• Journal of Microbiology
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• v.35 no.3
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• pp.177-180
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• 1997

The purpose of this study was to evaluate the efficiency of Line Probe Assay (LiPA) in detecting the rpoB gene mutation of clinically isolated Mycobacterium tuberculosis (MTB) and to compare the level of resistance to the various rifamycins with their mutation sites. The mutation in the rpoB gene was found in 84 (97.6%) out of 86 rifampicin (RMP) resistant strains as determined by LiPA. No mutation was observed in 2 RMP resistant strains and in any of 38 RMP susceptible strains tested. Only one of 3 strains with .DELTA.5/R5, one of 2 strains with .DELTA.3, and one of 3 strains with .DELTA.2/R2 LiPA profile showed a slightly lower level of resistance to the rifapentine than the other strains. Although we could not find correlations between mutation sites in the rpoB gene and the level of susceptibility to the various rifamycins, the LiPA is recommended as a fast screening tool for detection of RMP resistant MTB.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.3
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• pp.355-364
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• 2023

Objectives: The objective of the present study was to identify mycobacterial infection in retired dusty workers who were ineligible for medical care benefits for work-related pneumoconiosis. Methods: Sputum samples were collected from 170 retired dusty workers living in Gangwon-do. The mycobacterial culture was grown in 2% Ogawa medium and Mycobacteria Growth Indicator Tube(MGIT). Mycobacterial species were identified using MolecuTech REBA Myco-ID^Ⓡ. Results: Thirty-one(18.2%) out of 170 sputum samples were identified as positive for culture. Among the positive culture samples, eleven(6.5%) were identified as mycobacterial species. The proportion of mycobacteria was M. avium 2.3%(4/170), M. fortuitum complex 1.2%(2/170), M. intracellulare 1.2%(2/170), M. abscessus 0.6%(1/170), M. tuberculosis(MTB) complex 0.6%(1/170), and MYC(NTM except 19 species) 0.6%(1/170). Conclusions: In comparison with previous studies, the incidence rate of tuberculosis(TB) in retired dusty workers who were ineligible for medical care benefits for work-related pneumoconiosis was higher than in close contact with TB patients, workers exposed to silica, and patients with silicosis. And the proportion of non-tuberculosis mycobacteria(NTM) was higher than that of MTB.

• IMMUNE NETWORK
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• v.24 no.1
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• pp.4.1-4.19
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• 2024

TNF, a pleiotropic proinflammatory cytokine, is important for protective immunity and immunopathology during Mycobacterium tuberculosis (Mtb) infection, which causes tuberculosis (TB) in humans. TNF is produced primarily by phagocytes in the lungs during the early stages of Mtb infection and performs diverse physiological and pathological functions by binding to its receptors in a context-dependent manner. TNF is essential for granuloma formation, chronic infection prevention, and macrophage recruitment to and activation at the site of infection. In animal models, TNF, in cooperation with chemokines, contributes to the initiation, maintenance, and clearance of mycobacteria in granulomas. Although anti-TNF therapy is effective against immune diseases such as rheumatoid arthritis, it carries the risk of reactivating TB. Furthermore, TNF-associated inflammation contributes to cachexia in patients with TB. This review focuses on the multifaceted role of TNF in the pathogenesis and prevention of TB and underscores the importance of investigating the functions of TNF and its receptors in the establishment of protective immunity against and in the pathology of TB. Such investigations will facilitate the development of therapeutic strategies that target TNF signaling, which makes beneficial and detrimental contributions to the pathogenesis of TB.

• The Journal of the Petrological Society of Korea
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• v.19 no.2
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• pp.141-156
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• 2010

Dokdo Island, Korea, is located in the East Sea belonging to back arc basin. In this study we examined petrology and geochemistry of massive tuffaceous breccia (MTB) from Dongdo (Eastern islet) and Seodo(Western islet), the two largest islands of Dokdo. Field studies and chemical analysis distinguish the MTB in Dongdo and Seodo. The Dongdo MTB (DMTB) is exposed up to 50 m on the ocean cliff and it has dominant basalt and trachybasalt with moderate amount of trachyte and scoria. On the other hand, Seodo MTB (SMTB), which is preserved between trachyte dike and trachyandesite, is composed of roughly equal amounts of basalt, trachybasalt and trachyte. The location of the islets were related to the source vent having in contact with underlying trachyte lava and differential pyroclastic deposits made them different characteristics. According to trace element analysis of trachytic volcanic clasts, the Ba concentration ranges from 66 to 103 ppm and Sr varies from 44 to 56 ppm in DMTB. However, Br and Sr in SMTB correspondingly showed relatively wide ranges: Br 785-1259 ppm and Sr 466-1230 ppm. These differential trends between DMTB and SMTB, along with the difference in P and Ti, indicate that the crystallization of alkali feldspar, feldspathoid, biotite, apatite and titanium took place differently. Nevertheless, DMTB and SMTB are similar in REE patterns and they are correspondingly characterized by high LREE, low HREE and similar $(La/Yb)_N$ values with 23.9-40.2 in DMTB and 27.4-32.9 in SMTB. These patterns suggest that Dongdo and Seodo might be originated from coeval magma suites. Dokdo island shows high concentrations of Ba, K and Rb. These signatures mark a result attributed to the mantle upwelling because the magma derived from the asthenosphere was metasomatized with subduction-related fluids.

