• Korean Journal of Microbiology
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• v.37 no.2
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• pp.145-150
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• 2001

Reactivation of human cytomegalovirus (HCMV) from latency is often fatal to immunocompromised individuals. To understand the effect of HCMV on human monocytes where HCMV establishes latency, two human monocyte cell lines at different stages in differentiation, THP-1 and HL-60 were infected with HCMV. While the viability and morphology of HL-60 cells were not significantly affected by HCMV, the viability of THP-1 cells was dramatically decreased by HCMV infection. THP-1 cells infected with HCMV became aggregated and adhered to the surface of culture dishes, probably due to the increased expression of adherence molecules CD11b on the infected THP-1 cells. THP-1 cells established a latent HCMV infection were induced to differentiate by treatment with TPA and hydrocortisone. Recovery of infectious HCMV from the culture supernatant of differentiated THP-1 cells was dependent on the time of induction of differentiation after HCMV infection. Thus, in vitro model of reactivation of HCMV from latently infected monocytes was established.

• The Journal of the Korean Society for Microbiology
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• v.35 no.4
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• pp.317-324
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• 2000

Candida albicans is one of the most frequently isolated fungal pathogens in human. Recently, the prevalence of candida infection has markedly increased, partially due to the increase of immunocompromised hosts. Proposed virulence factors of the pathogenic Candida are the ability to form hyphae to adhere to epithelial cell surfaces, and to secrete acid proteinases and phospholipases. We measured the relative cell surface hydrophobicity (CSH) and the ability of proteinase production (PROT), phospholipase production (PLase), adherence to host epithelium (ADH), and hyphal transition (Germ). The relative risk of virulence factors was analyzed by lethality test in murine model of hematogeneously disseminated candidal infection. According to Cox's proportional hazard analysis, the statistically significant virulence factors were PROT, ADH, and CSH. PROT was the highest risk factor of them. To evaluate the applicability for the diagnosis and treatment of Candidiasis, we examined the protective effect of the active and passive immunizations with the materials purified from virulence factors and antibodies to them in Candia-infected mice model. The mean survival times of active and passive immunized groups were slightly longer than those of non-immunized groups.

• Tuberculosis and Respiratory Diseases
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• v.46 no.1
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• pp.82-88
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• 1999

Herpes simplex virus pneumonia in immunocompromised host is difficult to diagnose with non-invasive method, and has high mortality rate. Because early diagnosis and early treatment can significantly decrease the mortality rate, the enthusiastic efforts for the early diagnosis should be done. A 41-year-old woman who took prednisolone due to mixed connective tissue disease developed gradually increasing dyspnea with radiological features of interstitial lung disease. Initially, we treated her with empirical antibiotics, but failed to improve her dyspnea. So we performed bronchoalveolar lavage and open lung biopsy. Open lung biopsy specimen showed herpes simplex virus pneumonia. Herpes simplex virus was also isolated from bronchoalveolar lavage fluid. There was both clinical and radiological improvement after treatment with acyclovir for 14 days.

• Tuberculosis and Respiratory Diseases
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• v.72 no.5
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• pp.416-425
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• 2012

Background: The sensitivities and specificities of interferon-gamma release assays (IGRAs) vary among different population studies, and the data on the routine use of IGRAs are limited. The aim of this study was to evaluate the role of QuantiFERON-TB Gold In-Tube (QFT-GIT) test in the diagnosis of active tuberculosis. Methods: We conducted a prospective study, enrolling 77 patients with suspected pulmonary tuberculosis (TB), at a secondary care teaching hospital in Seoul. Results: In total, 12 (15.6%) patients showed indeterminate results due to positive control failure on the QFT-GIT test. Indeterminate results were significantly associated with the elderly, history of the intensive care unit stay, lymphocytopenia, especially low CD4 count, increased C-reactive protein and decreased protein levels. Of the 77 patients, 44 (57.1%) were diagnosed with active pulmonary tuberculosis, and the percentage of false negative results of the QFT-GIT was 36.4% (vs. 31.8% with TST). In the TB group with >65 years old (n=12), the proportions of the indeterminate (33.3% vs. 3.1%) and the false negative results (58.3% vs. 25.0%) of the QFT-GIT were significantly higher than in the younger TB group (n=32). Conclusion: Indeterminate and false negative results of QFT-GIT test were not infrequent in tuberculosis, especially in the elderly. Care should be considered for the interpretation with the elderly, immunocompromised, chronic and severely diseased patients.

• Journal of Microbiology and Biotechnology
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• v.26 no.11
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• pp.1855-1862
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• 2016

Cronobacter sakazakii (C. sakazakii) is a foodborne pathogen, posing a high risk of disease to infants and immunocompromised individuals. In order to develop a quick, easy, and sensitive assay for detecting C. sakazakii, a rabbit anti-C. sakazakii immunoglobulin G (IgG) was developed using sonicated cell protein from C. sakazakii. The developed anti-C. sakazakii (IgG) was of good quality and purity, as well as species-specific. The developed rabbit anti-C. sakazakii IgG was attached to the surface of a sulforhodamine B-encapsulated liposome to form an immunoliposome. A test strip was then prepared by coating goat anti-rabbit IgG onto the control line and rabbit anti-C. sakazakii IgG onto the test line, respectively, of a plastic-backed nitrocellulose membrane. A purple color signal both on the test line and the control line indicated the presence of C. sakazakii in the sample, whereas purple color only on the control line indicated the absence of C. sakazakii in the sample. This immunochromatographic strip assay could produce results in 15 min with a limit of detection of $10^7CFU/ml$ in C. sakazakii culture. The immunochromatographic strip assay also showed very good specificity without cross-reactivity with other tested Cronobacter species. Based on these results, the developed immunochromatographic strip assay is efficient for the detection of C. sakazakii and has high potential for on-site detection.

