• 보건세계
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• v.53 no.4 s.596
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• pp.35-39
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• 2006

폐결핵이 발생한 환자가 기침할 때 나오는 결핵균들은 새로 태어난 사람들을 포함하여 결핵균에 감염되지 않았던 다른 사람들을 새롭게 감염시키면서 인류 사회에 깊숙이 침투해서 번창하여 왔다. 그러나 1940년대에 접어들면서 인류는 결핵균에게 치명적인 무기들을 하나씩 개발하고 결핵균의 전략을 파악하면서 대대적인 반격을 시작하였다. 세월이 흘러 결핵퇴치사업이 성과를 보이면서 선진국들을 중심으로 결핵균의 세력이 급격히 위축되면서 위기를 맞고 있다.

• 보건세계
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• v.53 no.3 s.595
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• pp.35-39
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• 2006

인류는 수많은 연구들을 통하여 결핵의 원인균(결핵균:M.tuberculosis)과 발병기전을 밝혔으며, 결핵퇴치사업을 범세계적으로 추진하였음에도 불구하고 결핵은 아직도 전 세계적으로 만연하고 있다. 결핵균이 현대의학의 발전에도 불구하고 우리나라를 포함하여 전 세계적으로 맹위를 떨치고 있는 것은 대부분의 미생물들과는 달리 결핵균만이 가지는 아주 독특한 생존전략을 가지고 있기 때문일 것이다.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.2
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• pp.83-89
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• 2015

Although Mycobacterium tuberculosis complex strains remain responsible for the majority of diseases caused by mycobacterial infections worldwide, the increase in HIV (human immuno deficiency virus) infections has allowed for the emergence of other non-tuberculous mycobacteria as clinically significant pathogens. M. tuberculosis was detected by two-tube nested polymerase chain reaction (PCR) and non-tuberculous mycobacteria was detected by PCR-restriction fragment length polymorphism (RFLP) with Msp I. Result of niacin test is equal to result of two-tube nested PCR after culture for M. tuberculosis. In this study, acid fast bacilli stain (AFB. stain) >2+ case, Detection of Mycobacteria is similar to result before culture and after culture. AFB. stain <1+ case, result of mycobacteria is distinguished. Conclusionly, these results suggest that identification of mycobacteria must go side by side both culture and PCR for more fast and accuracy.

• Tuberculosis and Respiratory Diseases
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• v.44 no.3
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• pp.470-478
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• 1997

Background : Phagocytosis is probably the first step for mycobacteria to be virulent in host because virulent strains are more readily phagocytosed by macrophage than attenuated strains. According to the traditional concept, multi-drug resistant strains have been regarded as less virulent. However, this concept has been challenged, since recent studies(reported) showed that the degree of virulence and drug-resistance is not related. The purpose of this study is to evaluate whether the phagocytic activity of M.tuberculosis by peripheral blood mononuclear cells(PBMC) is different according to drug-resistance or host factor. To evaluate this, we estimated the difference of phagocytic activity of drug-resistant and drug-sensitive M.tuberculosis and also estimated the phagocytic activity of PBMC from intractable tuberculosis patients and healthy controls. Methods : PBMC from ten intractable tuberculosis patients and twelve healthy control, and three different strains of heat-killed M.tuberculosis, ie, ADS(all drug sensitive), MDR(multi-drug resistant), and ADR(all drug resistant) were used. After incubation of various strains of M.tuberculosis with PBMC, the phagocytic activity was evaluated by estimating proportion of PBMC which have phagocytosed M.tuberculosis. Results : Drug-resistant strains of M.tuberculosis were phagocytosed easily than drug sensitive strains(Percentage of PBMC phagocytosed M.tuberculosis in healthy control : ADS : $32.3{\pm}2.9%$, ADR : $49.6{\pm}3.4%$, p = 0.0022, Percentage of PBMC phagocytosed M.tuberculosis in intractable tuberculosis patients : ADS : $34.9{\pm}3.6%$, ADR : $50.7{\pm}4.5%$, p = 0.0069). However, there was no difference in phagocytic activity of PBMC from healthy control and intractable tuberculosis patients. Conclusion : Drug-resistant strains of M.tuberculosis were phagocytosed easily than drug sensitive strains and host factors does not seems to influence the phagocytosis of M.tuberculosis.

