• 미생물학회지
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• 제46권2호
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• pp.134-139
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• 2010

전 세계 인구의 1/3을 감염시키고 있는 결핵균은 21세기에도 인류를 위협하는 병원균이다. 결핵균에 대항하는 Th1 면역 반응은 결핵균의 세포 내 성장을 제어하는 것으로 알려져 있으나, 이는 결핵균 감염을 자연 치유하는 수준에는 미치지 못한다. 본 연구에서는 C57BL/6 마우스에 병원성 결핵균인 H37Rv를 감염시켰을 때 숙주의 면역 반응에 대항하여 결핵균이 자신의 유전자 발현을 변화시킨다는 사실을 규명하기 위하여, 결핵균 유전자 중 16S rRNA, acr, fbpA, aceA, ahpC 등의 발현을 real-time RT-PCR을 이용하여 연구하였다. 16S rRNA의 copy number는 감염 후 30일까지 급격하게 증가하였는데 이는 CFU 측정 결과와 일치하고 있다. 결핵균 유전자 중 주된 항원으로 작용하는 유전자인 fbpA의 copy number를 CFU로 나눈 값으로 표현한 발현 양상은 감염 후 10일까지 증가하다가 감소되었다. Heat shock protein인 ${\alpha}$-crystallin을 coding하는 acr은 감염 후 지속적으로 높아졌으나, 산화적 스트레스 환경에서 발현되는 효소들인 ahpC와 aceA의 발현은 감염 후 20일 동안 높아졌다가 30일에는 약간 감소하였으나 비교적 높은 수준을 유지하였다. 이상의 결과는 결핵균이 숙주의 면역 반응이 개시되면 결핵균의 주된 항원 중 하나인 Ag85A를 코딩하는 유전자인 fbpA의 발현 수준을 낮춰 숙주의 Th1 먼역 반응이 낮아지도록 유도한다는 증거로 볼 수 있으며, 면역 반응이 활발해 짐에 따라 큰포식세포 내에서 산화적 스트레스로부터 균을 보호하기 위하여 ahpC와 aceA의 발현이 높아진 것으로 해석된다. 따라서 본 연구는 결핵균이 유전자 발현을 숙주의 면역 반응에 대항하여 스스로 변화시켜 적대적인 숙주 세포 내에서 살아 남을 수 있는 생존 전략을 구사한다는 가능성을 제시한다.

• International Journal of Advanced Culture Technology
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• 제11권3호
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• pp.260-267
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• 2023

We aimed to investigate the proportions of MTB- and NTM-positive tests and the distribution patterns of species isolated by contracted testing agencies in South Korea. Respiratory specimens submitted to contracted testing agencies in South Korea for AFB culture from January 2014 to December 2021 were included (533,713 specimens in total). Trends based on MTB and NTM detection, patient sex and age, culture medium type, and testing year were analyzed. MTB and NTM positive detection increased in the patients. The average ages of MTB- and NTM-positive patients increased in those aged ≥61 years. For solid culture, the MTB detection rate decreased from 5.9% in 2014 to 3.3% in 2018 and increased to 4.7% in 2021; the NTM detection rate increased from 2.1% in 2014 to 3.4% in 2018 and 3.7% in 2021. For liquid culture, the MTB detection rate decreased from 8.3% in 2014 to 5.5% in 2018 and increased to 6.0% in 2021; the NTM detection rate increased from 3.5% in 2014 to 5.5% in 2018 and decreased to 5.3% in 2021. An isolation ratio reversal between MTB and NTM was observed in 2018. In this study, we provide information on mycobacterial isolation rates and species distributions using AFB culture test results from Korea's referral laboratories. Increased MTB- and NTM-isolation rates were observed in individuals aged ≥60 years, indicating the need for regular testing and focused management for them. Expanding liquid culture applications, which show higher positivity rates than solid culture methods, is necessary.