• Tuberculosis and Respiratory Diseases
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• v.45 no.1
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• pp.213-221
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• 1998

Pulmonary mucormycosis is an uncommon, but important opportunistic fungal infection associated with diabetes mellitus, leukemia, lymphoma and other immunocompromised states. Mucor species grow best in acidic-high glucose medium. which explaining the particular susceptibility of diabetic patient who are ketoacidic. Early consideration of this diagnosis, along with aggressive diagnostic evaluation, is critical to effective therapy and patient survival. We have experienced a case of pulmonary murcomycosis mimicking bilateral pulmonary edema on chest Xray that associated with diabetic ketoacidosis. A brief review of the literature was given.

• Tuberculosis and Respiratory Diseases
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• v.78 no.4
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• pp.366-370
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• 2015

Although influenza A (H1N1) virus leads to self-limiting illness, co-infection with bacteria may result in cases of severe respiratory failure due to inflammation and necrosis of intra-airway, as pseudomembranous tracheobronchitis. Pseudomembranous tracheobronchitis is usually developed in immunocompromised patients, but it can also occur in immunocompetent patients on a very rare basis. We report a case of pseudomembranous tracheobronchitis complicated by co-infection of inflenaza A and Staphylococcus aureus, causing acute respiratory failure in immunocompetent patients.

• Tuberculosis and Respiratory Diseases
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• v.81 no.1
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• pp.6-12
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• 2018

The role of the treatment for latent tuberculosis infection (LTBI) has been underscored in the intermediate tuberculosis (TB) burden countries like South Korea. LTBI treatment is recommended only for patients at risk for progression to active TB-those with frequent exposure to active TB cases, and those with clinical risk factors (e.g., immunocompromised patients). Recently revised National Institute for Health and Care Excellence (NICE) guideline recommended that close contacts of individuals with active pulmonary or laryngeal TB, aged between 18 and 65 years, should undergo LTBI treatment. Various regimens for LTBI treatment were recommended in NICE, World Health Organization (WHO), and Centers for Disease Control and Prevention guidelines, and superiority of one recommended regimen over another was not yet established. Traditional 6 to 9 months of isoniazid (6H or 9H) regimen has an advantage of the most abundant evidence for clinical efficacy-60%-90% of estimated protective effect. However, 6H or 9H regimen is related with hepatotoxicity and low compliance. Four months of rifampin regimen is characterized by less hepatotoxicity and better compliance than 9H, but has few evidence of clinical efficacy. Three months of isoniazid plus rifampin was proved equivalence with 6H or 9H regimen in terms of efficacy and safety, which was recommended in NICE and WHO guidelines. The clinical efficacy of isoniazid plus rifapentine once-weekly regimen for 3 months was demonstrated recently, which is not yet introduced into South Korea.

• IMMUNE NETWORK
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• v.14 no.6
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• pp.307-320
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• 2014

Mycobacterium scrofulaceum is an environmental and slow-growing atypical mycobacterium. Emerging evidence suggests that M. scrofulaceum infection is associated with cervical lymphadenitis in children and pulmonary or systemic infections in immunocompromised adults. However, the nature of host innate immune responses to M. scrofulaceum remains unclear. In this study, we examined the innate immune responses in murine bone marrow-derived macrophages (BMDMs) infected with different M. scrofulaceum strains including ATCC type strains and two clinically isolated strains (rough and smooth types). All three strains resulted in the production of proinflammatory cytokines in BMDMs mediated through toll-like receptor-2 and the adaptor MyD88. Activation of MAPKs (extracellular signal-regulated kinase 1/2, and p38, and c-Jun N-terminal kinase) and nuclear receptor (NF)-${\kappa}B$ together with intracellular reactive oxygen species generation were required for the expression of proinflammatory cytokines in BMDMs. In addition, the rough morphotypes of M. scrofulaceum clinical strains induced higher levels of proinflammatory cytokines, MAPK and NF-${\kappa}B$ activation, and ROS production than other strains. When mice were infected with different M. scrofulaceum strains, those infected with the rough strain showed the greatest hepatosplenomegaly, granulomatous lesions, and immune cell infiltration in the lungs. Notably, the bacterial load was higher in mice infected with rough colonies than in mice infected with ATCC or smooth strains. Collectively, these data indicate that rough M. scrofulaceum induces higher inflammatory responses and virulence than ATCC or smooth strains.

• Tuberculosis and Respiratory Diseases
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• v.45 no.5
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• pp.1087-1093
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• 1998

Mucormycosis is the common name given to several different diseases caused by fungi of the order Mucorales. The mucoraceae are ubiquitous fungi and are common inhabitants of decaying matter. In contrast to the widespread distribution of these fungi, disease in humans is limited, in most cases, to people with severe immunocompromised, diabetes mellitus, or trauma. 1be fungus gains entry to the body through the respiratory tract. The spores are presumably deposited in the nasal turbinates and may be inhaled into the pulmonary alveoli. The manifestations of mucormycosis are rhinocerebral, pulmonary, cutaneous, gastrointestinal, central nervous system, and miscellaneous. Sporadic reports can be found of mucormycosis involving other areas : heart, bones, kidney, bladder, mediastinum, and trachea. However, isolated tracheal mucormycosis is very rare. Therefore, we report a 57-year old, noninsulin dependent diabetic woman who presented with acute, severe degree of upper airway obstruction due to isolated mucormycosis of the trachea.