• Journal of Microbiology
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• 제35권3호
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• pp.177-180
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• 1997

The purpose of this study was to evaluate the efficiency of Line Probe Assay (LiPA) in detecting the rpoB gene mutation of clinically isolated Mycobacterium tuberculosis (MTB) and to compare the level of resistance to the various rifamycins with their mutation sites. The mutation in the rpoB gene was found in 84 (97.6%) out of 86 rifampicin (RMP) resistant strains as determined by LiPA. No mutation was observed in 2 RMP resistant strains and in any of 38 RMP susceptible strains tested. Only one of 3 strains with .DELTA.5/R5, one of 2 strains with .DELTA.3, and one of 3 strains with .DELTA.2/R2 LiPA profile showed a slightly lower level of resistance to the rifapentine than the other strains. Although we could not find correlations between mutation sites in the rpoB gene and the level of susceptibility to the various rifamycins, the LiPA is recommended as a fast screening tool for detection of RMP resistant MTB.

• Tuberculosis and Respiratory Diseases
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• 제84권3호
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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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• 제45권4호
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• pp.714-722
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• 1998

연구배경: Rifampicin은 항결핵 단기요법의 근간이 되는 약제로 rifampicin 내성용 다제내성의 지표이기도 하다. rpoB유전자는 rifampicin이 결합하여 약리작용을 나타내는 RNA polymerase의 $\beta$-subunit을 coding하는 유전자이며 rifampicin내성 결핵균의 약 96%에서 돌연변이가 관찰된다. 그러므로 rifampicin내성결핵을 빠르게 진단할 수 있는 유용한 방법을 확인하기 위하여 PCR-line probe법과 PCR-SSCP법을 이용하여 다음의 연구를 시행하였다. 방 법: 대한 결핵연구원의 약제감수성검사상 rifampicin 내성인 결핵균주 33예와 감수성인 결핵균주 12예를 대상으로 하였다. 각각 배양균 집락에서 DNA를 분리한 후, PCR-line probe법과 PCR-SSCP법을 이용하여 rifampicin 내성 여부를 단일맹검적으로 검사하였고, 이를 약제감수성검사 결과와 비교하였다. 결 과: PCR-line probe법으로는 내성균주 33예중 27예(81.8%)에서 rpoB 유전자의 돌연변이를 확인할 수 있었고, 감수성균주 12예는 모두 rpoB 유전자의 돌연변이는 없었다. PCR-SSCP 법으로는 내성균주 33예중 23예(69.7%)에서 rpoB 유전자의 돌연변이를 확인할 수 있었고, 감수성균주 12예는 모두 rpoB 유전자의 돌연변이는 없었다. Rifampicin내성균주에서 rpoB 유전자 돌연변이 검출율의 PCR-line probe 법과 PCR-SSCP법간의 차이는 없었다 (p=0.25). 결 론: PCR-line probe법은 PCR-SSCP법과 더불어 rifampicin 내성을 조기에 진단할 수 있는 좋은 방법으로 사료되며, 전통적인 약제감수성검사 결과를 기다릴 수 없는 국한된 환자에게 유용한 진단법으로 생각된다.

• Tuberculosis and Respiratory Diseases
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• 제76권5호
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• pp.245-248
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• 2014

Miliary tuberculosis (TB) is a rare extrapulmonary form of TB, and there have been only two reports of miliary TB associated with infection with multidrug-resistant (MDR)-TB pathogen in an immunocompetent host. A 32-year-old woman was referred to our hospital because of abnormal findings on chest X-ray. The patient was diagnosed with MDR-TB by a line probe assay and was administered proper antituberculous drugs. After eight weeks, a solid-media drug sensitivity test revealed that the pathogen was resistant to ethambutol and streptomycin in addition to isoniazid and rifampicin. The patient was then treated with effective antituberculous drugs without delay after diagnosis of MDR-TB. To the best of our knowledge, this is the first case of miliary TB caused by MDR-TB pathogen in Korea.

• Asian Pacific Journal of Cancer Prevention
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• 제13권11호
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• pp.5463-5467
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• 2012

Hepatitis B virus (HBV) infection is contagious with transmissiobn vertically or horizontally by blood products and body secretions. Over 50% of Iranian carriers contracted the infection prenatally, making this the most likely route of transmission of HBV in Iran. To evaluate the resistance to adefovir (ADV) therapy in patients with chronic hepatitis B infection, a study was conducted on 70 patients (63 males and 7 females), who had received in first line lamivudine and second line adefovir. All were tested for the presence of hepatitis B surface antigen (HBsAg), hepatitis B envelope antigen (HBeAg), serum alanine amino transferase (ALT) level and HBV DNA load before and after treatment with ADV. In all samples, resistance to lamivudine and ADV was tested with real time PCR. Among seventy patients with chronic hepatitis B infection, 18 (25.7%) were resistant to LAM and 8 (11.4%) were resistant to ADV. Only one patient was negative for the presence of HBS-Ag (5.6%) and two were negative for HBe-Ag (11.1%). In this study we used a new method (ALLGIO probe assay) that has high sensitivity in detection of adefovir resistance mutants, which we recommend to other researchers. Mutant strains of the YMDD motif of HBV polymerase can be found in some patients under treatment with lamivudine and ADV. ADV has been demonstrated to be efficient in patients with lamivudine resistant HBV.

