Latent tuberculosis infection in health-care workers in the government sector in Brunei Darussalam:A cross-sectional study

Objective:Health-care workers(HCWs)are known to be at high risk for occupational biological hazards,and this includes exposure to mycobacterium tuberculosis(TB)which can result in either active or latent TB infection(LTBI).This study aims to provide an overview of the incidence of LTBI among HCWs in Brunei Darussalam,to examine associated risk factors,and to evaluate LTBI treatment compliance.Materials and Methods:This is a retrospective cross-sectional study which was conducted using data from January 2018 to December 2021,on notified cases of LTBI in HCWs which identified 115 cases.Demographic data,underlying medical conditions,and compliance to treatment were assessed through reviews of their electronic health records.Results:The incidence of LBTI was 14.6/year/1000 HCWs.The incidence rate reached a high of 24.6/1000 in 2020,and majority of cases were in the older age groups.There was good treatment acceptance and compliance(82.6%),and this was observed to be significantly higher in females than males(P=0.02).Conclusion:This study showed an average incidence of LTBI of 14.6/1000 HCWs over 4 years and high LTBI treatment acceptance(82.6%)and compliance.Emphasis on infection prevention and control measures in health-care settings and actions to increase awareness of LTBI are crucial interventions toward reducing the burden of LTBI.

Acceptance of Chemo-prophylaxis for Latent Tuberculosis Infection among High School/College Student Contacts of Tuberculosis Patients in Shanghai, China

Student contacts of tuberculosis（TB）cases are susceptible to latent tuberculosis infection（LTBI）,and chemo-prophylaxis can reduce the risk of active TB among them.This study aimed to assess the acceptance of chemo-prophylaxis for LTBI among students, and their concerns regarding TB and its preventive treatment.

The Impact of Directly Observed Therapy on Preventive Treatment for Latent Tuberculosis Infection among Students in Dalian, China

Preventive treatment has an essential effect on latent tuberculosis infection(LTBI)[purified protein derivative(PPD)induration≥15 mm].Between2010 and 2013,there were 6 tuberculosis(TB)outbreaks in the universities in Dalian,China.So far,in Dalian,the directly observed therapy(DOT)and

Does “Latent Tuberculosis Infection” (LTBI)” Really Exist? Genealogy of a Medical Nosology

Introduction: The diagnosis of latent tuberculosis infection (LTBI) is based on secular ways: chest radiography and tuberculin skin test (TST). In front of a recent enthusiasm for LTBI, this paper reports a historical perspective of this concept. Method: Bibliometric analysis and literature review from medical databases, using the terms “latent tuberculosis infection (“LTBI”), “primary tuberculosis”, “tuberculin skin test”, “tuberculosis”, and from reference books on tuberculosis. Results: In the PubMED/MEDLINE search for LTBI, a total of 7787 articles were found between 1901 and 2020, 95% from 2000 to 2020. In the first part of the 20th century, LTBI term was used for sub-clinical tuberculosis disease, the latency being also called “primary tuberculosis” or “abortive tuberculosis infection”. From 1960, randomized prospective therapeutic studies mentioned “tuberculosis chemoprophylaxis”. By the end of the 20th century, the epidemic of AIDS impeded tuberculosis decrease, making LTBI search more efficient. In 2000, the American Thoracic Society and the Centers for Disease Controls and Prevention proposed the systematic used of LTBI, relayed through public health policies. A significant higher scientific production about LTBI was noted, supported by IGRA tests commercialization. Conclusion: In the recent years, health public policies, combined with epidemiologic and economic factors, strengthened the use of LTBI terminology.

Effect of Individualized Nursing Intervention on Patients with Tuberculosis Latent Infection and Active Tuberculosis

Objective:This paper aims to explore the effect of individualized nursing intervention on patients with active tuberculosis(ATB)and latent tuberculosis infection(LTBI).Methods:The nursing study started in January 2020 and ended in January 2023.A total of 60 patients with ATB and LTBI were included,and they were divided into two groups according to the intervention schemes selected for control testing,each with 30 cases.The intervention program selected for group A was routine care,and for group B was individualized nursing.The proportion of adverse reactions,changes in the level of lung items,self-management outcomes and satisfaction were evaluated and compared.Results:After evaluating the proportion of adverse reactions,the total proportion of ATB and LTBI in group B was lower than that in group A(P<0.05).Based on the evaluation and testing of the expiratory flow(EF),expiratory volume(EV),and vital capacity(VC)after the intervention,these levels in group B showed higher outcomes than those in group A(P<0.05).The scores in terms of living habits,sleep,diet,and compliance in group B were higher than those in group A(P<0.05).The total proportion of the satisfaction of ATB and LTBI patients in group B was higher than that in group A(P<0.05).Conclusion:After the intervention of individualized nursing measures in patients with ATB and LTBI,it was found that it can not only play a positive role in the prevention and control of adverse reactions,but also improve their lung function,and promote their self-management,with good satisfaction level,thus it has high research and clinical application values.

