• Tuberculosis and Respiratory Diseases
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• v.84 no.3
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• pp.237-244
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• 2021

Background: The emergence of drug-resistant tuberculosis (TB), is a major menace to cast off TB worldwide. Line probe assay (LPA; GenoType MTBDRplus ver. 2) and Xpert MTB/RIF assays are two rapid molecular TB detection/diagnostic tests. To compare the performance of LPA and Xpert MTB/RIF assay for early diagnosis of rifampicin-resistant (RR) TB in acid-fast bacillus (AFB) smear-positive and negative sputum samples. Methods: A total 576 presumptive AFB patients were selected and subjected to AFB microscopy, Xpert MTB/RIF assay and recent version of LPA (GenoType MTBDRplus assay version 2) tests directly on sputum samples. Results were compared with phenotypic culture and drug susceptibility testing (DST). DNA sequencing was performed with rpoB gene for samples with discordant rifampicin susceptibility results. Results: Among culture-positive samples, Xpert MTB/RIF assay detected Mycobacterium tuberculosis (Mtb) in 97.3% (364/374) of AFB smear-positive samples and 76.5% (13/17) among smear-negative samples, and the corresponding values for LPA test (valid results with Mtb control band) were 97.9% (366/374) and 58.8% (10/17), respectively. For detection of RR among Mtb positive molecular results, the sensitivity of Xpert MTB/RIF assay and LPA (after resolving discordant phenotypic DST results with DNA sequencing) were found to be 96% and 99%, respectively. Whereas, specificity of both test for detecting RR were found to be 99%. Conclusion: We conclude that although Xpert MTB/RIF assay is comparatively superior to LPA in detecting Mtb among AFB smear-negative pulmonary TB. However, both tests are equally efficient in early diagnosis of AFB smear-positive presumptive RR-TB patients.

• Tuberculosis and Respiratory Diseases
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• v.43 no.2
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• pp.128-137
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• 1996

Background : We can diagnose pulmonary tuberculosis with sputum AFB smear and culture, but sputum AFB smear has low sensitivity and culture needs long period, and they are not available in the patients who can not expectorate effectively. Recently developed, PCR is a fast diagnostic tool in tuberculosis, but false positive and false negative are important problems. So, we studied the diagnostic value of bronchoalveolar lavage fluid AFB smear, culture, PCR through the bronchoscopy. Methods : The 67 pulmonary tuberculosis patients and 43 non-pulmonary tuberculosis patients were analyzed with their sputum specimen AFB smear and culture. Also, bronchoscopy and bronchoalveolar lavage were done, and bronchoalveolar lavage fluid AFB smear, culture and PCR were done. Results: 1) In the cases of pulmonary tuberculosis, the sensitivity of sputum AFB smear and culture were 32.8% and 57.4%, respectively. And the sensitivity of bronchoalveolar lavage fluid AFB smear and culture were 47.8% and 80.6%. respectively. 2) In the cases of pulmonary tuberculosis, the sensitivity and the positive predictive value(for predicting a positive culture) of PCR were 80.6% and 81.5%, respectively. 3) In the cases of sputum AFB smear-negative and culture-negative pulmonary tuberculosis, the sensitivity of bronchoalveolar lavage fluid AFB smear, culture, PCR, and the positive predictive value(for predicting a positive culture) of PCR were 23.1%, 100%, 88.5%, and 82.4%, respectively. 4) The specificity of bronchoalveolar lavage fluid PCR was 77.0%. 5) The median number of days between obtaining a specimen and starting therapy was 5 days for sputum AFB smear, 9 days for bronchoalveolar lavage fluid AFB smear, 26 days for bronchoalveolar lavage fluid PCR, 32 days for sputum culture, 56 days for bronchoalveolar lavage fluid culture. Conclusion : The sensitivity of bronchoalveolar lavage fluid AFB smear and culture are higher than sputum AFB smear and culture. So, the bronchoscopy must be considered for evaluating suspected cases of pulmonary tuberculosis in patients from whom smears of expectorated sputum do not reveal mycobacteria or from whom no sputum can be obtained. Especially, combined with PCR, it is expected that pulmonary tuberculosis can be diagnosed more rapidly and more accurately, so bronchoalveolar lavage fluid APB smear and PCR can be helpful in the early treatment of pulmonary tuberculosis.