• Tuberculosis and Respiratory Diseases
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• 제44권2호
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• pp.251-263
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• 1997

연구배경 : 다제내성결핵의 증가는 효과적인 결핵 치료를 어렵게 할 뿐만 아니라 결핵관리 사업에 큰 장애로 대두되고 있다. 따라서 다제내성결핵균의 내성획득 기전에 대한 이해와 조기진단 방법의 개발이 시급한 실정이다. 최근 분자생물학의 발달로 결핵균의 유전학적인 검검출방법은 기존 배양검사의 감수성에 필적하는 수준이며, 더 나아가 1차 약제인 INH와 RMP 등의 핵산 수준에서 내성기전에 대한 최근의 연구 결과는 더욱 새롭고 빠른 감수성 검사의 기틀을 마련할 것으로 생각된다. RMP에 대한 M. tuberculosis의 주 내성기전은 RNA polymerase $\beta$subunit (rpoB)의 돌연변이로 보고되고 있다. 방 법 : 본 실험에서 42예의 결핵균 배양검체 (RMP 내성 32예, 감수성 10예)를 선택하여 rpoB 유전자의 돌연변이를 분석하였다. 역교잡법(reverse hybridization)을 이용한 상용화된 INNO-LiPA Line Probe Assay (LiPA)를 이용하여 돌연변이 양상을 검사하고 직접염기서열 방법으로 분석한 결과와 비교하였다. 결 과 : LiPA에서 RMP 감수성균주는 S띠의 발색이 모두 나타났으며, 내성균주는 모두 R띠의 발색이냐 S띠의 소실이 나타나 내성임을 확인할 수 있었다. 내성균주 32예중 22예(68.8%)는 4개의 R띠중 하나의 소실이 있어 바로 돌연변이 양상을 확인할 수 있었으며 R5(S531L)형이 17예(77.3%)로 제일 많았다. LiPA에서 확인되지 않았던 10예는 직접염기서열 분석법으로 내성양상을 검사한 바, 총 11예와 점돌연변이와 1예의 염기결실을 확인하였다. 이중 S522W와 9염기쌍의 결실은 현재까지 보고된 바 없는 처음으로 보고되는 유형의 돌연변이었다. 결 론 : 한국인의 결핵균에서 RMP 내성의 주 기전은 rpoB 유전자의 돌연변이에 의한 RNA polymerase의 구조 변화에 기인하는 것을 알 수 있었고 직접염기서열 결정법으로 그 양상을 확인하였으며, LiPA법이 RMP 내성의 조기진단에 유용하게 이용될 수 있는 것으로 판단되었다.

• Tuberculosis and Respiratory Diseases
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• 제50권3호
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• pp.334-342
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• 2001

배 경 : rpoB 유전자 돌연변이는 rifampicin 내성결핵의 96-98%에서 발견된다. 실험실 검사에서는 rpoB 유전자가 다제내성결핵의 지표로서 빠른 진단에 사용될 수 있음이 보고되었으나 임상적 적용에 대해서는 아직 국내 및 외국에도 보고가 없는 실정이다. 연구 방법 : 서울중앙병원에서 1998 년 6월부터 2000년 7월 까지 LiPA법을 이용하여 rpoB유전자 돌연변이분석이 시행된 33명 환자에서 후향적으로 의무기록을 조사하였다. 환자의 임상상, 약제 감수성, 그리고 LiPA 검사 결과를 비교 분석하였다. 전통적인 약제감수성 결과를 표준으로 하여 LiPA 검사 결과와 비교하였으며 양 검사결과가 불일치하는 경우에 rpoB 유전자 염기서열분석을 시행하였다. 연구결과 : 평균 나이는 $42{\pm}19$세이고, 남녀비는 24 : 9 이었다. rpoB 유전자 검사 요청 시간으로부터 결과 보고까지 평균 시간은 $5.2{\pm}2.6$일 이었다. rpoB 유전자 검사 결과는 약제 감수성 결과보다 평균시간은 $56{\pm}35$일 빠르게 보고되었다. 감수성 결과가 얄려진 33명 중 28(85%)명에서는 유전자 검사와 동일한 결과를 보였고, 5명은(15%) 반대 결과를 보였다. 반대 결과를 보인 5명에서 염기서열 분석을 하였을 때, 3예에서 약물 감수성 결과가 오류였을 가능성이 있고, 나머지 2예는 LiPA 검사결과가 오류였을 가능성이 있다. 치료 약 선택에 도움을 준 경우가 28예(85%) 있었다. 결 론 : LiPA 방법을 이용한 rpoB 유전자 검사는 임상에서도 다수에서 다제내성을 신속하고 정확하게 진단할 수 있었고, 치료약 선택에 도움을 주었다. 하지만 현재의 시점에서 LiPA 방법이 기존의 도말 및 배양검사를 완전히 대치할 수는 없고 임상상, 도말 및 배양검사결과와 종합하여 보조적으로 사용하면 도움이 될 것으로 사료되었다.

