{rd}$ cephalosporin was 92% at 1996, 89% at 1997, 88% at 1998,84% at 1999, 77% at 2000. Imipenem was 50% at 1996, 48% at 1997, 45% at 1998, 49% at 1999, 50% at 2000. Ciprofloxacin was 0% at 1996, 48% at 1997, 33% at 1998, 27% at 1999, 71% at 2000. Tobramycin was 67% at 1995, 100% at 1996, 89% at 1997, 95% at 1998, 87% at 1999, 77% at 2000. Gentamycin was 67% at 1995, 100% at 1996, 89% at 1997, 95% at 1998, 87% at 1999, 83% at 2000. Amikacin was 33% at 1995, 83% at 1996, 82% at 1997, 88% at 1998, 75% at 1999, 69% at 2000. Conclusion : The S.aureus resistance to methicillin, the Pseudomonas aeruginosa resistance to ciprofloxacin, and the Acinetobacter spp. resistance to ciprofloxacin have rapidly increased during 6 years. There is a need to pay speicial attention when using the the antibiotics for the above pathogens. This data may be useful in antibiotic therapy in newly opened intensive care units.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3267-3274
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• 2014

In order to investigate the effects of the double replacement of $\small{L}$-Pro, $\small{D}$-Pro, $\small{D}$-Leu or Nleu (the peptoid residue for Leu) in the hydrophobic face (positions 9 and 13) of amphipathic ${\alpha}$-helical non-cell-selective antimicrobial peptide $L_8K_9W_1$ on the structure, cell selectivity and mechanism of action, we synthesized a series of $L_8K_9W_1$ analogs with double replacement of $\small{L}$-Pro, $\small{D}$-Pro, $\small{D}$-Leu or Nleu in the hydrophobic face of $L_8K_9W_1$. In this study, we have confirmed that the double replacement of $\small{L}$-Pro, $\small{D}$-Pro, or Nleu in the hydrophobic face of $L_8K_9W_1$ let to a great increase in the selectivity toward bacterial cells and a complete destruction of ${\alpha}$-helical structure. Interestingly, $L_8K_9W_1$-$\small{L}$-Pro, $L_8K_9W_1$-$\small{D}$-Pro and $L_8K_9W_1$-Nleu preferentially interacted with negatively charged phospholipids, but unlike $L_8K_9W_1$ and $L_8K_9W_1$-$\small{D}$-Leu, they did not disrupt the integrity of lipid bilayers and depolarize the bacterial cytoplasmic membrane. These results suggested that the mode of action of $L_8K_9W_1$-$\small{L}$-Pro, $L_8K_9W_1$-$\small{D}$-Pro and $L_8K_9W_1$-Nleu involves the intracellular target other than the bacterial membrane. In particular, $L_8K_9W_1$-$\small{L}$-Pro, $L_8K_9W_1$-$\small{D}$-Pro and $L_8K_9W_1$-Nleu had powerful antimicrobial activity (MIC range, 1 to $4{\mu}M$) against methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Pseudomonas aeruginosa (MDRPA). Taken together, our results suggested that $L_8K_9W_1$-$\small{L}$-Pro, $L_8K_9W_1$-$\small{D}$-Pro and $L_8K_9W_1$-Nleu with great cell selectivity may be promising candidates for novel therapeutic agents, complementing conventional antibiotic therapies to combat pathogenic microorganisms.

• Clinical and Experimental Pediatrics
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• v.53 no.4
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• pp.495-502
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• 2010