• Tuberculosis and Respiratory Diseases
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• v.47 no.6
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• pp.747-756
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• 1999

Background: Acid-fast stain and cultures for diagnosis of pulmonary tuberculosis are primary and essential method, but have their limitation : low sensitivity and time consuming. The objective of this study is comparison of amplified Mycobacterium tuberculosis direct test(MTD) by the conventional AFB smears and cultures in the detection of Mycobacterium tuberculosis in respiratory specimens. Methods: During the period between November, 1997 and May, 1998 a total of 267 respiratory specimens (sputum 173, bronchial washing 94) from 187 patients suspected pulmonary tuberculosis were subjected to AFB smears, cultures and MID test. MID is based on nucleic acid amplification. We compared the MID with 3% Ogawa culture method. In positive AFB smear and negative MID specimen, positive culture identification between nontuberculous mycobacterium and M.tuberculosis was assesed by using Accuprobe M.tuberculosis complex probe. In negative AFB smear and negative AFB culture, MTD results are assessed by clinical follow-up. Results : 1) Compared with culture in sputum and bronchial fluid specimens, sensitivity and specificity of MTD in positive AFB smear is 79.7% and 20.0%, sensitivity and specificity of MTD in negative AFB smear specimens is 75.0% and 79.7%. 2) Discrepant analysis is assessed by clinical follow-up and other specimen results beyond study. Culture negative but MTD positive specimens were proved to be true positive and gave MTD sensitivity 79.2%, specificity of 84.4%, positive predictive value 80.5% and negative predictive value 83.2%. 3) 14 out of 31 specimens in negative AFB smear, negative AFB culture and positive MTD showed pulmonary tuberculosis diagnosed on clinical follow-up and sensitivity is 45.2%. 4) 2 out of 13 specimens in positive AFB smear, positive AFB culture and negative MID diagnosed as non tuberculous mycobacterium by Accuprobe culture. Conclusion: This study suggested that MID in respiratory specimens is simple and rapid diagnostic method, but considered adjuvant method rather than replace the conventional AFB smear and culture.

• Tuberculosis and Respiratory Diseases
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• v.44 no.5
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• pp.1001-1010
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• 1997

Background : PCR technique is useful in diagnosis of pulmonary tuberculosis. But, its sensitivity and specificity is some different among several studies. Our aim is compare our PCR results with other's previous PCR results in AFB smear negative patients. Methods : PCR were performed in patients that their disease were suspected as active pulmonary tuberculosis and that their initial serial sputum AFB smear results were negative. Total number of patients studied by PCR technique was 177. Also, we analyzed the data only in patients whose bronchial washing fluid AFB smear was negative. And the primer had been used was IS 6110. Results : In our retrograde study, the number of patients who are diagnosed as having active pulmonary tuberculosis, inactive pulmonary tuberculosis and nontuberculous pulmonary disease was 99, 28, 50, respectively. In the sputum study, the sensitivity of PCR is 41.5% (27 PCR positive cases/65 active TBc cases). And the sensitivity of TB culture is 53.8% (35 TB culture positive cases/65 active TBc cases). In the bronchial washing specimen study, the sensitivity of PCR is 53.8% (21 PCR positive cases/39 active TBc cases). And the sensitivity of TB culture is 43.6% (17 TB culture Positive cases/39 active TBc cases). The specificity of PCR in our study is 94.9%. (74 PCR negative cases/78 inactive TBc or nontubereulous cases) In the cases of patients who were never takened anti-TBc medication, the sensitivity of PCR (45.6%--25 positive cases/55 cases) is some lower than culture (58.2%--32 positive cases/55 cases). In the cases of patients who had been takened anti-TBC medication. the sensitivity of PCR (60%--18 positive cases/30 cases) is some superior than culture (50%--15 positive cases/30 cases). Conclusion : We think that PCR results in cases of sputum AFB smear negative patients is nearly same as culture. And PCR is especially useful in patients who had been takened anti-TBc medication on admission.

• Tuberculosis and Respiratory Diseases
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• v.44 no.4
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• pp.899-906
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• 1997

