• Tuberculosis and Respiratory Diseases
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• 제78권4호
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• pp.412-415
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• 2015

The prevalence of lung diseases caused by nontuberculous mycobacteria (NTM) is increasing worldwide. Unlike pulmonary tuberculosis, endobronchial NTM diseases are very rare with the majority of cases reported in patients with human immunodeficiency virus infection and acquired immune deficiency syndrome. We reported a rare case of endobronchial Mycobacterium avium disease associated with lobar atelectasis in a young immunocompetent patient and reviewed the relevant literature.

• 대한임상검사과학회지
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• 제46권2호
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• pp.47-53
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• 2014

The purpose of this study was to evaluate the clinical utility of TB/NTM PCR by comparing the results of TB PCR to detect Mycobacterium tuberculous (MTB) and nontuberculous mycobacteria (NTM) from paraffin-embedded tissue specimens. A total of 60 cases were tested using TB PCR and TB/NTM PCR. The MTB and NTM rate of TB/NTM PCR was 84.2% (16/19), 10.5% (2/19) in TB positive of TB PCR. The NTM rate of TB/NTM PCR was 29.3% (12/41) in TB negative of TB PCR. Fourteen different species of NTM were identified, the common isolate was M. gordonae (21.4%), M. avium (14.3%), M. ulcerans (7.1%), M. interjectum (7.1%), M. gilvum (7.1%), M. fortuitum (7.1%), M. mucogenicum (7.1%). The rare species identified were M. farcinogenes (7.1%), M. tokaiense (7.1%). Therefore, TB/NTM PCR is useful to differentiate MTB and NTM from paraffin-embedded tissue specimens and it is more effective in detecting NTM with TB PCR.

• Journal of Microbiology and Biotechnology
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• 제19권3호
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• pp.323-330
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• 2009

Nontuberculous mycobacteria (NTM) are a major cause of opportunistic infections in immunocompromised patients, making the reliable and rapid identification of NTM to the species level very important for the treatment of such patients. Therefore, this study evaluated the usefulness of the novel target genes tuf and tmRNA for the identification of NTM to the species level, using a PCRrestriction fragment length polymorphism analysis (PRA). A total of 44 reference strains and 17 clinical isolates of the genus Mycobacterium were used. The 741 bp or 744 bp tuf genes were amplified, restricted with two restriction enzymes (HaeIII/MboI), and sequenced. The tuf gene-PRA patterns were compared with those for the tmRNA (AvaII), hsp65 (HaeIII/HphI), rpoB (MspI/HaeIII), and 16S rRNA (HaeIII) genes. For the reference strains, the tuf gene-PRA yielded 43 HaeIII patterns, of which 35 (81.4%) showed unique patterns on the species level, whereas the tmRNA, hsp65, rpoB, and 16S rRNA-PRAs only showed 10 (23.3%), 32 (74.4%), 19 (44.2%), and 3 (7%) unique patterns after single digestion, respectively. The tuf gene-PRA produced a clear distinction between closely related NTM species, such as M. abscessus (557-84-58) and M. chelonae (477-84-80-58), and M. kansasii (141-136-80-63-58-54-51) and M. gastri (141-136-117-80-58-51). No difference was observed between the tuf-PRA patterns for the reference strains and clinical isolates. Thus, a diagnostic algorithm using a tuf gene-targeting PRA is a promising tool with more advantages than the previously used hsp65, rpoB, and 16S rRNA genes for the identification of NTM to the species level.