• 보건세계
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• v.53 no.7 s.599
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• pp.35-39
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• 2006

결핵균이 몸 속에 들어와서 결핵균 특이T-림프구의 분화 및 증식을 자극하여 투베르클린 검사 양성을 보일 정도로 충분한 숫자의 결핵균 특이T-림프구들이 형성될 때 까지는 약 4주가 소요된다.

• Tuberculosis and Respiratory Diseases
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• v.65 no.6
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• pp.512-516
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• 2008

결핵균은 공기를 매개로 전파되고 결핵균에 노출된 시간과 최초의 노출 정도가 전파의 위험을 증가 시키는 중요한 인자로 알려져 있다. 활동성 폐결핵 환자와 함께 생활하는 가족 내에서 감염이 현저히 증가하는데 이는 결핵균에 노출되는 기회 및 시간이 증가하기 때문이다. 하지만 고식적인 접촉자 조사만으로는 흔히 결핵 발생률을 과소평가할 수 있기 때문에 접촉자 조사와 결핵균의 유전형 조사를 병행하는 것이 감염의 위험이 높은 집단을 선별해내고 발생빈도 및 전염경로를 밝히는 데 보다 효과적인 것으로 보고되고 있다. 이에 접촉자 조사와 결핵균의 유전형 조사를 통해 가족 내 결핵균 전파를 증명한 1예를 보고하는 바이다.

• Korean Journal of Microbiology
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• v.46 no.2
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• pp.134-139
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• 2010

Mycobacterium tuberculosis (Mtb) is one of the most successful pathogens to infect one third of world population. Th1-mediated immunity against Mtb infection is known as critical to express mycobacteriostatic function but it is not sufficient to resolve the infection. In this study, to verify the possibility Mtb itself change the gene expression to survive against host immune response, expression pattern of selected H37Rv genes, 16S rRNA, acr, fbpA, aceA, and ahpC, during the course of infection was measured with absolute quantitation method using real-time RT-PCR. The total number of transcripts of 16S rRNA increased during the course of infection, which was coincide with the increasing CFU. The total number of fbpA transcripts per CFU, which encode typical secreted Mtb antigen, Ag85A, increased for 10 days of infection before decreasing. The number of transcripts of acr per CFU, which encode heat shock protein, ${\alpha}$-crystallin, increased during the infection, and ahpC and aceA, they both are enzymes produced in oxidative stressful condition, increased for 20 days and then slightly decreased on day 30. These findings are one of survival strategy of pathogen evading host immune response lead to persistent infection inside host cells.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.1
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• pp.20-28
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• 2018

Tuberculosis (TB) is a bacterial infection disease caused by members of the species Mycobacterium tuberculosis (MTB) complex. Approximately one third of the world's population is infected with TB. In Korea, approximately 40,000 new patients are identified each year. Moreover, infections from non-tuberculous mycobacteria (NTM) have also increased. In the diagnosis of TB and NTM, traditional bacterial cultures are required for 3 to 4 weeks. Therefore, rapid and accurate diagnostic tests for TB and NTM are needed. To distinguish between TB and NTM, a range of diagnostic methods have been developed worldwide. In vitro diagnostic assays are constantly being developed to meet the increasing need for the rapid and accurate identification for TB and NTM. On the other hand, the performance evaluations of in vitro diagnostic reagents for TB and NTM are lacking. Recently, the Korea Food and Drug Administration (KFDA) issued a guideline for in vitro diagnostic reagents for MTB and NTM. Here, this study analyzed the performance of currently developed in vitro diagnostic reagents for TB and NTM in the US FDA. This analysis of US FDA approved molecular assays could serve as a useful reference for an evaluation of the reagent performance of TB and NTM.

