• Tuberculosis and Respiratory Diseases
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• 제69권5호
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• pp.331-336
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• 2010

Background: Recently, the rate of infections with non-tuberculous mycobacteria (NTM) has been increasing in Korea. Precise identification of NTM is critical to determination of the pathogen and to target treatment of NTM patients. Methods: Sixty-eight unclassified mycobacteria isolates by rpoB PCR-RFLP assay (PRA) collected in 2008 were analyzed by National Center for Biotechnology Information (NCBI) Basic Local Alignment Search Tool (BLAST) search after sequencing of 16S rRNA, hsp65, rpoB genes. Results: Nineteen strains of 68 isolates were specified as species after sequencing analysis of 3 gene types. We found 3 M. lentifulavum, 5 M. arupense, 4 M. triviale, 4 M. parascrofulaceum, and one M. obuense. One M. tuberculosis and another M. peregrinum were mutated at the Msp I recognition site needed for rpoB PRA. The remaining 49 isolates did not coincide with identical species at the 3 kinds genes. Conclusion: Sequencing analysis of 16S rRNA, hsp65, rpoB was useful for identification of NTM unclassified by rpoB PRA.

• 한국산업보건학회지
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• 제33권3호
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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.

• 대한임상검사과학회지
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• 제47권2호
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• pp.83-89
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• 2015

결핵(Mycobacterium tuberculosis, MTB) 감염은 아직까지 전 세계에서 높은 유병률과 사망의 주요 원인이 되고 있으며 비정형 결핵(nontuberculous mycobacteria, NTM)은 최근 후천성 면역결핍증(AIDS)이나, 종양, 이식 등으로 면역력이 저하된 환자들의 임상 검체에서 분리빈도가 증가함에 따라 분리 균주의 임상적 의의가 중요시 되고 있다. 이에 항산균 염색을 이용한 객담 도말검사는 결핵균과 비정형 결핵균을 구별할 수 없다는 제한점이 있고, 균 분리배양검사는 시간이 오래 걸린다는 단점이 있어, 본 연구에서는 이러한 제한점을 가진 기존의 검사법을 대신하여 분자생물학적 방법인 중합효소 연쇄반응(polymerase chain reaction, PCR)을 이용하여 균 분리배양 검사와 비교하여 보았다. Mycobacteria를 동정하는데 항산균 염색과 3% ogawa 배지를 이용하였고, 균 분리배양 후 M. tuberculosis를 확인하기 위해서 niacin test를 실시한 결과 집락의 DNA를 추출하여 PCR후 동정된 M. tuberculosis와 niacin 양성이 일치함을 확인할 수 있었다. 또, 이 실험에서 항산성균 염색이 2+ 이상인 객담검체와 집락검체 각각에서 DNA를 추출하여 결핵균을 동정하는 방법으로 M. tuberculosis complex에 특징적으로 존재하는 insertion sequence (IS) 6110의 특정부위인 547 bp와 285 bp 부분을 증폭한 two-tube nested polymerase chain reaction을 시행하였고, 비정형 결핵균 동정법으로는 mycobacteria에 공통적으로 존재하는 rpoB 유전자 중 일부인 360 bp 부분을 증폭한 후, 제한효소 Msp I을 첨가 PCR-restriction fragment length polymorphism (RFLP)을 시행하였으며, 결핵균과 비정형 결핵균 모두 동정율에 거의 차이가 없었다. 1+인 경우는 객담검체에서 PCR한 결과가 31.2%에서 집락검체의 PCR한 결과 93.7%까지 결핵균과 비정형결핵균의 동정율이 높아졌고, trace인 경우 객담검체에서 PCR 결과가 2%에서 집락검체에서 PCR한 결과가 97.9%까지 결핵균과 비정형 결핵균의 동정율을 높일 수 있었다. 이 실험에서 항산성균 염색 1+이하 일때 객담검체와 집락검체로 PCR을 실시하면 결핵균과 비정형 결핵균의 동정율에 차이가 있고, 배양만으로는 결핵균의 동정은 가능하지만 비정형 결핵균의 동정이 가능하지 않으므로 배양검사와 PCR 검사 모두를 병행하므로써 보다 신속하고 정확한 검사결과를 내는데 도움 될 것이다.

