• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2000.04a
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• pp.3-6
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• 2000

Antimicrobial resistance has been a well-recognized problem ever since the introduction of penicillin into clinical use. History of antimicrobial development can be categorized based on the major antibiotics that had been developed against emerging resistant $pathogens^1$. In the first period from 1940 to 1960, penicillin was a dominating antibiotic called as a "magic bullet", although S.aureus armed with penicillinase led antimicrobial era to the second period in 1960s and 1970s. The second stage was characterized by broad-spectrum penicillins and early generation cephalosporins. During this period, nosocomial infections due to gram-negative bacilli became more prevalent, while those caused by S.aureus declined. A variety of new antimicrobial agents with distinct mechanism of action including new generation cephalosporins, monobactams, carbapenems, ${\beta}$-lactamase inhibitors, and quinolones characterized the third period from 1980s to 1990s. However, extensive use of wide variety of antibiotics in the community and hospitals has fueled the crisis in emerging antimicrobial resistance. Newly appeared drug-resistant Streptococcus pneumoniae (DRSP), vancomycin-resistant enterococci (VRE), extended-spectrum ${\beta}$-lactamase-producing Klebsiella, and VRSA have posed a serious threat in many parts of the world. Given the recent epidemiology of antimicrobial resistance and its clinical impact, there is no greater challenge related to emerging infections than the emergence of antibiotic resistance. Problems of antimicrobial resistance can be amplified by the fact that resistant clones or genes can spread within or between the species as well as to geographically distant areas which leads to a global concern$^2$. Antimicrobial resistance is primarily generated and promoted by increased use of antimicrobial agents. Unfortunately, as many as 50 % of prescriptions for antibiotics are reported to be inappropriate$^3$. Injudicious use of antibiotics even for viral upper respiratory infections is a universal phenomenon in every part of the world. The use of large quantities of antibiotics in the animal health industry and farming is another major factor contributing to selection of antibiotic resistance. In addition to these background factors, the tremendous increase in the immunocompromised hosts, popular use of invasive medical interventions, and increase in travel and mixing of human populations are contributing to the resurgence and spread of antimicrobial resistance$^4$. Antimicrobial resistance has critical impact on modem medicine both in clinical and economic aspect. Patients with previously treatable infections may have fatal outcome due to therapeutic failure that is unusual event no more. The potential economic impact of antimicrobial resistance is actually uncountable. With the increase in the problems of resistant organisms in the 21st century, however, additional health care costs for this problem must be enormously increasing.

• Journal of Life Science
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• v.24 no.1
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• pp.61-66
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• 2014

The purpose of this study was to investigate the immunomodulatory effects of Alpina officinarum (AO) ethanol extract on immunocompromised mice. The mice were injected intraperitoneally with an immunosuppressive drug, cyclophosphamide, and then administrated orally with 30, 100, and 300 mg/kg of ethanol extract of AO (AO 30, AO 100, and AO 300, respectively). The concentrations of cytokines and immunoglobulins (IgM, IgA, IgG) in serum were measured. The body weight of the mice and spleen cell number of the AO-fed group showed no significant difference compared to a control group. The concentrations of several cytokines, including IL-2, IFN-${\gamma}$, and TGF-${\beta}$, in serum showed a significant increase in the AO 100 group compared to the control and other groups (p<0.05). The IL-4 level showed no significant difference in the experimental groups. The supplementation of AO (30, 100, 300 mg/kg) significantly increased the concentration of IgM (p<0.05). The concentration of IgA was significantly increased in the AO 100 group (p<0.05) compared to the control group. It can be concluded that AO ethanol extract enhances immune function by promoting the production of cytokines and immunoglobulins.

• Tuberculosis and Respiratory Diseases
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• v.72 no.5
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• pp.452-456
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• 2012

Disseminated Mycobacterium avium complex (MAC) infection can occur in immunocompromised patients, and rarely in immunocompetent subjects. Due to the extensive distribution of the disease, clinical presentation of disseminated MAC may mimic malignancies, and thorough examinations are required in order to make accurate diagnosis. We report a case of disseminated Mycobacterium intracellulare disease in an immunocompetent patient, which involved the lung, lymph nodes, spleen, and multiple bones. F-18 fluorodeoxyglucose positron-emission tomography imaging showed multiple hypermetabolic lesions, which are suggestive of typical hematogenous metastasis. However, there was no evidence of malignancy in serial biopsies, and M. intracellulare was repeatedly cultured from respiratory specimens and bones. Herein, we should know that disseminated infection can occur in the immunocompetent subjects, and it can mimic malignancies.

