• Korean Journal of Clinical Laboratory Science
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• v.52 no.4
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• pp.335-341
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• 2020

This study investigates the association of the AFB stain with the cycle threshold (Ct) value of the Cobas TaqMan MTB test (CTM test, Roche Diagnostics, Basel, Switzerland), and it establishes the base data for semi-quantitative identification of M. tuberculosis by the Ct value. CTM test were simultaneously conducted on 8,389 specimens submitted to the Samsung Medical Center from January 2015 to December 2015, and the results were analyzed and compared retrospectively investigates the association of the AFB stain with the Ct value of the CTM test, and it establishes the base data for semi-quantitative identification of M. tuberculosis by the Ct value. The Ct values for 135 positive specimens of the CTM were inversely correlated with the AFB stain (rs=-0.545, P<0.01). When the Ct value of the CTM test and the time to positivity (TTP) of the mycobacteria cultures were verified based on the AFB stain, they were found to have a positive correlation (rs=0.136, P<0.01). The negative correlation between the CTM test and the AFB stain grade was demonstrated. The clinical significance was verified by applying these criteria to the clinical results. The semi-quantitative criteria of this study can be used to facilitate the rapid isolation of patients with active tuberculosis and infection control in the hospital.

• 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.69 no.4
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• pp.250-255
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• 2010

Background: The purpose of this study was to evaluate recently developed real-time polymerase chain reaction (PCR) assay kit to detect Mycobacterium tuberculosis (MTB) and nontuberculous mycobacteria (NTM) in respiratory specimens. Methods: We assessed the positive rate of the real-time PCR assay to detect MTB and NTM in 87 culture-positive specimens (37 sputum, 50 bronchial washing), which were performed real-time PCR by using $Real-Q_{TM}$ MTB&NTM Kit from January 2009 to June 2009, at Gyeongsang University Hospital. To compare the efficacy with the TB-PCR assay, we evaluated 63 culture-positive specimens (19 sputum, 44 bronchial washing) for MTB or NTM, which were performed TB-PCR by using ABSOLUTETM MTB II PCR Kit from March 2008 to August 2008. Results: Among 87 specimens tested using real-time PCR, MTB and NTM were cultured in 58 and 29, respectively. The positive rate of real-time PCR assay to detect MTB was 71% (22/31) and 92.6% (25/27) in AFB stain-negative and stain-positive specimens. For NTM, the positive rate of real-time PCR was 11.1% (2/18) and 72.7% (8/11) in AFB stain-negative and stain-positive specimens. Among 63 specimens performed using TB-PCR, MTB and NTM were cultured in 46 and 17, respectively. The positive rate of TB-PCR was 61.7% (21/34) and 100% (12/12) in AFB stain-negative and stain-positive specimens. TB-PCR was negative in all NTM-cultured 17 specimens. Conclusion: TB/NTM real-time PCR assay is useful to differentiate MTB and NTM in AFB stain-positive respiratory specimens and it is as effective in detecting MTB with TB-PCR.

• Journal of Chest Surgery
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• v.54 no.5
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• pp.408-411
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• 2021

Tuberculosis (TB)-infected giant bullae are rare. A 55-year-old man was referred when an infected bulla did not respond to empirical treatment. Computed tomography showed a giant bulla in the right upper lobe with an air-fluid level and surrounding infiltrate. Sputum culture, acid-fast bacilli (AFB) stain, and polymerase chain reaction (PCR) for TB were negative. Percutaneous drainage of the bullous fluid was performed. AFB stain and PCR were positive in the drained fluid. The patient was given anti-TB drugs and later underwent obliteration of the pulmonary cavity using talc. To summarize, we report a patient with a TB-infected giant bulla that was treated successfully with anti-TB drugs and obliteration of the pulmonary cavity using talc.

• Tuberculosis and Respiratory Diseases
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• v.38 no.4
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• pp.340-346
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• 1991

Tuberculous tracheobronchitis is defined as a specific inflammation of the trachea or major bronchi caused by the tubercle bacillus and recognized as one of the most common and serious complication of pulmonary tuberculosis. It had been a diagnostic challenge in prebronchoscopic era and since 1968, fiberoptic bronchoscopy has been accepted as a safe and valuable diagnostic procedure of tuberculous tracheobronchitis. Now, it remains a troublesome therapeutic problem due to its sequelae such as bronchostenosis, bronchiectasis and bronchial deformity. The authors analyzed the clinical features, radiological findings and bronchoscopic findings with pathologic and bacteriologic study on 61 cases of tuberculous tracheobronchitis and following results were obtained. 1) The peak incidence was in the fourth decade and male to female ratio was 1:3.4. 2) The most common symptom was cough (86.9%) and followed by sputum (49.2%), dyspnea (27.9%), fever (19.8%), weight loss (11.5%), hemoptysis (6.6%), hoarseness (6.6%) and chest discomfort (3.3%) and localized wheezing was heard in 18%. 3) In chest X-ray, consolidation with collapse was observed in 70.5%, and followed by consolidation only (18.0%), mediastinal node enlargement (8.2%), cavitary lesion (6.6%), suspicious hilar mass (3.3%) and miliary lesion (1.6%) and there was no abnormal findings in 4.9%. 4) Bronchoscopy showed hyperplastic lesion in 67.2%, mucosal lesion (18.0%), ulcerative lesion (9.8%) and stenotic lesion (4.9%). The most common site of bronchial lesion was right upper bronchus (36.1%) and followed by right main bronchus (34.4%), left main bronchus (29.5%), left upper bronchus (16.4%), right middle bronchus (8.2%), right lower bronchus (6.6%) and left lower bronchus (3.3%). 5) Chronic granulomatous inflammation with or without caseation necrosis on microscopic examination was confirmed in 69.7%, bronchial washing AFB stain was positive in 34.1%, prebronchoscopic sputum AFB stain was positive in 88.1% and postbronchoscopic sputum AFB stain was positive in 30.1%.

