• Tuberculosis and Respiratory Diseases
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• v.55 no.4
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• pp.344-352
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• 2003

Background : The prevalence of multidrug resistant tuberculosis (MDR-TB), resistant to isoniazid (INH) and rifampin (RFP), was 5.3% worldwide in 1995 and its increment has raised important public health problems. Resistance to RFP, one of the key drugs in the treatment of tuberculosis, results in grim clinical outcome. Recently rapid detection of RFP-resistant mutations in rpoB gene based on PCR method has become available. This study evaluated the prevalence of RFP resistance in first diagnosed, treatment failure, and recurred patients using INNO-LiPA test, and compared the results of INNO-LiPA with those of conventional mycobacterial drug susceptibility test. Methods : Forty-six patients, who were diagnosed of pulmonary tuberculosis and had revealed positive sputum AFB smear, were enrolled in this study from 1998 to 2002. The cases were classified as one three groups; first diagnosed, treatment failure, or recurred. RFP resistance was studied using an INNO-LiPA Rif. TB kit and compared with that obtained from drug susceptibility based on M. tuberculosis culture study. Results : Twenty-one out of 46 patients were enrolled under first diagnosis of pulmonary tuberculosis, 17 under treatment failure with first line drugs, and 8 under recurrence. The positive and negative predictive values of INNO-LiPA test in diagnosis in RFP resistant tuberculosis compared with conventional mycobacterial drug susceptibility test were 85.7% and 76.0%, respectively. INNO-LiPA result revealed rpoB gene mutation in 20 (80.0%) out of 25 patients who were diagnosed as treatment failure or recurrence, but in only 4 (19.0%) out of 21 patients who were first diagnosed as pulmonary tuberculosis. Conclusion : This study showed that RFP resistance could be diagnosed rapidly and accurately using INNO-LiPA test and that this test might be helpful for choosing second line anti-mycobacterial drugs. It might be of great help in clinical diagnosis and decision when used in complimentarily with drug susceptibility test based on M. tuberculosis culture.

• Tuberculosis and Respiratory Diseases
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• v.73 no.3
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• pp.143-150
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• 2012

Background: The release of interferon-gamma (IFN-${\gamma}$) by T lymphocytes increases after rechallenge with Mycobacterium tuberculosis antigen, especially, at a localized site of tuberculosis (TB) infection. We aimed to compare the clincial efficacy of two commercial IFN-${\gamma}$ release assays from pleural fluid for the diagnosis in tuberculous pleurisy. Methods: We performed T-SPOT.TB and QuantiFERON-TB Gold tests simultaneously on pleural fluid and peripheral blood samples from patients with pleural effusion, in South Korea, an area with intermediate TB burden. Results: Thirty-six patients were enrolled prospectively, and tuberculous pleurisy was found in 21 patients. Both the numbers of IFN-${\gamma}$ secreting T cells and the concentration of IFN-${\gamma}$ were greater in the pleural tuberculous group, comparing with the non-tuberculous group. Moreover, in the tuberculous group, there was a significant difference in IFN-${\gamma}$ producing spot-forming cells using the T-SPOT.TB method between pleural fluid and peripheral blood. The receiver operating characteristic (ROC) curve, was the greatest for pleural fluid T-SPOT.TB test, followed by peripheral blood T-SPOT.TB test, peripheral blood QuantiFERON-TB Gold test, and pleural fluid QuantiFERON-TB Gold test (area under the ROC curve of 0.956, 0.890, 0.743, and 0.721, respectively). The T-SPOT.TB assay produced less indeterminate results than did QuantiFERON-TB Gold assay in both pleural fluid and peripheral blood. Conclusion: These findings suggest that the pleural fluid T-SPOT.TB test could be the most useful test among the IFN-${\gamma}$ release assays for diagnosing tuberculous pleurisy in an area with an intermediate prevalence of TB infection.

• Korean Journal of Veterinary Service
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• v.41 no.2
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• pp.71-78
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• 2018

Bovine tuberculosis (bTB) is a wide-spread zoonotic disease in cattle, which is casued by Mycobacterium bovis that is a part of Mycobacterium tuberculosis complex (MTC). This study describes a field trial conducted in 42 herds with the history of prevalence bovine tuberculosis. Two cell-mediated immunity tests, the gamma-interferon (${\gamma}-IFN$) assay and the single intradermal tuberculin test (SIT) were applied for the diagnosis of bovine tuberculosis in 5,289 animals. The ${\gamma}-IFN$ assay presented 144 (2.7%) head of cattle with the positive result, and 112 (2.1%) head of cattle were shown to be bTB-positive by the SIT. The positive concordance was 45.5%, and the negative concordance was 98.2%. The ${\gamma}-IFN$ assay showed more positive results in younger cattle, especially between 12 and 23 months of age. It is shown that the strategic combination of both cell-mediated immunity test methods is more efficient for the detection of bTB to reduce the number of false positive individuals which are being slaughtered.