A prospective longitudinal study for latent tuberculosis infection in hospital in Beijing evaluating a T-cell-based assay health-care workers in a general

Background The health-care workers （HCWs） are at high risk of acquiring infection with Mycobacterium tuberculosis. The objectives of this study were to compare the performance of the T-SPOT.TB and tuberculin skin test （TST） for latent tuberculosis infection （LTBI）, evaluate diagnostic concordance and risk factors for LTBI, and observe the progression to active tuberculosis （TB） disease among HCWs in a general hospital in Beijing. Methods The prospective cohort study enrolled HCWs in a tertiary general hospital in Beijing, China, to evaluate LTBI with T-SPOT.TB and TST. The subjects were evaluated every 12 months during the 60-month follow-up. Results Of 101 participating HCWs, 96 and 101 had valid TST and T-SPOT.TB results, respectively. Twenty-nine （28.7%, 95% confidence interval （C/）, 19.9%-37.5%） were defined as positive by T-SPOT.TB and 53 （55.2%, 95% CI, 45.2%-64.9%） were defined as positive by TST （using a ≥10 mm cutoff）. An agreement between the two tests was poor （57.3%, K=0.18, 95% CI, 0.01%-0.52%）. In multJvariate analysis, direct exposure to sputum smear-positive TB patients was a significant risk factor for a positive T-SPOT.TB （OR 5.76; 95% CI 1.38-24.00）. Pooled frequency of antigen- specific IFN-y secreting T-cells for subjects who reported direct contact with sputum smear-positive TB patients was significantly higher than that for participants without direct contact （P=0.045）. One of 20 participants with positive result of T-SPOT.TB and TST developed active TB at 24-month follow-up.Conclusion T-SPOT.TB is a more accurate, targeted method of diagnosing LTBI than TST.

Mycobacterium tuberculosis latency-associated antigen Rv1733c SLP improves the accuracy of differential diagnosis of active tuberculosis and latent tuberculosis infection

Background: Differential diagnosis of active tuberculosis (ATB) and latent tuberculosis infection (LTBI) has been a challenge for clinicians in high TB burden countries. The purpose of this study was to improve the accuracy of differential diagnosis of ATB and LTBI by using fluorescent immunospot (FluoroSpot) assay to detect specific Th1 cell immune responses. The novelmycobacterium tuberculosis (MTB) latency-associated antigens Rv1733c and synthetic long peptides derived from Rv1733c (Rv1733c SLP) were used based on virulence factors early secreting antigen target-6 (ESAT-6) and culture filtrate protein-10 (CFP-10).Methods: Fifty-seven ATB cases, including 20 pathogen-confirmed ATB and 37 clinically diagnosed ATB, and 36 LTBI cases, were enrolled between January and December 2017. FluoroSpot assay was used to detect the interferon γ (IFN-γ) and interleukin 2 (IL-2) secreted by the specific T cells after being stimulated with MTB virulence factors ESAT-6 and CFP-10, MTB latency-associated antigens Rv1733c and Rv1733c SLP. The receiver operating characteristic (ROC) curve was used to define the best cutoff value of latency-associated antigens in the use of differentiating ATB and LTBI. The sensitivity, specificity, predictive value, and likelihood ratio of ESAT-6 and CFP-10-FluoroSpot combined with latency-associated antigen in the differential diagnosis of ATB and LTBI were also calculated.Results: Following the stimulation with Rv1733c and Rv1733c SLP, the frequency of single IL-2-secreting T cells stimulated by Rv1733c SLP had the largest area under the ROC curve, which was 0.766. With a cutoff value of 1 (spot-forming cells [SFCs]/2.5 × 105 peripheral blood mononuclear cells) for frequency, the sensitivity and specificity of distinguishing ATB from LTBI were 72.2% and 73.7%, respectively. ESAT-6 and CFP-10-FluoroSpot detected the frequency and proportion of single IFN-γ-secreting T cells;the sensitivity and specificity of distinguishing ATB from LTBI were 82.5% and 66.7%, respectively. Combined with the frequency of single IL-2-secreting T cells stimulated by Rv1733c SLP on the basis of ESAT-6 and CFP-10-FluoroSpot, the sensitivity and specificity increased to 84.2% and 83.3%, respectively.Conclusion: Rv1733c SLP, combined with ESAT-6 and CFP-10, might be used as a candidate antigen for T cell-based tuberculosis diagnostic tests to differentiate ATB from LTBI.