• Tuberculosis and Respiratory Diseases
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• 제74권4호
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• pp.191-194
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• 2013

Mycobacterium chelonae lung disease is very rare. We report a case of lung disease caused by M. chelonae in a previously healthy woman. A 69-year-old woman was referred to our hospital because of hemoptysis. A computed tomography (CT) scan of the chest revealed bronchiolitis associated with bronchiectasis in the lingular division of the left upper lobe. Nontuberculous mycobacteria were isolated three times from sputum specimens. All isolates were identified as M. chelonae by various molecular methods that characterized rpoB and hsp65 gene sequences. Although some new lesions including bronchiolitis in the superior segment of the left lower lobe developed on the chest CT scan 35 months after diagnosis, she has been followed up without antibiotic therapy because of her mild symptoms. To the best of our knowledge, this is the first case of M. chelonae lung disease in Korea in which the etiologic organisms were confirmed using molecular techniques.

• 대한의생명과학회지
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• 제26권3호
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• pp.170-178
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• 2020

Mycobacterium tuberculosis (MTB) continues to be one of the main causative agents of tuberculosis (TB); moreover, the incidence of nontuberculous mycobacteria (NTM) infections has been rising gradually in both immunocompromised and immunocompetent patients. Precise and rapid detection and identification of MTB and NTM in respiratory specimens are thus important for MTB infection control. Molecular diagnostic methods based on the nucleic acid amplification test (NAAT) are known to be rapid, sensitive, and specific compared to the conventional acid-fast bacilli (AFB) smear and mycobacterial culture methods. In the present study, the clinical performances of three commercial molecular diagnostic assays, namely TB/NTM PCR (Biocore), MolecuTech Real MTB-ID^® (YD Diagnostics), and REBA Myco-ID^® (YD Diagnostics), were evaluated with a total of 92 respiratory specimens (22 AFB smear positives and 67 AFB smear negatives). The sensitivity and specificity of TB/NTM PCR were 100% and 75.81%, respectively. The corresponding values of MolecuTech Real MTB-ID^® and REBA Myco-ID^® were 56.52% and 90.32%, and 56.52% and 82.26%, respectively. TB/NTM PCR showed the highest sensitivity; however, the concordant rate was 10% compared with sequence analysis. Although MolecuTech Real MTB-ID^® showed lower sensitivity, its specificity was the highest among the three methods. REBA Myco-ID^® allowed accurate classification of NTM species; therefore, it was the most specific diagnostic method. Of the three PCR-based methods, MolecuTech Real MTB-ID^® showed the best performance. This method is expected to enable rapid and accurate identification of MTB and NTM.

• 대한임상검사과학회지
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• 제45권2호
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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.

• Tuberculosis and Respiratory Diseases
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• 제83권2호
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• pp.141-146
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• 2020

Background: The burden of nontuberculous mycobacterial (NTM) pulmonary disease (PD) is increasing globally. To understand the treatment outcomes and prognosis of NTM-PD, a unified registry is needed. In this project, we aim to construct a multicenter prospective observational cohort with NTM-PD in South Korea (NTM-KOREA). Methods: The primary objective of this study is to analyze treatment outcomes according to the species. In addition, recurrence rate, adverse events, the impact of each drug on treatment outcomes as well as the impact of characteristics of mycobacteriology will be analyzed. The inclusion criteria for the study are as follows: fulfilling the criteria for NTM-PD having one of the following etiologic organisms: Mycobacterium avium complex, M. abscessus subspecies abscessus, M. abscessus subspecies massiliense, or M. kansasii; receiving the first treatment for NTM-PD after enrollment; age >20 years; and consenting to participate in the study. Seven institutions will participate in patient enrollment and about 500 patients are expected to be enrolled. Participants will be recruited from 1 March 2020 until 19 March 2024 and will be observed through 19 March 2029. During the follow-up period, participants' clinical course will be tracked and their clinical data as well as NTM isolates will be collected. Conclusion: NTM-KOREA will be the first nationwide observational cohort for NTM-PD in South Korea. It will provide the information to optimize treatment modalities and will contribute to deeper understanding of the treatment outcomes and long-term prognosis of patients with NTM-PD in South Korea.