• Clinical and Experimental Pediatrics
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• v.52 no.5
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• pp.529-537
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• 2009

Drug-resistant tuberculosis in children has important implications for both the patients and tuberculosis control programs. In Korea, among all new patients, the isoniazid resistance rate was 9.9% and multidrug-resistant tuberculosis rate was 2.7% in 2004 (in patients aged 10-19 yr, the multidrug-resistant tuberculosis rate reached 2.1%). Tuberculosis in pediatric patients is difficult to diagnose because many children have nonspecific clinical signs and the detection rates of acid-fast bacilli smears and cultures are low. Therefore, every effort should be made to identify adult sources and obtain information on drug susceptibility because symptomatic adult patients have a higher chance of culture positivity and drug-susceptibility patterns are the same in most adult-child pair patients. Korean children are at significant risk of drug-resistant tuberculosis. As the isoniazid resistance rate is greater than 4% among the new cases in Korea, a four-drug regimen should be considered for initial treatment of children with active tuberculosis, unless drug-susceptibility test results are available. Treatment of drug-resistant tuberculosis in children is challenging and there are only few available data. Tuberculosis control programs should be continuous with specific focus on pediatric populations because they can serve as reservoirs for future active cases. Further studies are needed regarding treatment of drug-resistant tuberculosis in children.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.3
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• pp.225-229
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• 2016

Tuberculosis (TB) is caused by a chronic infectious agent known as Mycobacterium tuberculosis. It is transmitted in airborne particles, called droplet nuclei which was generated by cough, sneeze, shout, or sing of persons who have TB disease. Most infections of TB do not have symptoms, well known as latent tuberculosis infection (LTBI). However, about 10% of LTBI progress to active disease a one or two years after infection. To investigate the LTBI rate of college students who were in contacted with TB patients, we performed chest X-ray, tuberculin skin test (TST) and Interferon-gamma release assay (IGRA) to 74 college students. At a results, 65 students were showed negative and 9 students positive results at chest X-ray and 1st TST test. When confirmed the 65 students who were showed negative by 2st TST, the results showed correctly. But, 9 students who were showed positive results on chest X-ray and 1st TST by IGRA, the only 3 students (4.05%) showed positive results. In conclusion, the LTBI rate in this study showed 4.05% (3/74) and we suggest to investigate other students LTBI rate for decreasing tuberculosis.

• Tuberculosis and Respiratory Diseases
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• v.78 no.4
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• pp.349-355
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• 2015

Background: The tuberculin skin test (TST) is the standard tool to diagnose latent tuberculosis infection (LTBI) in mass screening. The aim of this study is to find an optimal cut-off point of the TST+ rate within tuberculosis (TB) contacts to predict the active TB development among adolescents in school TB outbreaks. Methods: The Korean National Health Insurance Review and Assessment database was used to identify active TB development in relation to the initial TST (cut-off, 10 mm). The 7,475 contacts in 89 schools were divided into two groups: Incident TB group (43 schools) and no incident TB group (46 schools). LTBI treatment was initiated in 607 of the 1,761 TST+ contacts. The association with active TB progression was examined at different cut-off points of the TST+ rate. Results: The mean duration of follow-up was $3.9{\pm}0.9years$. Thirty-three contacts developed active TB during the 4,504 person-years among the TST+ contacts without LTBI treatment (n=1,154). The average TST+ rate for the incident TB group (n=43) and no incident TB group (n=46) were 31.0% and 15.5%, respectively. The TST+ rate per group was related with TB progression (odds ratio [OR], 1.025; 95% confidence interval [CI], 1.001-1.050; p=0.037). Based on the TST+ rate per group, active TB was best predicted at TST+ ${\geq}$ 16% (OR, 3.11; 95% CI, 1.29-7.51; area under curve, 0.64). Conclusion: Sixteen percent of the TST+ rate per group within the same grade students can be suggested as an optimal cut-off to predict active TB development in middle and high schools TB outbreaks.

• Tuberculosis and Respiratory Diseases
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• v.48 no.3
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• pp.315-323
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• 2000