Purpose : Sepsis is a significant cause of morbidity and mortality in the newborn, particularly in preterm. The objective of this study was to analyze the incidence rate, causative pathogens and clinical features of neonatal sepsis in one neonatal intensive care unit (NICU) for 6 years. Methods : This study was retrospectively performed to review the clinical and laboratory characteristics including sex, gestational age, birth weight, Apgar score, length of hospitalization, length of total parenteral nutrition, presence of central venous catheter, underlying diseases, laboratory findings, microorganisms isolated from blood culture, complications and mortality in 175 patients between January 2003 and December 2008. Results : 1) Sepsis was present in 175 of 3,747 infants for 6 years. There were more gram-positive organisms. 2) The gram-negatives were more prevalent in preterm. There were no significant differences of other clinical features between two groups. 3) Underlying diseases were found in 73.7%, and the most common disease was cardiovascular disease. The most common organisms of gram-positives and gram-negatives were methicillin resistant Staphylococcus aureus (MRSA) and Serratia marcescens. 4) There was statistically significant difference on platelet counts between two groups (P<0.05). 5) Complications were found in 18.3% and septic shock was the most common. MRSA was the most common pathogen in sepsis with complication. 6) The mortality rate was 7.4%. 7) There were differences in monthly blood stream infection/1,000 patient-days. Conclusion : The studies about the factors that can influence neonatal sepsis will contribute to decrease the infection rates in NICUs.

• Tuberculosis and Respiratory Diseases
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• v.55 no.1
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• pp.59-68
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• 2003

Background : In intubated patients, cultures of endotracheal aspirates (EA) are apt to contamination throughout the endotracheal tube. Therefore, the identification of etiologic agents via conventional EA cultures is not always reliable. In order to differentiate a pulmonary infection from a non-infectious disease, and to identify the true etiologic agent of acute pulmonary infection, blinded protected specimen brushing (PSB) was used, and its efficacy evaluated. Methods : In 51 intubated patients, with suspected pneumonia, blind PSB were performed, and the results compared with blood and EA cultures. A protected specimen brush was introduced through the endotracheal tube, and settled at the affected large bronchus. A specimen brush was introduced to the expected region using the blind method. The tip of the brush was introduced with an aseptic technique after vigorously mixed for 1 minute in $1cm^3$ of Ringer's lactate solution. The specimens were submitted for quantitative culture within 15 minutes, with a culture being regarded as positive if the colony forming units were above $10^3/ml$. Results : Of the 51 patients, 15 (29.4%) had community-acquired pneumonia (CAP), 27 (52.9%) hospital-acquired pneumonia (HAP) and 9 (17.6%) non-infectious diseases. The sensitivity and specificity of the quantitative PSB culture for the diagnosis of pneumonia were 52.4 and 88.9%, respectively. The sensitivity and specificity of EA were 78.6 and 77.8%, respectively. The blind PSB was superior to the EA for the identification of true etiologic agents. Of 53 episodes of 27 HAP patients, MRSA (Methicillin-resistant staphylococcus aureus) (41.5%) was the most common causative agent followed by Pseudomonas aeruginosa (15.1%), Klebsiella sp. (7.5%) and Acinetobacter sp. (7.5%). Conclusions : As a simple, non-invasive diagnostic modality, the blind PSB is a useful method for the differentiation of a pulmonary infection from non-infectious diseases and to identify the etiologic agents in intubated patients. A blind PSB can be performed without bronchoscopy, so is safer, more convenient and cost-effectiveness for patients where bronchoscopy can not be performed.

• Clinical and Experimental Pediatrics
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• v.53 no.4
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• pp.592-597
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• 2010

Hyperimmunoglobulin E syndrome (HIES) is a rare immunodeficiency disease which is characterized by high serum IgE levels, eczema, and recurrent infections. Herein we present the case of a patient with HIES associated with STAT3 gene ($stat3$) mutation. A 16 year-old girl was admitted to our hospital due to hemoptysis caused by pneumonia with bronchiectasis. She had a history of recurrent skin and respiratory tract infections, such as pneumonia caused by MRSA (methicillin-resistant $Staphylococcus$ $aureus$) and $Pseudomonas$ $aeruginosa$. On physical examination, a broad round shaped nose, oral thrush, and chronic eczematous skin rash over her whole body were found. Laboratory data showed an elevated eosinophil count ($750/{\mu}L$) and total IgE level (5,001 U/mL). The patient's National Institutes of Health (NIH) score for HIES was 44. Direct sequencing of the STAT3 gene revealed that the patient was heterozygous for a missense mutation in the DNA binding domain of the STAT3 protein (c.1144C>T, p. Arg382Trp). HIES should be suspected in patients with recurrent infections and can be confirmed by clinical scoring and genetic analysis.