• 보험의학회지
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• 제28권1_2호
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• pp.15-18
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• 2009

Background: Recent emergence of drug-resistant tuberculosis such as multidrug-resistant tuberculosis(MDR-TB) or extensively drug-resistant tuberculosis(XDR-TB) has become important health care problems. It has also became grave issues for insurance industries in determining medical risks. We have therefore strived to analyze the comparative mortality rates for drug-resistant tuberculosis through utilization of results from previous articles. Methods: Comparative mortality was calculated from source articles using mortality analysis methods. Results: Mortality ratio of MDR-TB was estimate to 1200%, and excess death rate was 110 per 1,000. Comparative mortality between MDR-TB and XDR-TB by Korean $study^{(1)}$ were 1750, 382, 405, 443, 1025, and 357%, for each 10 months study intervals, respectively. Total mortality ratio was 594% and total excess death rate was 60 per 1,000person. It was determined that the risk of XDR-TB was much greater than MDR-TB. Discussion; Pending the development of a novel anti-tuberculosis drug, it would be prudent to steer clear insuring XDR-TB during underwriting phase due to high medical cost that it creates.

• Tuberculosis and Respiratory Diseases
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• 제85권3호
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• pp.256-263
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• 2022

Background: Mycobacterium tuberculosis (Mtb) is resistant to the β-lactam antibiotics due to a non-classical transpeptidase in the cell wall with β-lactamase activity. A recent study showed that meropenem combined with clavulanate, a β-lactamase inhibitor, was effective in multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB). However, in Korea, clavulanate can only be used as drugs containing amoxicillin. In this study, we investigated the susceptibility and genetic mutations of drug-resistant Mtb isolates to amoxicillin-clavulanate and meropenem-clavulanate to improve the diagnosis and treatment of drug-resistant TB patients. Methods: The minimum inhibitory concentration (MIC) of amoxicillin-clavulanate and meropenem-clavulanate was examined by resazurin microtiter assay. We used 82 MDR and 40 XDR strains isolated in Korea and two reference laboratory strains. Mutations of drug targets blaC, blaI, ldtA, ldtB, dacB2, and crfA were analyzed by polymerase chain reaction and DNA sequencing. Results: The MIC₉₀ values of amoxicillin/clavulanate and meropenem/clavulanate in drug-resistant Mtb isolates were 64/2.5 and 16/2.5 mg/L, respectively. Gene mutations related to amoxicillin/clavulanate and meropenem/clavulanate resistance could not be identified, but T448G mutation was found in the blaC gene related to β-lactam antibiotics' high susceptibility. Conclusion: Our results provide clinical consideration of β-lactams in treating drug-resistant TB and potential molecular markers of amoxicillin-clavulanate and meropenem-clavulanate susceptibility.

• Tuberculosis and Respiratory Diseases
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• 제78권3호
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• pp.168-174
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• 2015

Drug-resistant tuberculosis (TB) is still a major threat worldwide. However, recent scientific advances in diagnostic and therapeutic tools have improved the management of drug-resistant TB. The development of rapid molecular testing methods allows for the early detection of drug resistance and prompt initiation of an appropriate treatment. In addition, there has been growing supportive evidence for shorter treatment regimens in multidrug-resistant TB; and for the first time in over 50 years, new anti-TB drugs have been developed. The World Health Organization has recently revised their guidelines, primarily based on evidence from a meta-analysis of individual patient data (n=9,153) derived from 32 observational studies, and outlined the recommended combination and correct use of available anti-TB drugs. This review summarizes the updated guidelines with a focus on the medical management of drug-resistant TB.

• 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.

