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Rationale: Mycobacterium tuberculosis is transmitted by infectious aerosols, but assessing infectiousness currently relies on sputum microscopy that does not accurately predict the variability in transmission.Objectives: To evaluate the feasibility of collecting cough aerosols and the risk factors for infectious aerosol production from patients with pulmonary tuberculosis (TB) in a resource-limited setting.Methods: We enrolled subjects with suspected TB in Kampala, Uganda and collected clinical, radiographic, and microbiological data in addition to cough aerosol cultures. A subset of 38 subjects was studied on 2 or 3 consecutive days to assess reproducibility.Measurements and Main Results: M. tuberculosis was cultured from cough aerosols of 28 of 101 (27.7%; 95% confidence interval [CI], 19.9-37.1%) subjects with culture-confirmed TB, with a median 16 aerosol cfu (range, 1-701) in 10 minutes of coughing. Nearly all (96.4%) cultivable particles were 0.65 to 4.7 μm in size. Positive aerosol cultures were associated with higher Karnofsky performance scores (P = 0.016), higher sputum acid-fast bacilli smear microscopy grades (P = 0.007), lower days to positive in liquid culture (P = 0.004), stronger cough (P = 0.016), and fewer days on TB treatment (P = 0.047). In multivariable analyses, cough aerosol cultures were associated with a salivary/mucosalivary (compared with purulent/mucopurulent) appearance of sputum (odds ratio, 4.42; 95% CI, 1.23-21.43) and low days to positive (per 1-d decrease; odds ratio, 1.17; 95% CI, 1.07-1.33). The within-test (kappa, 0.81; 95% CI, 0.68-0.94) and interday test (kappa, 0.62; 95% CI, 0.43-0.82) reproducibility were high.Conclusions: A minority of patients with TB (28%) produced culturable cough aerosols. Collection of cough aerosol cultures is feasible and reproducible in a resource-limited setting. [ABSTRACT FROM AUTHOR]

Rationale: Healthy household contacts (HHCs) of patients with active pulmonary tuberculosis are exposed aerogenically to Mycobacterium tuberculosis (Mtb), thus permitting the study of protective local immunity.Objectives: To assess alveolar macrophage (AM) and autologous blood CD4 and CD8 T-cell-mediated Mtb growth control in HHCs and healthy, unexposed community control subjects (CCs).Methods: AMs were infected with Mtb strains H(37)Ra and H(37)Rv at multiplicities of infection 0.1 and 1. Mtb colony-forming units were evaluated on Days 1, 4, and 7.Main Results: CD8 T cells from HHCs in 1:1 cocultures with AMs significantly (p < 0.05) increased Mtb growth control by AMs. In CCs, no detectable contribution of CD8 T cells to Mtb growth control was observed. CD4 T cells did not increase Mtb growth control in HHCs or in CCs. IFN-gamma, nitric oxide, and tumor necrosis factor were determined as potential mediators of Mtb growth control in AMs and AM/CD8 and AM/CD4 cocultures. IFN-gamma production in AM/CD4 was twofold higher than that in AM/CD8 cocultures in both HHCs and CCs (p < 0.05). Nitric oxide production from AMs of HHCs increased on Days 4 and 7 and was undetectable in AMs from CCs. IFN-gamma and nitric acid concentrations and Mtb growth control were not correlated. Tumor necrosis factor levels were significantly increased in AM/CD8 cocultures from HHCs compared with AM/CD8 cocultures from CCs (p < 0.05).Conclusion: Aerogenic exposure to Mtb in HHCs leads to expansion of Mtb-specific effector CD8 T cells that limit Mtb growth in autologous AMs. [ABSTRACT FROM AUTHOR]

Interleukin-10 (IL-10) inhibits intracellular Mycobacterium avium killing by cytokine-activated murine macrophages and may have a role in pathogenesis. Cytokine activities in supernatants of M. avium-infected human monocytes were maximal at 6-24 h for tumor necrosis factor (TNF)-alpha and 24-48 h for IL-10. TNF-alpha and IL-10 production increased with increasing M. avium-to-monocyte infection ratios (20:1 to 200:1). TNF-alpha production by monocytes infected with smooth, domed, and opaque organisms at 200:1 exceeded that of monocytes infected with smooth, flat, and transparent M. avium (P < .01). IL-10 induction demonstrated considerable strain-to-strain variability and did not correlate with intracellular M. avium growth. IL-10 significantly inhibited TNF-alpha, IL-1 beta, and IL-6 production by M. avium-infected monocytes. Coculturing monocytes with IL-10 after M. avium infection did not affect intracellular M. avium growth. Differential induction of TNF-alpha may be a factor in the intracellular growth of M. avium in human monocytes. IL-10, however, played no apparent role in pathogenicity in this model. [ABSTRACT FROM AUTHOR]