• Tuberculosis and Respiratory Diseases
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• v.79 no.4
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• pp.282-288
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• 2016

Background: Tuberculosis (TB) is a major health problem, and accurate and rapid diagnosis of multidrug-resistant (MDR) and extended drug-resistant (XDR) TB is important for appropriate treatment. In this study, performances of solid and liquid culture methods were compared with respect to MDR- and XDR-TB isolate recovery and drug susceptibility testing. Methods: Sputum specimens from 304 patients were stained with Ziehl-Neelsen method. Mycobacterium tuberculosis (Mtb) isolates were tested for recovery on $L{\ddot{o}wenstein$-Jensen (LJ) medium and the BacT Alert 3D system. For drug susceptibility testing of Mtb, isolates were evaluated on M-KIT plates and the BacT Alert 3D system. Results: The recovery rates were 94.9% (206/217) and 98.2% (213/217) for LJ medium and the BacT Alert 3D system, respectively (kappa coefficient, 0.884). The rate of drug resistance was 13.4% for at least one or more drugs, 6.0% for MDR-TB and 2.3% for XDR-TB. M-KIT plate and BacT 3D Alert 3D system were comparable in drug susceptibility testing for isoniazid (97.7%; kappa coefficient, 0.905) and rifampin (98.6%; kappa coefficient, 0.907). Antibiotic resistance was observed using M-KIT plates for 24 of the total 29 Mtb isolates (82.8%). Conclusion: The liquid culture system showed greater reduction in the culture period, as compared with LJ medium; however, drug susceptibility testing using M-KIT plates was advantageous for simultaneous testing against multiple drug targets.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.1
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• pp.20-28
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• 2018

Tuberculosis (TB) is a bacterial infection disease caused by members of the species Mycobacterium tuberculosis (MTB) complex. Approximately one third of the world's population is infected with TB. In Korea, approximately 40,000 new patients are identified each year. Moreover, infections from non-tuberculous mycobacteria (NTM) have also increased. In the diagnosis of TB and NTM, traditional bacterial cultures are required for 3 to 4 weeks. Therefore, rapid and accurate diagnostic tests for TB and NTM are needed. To distinguish between TB and NTM, a range of diagnostic methods have been developed worldwide. In vitro diagnostic assays are constantly being developed to meet the increasing need for the rapid and accurate identification for TB and NTM. On the other hand, the performance evaluations of in vitro diagnostic reagents for TB and NTM are lacking. Recently, the Korea Food and Drug Administration (KFDA) issued a guideline for in vitro diagnostic reagents for MTB and NTM. Here, this study analyzed the performance of currently developed in vitro diagnostic reagents for TB and NTM in the US FDA. This analysis of US FDA approved molecular assays could serve as a useful reference for an evaluation of the reagent performance of TB and NTM.

• Korean Journal of Clinical Laboratory Science
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• v.45 no.2
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• pp.48-53
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• 2013

Recently, the isolation rate of nontuberculous mycobacteria (NTM) in clinical laboratories and the incidence of NTM infections are on the increase in Korea, but there have been only a few studies that reveal the general aspect of NTM isolation or species distribution. Therefore, this study was performed to examine the species identification by PCR-restriction fragment length polymorphism analysis (PRA, PCR-RFLP), and the clinical significance of mycobacterial cultures. PRA was used during the novel region of the rpoB gene and was developed for rapid and precise identification of mycobacteria to the species level. From January 2012 to April 2012, we examined pre-identified nontuberculous mycobacteria (60 species in 3 hospital of Busan-Kyeongnam area). We confirmed 4 (6.6%) Mycobacterium tuberculosis (MTB) and 56 (93.4%) NTM from 60 pre-identified NTM species by multiplex PCR (MolecuTech $MTB-ID^R$ V3, YD Diagnostics, Korea) and PRA (Myco-ID, YD Diagnostics, Korea). The distribution of 56 NTM species were M. intracellulare type I 15 (26.7%), M. avium 14 (25%), M. abscessus 11 (19.5%), M. kansasii type I 3 (5.4%), M. pulveris 2 (3.6%), M. intracellulare type, M. chelonae, M. kansasii type V, M. gallinarum, M. wolinskyi. Respectively, 1 (1.8%) and 6 (10.7%) species were not identified.

