• Tuberculosis and Respiratory Diseases
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• v.56 no.1
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• pp.5-17
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• 2004

• Tuberculosis and Respiratory Diseases
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• v.60 no.5
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• pp.571-575
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• 2006

Mycobacterium avium has been traditionally described as an opportunistic organism that causes disseminated disease in human immunodeficiency virus-positive patients and acts as a pulmonary pathogen in patients with underlying lung diseases such as chronic obstructive pulmonary disease or previously treated tuberculosis. Infections caused by M. avium in immunocompetent hosts usually manifest as 2 distinct subtypes, the upper lobe cavitary form and the nodular bronchiectatic form. However endobronchial lesions due to M. avium infections in immunocompetent host are reasonably rare, and there are no reports of this condition in Korea. We report here a case of endobronchial lesions involved in an M. avium infection in an immunocompetent 21 year-old female patient with no preexisting lung disease.

• Tuberculosis and Respiratory Diseases
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• v.54 no.4
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• pp.459-466
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• 2003

Mycobacterium kansasii is the second most common cause of nontuberculous mycobacterial pulmonary disease in Western countries and Japan. The clinical and radiological features of pulmonary disease caused by M. kansasii usually resemble those of pulmonary tuberculosis including cavitary infiltrates with an upper lobe predilection. It is also now apparent that patients with M. kansasii pulmonary disease can present with noncavitary nodular bronchiectatic infiltrates similar to lung diseases of M. avium complex. With rifampin-containing regimens, treatment success rates are almost 100%. Timely diagnosis before the development of extensive disease and effective overall treatment strategies are very important to ensure that patients receive the appropriate medications for a sufficiently long period of time. To our knowledge, there has been no Korean case report of M. kansasii pulmonary disease in the immunocompetent patient until now. We report three cases of M. kansasii pulmonary disease in immunocompetent adult patients.

• Tuberculosis and Respiratory Diseases
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• v.54 no.1
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• pp.33-44
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• 2003

Background : Mycobacterium avium complex(MAC) is the most common respiratory pathogen in nontuberculous mycobacterial pulmonary disease. This study described the clinical characteristics of the patients with pulmonary disease caused by MAC. Materials and Methods : The clinical characteristics of 24 patients with pulmonary disease caused by the MAC, who fulfilled the 1997 American Thoracic Society diagnostic criteria for nontuberculous mycobacterial pulmonary disease, were retrospectively analyzed. Results : Fourteen patients(58%) were male and the median age at diagnosis was 61 years(range 46-75). Of the 24 patients, 16(67%) had a M. intracellulare infection, 7(29%) had a M. avium infection and one patient was not identified. Coughing (92%) and sputum (88%) were most frequently observed symptoms. The sputum smear for acid-fast bacilli was positive in 17(71%) patients. Fourteen(58%) patients had the upper lobe cavitary form and 10(42%) patients had the nodular bronchiectatic form. In a comparison between the patients with the upper lobe cavitary form and those with the nodular bronchiectatic form, significant differences were found according to sex(male 86% vs. 20%, p=0.003), smoking history(79% vs. 10%, p=0.008), the presence of an underlying disease(64% vs. 20%, p=0.036), the pulmonary function(% forced vital capacity, median 71% vs. 88%, p=0.022; % forced expiratory volume in one second, median 69% vs. 89%, p=0.051) and bilateral disease at chest radiography(29% vs. 90%, p=0.005). The time from the onset of symptoms to diagnosis was longer in those with the nodular bronchiectatic form(median 72 months, range 8-132) than those with the upper lobe cavitary form(median 22 months, range 6-60) Conclusions : MAC pulmonary disease occurs in two distinct populations with two distinct clinical presentations. For a correct diagnosis of MAC pulmonary disease, knowledge of the diverse clinical and radiological findings is essential.

• Tuberculosis and Respiratory Diseases
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• v.67 no.3
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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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• v.59 no.6
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• pp.606-612
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• 2005

Background : It has been reported that nontuberculosis mycobacterium(NTM) isolates account for approximately 10% of patients with a positive Acid-Fast Bacilli(AFB) smear. Therefore, it is necessary to consider NTM pulmonary disease when such a positive test is encountered. The aim of this study was to evaluate the etiologies and clinical characteristics of patients with NTM pulmonary disease who had been treated at a national tuberculosis hospital. Methods : The NTM isolates were recovered from the sputum or bronchial washing specimens submitted to a clinical laboratory of National Masan TB Hospital from August 2002 to July 2003. All samples were identified using a polymerase chain reaction-restriction fragment length polymorphism analysis method, which amplifies the rpoB gene. The patients were diagnosed with NTM disease according to the American Thoracic Society diagnostic criteria. Results : One hundred NTM isolates were recovered from 57 patients. Of the 100 isolates, M. avium complex(MAC) was the most common species, which was found 55%(n=55) of patients, followed by M. abscessus(n=25), and M. fortuitum( n=9). 26(45.6%) patients had NTM disease. Twenty-six (45.6%) patients had NTM disease according to The American Thoracic Society classification. The main organisms involved in NTM disease were MAC(n=19, 73.1%) and M. abscessus(n=5, 19.2%). The pathogenic potential was 67.9% in M. intracellulare and 41.7% in M. abscessus. The predictive factors related to NTM disease were a positive sputum smear (OR 6.4, p=0.02) and the isolation of either MAC or M. abscessus(OR 6.9, p=0.007). Fifteen patients(57.7%) were cured. There were no significant factors associated with the treatment success. Conclusion : There was a relatively high proportion of NTM disease in NTM isolates and the common species were MAC and M. abscessus. The predictive factors for NTM disease were a positive sputum smear and the isolation of either MAC or M. abscessus.