Undernutrition is the leading risk factor for tuberculosis (TB) globally and in India. This multicenter prospective cohort analysis from India suggests that undernutrition is associated with increased risk of TB disease but not TB infection among household contacts of persons with TB., Competing Interests: Potential conflicts of interest. The authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Blood-based transcriptional gene signatures for tuberculosis (TB) have been developed with potential use to diagnose disease. However, an unresolved issue is whether gene set enrichment analysis of the signature transcripts alone is sufficient for prediction and differentiation or whether it is necessary to use the original model created when the signature was derived. Intra-method comparison is complicated by the unavailability of original training data and missing details about the original trained model. To facilitate the utilization of these signatures in TB research, comparisons between gene set scoring methods cross-data validation of original model implementations are needed., Methods: We compared the performance of 19 TB gene signatures across 24 transcriptomic datasets using both rrebuilt original models and gene set scoring methods. Existing gene set scoring methods, including ssGSEA, GSVA, PLAGE, Singscore, and Zscore, were used as alternative approaches to obtain the profile scores. The area under the ROC curve (AUC) value was computed to measure performance. Correlation analysis and Wilcoxon paired tests were used to compare the performance of enrichment methods with the original models., Results: For many signatures, the predictions from gene set scoring methods were highly correlated and statistically equivalent to the results given by the original models. In some cases, PLAGE outperformed the original models when considering signatures' weighted mean AUC values and the AUC results within individual studies., Conclusion: Gene set enrichment scoring of existing gene sets can distinguish patients with active TB disease from other clinical conditions with equivalent or improved accuracy compared to the original methods and models. These data justify using gene set scoring methods of published TB gene signatures for predicting TB risk and treatment outcomes, especially when original models are difficult to apply or implement., (© 2024. The Author(s).)

Background: Xpert MTB/RIF Ultra (Ultra) is an automated molecular test for the detection of Mycobacterium tuberculosis in sputum. We compared the sensitivity of Ultra to that of mycobacterial growth indicator tube (MGIT) liquid culture, considered the most sensitive assay in routine clinical use., Methods: In this prospective, multicentre, cross-sectional diagnostic accuracy study, we used a non-inferiority design to assess whether the sensitivity of a single Ultra test was non-inferior to that of a single liquid culture for detection of M tuberculosis in sputum. We enrolled adults (age ≥18 years) with pulmonary tuberculosis symptoms in 11 countries and each adult provided three sputum specimens with a minimum volume of 2 mL over 2 days. Ultra was done directly on sputum 1, and Ultra and MGIT liquid culture were done on resuspended pellet from sputum 2. Results of MGIT and solid media cultures done on sputum 3 were considered the reference standard. The pre-defined non-inferiority margin was 5·0%., Findings: Between Feb 18, 2016, and Dec 4, 2019, we enrolled 2906 participants. 2600 (89%) participants were analysed, including 639 (25%) of 2600 who were positive for tuberculosis by the reference standard. Of the 2357 included in the non-inferiority analysis, 877 (37%) were HIV-positive and 984 (42%) were female. Sensitivity of Ultra performed directly on sputum 1 was non-inferior to that of sputum 2 MGIT culture (MGIT 91·1% vs Ultra 91·9%; difference -0·8 percentage points; 95% CI -2·8 to 1·1). Sensitivity of Ultra performed on sputum 2 pellet was also non-inferior to that of sputum 2 MGIT (MGIT 91·1% vs Ultra 91·9%; difference -0·8 percentage points; -2·7 to 1·0)., Interpretation: For the detection of M tuberculosis in sputum from adults with respiratory symptoms, there was no difference in sensitivity of a single Ultra test to that of a single MGIT culture. Highly sensitive, rapid molecular approaches for M tuberculosis detection, combined with advances in genotypic methods for drug resistance detection, have potential to replace culture., Funding: US National Institute of Allergy and Infectious Diseases., Competing Interests: Declaration of interests SGS was employed by FIND during conduct of the study. FIND is a not-for-profit foundation that supports the evaluation of publicly prioritised tuberculosis assays and the implementation of WHO-approved (guidance and prequalification) assays using donor grants. FIND has product evaluation agreements with several private sector companies that design diagnostics and related products for treatment of tuberculosis and other diseases. These agreements strictly define FIND’s independence and neutrality with regard to the companies whose products get evaluated and describe roles and responsibilities. DA receives income from licence payments from Cepheid to Rutgers University and reports receiving research contracts and research support from Cepheid. All other authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Undernutrition is the leading risk factor for tuberculosis (TB) globally. Its impact on treatment outcomes is poorly defined., Methods: We conducted a prospective cohort analysis of adults with drug-sensitive pulmonary TB at 5 sites from 2015-2019. Using multivariable Poisson regression, we assessed associations between unfavorable outcomes and nutritional status based on body mass index (BMI) nutritional status at treatment initiation, BMI prior to TB disease, stunting, and stagnant or declining BMI after 2 months of TB treatment. Unfavorable outcome was defined as a composite of treatment failure, death, or relapse within 6 months of treatment completion., Results: Severe undernutrition (BMI <16 kg/m2) at treatment initiation and severe undernutrition before the onset of TB disease were both associated with unfavorable outcomes (adjusted incidence rate ratio [aIRR], 2.05; 95% confidence interval [CI], 1.42-2.91 and aIRR, 2.20; 95% CI, 1.16-3.94, respectively). Additionally, lack of BMI increase after treatment initiation was associated with increased unfavorable outcomes (aIRR, 1.81; 95% CI, 1.27-2.61). Severe stunting (height-for-age z score <-3) was associated with unfavorable outcomes (aIRR, 1.52; 95% CI, 1.00-2.24). Severe undernutrition at treatment initiation and lack of BMI increase during treatment were associated with a 4- and 5-fold higher rate of death, respectively., Conclusions: Premorbid undernutrition, undernutrition at treatment initiation, lack of BMI increase after intensive therapy, and severe stunting are associated with unfavorable TB treatment outcomes. These data highlight the need to address this widely prevalent TB comorbidity. Nutritional assessment should be integrated into standard TB care., Competing Interests: Potential conflicts of interest . D. J. C., N. P., and S. P. B. report grants or contracts to institution from the Warren Alpert Foundation. N. S. H. reports a Warren Alpert Foundation grant paid to institution and current employment with the Novartis Institute for Biomedical Research. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Tuberculosis (TB) is a leading cause of morbidity and mortality from a single infectious agent, despite being preventable and curable. Early and accurate diagnosis of active TB is critical to both enhance patient care, improve patient outcomes, and break Mycobacterium tuberculosis (Mtb) transmission cycles. In 2020 an estimated 9.9 million people fell ill from Mtb, but only a little over half (5.8 million) received an active TB diagnosis and treatment. The World Health Organization has proposed target product profiles for biomarker- or biosignature-based diagnostics using point-of-care tests from easily accessible specimens such as urine or blood. Here we review and summarize progress made in the development of pathogen- and host-based biomarkers for active TB diagnosis. We describe several unique patient populations that have posed challenges to development of a universal diagnostic TB biomarker, such as people living with HIV, extrapulmonary TB, and children. We also review additional limitations to widespread validation and utilization of published biomarkers. We conclude with proposed solutions to enhance TB diagnostic biomarker validation and uptake., (© 2022 The Authors. Published under the terms of the CC BY 4.0 license.)

