• Journal of Yeungnam Medical Science
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• v.32 no.2
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• pp.71-79
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• 2015

Background: Recent studies have shown that the nontuberculosis mycobacterium (NTM) recovery rate in clinical cultures has increased within Korea. However, another study conducted by a secondary hospital within Daegu reported different results. Therefore, the purpose of this study is to understand and evaluate the microbiological distribution and clinical features of NTM in Daegu. Methods: A retrospective study was conducted on 11,672 respiratory specimens undergoing acid fast bacilli (AFB) culture from 6,685 subjects who visited Yeungnam University Respiratory Center from January 2012 to December 2013. Results: Of the 11,672 specimens undergoing AFB culture, 1,310 specimens (11.2%) showed positive results. Of these specimens, NTM was recovered from 587 specimens, showing a recovery rate of 44.8%. Identification test for NTM was performed on 191 subjects; the results were as follows: M. avium-intracellulare complex (MAC) 123 (64.4%), M. abscessus 20 (10.5%), M. kansasii 12 (6.3%), and 33 other NTM germ strains. Of the 382 subjects with NTM, 167 were diagnosed with pulmonary NTM disease (43.7%), however virulence differed depending on NTM strain. Multivariate analysis showed that nodular bronchiectasis, the nodules, and finding consistent with cavity under imaging study were statistically significant for triggering pulmonary NTM disease. AFB culture showing MAC and M. abscessus was statistically significant as well. Positive predictive value for NTM polymerase chain reaction (NTM-PCR) was 88.6%. Conclusion: Results for NTM recovery rate within the Daegu area were similar to those for the Seoul metropolitan area. We can assume that NTM infection is increasing in our community, therefore AFB-positive subjects (1) should undergo NTM-PCR, (2) should have their culture results checked for differentiation of mycobacterium tuberculosis complex (MTB) from NTM, and (3) undergo NTM identification test to confirm its type. Administration of treatment with the above results should be helpful in improving the patients' prognosis.

• Tuberculosis and Respiratory Diseases
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• v.40 no.5
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• pp.483-494
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• 1993

Cell surface antigenic relationships between pathogenic mycobacteria have been investigated by the enzyme-linked immunosorbent assay using phenolkilled cells and their rabbits antisera. Homologous and heterologous reactions of Mycobacterium avium-intracellulare antisera before and after homologous and heterologous absorption revealed a close antigenic relationship between strains of the same species and between species if they were members of M. avium(MA)-intracellulare(MI)-scrofulaceum(MG) complex. MAI sera showed a considerable reaction with M. kansasii(MK) and tuberculosis(MTB), but not with the other species. MA(K40004) antiserum reacted with other mycobacteria except few strains of MI and 50~89% of homologous reaction was reduced by heterologous absorption with cells of MI or MS. Intraspecific reaction of MI antisera was natural1y stronger than interspecific reaction and different in extent due to a magnitude of antigenic sharing. Antigenic relationships between N-260D, N-260R, N-260T, and K41014 was somewhat closer than that with N-242D, N-257T, N-28ID, and N-275T. M. nonchromogenicum(MNC) antisera showed a strong interspecific reaction with exception of M. chelonei(MC) and triviale(MTV) to which they reacted weakly or none. Antigenic sharing with M. terrae(MTR) and MG(K30003) was next to intraspecific sharing. NC-3 shared antigens considerably with MA, MC, and M. fortuitum(MF) while NC-11 did not. MTR antisera showed a strong cross-reaction with MI but their homologous reaction was not reduced by MI absorption indicating a paucity of shared antigen of MTR surface. Intraspecific antigenic sharing of course was large with on exception between T-8 and T-13. A considerable amount of antigenic sharing was also found with MNC, MC and MF. Unlike T-8 serum, T-13 antiserum strongly cross-reacted with MA, MG, MK, and MTB. In general, antigenic relationships of mycobacteria, that have been elucidated in this study, well conformed to taxons delineated by the various biological and biochemical means.