Evaluation of IFIT3 and ORM1 as Biomarkers for Discriminating Active Tuberculosis from Latent Infection

Objective Current commercially available immunological tests cannot be used for discriminating active tuberculosis(TB)from latent TB infection.To evaluate the value of biomarker candidates in the diagnosis of active TB,this study aimed to identify differentially expressed genes in peripheral blood mononuclear cells(PBMCs)between patients with active TB and individuals with latent TB infection by transcriptome sequencing.Methods The differentially expressed genes in unstimulated PBMCs and in Mycobacterium tuberculosis(Mtb)antigen-stimulated PBMCs from patients with active TB and individuals with latent TB infection were identified by transcriptome sequencing.Selected candidate genes were evaluated in cohorts consisting of 110 patients with TB,30 individuals with latent TB infections,and 50 healthy controls by quantitative real-time RT-PCR.Receiver operating characteristic(ROC)curve analysis was performed to calculate the diagnostic value of the biomarker candidates.Results Among the differentially expressed genes in PBMCs without Mtb antigen stimulation,interferon-induced protein with tetratricopeptide repeats 3(IFIT3)had the highest area under curve(AUC)value(0.918,95%CI:0.852-0.984,P<0.0001)in discriminating patients with active TB from individuals with latent TB infection,with a sensitivity of 91.86%and a specificity of 84.00%.In Mtb antigen-stimulated PBMCs,orosomucoid 1(ORM1)had a high AUC value(0.833,95%CI:0.752-0.915,P<0.0001),with a sensitivity of 81.94%and a specificity of 70.00%.Conclusion IFIT3 and ORM1 might be potential biomarkers for discriminating active TB from latent TB infection.

Development and Evaluation of a Promising Biomarker for Diagnosis of Latent and Active Tuberculosis Infection

Background:Diagnosing latent tuberculosis(TB)infection(LTBI)and active TB(ATB)is crucial for preventing disease progression and transmission.However,current diagnostic tests have limitations in terms of accuracy and sensitivity,making it challenging to diagnose these different infection states.Therefore,this study intends to develop a promising biomarker for LTBI and ATB diagnosis to overcome the limitations of the current diagnostic tests.Methods:We developed a novelmultiepitope-based diagnostic biomarker(MEBDB)fromLTBI region of differentiation antigens using bioinformatics and immunoinformatics.Immune responses induced byMEBDM were detected using enzyme-linked immunosorbent spot and cytometric bead assays.This study was conducted from April 2022 to December 2022 in the SeniorDepartment of Tuberculosis at the 8thMedical Center of PLA General Hospital,China.Blood samples were collected from participants with ATB,individuals with LTBI,and healthy controls(HCs).The diagnostic efficacy of MEBDB was evaluated using receiver operating characteristic curves.Results:A novel MEBDB,designated as CP19128P,was generated.CP19128P comprises 19 helper T lymphocyte epitopes,12 cytotoxic T lymphocyte epitopes,and 8 B-cell epitopes.In silico simulations demonstrated that CP19128P possesses strong affinity for Toll-like receptors and elicits robust innate and adaptive immune responses.CP19128P generated significantly higher levels of tumor necrosis factor(TNF-α),interleukin 4(IL-4),and IL-10 in ATB patients(n=7)and LTBI(n=8)individuals compared with HCs(n=62)(P<0.001).Moreover,CP19128P-induced specific cytokines could be used to discriminate LTBI and ATB from healthy subjects with high sensitivity and specificity.Combining IL-2 with IL-4 or TNF-α could differentiate LTBI from HCs(the area under the receiver operating characteristic curve[AUC],0.976[95% confidence interval[CI],0.934-1.000]or 0.986[0.956-1.000]),whereas combining IL-4 with IL-17A or TNF-α could differentiate ATB from HCs(AUC,0.887[0.782-0.993]or 0.984[0.958-1.000]).Conclusions:Our study revealed that CP19128P is a potential MEBDBfor the diagnosis of LTBI andATB.Our findings suggest a promising strategy for developing novel,accurate,and sensitive diagnostic biomarkers and identifying new targets for TB diagnosis and management.