• Tuberculosis and Respiratory Diseases
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• v.49 no.5
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• pp.633-638
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• 2000

Pulmonary mucormycosis is an opportunistic infection in patients with severe underlying illness such as immunocompromised diseases or uncontrolled diabetes mellitus. While patients with leukemia and lymphoma usually present with diffuse parenchymal disease, diabetic patients usually have a localized endobronchial disease involving central airways. We report upon a case of pulmonary mucormycosis in diabetes mellitus patient presenting as an endobronchial mass, which was cured with antifungal therapy, rigid bronchoscopic mass removal and right pneumonectomy.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.277-281
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• 2008

HIV affects many organ systems. Patients with HIV infection have substantially increased risk of developing various cancers, primarily by opportunistic infection with oncogenic viruses due to their immunocompromised status. However, extensive evidence also indicates that the viral protein, Tat itself, may playas a major factor in the development of AIDS-related neoplasms. The molecular mechanism underlying Tat's oncogenic activity may include deregulation of cellular genes. Therefore, in this study, we examined the effect of HIV-l Tat on CD99 as one of the target cellular genes, which is a well-known tumor marker in several cancers. By using established HeLa clones that are stably expressing Tat, we found that CD99 is upregulated by endogenous Tat, whereas STAT3 is down regulated. Upon the screening of genes differentially expressed between Tat-stable cells and the control cells by using the gene fishing technique, DEG, we detected 3 genes which expression is affected by the presence of Tat. Furthermore, the methylation specific PCR analysis of the stably Tat expressing cell lines revealed that the CD99 promoter is de methylated in the presence of Tat. Taken together, these results open a potential role of CD99 in AIDS-related oncogenesis via epigenetic regulation by HIV-1 Tat.

• Korean Journal of Microbiology
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• v.50 no.4
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• pp.360-367
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• 2014

Candida albicans is an opportunistic and the most prevalent fungal pathogen that can cause superficial and systemic infections in immunocompromised patients. C. albicans can promote the transition from budding yeast to filamentous form, generating biofilms. Infections associated with C. albicans biofilms are frequently resistant to conventional antifungal therapy. Therefore, the development of more effective antifungal drugs related with biofilm formation is required urgently. The roots of Rheum undulatum have been used for medicinal purposes in Korea and China traditionally. The aim of present study was to evaluate the effect of R. undulatum extract upon preformed biofilms of 12 clinical C. albicans isolates and the antifungal activities. Its effect on preformed biofilms was evaluated using XTT reduction assay, and metabolic activity of all tested strains was reduced significantly ($49.4{\pm}6.0%$) at 0.098 mg/ml R. undulatum. The R. undulatum extract blocked the adhesion of C. albicans biofilms to polystyrene surfaces, and damaged the cell membrane integrity of C. albicans which was analyzed by CFDA, AM, and propidium iodide double staining. It caused cell lysis which was observed by Confocal laser scanning and phase contrast microscope after propidium iodide and neutral red staining, respectively. Membrane permeability was changed as evidenced by crystal violet uptake. The data suggest that R. undulatum inhibits biofilm formation by C. albicans, which can be associated with the damage of the cell membrane integrity, the changes in the membrane permeability and the cell lysis of C. albicans.

• Journal of Chest Surgery
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• v.40 no.9
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• pp.617-623
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• 2007

Background: Invasive pulmonary aspergillosis, a frequent fungal infection in immunocompromised patients, is known to have a poor prognosis despite the use of antifungal therapy in leukemic patients. We studied the outcome of surgical resection of invasive pulmonary aspergillosis where bleeding tendency, localized recurrence of infection, and incidence could be reduced. Material and Method: We retrospectively reviewed 14 patients with a hematological malignancy where invasive pulmonary aspergillosis was diagnosed during the 10 years between 1998 and 2007. From the medical records, we reviewed the type and treatment of the hematological malignancy, including the diagnostic methods of invasive pulmonary aspergillosis, the preoperative hematological conditions and their management, and the surgical methods and records. We also analyzed the development of postoperative complications and patient mortality, the recurrence of postoperative invasive pulmonary aspergillosis, and if the patients had a bone marrow transplant. Result: Fourteen patients with invasive pulmonary aspergillosis and a hematological malignancy underwent a pulmonary lobectomy. One patient had a complication of bronchopleural fistula, but there were no other serious complications such as bleeding or wound infection, and none of the patients died postoperatively. Conclusion: We have shown that pulmonary lobectomy is a safe and effective therapy for invasive pulmonary aspergillosis in patients with hematological malignancies that allow further treatment of the hematological malignancy.