• 대한의생명과학회지
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• 제19권2호
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• pp.153-157
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• 2013

Although culture is the gold standard method to identify mycobacteria, its use in tuberculous lymphadenitis (TBL) is limited due to formalin fixation of the submitted specimens. We evaluated the performance of quantitative real-time PCR (q-PCR) for Mycobacterium Tuberculosis (MTB) in granulomatous lymphadenitis using formalin-fixed paraffin-embedded (FFPE) tissues. From 2000 to 2010, a total number of 117 cases of lymph node samples with granulomatous inflammation which were surgically removed and fixed in formalin were studied. Hematoxylin & Eosin (H&E) and Ziehl-Neelsen-stained (ZN) slides were reviewed. qPCR using Real TB-Taq$^{(R)}$ was performed for all cases to identify Mycobacterium tuberculosis. Thirteen non-tuberculous lymphadenopathy cases were used as negative control. Cervical lymph nodes were more frequently affected (60%, 70/117) than other sites. ZN stain for acid fast bacilli was positive in 19 (16.24%) cases. qPCR for tuberculosis was positive in 92 (78.63%) cases. Caseous necrosis was found in 103 (88.03%) cases. While the ZN stain and qPCR were both negative in all control cases, the qPCR showed a significantly higher positive rate (78.63% vs. 16.24%) compared to ZN stain in histologically diagnosed TBL. Quantitative real-time PCR proves to be more sensitive than ZN stain for diagnosis of tuberculous lymphadenitis.

• Tuberculosis and Respiratory Diseases
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• 제69권1호
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• pp.52-55
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• 2010

Pulmonary tuberculosis has intermediate prevalence in Korea. It is known that tuberculosis infection predominantly involves the upper lobes, based on the fact that multiplication of Mycobacterium tuberculosis is favored in areas with decreased pulmonary blood flow, impaired lymphatic drainage, and high oxygen tension. We report this case of a 40-year-old man who was brought to our hospital with hemoptysis and dyspnea. Prior to admission, the patient had been in a bedridden state for 15 years due to an injury of the cervical spine 4~5. A 3-Dimensional computed tomography showed predominantly longitudinal distribution of centrilobular nodules along the anterior chest wall, in the left lung. MTB-PCR and AFB culture of bronchial washing fluid revealed pulmonary tuberculosis. This case shows that long-standing supine posture and decreased motion of the anterior chest wall may change the distribution of preferential infection site of Mycobacterium tuberculosis in the lung, resulting in a ventral predominance of tuberculosis infection in the quadriplegic patient.

• Journal of Microbiology and Biotechnology
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• 제25권9호
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• pp.1559-1567
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• 2015

The combination of trimethoprim (TMP) and sulfamethoxazole (SMX) has been shown to be active against Mycobacterium tuberculosis (Mtb) in clinical tuberculosis (TB) treatment. However, the mechanism of action of TMP-SMX against Mtb is still unknown. To unravel this, we have studied the effect of TMP and SMX by deleting the folP2 gene in Mycobacterium smegmatis (Msm), and overexpressing the Mtb and Msm folP1/2 genes in Msm. Knocking out of the folP2 gene in Msm reduced the minimum inhibitory concentration of SMX 8-fold compared with wild type. Overexpression of the folP1 genes from Mtb and Msm increased the MICs by 4- and 2-fold in Msm for SMX and TMP, respectively. We show a strong correlation between the expression of folP1 and folP2 genes and TMP-SMX resistance in mycobacteria. This suggests that a combination of FolP2 inhibitor and SMX could be used for TB treatment with a better outcome.

• The Korean Journal of Physiology and Pharmacology
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• 제22권4호
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• pp.369-377
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• 2018

Spinal tuberculosis (ST) is the tuberculosis caused by Mycobacterium tuberculosis (Mtb) infections in spinal curds. Isoliquiritigenin (4,2',4'-trihydroxychalcone, ISL) is an anti-inflammatory flavonoid derived from licorice (Glycyrrhiza uralensis), a Chinese traditional medicine. In this study, we evaluated the potential of ISL in treating ST in New Zealand white rabbit models. In the model, rabbits (n=40) were infected with Mtb strain H37Rv or not in their $6^{th}$ lumbar vertebral bodies. Since the day of infection, rabbits were treated with 20 mg/kg and 100 mg/kg of ISL respectively. After 10 weeks of treatments, the adjacent vertebral bone tissues of rabbits were analyzed through Hematoxylin-Eosin staining. The relative expression of Monocyte chemoattractant protein-1 (MCP-1/CCL2), transcription factor ${\kappa}B$ ($NF-{\kappa}B$) p65 in lymphocytes were verified through reverse transcription quantitative real-time PCR (RT-qPCR), western blotting and enzyme-linked immunosorbent assays (ELISA). The serum level of interleukin (IL)-2, IL-4, IL-10 and interferon ${\gamma}$ ($IFN-{\gamma}$) were evaluated through ELISA. The effects of ISL on the phosphorylation of $I{\kappa}B{\alpha}$, $IKK{\alpha}/{\beta}$ and p65 in $NF-{\kappa}B$ signaling pathways were assessed through western blotting. In the results, ISL has been shown to effectively attenuate the granulation inside adjacent vertebral tissues. The relative level of MCP-1, p65 and IL-4 and IL-10 were retrieved. $NF-{\kappa}B$ signaling was inhibited, in which the phosphorylation of p65, $I{\kappa}B{\alpha}$ and $IKK{\alpha}/{\beta}$ were suppressed whereas the level of $I{\kappa}B{\alpha}$ were elevated. In conclusion, ISL might be an effective drug that inhibited the formation of granulomas through downregulating MCP-1, $NF-{\kappa}B$, IL-4 and IL-10 in treating ST.