• Tuberculosis and Respiratory Diseases
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• v.83 no.2
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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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• v.58 no.4
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• pp.385-391
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• 2005

Background : The incidence of nontuberculous mycobacterium (NTM) infections in Korea is increasing. This retrospective study was performed to examine the recovery rate of NTM from respiratory specimens as well as the isolated NTM colony characteristics, and to assess the clinical significance of a NTM isolation. Methods : The results of the respiratory specimens requested for an acid-fast bacilli (AFB) examination during 2002 at Asan Medical Center, along with the patients clinical characteristics were analyzed. Results : A total 26,820 respiratory specimens were requested for the acid-fast bacilli (AFB) smear and culture during the study period. The proportion of M. tuberculosis and NTM isolation was 5.7% and 2.2%, respectively. Among the AFB smear and culture positive specimens, 12.2% were found to be NTM. The scotochromogen showing a low colony count < 20, which appeared to be contaminants, were isolated in 31.8% of the 584 NTM isolates. Excluding the low-colony scotochromogens, the M. avium-intracellulare complex was the most common NTM isolates (42.1%), and was also the most common causative organism for NTM pulmonary diseases. 8.4% (23/275) and 17.8% (49/275) of patients with NTM isolates met the American and British Thoracic Society diagnostic criteria for NTM pulmonary disease, respectively. Conclusion : In case of a positive AFB-smear or culture result, the possibility of NTM being a causative organism should always be considered, even in Korea, which has an intermediate incidence of tuberculosis.

• Tuberculosis and Respiratory Diseases
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• v.57 no.6
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• pp.528-534
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• 2004

Background : Microscopic examination of sputum smears for acid-fast bacilli (AFB) is the most important and rapid diagnostic test for pulmonary tuberculosis. However, the AFB observed on the smear may represent either M. tuberculosis or nontuberculous mycobacteria (NTM). This study examined the clinical usefulness of a polymerase chain reaction test for M. tuberculosis (TB-PCR) for the differentiation of pulmonary tuberculosis and NTM lung disease in patients with smear-positive sputums in a tertiary hospital in Korea. Material and Methods : From January, 2003 to December, 2003, 826 AFB smear-positive and culture-positive sputum specimens were collected from 299 patients. Results : NTM were recovered from 26.6% (220/826) of the smear-positive sputum specimens and 23.4% (70/299) of the patients with smear-positive sputum. All the patients with isolated NTM had clinically significant NTM lung disease; 38 patients (54.3%) had M. avium and 26 patients (37.1%). had M. abscessus. In the patients with pulmonary tuberculosis, 78.7% of the patients (74/94) showed TB-PCR positivity, and all the patients with NTM lung disease showed negative results on the TB-PCR test (p<0.001). A positive result of the TB-PCR test on the sputum or bronchial washing fluid specimens was able to predict pulmonary tuberculosis with 88.4% sensitivity, 100% specificity, a 100% positive predictive value and a 79.7% negative predictive value for the patients with smear-positive sputum. Conclusion : The TB-PCR test for sputum specimens or bronchial washing fluid specimens could be useful for differentiating pulmonary tuberculosis and NTM lung disease for the patients with smear-positive sputum in Korea.

• Tuberculosis and Respiratory Diseases
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• v.66 no.1
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• pp.37-41
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• 2009

Hot tub lung has been described as a pulmonary illness associated with exposure to nontuberculous mycobacteria,mainly hot bathtub water contaminated with Mycobacterium avium complex (MAC) and hence the name. Although not entirely clear, its etiology has been thought to involve either an infection or a hypersensitivity pneumonitis secondary to MAC. Herein, we describe 2 female patients (60 and 53 years old) admitted to our hospital with hot tub lung, and both of whom worked in a public bath. Both women were initially admitted following several months of exertional dyspnea and cough. The patients had been working as body-scrubbers in a public bath for several years. Their chest CT scans showed bilateral diffuse ground-glass opacities with multifocal air-trappings and poorly defined centrilobular nodules in both lungs. Pathological findings from lung specimens revealed small non-necrotizing granuloma in the lung parenchyme with relatively normal-looking adjacent alveoli. Discontinuation of working in the public bath led to an improvement in symptoms and radiographic abnormalities, without antimycobacterial therapy.