• Tuberculosis and Respiratory Diseases
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• v.84 no.1
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• pp.1-12
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• 2021

Mycobacterium tuberculosis has infected more than two billion individuals worldwide, of whom 5%-10% have clinically active disease and 90%-95% remain in the latent stage with a reservoir of viable bacteria in the macrophages for extended periods of time. The tubercle bacilli at this stage are usually called dormant, non-viable, and/or non-culturable microorganisms. The patients with latent bacilli will not have clinical pictures and are not infectious. The infections in about 2%-23% of the patients with latent status become reactivated for various reasons such as cancer, human immunodeficiency virus infection, diabetes, and/or aging. Many studies have examined the mechanisms involved in the latent state of Mycobacterium and showed that latency modified the expression of many genes. Therefore, several mechanisms will change in this bacterium. Hence, this study aimed to briefly examine the genes involved in the latent state as well as the changes that are caused by Mycobacterium tuberculosis. The study also evaluated the relationship between the functions of these genes.

• Tuberculosis and Respiratory Diseases
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• v.79 no.4
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• pp.201-206
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• 2016

Active tuberculosis (TB) has a greater burden of TB bacilli than latent TB and acts as an infection source for contacts. Latent tuberculosis infection (LTBI) is the state in which humans are infected with Mycobacterium tuberculosis without any clinical symptoms, radiological abnormality, or microbiological evidence. TB is transmissible by respiratory droplet nucleus of $1-5{\mu}m$ in diameter, containing 1-10 TB bacilli. TB transmission is affected by the strength of the infectious source, infectiousness of TB bacilli, immunoresistance of the host, environmental stresses, and biosocial factors. Infection controls to reduce TB transmission consist of managerial activities, administrative control, engineering control, environmental control, and personal protective equipment provision. However, diagnosis and treatment for LTBI as a national TB control program is an important strategy on the precondition that active TB is not missed. Therefore, more concrete evidences for LTBI management based on clinical and public perspectives are needed.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.471-478
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• 2021

The purpose of this study were to investigate knowledge, awareness, performance, and preventive behavior of latent tuberculosis infection management, and to identify influencing factors on preventive behavior of latent tuberculosis infection management of nursing students. The subjects of this study were completed by 191 nursing students from 2 colleges in D City. Data were collected from August 1 to November 30, 2020. Data were analyzed using the t-test, the ANOVA, the Pearson correlation coefficient, and stepwise multiple regression analysis by SPSS ver. 21.0. There were significant positive correlations between preventive behavior of latent tuberculosis infection management and performance(r=.21, p=.003), awareness and performance(r=.88, p<.001). The factors influencing grade and education experience about latent tuberculosis infection management of the study subjects were grade(β=.29, p<.001), final time of education experience about tuberculosis(β=.19, p=.004), and the explanatory power of these variables was 11.9%. The development of preventive behavior of latent tuberculosis infection management education program that focuses grade and final time of education experience about tuberculosis is needed.

• Tuberculosis and Respiratory Diseases
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• v.86 no.2
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• pp.94-101
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• 2023

A recent understanding of the dynamic continuous spectrum of Mycobacterium tuberculosis infection has led to the recognition of incipient tuberculosis, which refers to the latent infection state that has begun to progress to active tuberculosis. The importance of early detection of these individuals with a high-risk of progression to active tuberculosis is emphasized to efficiently implement targeted tuberculosis preventive therapy. However, the tuberculin skin test or interferon-γ release assay, which is currently used for the diagnosis of latent tuberculosis infection, does not aid in the prediction of the risk of progression to active tuberculosis. Thus, a novel test is urgently needed. Recently, simultaneous and systematic analysis of differentially expressed genes using a high-throughput platform has enabled the discovery of key genes that may serve potential biomarkers for the diagnosis or prognosis of diseases. This host transcriptional investigation has been extended to the field of tuberculosis, providing promising results. The present review focuses on recent progress and challenges in the field of blood transcriptional signatures to predict progression to active tuberculosis.

• Tuberculosis and Respiratory Diseases
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• v.79 no.3
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• pp.127-133
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• 2016

Tuberculosis (TB) is one of the most important occupational risks for healthcare workers (HCWs) in South Korea. Many policies regarding the control and prevention of TB in healthcare settings recommend that HCWs are tested for latent tuberculosis infection (LTBI) in addition to active TB. Moreover, the Korean Tuberculosis Prevention Act also recommends that HCWs receive regular testing for LTBI. However, there are no specific or detailed guidelines for dealing with LTBI in HCWs. Herein, we discuss the diagnosis and treatment of LTBI in HCWs and focus particularly on the baseline screening of hired HCWs, routine follow-up, and contact investigation.