Background : An immunochromatographic assay (ICT Diagnostics) which facilitates the diagnosis of tuberculosis(TB) by detecting serum antibodies mainly directed against specific 38KDa of Mycobacterium tuberculosis has come into the market. The test consists of a cardboard folding device containing nitrocellulose strip and absorbent pads. The whole procedure is completed within 15 min and does not require any additional equipment. The test has been reported to be sensitive and specific in diagnosing active TB. Thus the test had been evaluated with sera from TB patients and TB-free subjects. Method : Sera from patients with active pulmonary tuberculosis(40 sputum positives for Mycobacterium tuberculosis, 79 sputum negatives, and 3 extrapulmonary tuberculosis) were obtained from the Double-Cross Chest Clinic of the Korean National Tuberculosis Association (KNTA) in Seoul. The control group consisted of TB-free 68 subjects(21 children under 7 years old and 47 healthy staff members of KNTA). Results : Nine out of 68(13.2%) TB-free controls had positive antibody response. Total 106 of 122(86.9%) radiologically active patients had positive antibodies while 16 (13.1%) showed negative reaction. Antibody was detected in 38 of 40(95.0%) sputum positive patients and 68 of 82(82.9%) sputum negative patients who were under the antituberculosis chemotherapy. The sensitivity and specificity were all 87% and the positive predictive value was 92.2% while the negative predictive value was 78.7%, when the prevalence of TB in the sample was 64.2%. Our results clearly show that the detection of antibodies which mainly react with the 38KDa antigen of M. tuberculosis is not suitable as the first-line method of diagnosis but considered only as an adjunctive test to standard techniques of tuberculosis diagnosis. when considering its high false positivity.

• Tuberculosis and Respiratory Diseases
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• v.72 no.6
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• pp.475-480
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• 2012

Background: Pyrazinamide (PZA) is an effective antitubercular drug that becomes toxic to Mycobacterium tuberculosis when converted to pyrazinoic acid by pyrazinamidase (PZase), encoded by mycobacterial pncA. A strong association was noted between the loss of PZase activity and PZA resistance. The causative organisms in extrapulmonary tuberculosis are rarely cultured and isolated. To detect pncA mutations in specimens from extrapulmonary tuberculosis as confirmative diagnosis of mycobacterial infection and alternative susceptibility test to PZA. Methods: Specimens were collected from clinically proven extrapulmonary tuberculosis. pncA was sequenced and compared with wild-type pncA. Results: pncA from 30 specimens from 23 donors were successfully amplified (56.6% in specimens, 59% in donors). Six mutations in pncA were detected (20.0% in amplified specimens, 26.1% in specimen donors) at nucleotide positions of 169, 248 and 419. The mutation at position 169 results in substitution of aspartic acid for histidine, a possible allelic variation of M. bovis that have intrinsic PZA resistance. The mutation at position 248 changes proline into arginine and that at position 419, arginine into histidine. Conclusion: DNA-based diagnosis using pncA may be simultaneously useful for the early diagnosis of mycobacterial infection and the rapid susceptibility to PZA in extrapulmonary tuberculosis. A potential implication of pncA allelic variation at 169 might be suggested as a rapid diagnostic test for M. bovis infection or Bacille Calmette-Gu$\acute{e}$rin (BCG) reactivation.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.471-478
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• 2021

The purpose of this study were to investigate knowledge, awareness, performance, and preventive behavior of latent tuberculosis infection management, and to identify influencing factors on preventive behavior of latent tuberculosis infection management of nursing students. The subjects of this study were completed by 191 nursing students from 2 colleges in D City. Data were collected from August 1 to November 30, 2020. Data were analyzed using the t-test, the ANOVA, the Pearson correlation coefficient, and stepwise multiple regression analysis by SPSS ver. 21.0. There were significant positive correlations between preventive behavior of latent tuberculosis infection management and performance(r=.21, p=.003), awareness and performance(r=.88, p<.001). The factors influencing grade and education experience about latent tuberculosis infection management of the study subjects were grade(β=.29, p<.001), final time of education experience about tuberculosis(β=.19, p=.004), and the explanatory power of these variables was 11.9%. The development of preventive behavior of latent tuberculosis infection management education program that focuses grade and final time of education experience about tuberculosis is needed.

• Tuberculosis and Respiratory Diseases
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• v.68 no.6
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• pp.328-333
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• 2010

Background: There are several active tuberculosis (TB) cases in Korean high schools each school year. The risk of transmission in schools is extremely high due to the considerable time spent in closed classrooms. We evaluated the control of latent tuberculosis infection in Korean high schools. Methods: When a student was identified with active TB, tuberculin skin testing was performed on their classmates and on students in their same school grade. When a student had a positive tuberculin skin tests (TST), they underwent follow-up testing with QuantiFERON-TB Gold In-Tube (QFT). The manufacturer recommended a cut-off of 0.35 IU/mL to determine QFT positivity was applied. Results: A total of 131 pulmonary tuberculosis (TB) patients were included based on the criteria for screening TB contacts in the National Tuberculosis Control Program. Seventy-five (57.2%) students tested smear positive. TST were performed on 7,109 students who were classmates of, or in the same grade as, a TB patient. Of the contacts, 1,231 students (17.3%) were TST positive and they were screened with QFT. Six hundred-sixty-six (55.0%) of the tested students returned a positive QFT result and the rate of positivity was significantly associated with the increasing size of TST indurations (p<0.0001). Conclusion: The use of QFT resulted in approximately 45% of TST positive students not being given chemoprophylaxis.