• Biomedical Science Letters
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• v.5 no.2
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• pp.191-200
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• 1999

In recent years continuously increasing number of tuberculosis (TB) cases due to the emergence of strains with multidrug resistance and AIDS is a significant global health problem. Therefore, more rapid and reliable diagnosis of TB may be one of the most urgent needs in efforts to eradicate the disease. The present study was designed to compare and assess the diagnostic values and efficiencies between the conventional methods (X-ray, AFB stain and culture) and PCR for pulmonary TB on 171 cases. Chest X-ray finding and clinical features revealed that 39 (22.8%) of 171 sputum specimens were pulmonary TB cases. The statistical data were taken on the basis of the definitive diagnosis: In X-ray, overall sensitivity, specificity, efficiency and false positive and false negative incidence was respectively 69.2%, 87.1％, 83.0%, 12.9%, and 30.8％； 79.5%, 95.5%, 91.8%,4.6％ and 20.5％ in AFB-stain; 56.4%, 99.2%,89.5%, 0.8% and 43.6% in culture; 82.1%, 96.2%, 93.0%, 3.8% and 17.9% in PCR. PCR got a highest sensitivity and efficiency as well as a lowest false negative incidence. Culture had a highest specificity with a lowest false positive incidence. These results imply that PCR assay is fast, sensitive and efficient method for diagnosis of pulmonary TB. However, combined use of the conventional methods with thorough quality control may offer more opportunities for detecting Mycobacterium tuberculosis and diagnosting TB although they have some limits.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.1
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• pp.1-5
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• 2015

The nontuberculous mycobacteria (NTM) have been found in different environmental sources. They tend to colonize different body surfaces and secretions. The purpose of this study is to evaluate the presence of NTM in the theater environment. Fifty of Theater environment sample were examined using acid-fast stain, Lowenstein-Jensen medium culture, PCR and DNA-Sequencing. 4 of 50 samples were detected as NFB in AFB stain, L-J medium culture, PCR. and then, All of 4 NTM stains identified as Mycobacterium fortitum type in DNA-sequencing result.

• Biomedical Science Letters
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• v.22 no.1
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• pp.24-28
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• 2016

Tuberculosis (TB) remains an unsolved community health problem since identification of its causing microorganism called Mycobacterium tuberculosis (MTB) by Robert Koch in 1882. Annually, eight million TB cases are newly reported and 2~3 million patients die from TB. Pulmonary TB is highly infectious and untreated pulmonary TB patients are believed to infect >10 people in a year. The conventional methods for diagnosis of TB are chest X-ray and isolation of the causing microorganisms from patient specimens. Screening of TB is conducted with smeared sputum in slides, and TB is confirmed by identification of MTB in cultured specimens. One of the fatal pitfalls of screening detection for smeared sputum is that it is impossible to distinguish MTB and other acid-fast bacilli (AFB) because they are stained equally with Ziehl-Neelsen (ZN) stain. Culture of MTB is the most reliable method for diagnosis of TB but it takes 4~8 weeks. In this report, we suggest a fast and highly-reliable MTB detection method that distinguishes AFB in sputum samples. Purified DNA from the AFB stained slide samples offered by The Korean Institute of Tuberculosis were used to detect infected MTB in patients. PCR, real-time PCR and reverse blot hybridization assay (REBA) methods were applied to purified DNA. Conclusively, the real-time PCR method was confirmed to produce high sensitivity and we were able to further detect drug-resistant MTB with REBA.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.2
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• pp.83-89
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• 2015

Although Mycobacterium tuberculosis complex strains remain responsible for the majority of diseases caused by mycobacterial infections worldwide, the increase in HIV (human immuno deficiency virus) infections has allowed for the emergence of other non-tuberculous mycobacteria as clinically significant pathogens. M. tuberculosis was detected by two-tube nested polymerase chain reaction (PCR) and non-tuberculous mycobacteria was detected by PCR-restriction fragment length polymorphism (RFLP) with Msp I. Result of niacin test is equal to result of two-tube nested PCR after culture for M. tuberculosis. In this study, acid fast bacilli stain (AFB. stain) >2+ case, Detection of Mycobacteria is similar to result before culture and after culture. AFB. stain <1+ case, result of mycobacteria is distinguished. Conclusionly, these results suggest that identification of mycobacteria must go side by side both culture and PCR for more fast and accuracy.

• 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.