• 대한임상검사과학회지
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• 제47권2호
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• pp.83-89
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• 2015

결핵(Mycobacterium tuberculosis, MTB) 감염은 아직까지 전 세계에서 높은 유병률과 사망의 주요 원인이 되고 있으며 비정형 결핵(nontuberculous mycobacteria, NTM)은 최근 후천성 면역결핍증(AIDS)이나, 종양, 이식 등으로 면역력이 저하된 환자들의 임상 검체에서 분리빈도가 증가함에 따라 분리 균주의 임상적 의의가 중요시 되고 있다. 이에 항산균 염색을 이용한 객담 도말검사는 결핵균과 비정형 결핵균을 구별할 수 없다는 제한점이 있고, 균 분리배양검사는 시간이 오래 걸린다는 단점이 있어, 본 연구에서는 이러한 제한점을 가진 기존의 검사법을 대신하여 분자생물학적 방법인 중합효소 연쇄반응(polymerase chain reaction, PCR)을 이용하여 균 분리배양 검사와 비교하여 보았다. Mycobacteria를 동정하는데 항산균 염색과 3% ogawa 배지를 이용하였고, 균 분리배양 후 M. tuberculosis를 확인하기 위해서 niacin test를 실시한 결과 집락의 DNA를 추출하여 PCR후 동정된 M. tuberculosis와 niacin 양성이 일치함을 확인할 수 있었다. 또, 이 실험에서 항산성균 염색이 2+ 이상인 객담검체와 집락검체 각각에서 DNA를 추출하여 결핵균을 동정하는 방법으로 M. tuberculosis complex에 특징적으로 존재하는 insertion sequence (IS) 6110의 특정부위인 547 bp와 285 bp 부분을 증폭한 two-tube nested polymerase chain reaction을 시행하였고, 비정형 결핵균 동정법으로는 mycobacteria에 공통적으로 존재하는 rpoB 유전자 중 일부인 360 bp 부분을 증폭한 후, 제한효소 Msp I을 첨가 PCR-restriction fragment length polymorphism (RFLP)을 시행하였으며, 결핵균과 비정형 결핵균 모두 동정율에 거의 차이가 없었다. 1+인 경우는 객담검체에서 PCR한 결과가 31.2%에서 집락검체의 PCR한 결과 93.7%까지 결핵균과 비정형결핵균의 동정율이 높아졌고, trace인 경우 객담검체에서 PCR 결과가 2%에서 집락검체에서 PCR한 결과가 97.9%까지 결핵균과 비정형 결핵균의 동정율을 높일 수 있었다. 이 실험에서 항산성균 염색 1+이하 일때 객담검체와 집락검체로 PCR을 실시하면 결핵균과 비정형 결핵균의 동정율에 차이가 있고, 배양만으로는 결핵균의 동정은 가능하지만 비정형 결핵균의 동정이 가능하지 않으므로 배양검사와 PCR 검사 모두를 병행하므로써 보다 신속하고 정확한 검사결과를 내는데 도움 될 것이다.

• IMMUNE NETWORK
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• 제11권2호
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• pp.123-133
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• 2011

