• 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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• 제66권3호
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• pp.198-204
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• 2009

연구배경: 다제내성결핵 치료에서 감수성으로 증명된 1차 항결핵제는 가장 항결핵효과가 큰 약제로 알려져 있다. 본 연구는 다제내성결핵 환자에서 표준 1차 항결핵제사용 후 1차 항결핵제에 대한 추가 내성 획득의 빈도와 그 위험 인자를 알아보고자 시행되었다. 방 법: 2004년 1월에서 2008년 5월까지 국립마산결핵병원에서 약제감수성 검사가 보고되기 전 표준 1차 항결핵제로 치료받은 다제내성결핵 환자 중에서 1차 항결핵제 치료 전과 1차 항결핵제 치료 후의 연속된 두 시점의 약제 감수성 검사 결과가 모두 있는 환자를 대상으로 하여 의무기록을 후향적으로 검토하였다. 결 과: 표준 1차 항결핵제로 치료 받은 41명 중 14명 (34.1%)에서 ethambutol (EMB) 혹은 pyrazinamide (PZA)에 대한 추가 내성이 획득되었다. 치료 전 isoniazid (INH), rifampicin (RFP)에만 내성을 보였던 11명 중 3명(27.3%)에선 EMB와 PZA에 동시 내성, 3명(27.3%)에선 PZA에 추가 내성이 획득되었다. INH, RFP, EMB에 내성을 보인 18명 중 6명(33.3%)에서 PZA에, INH, RFP, PZA에 내성을 보인 6명 중 2명(33.3%)에서 EMB에 추가 내성이 획득되었다. 대상 환자 중 10명(24.4%)에서 1차 항결핵제 치료 전 내성이었던 약제가 치료 후 감수성으로 전환되었다. 추가 내성획득과 연관된 통계학적으로 유의한 위험인자를 발견할 수 없었다. 결 론: 우리나라의 다제내성결핵 치료에서 1차 항결핵제는 추가 획득 내성의 위험을 고려하여 주의 깊게 사용해야 할 것으로 사료된다.

• 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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• 제81권3호
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• pp.222-227
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• 2018

Background: Rifampicin (RFP) is one of the principal first-line drugs used in combination chemotherapies against Mycobacterium tuberculosis, and its use has greatly shortened the duration of chemotherapy for the successful treatment of drug-susceptible tuberculosis. Compensatory mutations have been identified in rpoC that restore the fitness of RFP-resistant M. tuberculosis strains with mutations in rpoB. To investigate rpoC mutation patterns, we analyzed 93 clinical M. tuberculosis isolates from patients in South Korea. Methods: Drug-resistant mycobacterial isolates were cultured to determine their susceptibility to anti-tubercular agents. Mutations in rpoC were identified by sequencing and compared with the relevant wild-type DNA sequence. Results: In total, 93 M. tuberculosis clinical isolates were successfully cultured and tested for drug susceptibilities. They included 75 drug-resistant tuberculosis species, of which 66 were RFP-resistant strains. rpoC mutations were found in 24 of the 66 RFP-resistant isolates (36.4%). Fifteen different types of mutations, including single mutations (22/24, 91.7%) and multiple mutations (2/24, 8.3%), were identified, and 12 of these mutations are reported for the first time in this study. The most frequent mutation involved a substitution at codon 452 (nt 1356) resulting in amino acid change F452L. Conclusion: Fifteen different types of mutations were identified and were predominantly single-nucleotide substitutions (91.7%). Mutations were found only in dual isoniazid- and RFP-resistant isolates of M. tuberculosis. No mutations were identified in any of the drug-susceptible strains.