• Tuberculosis and Respiratory Diseases
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• 제67권3호
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• pp.199-204
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• 2009

Background: To examine the recovery rate of nontuberculous mycobacteria (NTM) from respiratory specimens and the clinical course of NTM pulmonary disease at a 700-bed secondary hospital. Methods: This study analyzed the results of 843 acid-fast bacilli (AFB) culture-positive respiratory specimens from 650 subjects collected between May 2003 and April 2008. In addition, the clinical course of NTM pulmonary disease, diagnosed using criteria established by the American Thoracic Society, was examined. Results: There were 67 (7.9%) NTM isolates recovered from 52 (8.0%) subjects. Among the 535 AFB smear-positive specimens, 34 (6.3%) NTM isolates were recovered. There were 33 (10.7%) NTM isolates were recovered from 308 AFB smear-negative specimens. Of 52 subjects with isolated NTM, M. intracellulare was the most common species at 73.1% (n=33), followed by M. kansassi (n=7), M. abscessus (n=2), M. fortuitum (n=2), and M. avium (n=1). Sixteen (30.8%) patients had NTM pulmonary disease and the most common causative organism was M. intracellulare (n=14, 87.5%). Of these, 6 cases attained negative conversion in culture, 4 cases failed to attain negative conversion because of poor cooperation or expiration from complicated underlying lung disease, and 5 cases were transferred to a higher-grade hospital. Conclusion: The recovery rate of NTM from respiratory specimens was relatively low and the most common species was M. intracellulare. Patients with NTM pulmonary disease showed variable clinical outcomes.

• Tuberculosis and Respiratory Diseases
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• 제77권3호
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• pp.136-140
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• 2014

Primary ciliary dyskinesia (PCD) is characterized by the congenital impairment of mucociliary clearance. When accompanied by situs inversus, chronic sinusitis and bronchiectasis, PCD is known as Kartagener syndrome. The main consequence of impaired ciliary function is a reduced mucus clearance from the lungs, and susceptibility to chronic respiratory infections due to opportunistic pathogens, including nontuberculous mycobacteria (NTM). There has been no report of NTM lung disease combined with Kartagener syndrome in Korea. Here, we report an adult patient with Kartagener syndrome complicated with Mycobacterium abscessus lung disease. A 37-year-old female presented to our hospital with chronic cough and sputum. She was ultimately diagnosed with M. abscessus lung disease and Kartagener syndrome. M. abscessus was repeatedly isolated from sputum specimens collected from the patient, despite prolonged antibiotic treatment. The patient's condition improved and negative sputum culture conversion was achieved after sequential bilateral pulmonary resection.

• Tuberculosis and Respiratory Diseases
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• 제75권5호
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• pp.199-204
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• 2013

Background: The number of patients with pulmonary disease caused by nontuberculous mycobacteria (NTM) has been increasing worldwide. The aim of this study was to evaluate long-term trends in the NTM recovery rate from respiratory specimens over a 10-year period in a tertiary referral hospital in South Korea. Methods: We retrospectively reviewed the records of mycobacterial cultures of respiratory specimens at Samsung Medical Center from January 2001 to December 2011. Results: During the study period, 32,841 respiratory specimens from 10,563 patients were found to be culture-positive for mycobacteria. These included 12,619 (38%) Mycobacterium tuberculosis and 20,222 (62%) NTM isolates. The proportion of NTM among all positive mycobacterial cultures increased from 43% (548/1,283) in 2001 to 70% (3,341/4,800) in 2011 (p<0.001, test for trend). The recovery rate of NTM isolates from acid-fast bacilli smear-positive specimens increased from 9% (38/417) in 2001 to 64% (1,284/1,997) in 2011 (p<0.001, test for trend). The proportion of positive liquid cultures was higher for NTM than for M. tuberculosis (p<0.001). The most frequently isolated NTM were Mycobacterium avium-intracellulare complex (53%) and Mycobacterium abscessus-massiliense complex (25%). Conclusion: The recovery rate of NTM from respiratory specimens in South Korea has increased steadily.