Background : The percutaneous pleural needle biopsy have been regarded as cornerstone in the diagnosis of lymphocyte dominant pleural effusions of which acid fast bacilli smear and cytologic exam was negative. However, the complications of percutaneous pleural needle biopsy is not rare and its diagnostic efficacy is not always satisfactory. Recently, pleural fluid adenosine deaminase (ADA) and carcinoembryonic antigen (CEA) are widely accepted as markers of tuberculous pleurisy and malignant pleural effusion respectively. We designed this study to re-evaluate the role of percutaneous pleural needle biopsy in the diagnosis of lymphocyte dominant exudative pleural effusions whose AFB smear, cytologic exam was negative. Method : Retrospective analysis of 73 cases of percutaneous pleural needle biopsy in case of lymphocyte dominant exudative pleural effusions whose AFB smear and cytoloic exam was negative from Jan 1994 to Feb 1996 was done. Result : In 35 cases, specific diagnosis was obtained(all cases were tuberculous pleurisy), and in 30 cases specific diagnosis was not obtained in spite of getting adequate pleural tissues, and in the other 8 cases, percutaneous pleural biopsy failed to get pleural tissues. In 9 cases, complications were combined including pneuomothorax and hemothorax. All 49 cases of pleural effusions whose ADA value was higher than 40IU/L and satisfying other categories were finally diagnosed as tuberculous pleurisy, however, the pleural biopsy confirmed only 28 cases as tuberculous pleurisy. In 6 cases of pleural effusions of which CEA value is higher than 10ng/ml, the pleural biopsy made specific diagnosis in no case. Final diagnosis of above 6 cases consisted of 4 malignant effusions, 1 malignancy associated effusion and 1 tuberculous pleurisy. Conclusion : In the diagnosis of 73 cases of lymphocyte dominant pleural effusions of which acid fast bacilli smear and cytologic exam was negative, percutaneous pleural biopsy diagnosed only in 35 cases. In the diagnosis of tuberculous pleurisy, the positive predictive value of higher ADA than 40 IU/L in lymphocyte dominant pleural effusion with negative AFB smear and negative cytologic exam was 100%. And the diagnostic efficacy of pleural biopsy was 57%. In cases of effusions with high CEA than 10ng/ml 83% and 0% respectively. Finally, we concluded that percutaneous pleural needle biopsy in the diagnosis of AFB smear negative and cytologic exam negative lymphocyte dominant exudative pleural effusion was not obligatory. especially in effusions with high ADA and low CEA value.

• Korean Journal of Clinical Laboratory Science
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• v.38 no.3
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• pp.152-157
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• 2006

The purpose of this study was to evaluate the usefulness of the automated TB-PCR assay for the detection of Mycobacterium tuberculosis. The 807 cases were analyzed with their TB-PCR, AFB smear and culture in bronchial washing fluids, sputum and body fluids samples. The TB-PCR positive of the bronchial washing fluid, sputum and body fluids were 11.3%, 7.3% and 3.6%, respectively, in cases of AFB smear-negative and culture-negative. The sensitivity values of the bronchial washing fluid, sputum and body fluids were 93.3%, 100% and 50%, respectively, according to the culture result. The sensitivity of body fluids was lower than that of the bronchial washing fluid and sputum. The specificity values of the bronchial washing fluid, sputum and body fluids were 83.3%, 89.0% and 95.7%, respectively, according to the culture result. In conclusion, the automated TB-PCR assay proved to be a useful method for the detection of Mycobacterium tuberculosis in the bronchial washing fluid and sputum. But we think that there is still a need for us to study body fluids further.

• Tuberculosis and Respiratory Diseases
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• v.58 no.5
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• pp.452-458
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• 2005

Background : In Korea, polymerase chain reaction (PCR) test for M. tuberculosis has been used for the diagnosis of acid-fast bacilli (AFB) smear-negative tuberculosis in order to increase diagnostic sensitivity. However, there have been no data dealing with the clinical utility of PCR in AFB smear-positive patients to differentiate between M. tuberculosis and nontuberculous mycobacteria. Method : We retrospectively analyzed the PCR test results which have been performed in patients who had AFB smear-positive sputum but had ambiguous clinical manifestations of active tuberculosis. PCR test was done using $AMPLICOR^{\hat{a}}$ M. tuberculosis kit. The sensitivity, specificity, and positive and negative predictive values of the PCR test were calculated based on culture and final clinical diagnosis result. Results : Fifty-six consecutive patients (62 PCR tests) were included in the study. Active tuberculosis was diagnosed in 23 patients (41.0%), while 9 patients had NTM infection (16.0%). The sensitivity, specificity, positive- and negative-predictive value of PCR test were 88.8%, 86.8%, 76.1% and 94.3%, respectively, according to the culture result. In comparison, they were 91.3%, 100%, 100%, 94.3%, respectively, according to the final clinical diagnosis. All 15 patients with NTM isolates, including 6 patients who had other lung diseases but expectorated NTM isolate, were negative for PCR test. Conclusion : Even though tuberculosis is still prevalent in Korea, PCR test is useful to differentiate between M. tuberculosis and NTM in patients with AFB-smear positive sputum but with ambiguous clinical manifestations of active tuberculosis.