• Tuberculosis and Respiratory Diseases
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• 제83권4호
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• pp.289-294
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• 2020

Background: Line probe assay (LPA) is standard diagnostic tool to detect multidrug resistant tuberculosis. Non-interpretable (NI) results in LPA (complete missing or light wild-type 3 and 8 bands with no mutation band in rpoB gene region) poses a diagnostic challenge. Methods: Sputum samples obtained between October 2016 and July 2017 at the Intermediate Reference Laboratory, All India Institute of Medical Sciences Hospital, New Delhi, India were screened. Smear-positive and smear-negative culture-positive specimens were subjected to LPA Genotype MTBDRplus Ver 2.0. Smear-negative with culture-negative and culture contamination were excluded. LPA NI samples were subjected to phenotypic drug susceptibility testing (pDST) using MGIT-960 and sequencing. Results: A total of 1,614 sputum specimens were screened and 1,340 were included for the study (smear-positive [n=1,188] and smear-negative culture-positive [n=152]). LPA demonstrated 1,306 (97.5%) valid results with TUB (Mycobacterium tuberculosis) band, 24 (1.8%) NI, three (0.2%) valid results without TUB band, and seven (0.5%) invalid results. Among the NI results, 22 isolates (91.7%) were found to be rifampicin (RIF) resistant and two (8.3%) were RIF sensitive in the pDST. Sequencing revealed that rpoB mutations were noted in all 22 cases with RIF resistance, whereas the remaining two cases had wild-type strains. Of the 22 cases with rpoB mutations, the most frequent mutation was S531W (n=10, 45.5%), followed by S531F (n=6, 27.2%), L530P (n=2, 9.1%), A532V (n=2, 9.1%), and L533P (n=2, 9.1%). Conclusion: The present study showed that the results of the Genotype MTBDRplus assay were NI in a small proportion of isolates. pDST and rpoB sequencing were useful in elucidating the cause and clinical meaning of the NI results.

• Journal of Yeungnam Medical Science
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• 제41권2호
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• pp.113-119
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• 2024

Background: Missing isoniazid (INH) resistance during tuberculosis (TB) diagnosis can worsen the outcomes of INH-resistant TB. The BD MAX MDR-TB assay (BD MAX) facilitates the rapid detection of TB and INH and rifampin (RIF) resistance; however, data related to its performance in clinical setting remain limited. Moreover, its effect on treatment outcomes has not yet been studied. Methods: We compared the performance of BD MAX for the detection of INH/RIF resistances to that of the line probe assay (LPA) in patients with pulmonary TB (PTB), using the results of a phenotypic drug sensitivity test as a reference standard. The treatment outcomes of patients who used BD MAX were compared with those of patients who did not. Results: Of the 83 patients included in the study, the BD MAX was used for an initial PTB diagnosis in 39 patients. The sensitivity of BD MAX for detecting PTB was 79.5%. The sensitivity and specificity of BD MAX for INH resistance were both 100%, whereas these were 50.0% and 95.8%, respectively, for RIF resistance. The sensitivity and specificity of BD MAX were comparable to those of LPA. The BD MAX group had a shorter time interval from specimen request to the initiation of anti-TB drugs (2.0 days vs. 5.5 days, p=0.001). Conclusion: BD MAX showed comparable performance to conventional tests for detecting PTB and INH/RIF resistances. The implementation of BD MAX as a diagnostic tool for PTB resulted in a shorter turnaround time for the initiation of PTB treatment.

• 대한의생명과학회지
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• 제9권4호
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• pp.209-214
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• 2003

To determine the clinical usefulness of Immuno Blot test, 160 samples from the patients with chronic HCV infection were analyzed. And serotyping and line probe assay were performed to evaluate the distribution of hepatitis C virus genotypes in Korean isolates. In this group, as a result of genotyping type 1 band 2a, the serotype I and II were the most common source of HCV infection. There were no significant difference in response to the alpha-interferon HCV infection treatment with the subtype 1 b or 2a. And the serotypes of NS4 peptides were compared with the genotypes to evaluate their clinical usefulness. Among 49 cases studied for genotypes and serotype, genotype 1 b, 1 b/2b, 2a, 2a/2c and 2b were 51.0％, 2.0％, 34.6％, 8.1％ and 4.0％, respectively. The serotypes I and II were 57.1％ and 42.8％, respectively; they were matched with genotypes in 85.7％ and seemed to be easy to perform. To monitor their performing progress or treatment response, serotype test was made before the genotype test. The Result showed that there was no significant difference in response to the alpha-interferon HCV infection treatment with the subtype 1 b or 2a in Korea.