• 약학회지
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• 제41권4호
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• pp.450-455
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• 1997

The preparation of Bacillus coagulans is used as a therapeutics for human intestinal disorders. However, the bacterium in the preparation is very susceptible to rifampic in and fluoroquinolones. When the preparation is taken with rifampicin or fluoroquinolones, its therapeutic effect can not be expected. So B. coagulans RFR17 resistant to rifampicin was obtained by treating the parent B. coagulans with N-methyl-N'-nitro-N-nitrosoguanidine. B. coagulans OFR17 was produced by serial passage of B. coagulans RFR17 on agar with 2-fold minimal inhibitory concentration of ofloxacin or ciprofloxacin. B. coagulans OFR17 was resistant to fluoroquinolones up to 16~64 fold higher than that for the original strain. B. coagulans OFR17 also exhibited identical characteristics with the parent strain when they were tested for lactic acid production and growth inhibition of E. coli MB4-01 and Shigella sonnei MB4-10411. From in vitro test, it was also identified that rifampicin and ofloxacin are not inactivated by certain factors of B. coagulans OFR17. Conclusively, B. coagulans OFR17 can be regarded as a promising strain which can be developed as the preparation for the treatment of the intestinal disorders of the tuberculosis patients under rifampicin and ofloxacin therapy.

• Tuberculosis and Respiratory Diseases
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• 제77권4호
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• pp.161-166
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• 2014

Since tuberculosis (TB) remains a major global health concern and the incidence of multi-drug resistant (MDR)-TB is increasing globally, new modalities for the detection of TB and drug resistant TB are needed to improve TB control. The Xpert MTB/RIF test can be a valuable new tool for early detection of TB and rifampicin resistance, with a high sensitivity and specificity. Late-generation fluoroquinolones, levofloxacin, and moxifloxacin, which are the principal drugs for the treatment of MDR-TB, show equally high efficacy and safety. Systemic steroids may reduce the overall TB mortality attributable to all forms of TB across all organ systems, although inhaled corticosteroids can increase the risk of TB development. Although fixed dose combinations were expected to reduce the risk of drug resistance and increase drug compliance, a recent meta-analysis found that they might actually increase the risk of relapse and treatment failure. Regarding treatment duration, patients with cavitation and culture positivity at 2 months of TB treatment may require more than 6 months of standard treatment. New anti-TB drugs, such as linezolid, bedaquiline, and delamanid, could improve the outcomes in drug-resistant TB. Nontuberculous mycobacterial lung disease has typical clinical and immunological phenotypes. Mycobacterial genotyping may predict disease progression, and whole genome sequencing may reveal the transmission of Mycobacterium abscessus. In refractory Mycobacterium avium complex lung disease, a moxifloxacin-containing regimen was expected to improve the treatment outcome.

• Tuberculosis and Respiratory Diseases
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• 제85권2호
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• pp.111-121
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• 2022

Multidrug-resistant tuberculosis (MDR-TB) is caused by an organism that is resistant to both rifampicin and isoniazid. Extensively drug-resistant TB, a rare type of MDR-TB, is caused by an organism that is resistant to quinolone and one of group A TB drugs (i.e., linezolid and bedaquiline). In 2018, the World Health Organization revised the groupings of TB medicines and reclassified linezolid as a group A drug for the treatment of MDR-TB. Linezolid is a synthetic antimicrobial agent in the oxazolidinone class. Although linezolid has a good efficacy, it can cause substantial adverse events, especially hematologic toxicity. In both TB infection and linezolid mechanism of action, mitochondrial dysfunction plays an important role. In this concise review, characteristics of linezolid as an anti-TB drug are summarized, including its efficacy, pathogenesis of hematologic toxicity highlighting mitochondrial dysfunction, and the monitoring and management of hematologic toxicity.

• Journal of Preventive Medicine and Public Health
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• 제52권1호
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• pp.66-70
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• 2019