• Journal of Microbiology and Biotechnology
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• 제29권9호
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• pp.1401-1411
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• 2019

Mycobacterial cell walls comprise thick and diverse lipids and glycolipids that act as a permeability barrier to antibiotics or other chemical agents. The use of OH radicals from a non-thermal plasma jet (NTPJ) for the inactivation of mycobacteria in aqueous solution was adopted as a novel approach. Addition of water vapor in a nitrogen plasma jet generated OH radicals, which converted to hydrogen peroxide ($H_2O_2$) that inactivated non-pathogenic Mycobacterium smegmatis and pathogenic Mycobacterium tuberculosis H37Rv. A stable plasma plume was obtained from a nitrogen plasma jet with 1.91 W of power, killing Escherichia coli and mycobacteria effectively, whereas addition of catalase decreased the effects of the former. Mycobacteria were more resistant than E. coli to NTPJ treatment. Plasma treatment enhanced intracellular ROS production and upregulation of genes related to ROS stress responses (thiolrelated oxidoreductases, such as SseA and DoxX, and ferric uptake regulator furA). Morphological changes of M. smegmatis and M. tuberculosis H37Rv were observed after 5 min treatment with $N_2+H_2O$ plasma, but not of pre-incubated sample with catalase. This finding indicates that the bactericidal efficacy of NTPJ is related to the toxicity of OH and $H_2O_2$ radicals in cells. Therefore, our study suggests that NTPJ treatment may effectively control pulmonary infections caused by M. tuberculosis and nontuberculous mycobacteria (NTM) such as M. avium or M. abscessus in water.

• The Korean Journal of Medicine
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• 제99권4호
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• pp.169-179
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• 2024

In recent years, the incidence and prevalence of non-tuberculous mycobacteria lung disease (NTM-LD) has been increasing worldwide. In Korea, Mycobacterium avium complex (MAC) and Mycobacterium abscessus complex account for most common cause of NTM-LD. It is essential to elucidate the pathophysiology of NTM-LD. The pathophysiology of NTM-LD has not been fully understood, however, it can be divided into bacterial and host-side factor. Among the host factor, innate immunity plays an essential role in the initial host immune response against intracellular non-tuberculous mycobacteria (NTM), and adaptive immunity also has a role. However, the role of these immunity in mycobacterial disease has been mainly studied in tuberculosis, but studies on its role in NTM are limited. In this review, I focus on NTM innate and adaptive immunity, the role of macrophages and neutrophils, and host interaction in NTM infection.

• Tuberculosis and Respiratory Diseases
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• 제71권4호
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• pp.249-253
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• 2011

Background: Mycobacterial infection is a problem throughout the world along with the increase of immunocompromised patients. For this reason, there have been many methods for faster and more accurate diagnosis. In this study, we evaluated several laboratory methods for mycobacterial infection. Methods: From January to December 2009, 635 specimens were cultured with mycobacteria growth indicator tube (MGIT) and Ogawa media. Polymerase chain reaction (PCR) was performed with the AdvanSure tuberculosis (TB)/non-tuberculosis mycobacterium (NTM) real-time PCR Kit (LG Life Sciences, Seoul, Korea). The 69 samples showing positive culture results were identified with the AdvanSure Mycobacteria Genotyping Chip Kit (LG Life Science, Seoul, Korea). Results: Sixty-nine (10.9%) out of 635 samples showed positive results for mycobacterial culture. Among the 635 samples, 64 were positive in MGIT, but only 42 were positive in Ogawa media. Of the 635 samples, 607 (95.6%) showed the same results between MGIT and Ogawa and the results of 579 (95.4%) were also consistent with the TB/NTM real-time PCR results. However, in the case of NTM, only one (1/24, 4.2%) was positive in PCR. In the Mycobacteria genotyping chip analysis, the most frequently identified NTM species in descending order were M. avium, M. intracellulare, M. chelonae and M. abscessus. Conclusion: Culturing with a combination of MGIT and Ogawa is recommended to increase the recovery rate of mycobacteria. Although PCR missed a reasonable number of NTM, it is faster and usually gives results that concur with those from the culture. The appropriate combination of diagnostic methods with clinical correlation are necessary.

• Journal of Microbiology and Biotechnology
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• 제25권5호
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• pp.745-752
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• 2015