• Tuberculosis and Respiratory Diseases
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• v.56 no.3
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• pp.261-268
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• 2004

Background : The resurgence of tuberculosis and outbreaks of multidrug resistant (MDR) tuberculosis have increased the emphasis for the development of new susceptibility testing of the Mycobacterium tuberculosis for the effective treatment and control of the disease. Conventional drug susceptibility testings, such as those using egg-based or agar-based media have some limits, such as the time required and difficulties in determining critical inhibitory concentrations, but these are still being used in many diagnostic laboratories because of no better lternatives, considering cost and accuracy. To overcome these limits, a rapid and simple method for new susceptibility testing, using live and dead assays, was applied for a bacterial cell viability assay to distinguish dead from live bacterial cells based on two-color fluorescence. Materials and Methods Strains : Forty strains were used in this study, 20 susceptible to all antituberculosis drugs and the other 20 resistant to the four first line antituberculosis drugs isoniazid, rifampicin, streptomycin and ethambutol. Antibiotics : The four antibiotics were dissolved in 7H9 broth to make the following solutions: $0.1{\mu}g\;isoniazid(INH)/m{\ell}$, $0.4{\mu}g\;rifampicin(RMP)/m{\ell}$, $4.0{\mu}g\;streptomycin(SM)/m{\ell}$ and $4.0{\mu}g\;ethambutol(EMB)/m{\ell}$. Results : Live and dead Mycobacterium tuberculosis cells fluoresced green and red with the acridin (Syto 9) and propidium treatments, respectively. These results are very well accorded with conventional drug susceptibility testing by proportional method on Lowensen-Jensen media (L-J) containing 4 drugs (INH, RMP, EMB and SM), showing a 93.7 % accordance rate in susceptible strains and 95% in resistant strains. Conclusion : The results of the drug susceptibility testing using the live and dead bacterial cell assay showed high accordance rates compared with the conventional proportion method on L-J. This finding suggests that the live and dead bacterial cell assay can be used as an alternative to conventional drug susceptibility testing for M. tuberculosis strains.

• Tuberculosis and Respiratory Diseases
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• v.47 no.6
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• pp.747-756
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• 1999

Background: Acid-fast stain and cultures for diagnosis of pulmonary tuberculosis are primary and essential method, but have their limitation : low sensitivity and time consuming. The objective of this study is comparison of amplified Mycobacterium tuberculosis direct test(MTD) by the conventional AFB smears and cultures in the detection of Mycobacterium tuberculosis in respiratory specimens. Methods: During the period between November, 1997 and May, 1998 a total of 267 respiratory specimens (sputum 173, bronchial washing 94) from 187 patients suspected pulmonary tuberculosis were subjected to AFB smears, cultures and MID test. MID is based on nucleic acid amplification. We compared the MID with 3% Ogawa culture method. In positive AFB smear and negative MID specimen, positive culture identification between nontuberculous mycobacterium and M.tuberculosis was assesed by using Accuprobe M.tuberculosis complex probe. In negative AFB smear and negative AFB culture, MTD results are assessed by clinical follow-up. Results : 1) Compared with culture in sputum and bronchial fluid specimens, sensitivity and specificity of MTD in positive AFB smear is 79.7% and 20.0%, sensitivity and specificity of MTD in negative AFB smear specimens is 75.0% and 79.7%. 2) Discrepant analysis is assessed by clinical follow-up and other specimen results beyond study. Culture negative but MTD positive specimens were proved to be true positive and gave MTD sensitivity 79.2%, specificity of 84.4%, positive predictive value 80.5% and negative predictive value 83.2%. 3) 14 out of 31 specimens in negative AFB smear, negative AFB culture and positive MTD showed pulmonary tuberculosis diagnosed on clinical follow-up and sensitivity is 45.2%. 4) 2 out of 13 specimens in positive AFB smear, positive AFB culture and negative MID diagnosed as non tuberculous mycobacterium by Accuprobe culture. Conclusion: This study suggested that MID in respiratory specimens is simple and rapid diagnostic method, but considered adjuvant method rather than replace the conventional AFB smear and culture.