• Annals of Laboratory Medicine
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• 제38권6호
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• pp.563-568
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• 2018

Background: Delamanid, bedaquiline, and linezolid have recently been approved for the treatment of multidrug- and extensively drug-resistant (MDR and XDR, respectively) tuberculosis (TB). To use these drugs effectively, drug susceptibility tests, including rapid molecular techniques, are required for accurate diagnosis and treatment. Furthermore, mutation analyses are needed to assess the potential for resistance. We evaluated the minimum inhibitory concentrations (MICs) of these three anti-TB drugs for Korean MDR and XDR clinical strains and mutations in genes related to resistance to these drugs. Methods: MICs were determined for delamanid, bedaquiline, and linezolid using a microdilution method. The PCR products of drug resistance-related genes from 420 clinical Mycobacterium tuberculosis strains were sequenced and aligned to those of M. tuberculosis H37Rv. Results: The overall MICs for delamanid, bedaquiline, and linezolid ranged from ${\leq}0.025$ to >1.6 mg/L, ${\leq}0.0312$ to >4 mg/L, and ${\leq}0.125$ to 1 mg/L, respectively. Numerous mutations were found in drug-susceptible and -resistant strains. We did not detect specific mutations associated with resistance to bedaquiline and linezolid. However, the Gly81Ser and Gly81Asp mutations were associated with resistance to delamanid. Conclusions: We determined the MICs of three anti-TB drugs for Korean MDR and XDR strains and identified various mutations in resistance-related genes. Further studies are needed to determine the genetic mechanisms underlying resistance to these drugs.

• Archives of Pharmacal Research
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• 제6권1호
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• pp.93-102
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• 1983

Waksman's group discovered SM in 1944, and opened a new field of antibiotcs: i. e. AGs. A large group of antibiotics containing aminosugar and/or aminocyclitol is called the AGs. A majority of AGs are produced by actinomycetes. In the first period, AGs effective against tuberculosis were chiefly examined. Following the studies on NM and KM, AGs active against staphyllococci and gram-negative robs were investigated. The discovery of GM and synthesis of DKB and AMK led to the studies on the third generation AGs, which show a broad antimicrobial spectrum including Pseudomonas aeruginosa and drug-resistant bacteria. Since opportunistic infection caused by drug-resistant bacteria are increasing, the third generation AGs are extensively investigated at present.

• Tuberculosis and Respiratory Diseases
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• 제68권3호
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• pp.146-154
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• 2010

Background: The increasing incidence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) has become a serious worldwide problem. However, there is insufficient data regarding the current status of MDR-TB and XDR-TB in Korea. This study examined the recent status of MDR- and XDR-TB using the data from 7 laboratories, in which almost all drug susceptibility tests (DST) for Mycobacterium tuberculosis were performed. Methods: The patients' identification data and DST results were collected from all 7 laboratories from 2001 to 2006 and the number of patients with MDR-TB and XDR-TB were calculated. Results: The number of DSTs was 140,638 for 6 years with an increasing incidence each year (p<0.001). The number of DST with MDR results was 18,510 and personal identifying information was obtained in 16,640 (89.9%) tests. The number of MDR-TB patients from 2001 to 2006 was 2,329, 2,496, 2,374, 2,300, 2,354, and 2,178, respectively, when counting the duplications in a year as one patient. The number of MDR-TB patients when counting the duplications in 6 years as one patient was 2,281, 1,977, 1,620, 1,446, 1,512, and 1,373, respectively. When the same method was adopted, the number of XDR-TB patients was 191, 238, 282, 260, 272, and 264, respectively, and 189, 150, 130, 90, 122, and 110 patients, respectively. Conclusion: Despite the national efforts to control TB, there are still a large number of MDR- and XDR-TB patients in Korea.

• Tuberculosis and Respiratory Diseases
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• 제64권3호
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• pp.187-193
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• 2008

연구배경: 다제내성결핵과 광범위내성결핵은 전세계적으로 결핵 치료에 큰 위협으로 등장하고 있지만 이에 대한 국내의 정확한 실태 및 추이는 잘 알려져 있지 않다. 일개 결핵병원에서 다제내성결핵과 광범위내성결핵의 빈도 및 추이를 살펴봄으로써 국내 실태를 간접적으로 파악하고자 하였다. 방법: 2001년부터 2005년 사이에 국립마산병원에 입원하여 배양양성 결핵으로 진단된 환자를 대상으로 약제 감수성검사 결과와 의무기록을 후향적으로 분석하였다. 결과: 2001년부터 2005년 사이에, 다제내성결핵은 신환자에서 9.2%, 13.8%, 16.9%, 23%, 27.0%로 의미있게 증가하였고(p<0.001 for trend) 재치료환자에서 9.1%, 15.7%, 17.3%, 19.9%, 19.1%로 의미있게 증가하였다 (p=0.002 for trend). 광범위내성결핵은 신환자에서 0%, 2.3%, 3.1%, 2.5%, 6.3%로 의미있게 증가하였고(p=0.005 for trend) 재치료환자에서 9.1%, 15.7%, 17.3%, 19.9%, 19.1%로 의미있게 증가하였다(p<0.001 for trend). 결론: 다제내성결핵과 광범위내성결핵은 신환자와 재치료환자 모두에서 증가하는 추이를 보였다. 국내의 정확한 실태 파악을 위하여 공공 및 민간의료기관을 포괄하는 통합적인 약제내성실태 조사가 필요할 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제25권6호
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• pp.946-950
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• 2015