• Tuberculosis and Respiratory Diseases
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• v.78 no.2
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• pp.56-63
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• 2015

A small number of viable tuberculosis bacilli can reside in an individual with latent tuberculosis infection (LTBI) without obvious clinical symptoms or abnormal chest radiographs. Diagnosis and treatment for LTBI are important for tuberculosis (TB) control in public and private health, especially in high-risk populations. The updated 2014 Korean guidelines for TB recommend that tuberculin skin tests, interferon-gamma release assays, or a combination of the two can be used for LTBI diagnosis according to age and immune status of the host as well as TB contact history. The regimens for LTBI treatment include isoniazid, rifampicin, or isoniazid/rifampicin. However, results of drug susceptibility test from the index case must be considered in selecting the appropriate drug for recent contacts. Standardized LTBI diagnosis and treatment based on the new 2014 guidelines will contribute to the effective TB control in Korea as well as to the establishment of updated guidelines.

• Journal of Preventive Medicine and Public Health
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• v.52 no.4
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• pp.272-275
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• 2019

The 2018 National Guideline for Tuberculosis Control, which was published by the Korea Centers for Diseases Prevention and Control (KCDC), mandates conducting an epidemiological survey among close contacts of active tuberculosis patients at public institutions such as schools. In the procedure for these surveys, the tuberculin skin test (TST) is mandated as the screening test for latent tuberculosis infection in elementary school students. However, several guidelines recommend using the interferon-gamma releasing assay (IGRA) for contacts aged over 5 years with a Bacillus Calmette-$Gu{\acute{e}}rin$ vaccination history. The main reason for this is that IGRA has a higher specificity and lower false positive rate than TST. In addition, IGRA requires only a single visit to draw blood and the results are available within 24 hours. These advantages could promote cooperation from both parents and students in conducting these surveys. Thus, these findings regarding the benefits of IGRA for surveys of close contacts at elementary schools should be incorporated into the KCDC guideline.

• Clinical and Experimental Pediatrics
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• v.52 no.5
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• pp.519-528
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• 2009

Tuberculosis continues to cause an unacceptably high toll of disease and death among children worldwide. Whereas intense scientific and clinical research efforts into novel diagnostic, therapeutic, and preventive interventions have focused on tuberculosis in adults, childhood tuberculosis has been relatively neglected. However, children are particularly vulnerable to severe disease and death following infection, and those with latent infection become the reservoir for future transmission following disease reactivation in adulthood, fuelling future epidemics. Therefore, it is very important to understand the significance, diagnosis and treatment of latent tuberculous infection to decrease a future disease burden of tuberculosis. Unfortunately, these concept still have not fully implicated in Korean National Tuberculosis Control Program, it should be engaged and enforced as soon as possible.

• Pediatric Infection and Vaccine
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• v.18 no.1
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• pp.1-14
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• 2011

Tuberculosis is a disease with high morbidity and mortality in children worldwide. Despite the decrease in the incidence of tuberculosis in Korea, more than 30,000 new patients are diagnosed each year. Active tuberculosis is less frequent in children compared to adults but the risk of miliary tuberculosis and CNS tuberculosis is much higher. The diagnosis of tuberculosis in children and adolescents is difficult due to the nonspecific symptoms upon presentation. Diagnostic work up is based on the confirmation of tuberculosis infection by tuberculin skin test, abnormal radiologic findings, and contact with an adult with active tuberculosis. Anti-tuberculosis medications are prescribed according to the drug susceptibility of the index patient. Latent tuberculosis infection plays an important role in adult tuberculosis by reactivation. Thus, it is critical to accurately diagnose latent tuberculosis in children to prevent reactivation in adulthood. Korean guidelines for diagnosis and treatment of tuberculosis in children and adolescents provide evidence based recommendations in the optimal diagnosis and treatment for active and latent tuberculosis in children and adolescents based on the current Korean situation.

• Tuberculosis and Respiratory Diseases
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• v.76 no.6
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• pp.261-268
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• 2014

Patients with immune-mediated inflammatory diseases (IMIDs) are increasingly being treated with anti-tumor necrosis factor (TNF) agents and are at increased risk of developing tuberculosis (TB). Therefore, diagnosis and treatment of latent TB infection (LTBI) is recommended in these patients due to the initiation of anti-TNF therapy. Traditionally, LTBI has been diagnosed on the basis of clinical factors and a tuberculin skin test. Recently, interferon-gamma releasing assays (IGRAs) that can detect TB infection have become available. Considering the high-risk of developing TB in patients on anti-TNF therapy, the use of both a tuberculin skin test and an IGRA should be considered to detect and treat LTBI in patients with IMIDs. The traditional LTBI treatment regimen consisted of isoniazid monotherapy for 9 months. However, shorter regimens such as 4 months of rifampicin or 3 months of isoniazid/rifampicin are increasingly being used to improve treatment completion rates. In this review, the screening methods for diagnosing latent and active TB before anti-TNF therapy in patients with IMIDs will be briefly described, as well as the current LTBI treatment regimens, the recommendations for managing TB that develops during anti-TNF therapy, the necessity of regular monitoring to detect new TB infection, and the re-initiation of anti-TNF therapy in patients who develop TB.