• Tuberculosis and Respiratory Diseases
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• v.54 no.1
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• pp.45-56
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• 2003

Background : Mycobacterium abscessus is the most common respiratory pathogen in rapidly growing mycobacteria and is resistant to all of the first-line antituberculosis drugs. This report describes the clinical and radiographic characteristics in patients with pulmonary disease caused by M. abscessus. Materials and Methods : Twelve patients with pulmonary disease caused by M. abscessus who fulfilled the 1997 American Thoracic Society diagnostic criteria for a nontuberculous mycobacterial pulmonary infection were observed over a five-and-a-half year period. The clinical characteristics and chest radiographic findings were analyzed, retrospectively. Results : The patients were predominantly female(11/12, 92%) and nonsmokers(12/12, 100%). Coughing (10/12, 83%), sputum(10/12, 83%) and hemoptysis(10/12, 83%) were the common symptoms and they had prolonged periods from the onset of symptoms to the diagnosis of their disease(median 6.5 years). Eleven (92%) patients had a previous history of being treated for pulmonary tuberculosis. The sputum specimens were acid-fast bacilli smear-positive in all patients. All patients were administered antituberculosis drugs. Six (50%) patients were treated with second-line antituberculosis drugs on account of persistent smear-positive sputum specimens. The chest radiographs showed that reticulonodular opacities(11/12, 92%) were the most common pattern of abnormality, followed by cavitary lesions(5/12, 42%). The computed tomography findings suggested bronchiolitis from the centrilobular nodules with a tree-in-bud appearances(9/10, 90%) and bronchiectasis (9/10, 90%) were the most common, followed by well-defined nodules smaller than 10-mm in diameter(7/10, 70%). Conclusions : M. abscessus pulmonary disease should be recognized as a cause of chronic mycobacterial lung disease, and respiratory isolates should be assessed carefully.

• Tuberculosis and Respiratory Diseases
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• v.54 no.1
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• pp.22-32
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• 2003

Background : Sputum smears for acid-fast bacilli(AFB) examined microscopically is the most important 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 recovery rate of NTM from the AFB smear-positive sputum specimens in a tertiary hospital in Korea. Materials and Methods : This study analyzed the results for the 1,889 AFB smear-positive and culture-positive sputum specimens collected from 844 patients from July, 1997 to December, 2001. Results : The 1,889 sputum specimens collected from 844 patients tested positive on both microscopy and culture during the 4.5 years. The NTM were recovered from 10.3% (195/1,889) of the smear-positive sputum specimens and 11.0% (93/844) of patients with smear-positive sputum. The NTM were isolated more than two times in 44.1% (41/93) of the patients from whom the NTM was recovered. Trends of the recovery rate of the NTM from the AFB smear-positive sputum specimens were increasing from 6.5%(17/262) in the latter half of 1997 to 17.8%(36/202) in the latter half of 2001 (p<0.001, test for trend). Conclusions : These results suggest that some patients with AFB smear-positive sputum have NTM pulmonary disease rather than pulmonary tuberculosis in Korea.

• Tuberculosis and Respiratory Diseases
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• v.57 no.4
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• pp.311-319
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• 2004

Background : It has been well known that bronchiectasis (BE) is a predisposing condition for pulmonary NTM infection, whereas there are some suggestions that BE, especially nodular BE, may be a result of NTM pulmonary infection. This retrospective study was done to investigate the prevalence of NTM pulmonary infection in the patients with BE. Methods : Eight hundred sixty-six patients, who underwent chest CT and sputum AFB examination and had BE detected by chest CT at Asan Medical Center in 2002, were included in this study. They were divided into Group I (bilateral BE, especially in RML, lingular or both lower lobes; 134), Group II (BE accompanied with fibrocavitary lesions commonly found in tuberculosis, usually both upper lobes; 233) and Group III (except Group I, II; 499) according to the radiological findings. Group I was subdivided into Group I+ (62) or Group I- (72) according to the presence or absence of centrilobular nodules, respectively. The sputum AFB examination, clinical and radiological findings were analyzed and compared between groups. Results : The number of patients who had at least one positive NTM culture was significantly higher in Group I+ compared with others (p<0.05); 24.2% in Group I+, 6.9% in Group I-, 9.9% in Group II, 6.0% in Group III and 4.1% in control. The number of patients who had true NTM infection defined by ATS guideline was higher in Group I+ (5, 8.1%) compared with others (p<0.05). In all groups, M. avium-intracellulare comlex was the most common isolates. Conclusion : Even though true NTM pulmonary disease was more prevalent in the patients with nodular BE, especially located in RML, left linguar, or both lower lobes, only a small population of the patients with nodular BE met the ATS diagnostic criteria for NTM pulmonary disease. The other patients in nodular BE group may have subclinical stage of NTM infection or completely different diseases from NTM infection. Long-term clinical studies are needed to clarify this issue.