• Korean Journal of Clinical Laboratory Science
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• v.41 no.1
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• pp.24-30
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• 2009

Rifampicin (RIF) and isoniazid (INH) are the most important drug for the treatment of Mycobacterium tuberculosis. Mutations correlated to rifampicin and isoniazid-resistance have been detected in rpoB gene and katG gene, respectively. Of the rifampicin-resistant isolates, 90% showed mutations in rpoB gene at codon 507 to 533. Isoniazid-resistant isolates analysed had a mutation in katG at codon 315. The aim of this study is to develop a pyrosequencing-based approach for rapid detection of ripampin or isoniazid resistant M. tuberculosis based on characterization of all possible mutation in the target region. For this study, the DNA selected from 35 cases of MTB PCR positive clinical sample such as bronchial washing, sputum, and pleural fluid. RIF or INH resistant was analyzed by pyrosequencing data of rpoB and katG gene. 28 (80%) and 7 (20%) of 35 MTB PCR positive DNAs were occured rifampicin-sensitivity and resistant, respectively. For INH, 30 (85.7%) and 5 (14.5%) cases were detected isoniazid-sensitivity and resistant, respectively. When pyrosequencing analysis was compared with ABI sequencing analysis, both analysis were presented same result, but pyrosequencing analysis was more rapid than ABI sequencing analysis. In conclusion, we found that pyrosequencing technology offers high accuracy, specificity, short turn around time and a high throughput in detection of rifampicin or isoniazid resistance in M. tuberculosis.

• Biomedical Science Letters
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• v.24 no.2
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• pp.94-101
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• 2018

Tuberculosis (TB) is infectious disease caused by Mycobacterium tuberculosis (MTB) infection. It is known that not only the property of microorganism but also the genetic susceptibility of infected patients is controlled. Interleukin 2 (IL-2) is a cytokine belonging to type 1 T helper (Th1) activity. In addition, IL-2, when infected with MTB, binds IL-2 receptor and promotes T cell replication and is involved in granuloma formation. The aim of this study was to investigate the genetic polymorphisms of the IL-2 receptor gene in tuberculosis patients and normal individuals. We analyzed 22 SNPs in three genes using the genotype data of 443 tuberculosis cases and 3,228 healthy controls from the Korea Association Resource for their correlation with tuberculosis case. IL2RA, IL2RB, and IL2RG genes were genotyped of 16, 4, and 2 SNPs, respectively. Among three genes, only IL2RA gene polymorphisms showed statistically significant association with tuberculosis case. 6 SNPs with high significance were identified in the IL2RA gene. In addition, the linkage disequilibrium (LD) structure of IL2RA gene was confirmed. SNP imputation of IL2RA gene was performed, it was confirmed that more SNPs were significant between case and control. If we look at the results of IL2RA gene analysis above, we can see that genetic polymorphism in the gene expressing $IL-2R{\alpha}$ will regulate the expression level of $IL-2R{\alpha}$, and the change in the immune system involved in $IL-2R{\alpha}$. In this study, genetic polymorphism that may affect host immunity suggests that susceptibility to tuberculosis may be controlled.

• Journal of Microbiology and Biotechnology
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• v.25 no.5
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• pp.738-744
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• 2015

Tuberculosis is one of the most threatening infectious diseases to public health all over the world, for which Mycobacterium tuberculosis (MTB) is the etiological agent of pathogenesis. Ursolic acid (UA) has immunomodulatory function and exhibits antimycobacterial activity. However, the intracellular killing effect of UA has yet to be elucidated. The aim of this study was to evaluate the intracellular killing effect of UA during mycobacterial infection. The intracellular killing activity of UA was evaluated in the macrophage cell line THP-1 by the MGIT 960 system as well as by CFU count. The production of reactive oxygen species (ROS) and the level of nitric oxide (NO) were measured using DCF-DA and Griess reagent, respectively. Phagocytosis was observed by a fluorescence-based staining method, and the colony forming units were enumerated on 7H11 agar medium following infection. In addition, MRP8 mRNA expression was measured by qRT-PCR. UA significantly decreased the number of intracellular Mycobacterium through generation of ROS and NO. In addition, it profoundly activated the phagocytosis process of THP-1 cells during MTB-infection. Furthermore, our data demonstrated that UA activated the phagocytosis process in human monocyte cells through MRP8 induction. These data suggest that UA firmly contributes to the intracellular killing effect of macrophages during mycobacterial infection.