• Journal of Trauma and Injury
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• v.20 no.1
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• pp.40-46
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• 2007

Purpose: The primary goal of wound management is to avoid infection. Wounds in all patients presenting to the Emergency Department are contaminated with bacteria. Despite this, there is a low incidence of infection. Unfortunately, physicians continue to use antimicrobial agents indiscriminately. The authors intended to determine the effect of selective antimicrobial agents and the indications for appropriate antimicrobial agent use in traumatic simple wounds. Methods: This prospective study was performed from Jul. 2005 to Aug. 2005. A pilot study had been performed from Nov. 2003 to Jul. 2004 at the Ewha Woman's University Mokdong Hospital. Structured data sheets were completed at the times of the patient's visits to the Emergency Department and to the Outpatient Department for follow-up. Infection was determined at the time of follow-up. The indications of antimicrobial agent use are immunocompromised patients, wounds contaminated for 3 hours or longer, devitalized tissue, and extremity wounds except hand wounds caused by sharp objects. Results: The study enrolled 216 injured patients. The general characteristics of patients and wounds between the two groups were not significantly different. The antimicrobial agent use and infection rate of the pilot study were 227 cases (90.4%) and 10 cases (4.0%), and those of this study were 100 cases (46.3%) and 9 cases (4.1%). In this study, antibiotic use was reduced to almost half compared with the previous study, but the infection rate was similar (p<0.001). Conclusion: Rational use of antimicrobial agents in simple wounds reduced the use of antimicrobial agents in the Emergency Department without increasing the infection rate.

• Journal of Korean Neurosurgical Society
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• v.30 no.7
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• pp.896-902
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• 2001

Objectives : Aspergillosis of central nervous system(CNS) is a rare pathologic condition and it has been known to be difficult to diagnose and treat. We analyzed seven cases of central nervous system aspergillosis. The clinical characteristics, and the problems in diagnosis and treatment are discussed with review of previous literatures. Material and Methods : We reviewed the clinical records, radiological findings, and pathologic reports of 7 patients with aspergillosis which involved CNS. Results : Five patients were immunocompetent, and infection was related with previous operation in 4 of them. Two patients were immunocompromised and had no history of operation. Five patients had intracranial lesions and two had spinal lesions. Mean duration from the onset of initial symptom to pathologic diagnosis was 2.4 months. Mean duration from the previous operation to the onset of symptom was 9.3 months, and from the onset of symptom to diagnosis was 2.9 months in the patients who had histories of operation. All of them were treated with surgical procedures and intravenous and oral antifungal agents, resulting in cure in 6 cases. Mean duration of the treatment was 4.9 months. Conclusion : Because aspergillosis of CNS is a rare disease and is difficult to be differentiated from the pyogenic abscess or recurrent tumor, the pathologic diagnosis is very important for adequate treatment. Although the prognosis of aspergillosis of CNS has been known to be poor, adequate surgery for both diagnosis and treatment and antifungal chemotherapy resulted in good outcome.

• Tuberculosis and Respiratory Diseases
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• v.82 no.3
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• pp.242-250
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• 2019

Background: Data on noninvasive ventilation (NIV) use in intensive care units (ICUs) are very limited in South Korea. Methods: A prospective observational study was performed in 20 ICUs of university-affiliated hospitals from June 2017 to February 2018. Adult patients (age>18 years) who were admitted to the ICU and received NIV treatment for acute respiratory failure were included. Results: A total of 156 patients treated with NIV were enrolled (mean age, $71.9{\pm}11.6years$). The most common indications for NIV were acute hypercapnic respiratory failure (AHRF, n=89) and post-extubation respiratory failure (n=44). The main device for NIV was an invasive mechanical ventilator with an NIV module (61.5%), and the majority of patients (87.2%) used an oronasal mask. After the exclusion of 32 do-not-resuscitate patients, NIV success rate was 68.5% (85/124); ICU and hospital mortality rates were 8.9% and 15.3%, respectively. However, the success rate was lower in patients with de novo respiratory failure (27.3%) compared to that of patients with AHRF (72.8%) or post-extubation respiratory failure (75.0%). In multivariate analysis, immunocompromised state, de novo respiratory failure, post-NIV (2 hours) respiratory rate, NIV mode (i.e., non-pressure support ventilation mode), and the change of NIV device were significantly associated with a lower success rate of NIV. Conclusion: AHRF and post-extubation respiratory failure were the most common indications for NIV in Korean ICUs. Overall NIV success was achieved in 68.5% of patients, with the lowest rate in patients with de novo respiratory failure.