• Tuberculosis and Respiratory Diseases
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• v.48 no.5
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• pp.709-719
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• 2000

Background : The different features of high-resolution CT(HRCT) findings of active pulmonary tuberculosis(TB) were studied between acid fast bacilli(AFB) smear or culture positive and negative group. Methods : We prospectively evaluated 36 patients who had been confirmed for active pulmonary tuberculosis by the smear or culture of AFB in sputum(n=25), and changes on serial chest radiographs(n=11). The patients were divided into 3 groups by the results of sputum AFB stain and culture. Group 1(n= 11) is negative in both AFB stain and culture; group 2(n=13) is negative in AFB stain but positive in culture ; and group 3(n=12) is positive in both AFB stain and culture. We evaluated the findings of HRCT in each group randomly. Result : On the HRCT scans, acinar nodule(100%), macronodule(75%), and cavity(75%) in group 3 were more frequently found than group 1(63%. 18%, 9%) and group 2(46%, 15%, 23%)(p<0.05). The centrilobular nodule and branching structure were more frequently observed in group 3(92%) than in group 1(54%)(p<0.05), but were similarly observed in group 2(77%)(p>0.05). AFB positive group was statistically different than the negative group in the HRCT findings with to acinar nodule(100% vs 54%), macronodule(75% vs 17%), and cavity(75% vs 17%)(p<0.05). TB culture positive group was statistically different than the negative group in the HRCT findings with respect to acinar nodule(72% vs 45%) and cavity(48% vs 9%)(p<0.05). Conclusions : HRCT scans are helpful in determining disease acitivity in sputum AFB stain-negative pulmonary tuberculosis. When HRCT shows centrilobular nodule and branching structure, acinar nodule, macronodule, cavity, further studies as sputum induction and bronchoscopy can be performed to determine the presence of bacilli in patients of AFB stain-negative tuberculosis.

• Tuberculosis and Respiratory Diseases
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• v.72 no.1
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• pp.82-87
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• 2012

In 2005, a group of mycolic acid-containing bacteria was characterized as belonging to a novel genus, Segniliparus with species Segniliparus rugosus and S. rotundus. We report a case of the S. rugosus isolated from a 54-year-old woman with radiologic features mimicking that of non-tuberculous mycobacteriosis (NTM). When the patient first visited our hospital, an acid-fast bacteria (AFB) smear tested positive and Mycobacterium tuberculosis polymerase chain reaction (TB PCR) was negative in the bronchoalveolar lavage sample. After 2 months, the growing colonies were reported as NTM, but could not be identified because they had died. One year after the initial visit, induced sputum samples showed the same results, positive AFB smear and negative TB PCR. At this point, the growing colonies were identified as S. rugosus. Therefore, we should consider Segniliparus genus as a differential diagnosis for AFB in respiratory specimens in addition to the genus Mycobacterium.

• Tuberculosis and Respiratory Diseases
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• v.56 no.3
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• pp.268-279
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• 2004

Background : The tuberculin skin test has been used to diagnose latent tuberculosis infection, but is not widely used to diagnose or exclude pulmonary tuberculosis. The objective of this study was to evaluate the diagnostic utility of the tuberculin test in diagnosing and excluding pulmonary tuberculosis, and differentiating pulmonary tuberculosis from nontuberculous mycobacteria (NTM) pulmonary disease, when a sputum acid-fast bacilli (AFB) smear was positive. Material and Methods : From October 2002 to August 2003, among all the inpatients of the Division of Pulmonary and Critical Care Medicine at Samsung Medical Center, 258 patients with clinical suspicion of pulmonary tuberculosis were enrolled and underwent a tuberculin test. Results : 156 males and 102 females were included, with a mean age of 57.5 years. The final diagnoses included lung cancer in 89 cases (34.5%), pulmonary tuberculosis in 59 cases (22.9%), bacterial pneumonia in 33 cases (12.8%) and NTM pulmonary disease in 24 cases (9.3%). The positive tuberculin test rate was higher in the tuberculosis than non-tuberculosis group; 81.4 (48/59) vs. 42.4% (81/199). (p<0.001). In 208 patients with a negative sputum AFB smear, the result of the tuberculin test was positive in 69.4% (25/36) of the tuberculosis group and in 44.8% (77/172) of the non-tuberculosis group (p=0.007), so a positive result of the tuberculin test could predict pulmonary tuberculosis with 69.4% sensitivity, 55.2% specificity, a 24.5% positive predictive value and a 89.6% negative predictive value. In 50 patients with a positive sputum AFB smear, the positive rates of the tuberculin test were 83.9% (26/31) in tuberculosis group and 21.1% (4/19) in NTM pulmonary disease group (p<0.001), so a positive result of the tuberculin skin test could predict pulmonary tuberculosis with 83.9% sensitivity, 78.9% specificity, a 86.7% positive predictive value and a 75.0% negative predictive value. Conclusion : The tuberculin test could be useful in excluding pulmonary tuberculosis when the sputum AFB smear is negative, and to differentiate pulmonary tuberculosis from NTM pulmonary disease when the sputum AFB smear is positive.