Background: Mycobacterium tuberculosis (Mtb) heparin binding hemagglutinin (HBHA) is an Ag known to evoke effective host immune responses during tuberculosis infection. However, the molecular basis of the host immune response to HBHA has not been fully characterized. In this study, we examined the molecular mechanisms by which HBHA can induce the expression of proinflammatory cytokines in macrophages. Methods: HBHA-induced mRNA and protein levels of proinflammatory cytokines were determined in bone marrow-derived macrophages (BMDMs) using RT-PCR and ELISA analysis. The roles of intracellular signaling pathways for NF-${\kappa}B$, PI3-K/Akt, and MAPKs were investigated in macrophage proinflammatory responses after stimulation with HBHA. Results: HBHA robustly activated the expression of mRNA and protein of both TNF-${\alpha}$ and IL-6, and induced phosphorylation of NF-${\kappa}B$, Akt, and MAPKs in BMDMs. Both TNF-${\alpha}$ and IL-6 production by HBHA was regulated by the NF-${\kappa}B$, PI3-K, and MAPK pathways. Furthermore, PI3-K activity was required for the HBHA-induced activation of ERK1/2 and p38 MAPK, but not JNK, pathways. Conclusion: These data suggest that mycobacterial HBHA significantly induces proinflammatory responses through crosstalk between the PI3-K and MAPK pathways in macrophages.

• IMMUNE NETWORK
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• 제9권5호
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• pp.192-202
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• 2009

Background: Little information is available the role of Nitric Oxide (NO) in host defenses during human tuberculosis (TB) infection. We investigated the modulating factor(s) affecting NO synthase (iNOS) induction in human macrophages. Methods: Both iNOS mRNA and protein that regulate the growth of mycobacteria were determined using reverase transcriptase-polymerase chain reaction and western blot analysis. The upstream signaling pathways were further investigated using iNOS specific inhibitors. Results: Here we show that combined treatment with 1,25-dihydroxyvitamin D3 (1,25-D3) and Interferon (IFN)-${\gamma}$ synergistically enhanced NO synthesis and iNOS expression induced by Mycobacterium tuberculosis (MTB) or by its purified protein derivatives in human monocyte-derived macrophages. Both the nuclear factor-${\kappa}B$ and MEK1-ERK1/2 pathways were indispensable in the induction of iNOS expression, as shown in toll like receptor 2 stimulation. Further, the combined treatment with 1,25-D3 and IFN-${\gamma}$ was more potent than either agent alone in the inhibition of intracellular MTB growth. Notably, this enhanced effect was not explained by increased expression of cathelicidin, a known antimycobacterial effector of 1,25-D3. Conclusion: These data support a key role of NO in host defenses against TB and identify novel modulating factors for iNOS induction in human macrophages.

• Tuberculosis and Respiratory Diseases
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• 제62권3호
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• pp.184-191
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• 2007

연구 배경: 결핵성 흉막염의 진단에 있어서 흉수에 대한 중합효소연쇄반응 검사는 매우 낮은 민감도를 보였으며, 이는 흉수 내의 결핵균의 수가 적은 데에 기인하는 것으로 추정된다. 이번 연구에서는 흉수의 검체양을 증가시켰을 때 결핵성 흉수에 대한 중합효소연쇄반응 검사의 민감도가 향상되는지를 알아보고자 하였다. 방 법: 결핵성 흉막염에 대한 감별 진단이 필요하였던 53명의 환자에 대하여 전향적인 연구를 시행하였다. 각각의 환자로부터 얻은 흉수를 10 ml, 25 ml, 50 ml로 양을 달리 하여 결핵균에 대한 중합효소연쇄반응 검사를 시행하였으며, Cobas Amplicor MTB (Roche Diagnostic Systems)를 이용하였다. 결핵성 흉막염은 흉수에서 결핵균이 배양된 경우, 흉막 생검에서 결핵이 진단된 경우, 가래에서 결핵균이 배양된 경우 및 기타 원인이 배제된 상태에서 임상적으로 결핵성 흉수가 의심되며 항결핵제 투약으로 흉수가 호전된 경우를 포함하였다. 결 과: 53명의 환자 중 26명이 결핵성 흉막염으로 진단되었다. 흉수에 대한 항산균 바름질, 결핵균 배양, 아데노신 디아미나아제 측정 및 흉막 생검의 민감도는 각각 3.8%, 15.4%, 88.5%, 84.6%이었다. 10 ml, 25 ml, 50 ml의 흉수를 이용한 결핵균 중합효소연쇄반응 검사는 각각 3명(11.5%), 4명(15.4%), 3명(11.5%)에서 양성이었으며, 통계적으로 유의한 차이를 보이지 않았다(p>0.05, symmetry exact 검사). 결 론: 결핵균의 수가 극히 적을 것으로 예상되는 흉수 등의 검사물에 대해서는 결핵균 중합효소연쇄반응 검사의 임상적 유용성이 극히 제한적이며, 검사물의 양을 증가시키더라도 민감도는 향상되지 않는다.