Tuberculosis (TB) is the most common mycobacterial infection in developing countries, requiring a rapid, accurate, and well-differentiated detection/diagnosis. For the rapid detection and discrimination of Mycobacterium tuberculosis complex (MTC) from non-tuberculous mycobacteria (NTM), a novel, simple, and primer-combined single-step multiplex PCR using three primer pairs (6110F-6110R, 1081F-1081R, and 23SF-23SR; annealing on each of IS6110, IS1081, and 23S rDNA targets), hereafter referred to as a triplex PCR, has been developed and evaluated. The expected product for IS6110 is 416 bp, for IS1081 is 300 bp, and for 23S rDNA is 206 bp by single PCR, which was used to verify the specificity of primers and the identity of MTC using DNA extracted from the M. tuberculosis H37Rv reference strain (ATCC, USA) and other mycobacteria other than tuberculosis (MOTT) templates. The triplex PCR assay showed 100% specificity and 96% sensitivity; the limit of detection for mycobacteria was ~100 fg; and it failed to amplify any target from DNA of MOTT (50 samples tested). Of 307 blinded clinical samples, overall 205 positive M. tuberculosis samples were detected by single PCR, 142 by conventional culture, and 90 by AFB smear methods. Remarkably, the triplex PCR could subsequently detect 55 positive M. tuberculosis from 165 culture-negative and 115 from 217 AFB smear-negative samples. The triplex PCR, targeting three regions in the M. tuberculosis genome, has proved to be an efficient tool for increasing positive detection/discrimination of this bacterium from clinical samples.

• Journal of Microbiology and Biotechnology
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• 제19권10호
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• pp.1259-1264
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• 2009

We assessed the capacity of two liquid-medium culture methods with automated incubation and reading systems (MB/BacT ALERT 3D System and BACTEC MGIT 960 System) and one solid-medium culture method ($L\ddot{o}wenstein$-Jensen) to detect mycobacteria in different types of clinical samples. Out of 1,770 cultured clinical samples (1,519 of respiratory origin and 251 of non respiratory origin), mycobacteria were isolated in 156 samples (135 M. tuberculosis complex, 8 M. chelonae, 6 M. kansasii, 4 M. fortuitum, 2 M. gordonae, and 1 M. marinum) by at least one of the methods used. The BACTEC MGIT 960 System proved to be the most sensitive method (86.5%), especially in the detection of M. tuberculosis complex (89.1%). However, $L\ddot{o}wenstein$-Jensen culture was the most sensitive (76.2%) to detect nontuberculous mycobacteria. The BACTEC MGIT 960 System showed the lowest mean detection time for mycobacterial growth (15.3 days), significantly shorter than the other two methods. Highest sensitivity (95.5%) and specificity (99.6%) values were obtained using the BACTEC MGIT 960 System with the $L\ddot{o}wenstein$-Jensen culture method, which was also the only combination capable of detecting 100% of the nontuberculous mycobacteria.

• 대한임상검사과학회지
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• 제52권4호
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• pp.349-355
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• 2020

최근 호흡기 검체에서 결핵균(Mycobacterium tuberculosis complex, MTBC) 검출은 감소하고 비결핵 항산균(nontuberculous mycobacteria, NTM)은 증가하고 있다. 본 연구는 2010년부터 2019년까지 광주 2차 병원에 의뢰된 호흡기검체 132,359예를 대상으로 NTM 검출 증가 대비 NTM 폐질환 환자의 증가와 연령 및 성별 분포를 조사하였다. 그리고 NTM양성환자의 폐결핵 감염 여부를 확인하고자 하였다. 항산균배양 양성률은 2010년 21.9% (1,624/7,403), 2019년 17.4% (1,937/11,161)였다. NTM 분리 비율은 2010년 38.0% (617/1,624)에서 2019년에 72.4% (1,403/1,937)로 증가하였다. NTM 양성환자의 NTM 폐질환 진단률은 평균 27.1%였다. 이 중 현재 폐결핵에 감염된 사례는 2010년 44.4%에서 2019년 23.5%로 감소하고 과거 진단 또는 치료 사례도 15.6%에서 10.6%로 감소하였다. 전체 NTM 폐질환 중 69.0%가 60대 이상이었으며 남자보다 여자 환자가 더 많았다. 향후 고령화와 결핵 관리 정책에 따라 NTM 검출은 증가하는 반면 MTBC는 감소할 것으로 예상되며, 실험실에서는 이 현상에 세심한 주의를 기울이고 지속적으로 검사 결과를 감시해야 할 것이다.

• Tuberculosis and Respiratory Diseases
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• 제79권3호
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• pp.134-142
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• 2016

In recent years, in spite of medical advancement, tuberculosis (TB) remains a worldwide health problem. Although many laboratory methods have been developed to expedite the diagnosis of TB, delays in diagnosis remain a major problem in the clinical practice. Because of the slow growth rate of the causative agent Mycobacterium tuberculosis, isolation, identification, and drug susceptibility testing of this organism and other clinically important mycobacteria can take several weeks or longer. During the past several years, many methods have been developed for direct detection, species identification, and drug susceptibility testing of TB. A good understanding of the effectiveness and practical limitations of these methods is important to improve diagnosis. This review summarizes the currently-used advances in non-molecular and molecular diagnostics.