Recently, it has become a struggle to treat tuberculosis with the current commercial antituberculosis drugs because of the increasing emergence of multidrug-resistant (MDR) tuberculosis and extensively drug-resistant (XDR) tuberculosis. We evaluated here the antimycobacterial activity of tamoxifen, known as a synthetic anti-estrogen, against eight drugsensitive or resistant strains of Mycobacterium tuberculosis (TB), and the active intracellular killing of tamoxifen on TB in macrophages. The results showed that tamoxifen had antituberculosis activity against drug-sensitive strains (MIC, 3.125-6.25 µg/ml) as well as drugresistant strains (MIC, 6.25 to 12.5 µg/ml). In addition, tamoxifen profoundly decreased the number of intracellular TB in macrophages in a dose-dependent manner.

• Tuberculosis and Respiratory Diseases
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• 제64권6호
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• pp.414-421
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• 2008

연구배경: 최근 광역내성 결핵은 공공보건에 중대한 문제가 되고 있다. 본 연구의 목적은 국립의료원에 내원한 폐결핵 환자들 중 광역내성 폐결핵 환자와 다제내성 폐결핵 환자의 임상적 특성을 비교 연구 하여 광역내성 및 다제내성 폐결핵에 대한 관심을 높이고 폐결핵 퇴치에 이바지하고자 하였다. 방 법: 2000년 1월부터 2007년 8월까지 객담 결핵균배 양양성 및 항결핵 약제에 대한 감수성검사가 행해진 환자를 대상으로 하였다. 감수성결과에 따라 광역내성군과 다제내성군으로 나눈 뒤, 의무기록을 토대로하여 임상적 특성을 후향적으로 비교분석 하였다. 결 과: 총 314명의 환자들 중 18명(5.7%)이 광역내성, 69명(22%)이 다제내성이었고 광역내성을 다제내성에 포함시켰을 때 광역내성이 다제내성에서 차지하는 비율은 20.69%였다. 연구된 임상적 특성들 중, 광역내성 또는 다제내성이 진단될 당시 결핵치료를 위한 폐절제술의 과거력이 광역내성군에서 더 많았으며(OR, 3.974; 95% CI, 1.052~15.011; p value, 0.032), 광역내성이나 다제내성으로 진단되기 전 복용중단기간을 포함한 이전 항결핵약제 복용기간의 평균도 광역내성군에서 더 길었다(광역내성군: 72.67개월, 다제내성군: 13.09개월, 평균복용기간의차이, 59.582개월; 95% CI, 31.743~87.420; p value, 0.000). 또한 복용기간이 길수록 광역내성 발생과 유의한 관계가 있었다(OR, 1.076; 95% CI, 1.038~1.117; p value, 0.000). 그 외 남성의 비율, 당뇨병의 빈도, 45세 미만의 연령, 2개월 이상 항결핵약제 복용을 중단한 경력, 다제내 성이나 광역내성으로 진단될 당시 흉부방사선사진에서 공동의 존재 빈도와 내성 진단 당시 객담 항산성균 도말 양성 검사 비율은 전체적으로 광역내성군에서 더 높았으나 통계적으로 유의하지는 않았다. 결 론: 광역내성 폐결핵 환자들에서 광역내성으로 진단될 당시 결핵치료를 위한 폐절제술의 과거력의 비율이 더 높았으며, 내성 진단 전 더 긴 항결핵약제 복용기간을 보여주었다. 또한 긴 복용기간은 유의하게 광역내성의 발생과 관련되어 있었다.