Comparison between Quanti-FERON-TB Gold In-Tube test and tuberculin skin test for diagnosis of latent tuberculosis in children: A cross-section study

Objective: To compare Quanti-FERON-TB Gold In-Tube (QFT-GIT) test and tuberculin skin test (TST) for the diagnosis of latent tuberculosis infection in children. Methods: In this cross-sectional study, 64 participants who were between 3 months and 14 years old and had close contact with smear-positive pulmonary tuberculosis were included. Both QFT-GIT test and TST were done and the results were analyzed by SPSS software and Kappa test. Results: The distribution of gender and age according to QFT-GIT and TST results were matched (P>0.05). Overall agreement between QFT-GIT and TST for diagnosis of latent tuberculosis infection in children was 75%. In addition, the contingency coefficient was 0.257, and the Kappa measure of agreement was 0.246 (P=0.034). Conclusions: Compared to TST, QFT-GIT shows no apparent advantage for diagnosis of latent tuberculosis infection in children.

Purified protein derivative skin testing on HIV/AIDS patients and logistic regression analysis of its risk factors

Objective： To understand the reactivity of purified protein derivative skin test（PPD test） in HIV-infected persons and to determine the influential factors associated with PPD. Methods： 174 HIV/AIDS patients registered in the local center for disease control and prevention（CDC） participated this study from April to June in 2006. Questionnaire,CD4 count and thoracic roentgenogram were performed for all participants. Results： In this study, response rate of questionnaires was 83.65%. The majority of these participants had a different degree of immunodeficiency that accounted for 93.64%. Female patients had a higher CD4 count than that of males. The total positive rate of PPD was 38.15%. Analysis of single factor in our study indicated that CD4 count, previous tubereulosis history, tuberculosis contact history and thoracic roentgenogram manifestation of patients were related to their PPD diameters. Further analysis of multiple factors also supports the previous conclusion that CD4 count and previous tuberculosis history of patients were risk factors in the PPD test. Conclusion： The PPD test of HIV/AIDS patients could be affected by several factors. For persons infected with HIV, the confirmation of latent tuberculosis infection （LTBI） should be considered the combination effect of previous MTB infection and body cellular immune function.

Controlling strategy of dormant Mycobacterium tuberculosis

Objective This study aimed to review the available literatures on control of latent tuberculosis （TB） infection and propose a new control strategy to shorten the course of TB chemotherapy. Data sources The data used in this review were mainly obtained from articles listed in PubMed. The search terms were ＂therapy （treatment） of tuberculosis; ＂therapy （treatment） of latent TB infection; and ＂vaccine of TB.＂ Study selection Articles regarding treatment and vaccine of TB were selected and reviewed. Results The most crucial reason causing the prolonged course of TB chemotherapy is the dormant state of Mycobacterium tuberculosis （M. tuberculosis）. Nevertheless, there are, to date, no effective drugs that can directly kill the dormant cells of M. tuberculosis in clinical therapy. In accordance with the growth cycle of dormant M. tuberculosis in the body, the methods for controlling dormant M. tuberculosis include direct killing with drugs, prevention of dormant M. tuberculosis resuscitation with vaccines, and resuscitating dormant M. tuberculosis with preparations or drugs and then thoroughly killing these resuscitated M. tuberculosis by using anti-TB therapy. Conclusions The comprehensive analysis of the above three methods suggests that the drugs directly killing dormant cells are in clinical trials, TMC207 is the most beneficial for controlling TB. Because the side effect of vaccines is less and their action period is long, prevention of dormant cells resuscitation with vaccines is promising. The last control method makes it probable that when a huge number of active cells of M. tuberculosis have been killed and eradicated after 1-month short chemotherapy, only a strong short-term subsequent chemotherapy can completely kill and eradicate the remaining M. tuberculosis. This control strategy is expected to significantly shorten the course of TB chemotherapy and bring a new change and breakthrough in TB treatment.