Objectives: In the Republic of Korea (ROK), the notified incidence of tuberculosis in foreign-born individuals (NITFBI) has increased recently, as has the rate of multidrug-resistant (MDR) and rifampicin-resistant (RR) tuberculosis in foreigners staying in the ROK. As Jeju Province in ROK has a no-visa entry policy, control programs for NITFBI should be consolidated. The aim was to evaluate the status of NITFBI, with a focus on the distribution of MDR/RR tuberculosis by nationality. Methods: Data on tuberculosis incidence in individuals born in Jeju Province and in foreign-born individuals were extracted from the Korean Statistical Information Service of Statistics Korea, and the Infectious Disease Surveillance Web Statistics of the Korea Centers for Disease Control and Prevention, respectively. Results: Among all notified incident cases of tuberculosis, the proportion of NITFBI increased from 1.46% in 2011 to 6.84% in 2017. China- and Vietnam-born individuals accounted for the greatest proportion of the 95 cases of NITFBI. Seven cases of MDR/RR tuberculosis were found, all involving patients born in China. Conclusions: In Jeju Province, ROK, NITFBI might become more common in the near future. Countermeasures for controlling active tuberculosis in immigrants born in high-risk nations for tuberculosis should be prepared in Jeju Province, since it is a popular tourist destination.

• Tuberculosis and Respiratory Diseases
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• 제83권1호
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• pp.20-30
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• 2020

Tuberculosis (TB) remains a threat to public health and is the leading cause of death globally. Isoniazid (INH) is an important first-line agent for the treatment of TB considering its early bactericidal activity. Resistance to INH is now the most common type of resistance. Resistance to INH reduces the probability of treatment success and increases the risk of acquiring resistance to other first-line drugs such as rifampicin (RIF), thereby increasing the risk of multidrug-resistant-TB. Studies in the 1970s and 1980s showed high success rates for INH-resistant TB cases receiving regimens comprised of first-line drugs. However, recent data have indicated that INH-resistant TB patients treated with only firs-tline drugs have poor outcomes. Fortunately, based on recent systematic meta-analyses, the World Health Organization published consolidated guidelines on drug-resistant TB in 2019. Their key recommendations are treatment with RIF-ethambutol (EMB)-pyrazinamide (PZA)-levofloxacin (LFX) for 6 months and no addition of injectable agents to the treatment regimen. The guidelines also emphasize the importance of excluding resistance to RIF before starting RIF-EMB-PZA-LFX regimen. Additionally, when the diagnosis of INH-resistant TB is confirmed long after starting the first-line TB treatment, the clinician must decide whether to start a 6-month course of RIF-EMB-PZA-LFX based on the patient's condition. However, these recommendations are based on observational studies, not randomized controlled trials, and are thus conditional and based on low certainty of the effect estimates. Therefore, further work is needed to optimize the treatment of INH-resistant TB.

• Tuberculosis and Respiratory Diseases
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• 제55권5호
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• pp.440-448
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• 2003

연구배경 : 다제내성균의 신속한 확인을 가능케 해주는 감수성검사법은 신속한 처방결정을 통해 환자의 치료 성공률을 향상 시킴과 동시에 다제내성균의 전파를 조기에 차단할 수 있게 되어, 국가 결핵관리 사업의 효율성을 증대시킬 수 있다. 방 법 : 아이나 또는 리팜피신 내성에 관련된 유전자 rpoB, katG, inhA, ahpC 등의 돌연변이를 검출할 수 있는 probe를 합성하였고, 총 502개의 내성균을 대상으로 중함효소연쇄반응 역교잡반응법으로 내성균 검출을 시도하였다. 결 과 : 264개의 리팜피신 내성균 중에서 Ser531Leu돌연변이가 46%를 차지하였고, codon 526에서는 32% 의 균주에서 돌연변이를 보였으며, codon 516에서는 10%의 균주가 돌연변이를 나타냈다. 469개의 아이나 내성균 중에서는 64%가 katG 유전자의 Ser315Thr 돌연변이를 나타내었고, 19%의 균은 inhA 유전자 promoter 돌연변이를 가지고 있었으며, ahpC유전자 돌연변이는 3%에 불과하였다. 역교잡반응법에 의한 검출율은 아이나 내성균 중 80%이상이었으며, 리팜피신 내성균에서도 92%이상을 검출할 수 있었다. 결 론 : 역교잡반응법에 의해 리팜피신 뿐만 아니라 아이나에 대한 감수성검사를 신속하게 수행할 수 있음을 확인하였고, 이 검사법은 특히 재발 또는 다제내성이 의심되는 환자의 처방 결정에 매우 유용한 수단이 될 수 있다.