India has made substantial advancements in reducing the burden of tuberculosis (TB), but persons living with active TB (PLWATB) still face myriad challenges in seeking and receiving care, including TB-related stigma. To meet the END TB targets, it is critical that PLWATB engage in care and are able to adhere to treatment. This qualitative study aimed to understand TB-related stigma (perceived, enacted, and internalised) and possible interventions to reduce stigma in Puducherry and Tamil Nadu, India. We conducted 47 in-depth interviews with PLWATB and household members and eight focus group discussions: two each with PLWATB, their household members, healthcare workers, and key informants. We found varying TB-related knowledge: the vast majority of interview participants reported incorrect modes of transmission, although most were also aware that TB is curable. Participants reported high levels of perceived stigma, with nearly two-thirds of PLWATB choosing to hide their disease to avoid being stigmatised in their community. Participants supported interventions including celebrity advocacy and school-based programming to increase community knowledge and reduce enacted stigma as well as support groups and counselling to reduce internalised stigma in PLWATB. This study has the potential to inform future interventions to reduce TB-related stigma in India.

Background: Blood-based biomarkers for diagnosing active tuberculosis (TB), monitoring treatment response, and predicting risk of progression to TB disease have been reported. However, validation of the biomarkers across multiple independent cohorts is scarce. A robust platform to validate TB biomarkers in different populations with clinical end points is essential to the development of a point-of-care clinical test. NanoString nCounter technology is an amplification-free digital detection platform that directly measures mRNA transcripts with high specificity. Here, we determined whether NanoString could serve as a platform for extensive validation of candidate TB biomarkers., Methods: The NanoString platform was used for performance evaluation of existing TB gene signatures in a cohort in which signatures were previously evaluated on an RNA-seq dataset. A NanoString codeset that probes 107 genes comprising 12 TB signatures and 6 housekeeping genes (NS-TB107) was developed and applied to total RNA derived from whole blood samples of TB patients and individuals with latent TB infection (LTBI) from South India. The TBSignatureProfiler tool was used to score samples for each signature. An ensemble of machine learning algorithms was used to derive a parsimonious biomarker., Results: Gene signatures present in NS-TB107 had statistically significant discriminative power for segregating TB from LTBI. Further analysis of the data yielded a NanoString 6-gene set (NANO6) that when tested on 10 published datasets was highly diagnostic for active TB., Conclusions: The NanoString nCounter system provides a robust platform for validating existing TB biomarkers and deriving a parsimonious gene signature with enhanced diagnostic performance., Competing Interests: Potential conflict of interest. N. S. H. reports grants or contracts from Warren Alpert Foundation, Boston University School of Medicine, Partnership 2020: Leveraging US–India Cooperation in Higher Education to Harness Economic Opportunities and Innovation; and leadership or fiduciary role in a working group on nutrition and tuberculosis for the International Union Against TB and Lung Disease. All remaining authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: Most individuals exposed to Mycobacterium tuberculosis (Mtb) develop latent tuberculosis infection (LTBI) and remain at risk for progressing to active tuberculosis disease (TB). Malnutrition is an important risk factor driving progression from LTBI to TB. However, the performance of blood-based TB risk signatures in malnourished individuals with LTBI remains unexplored. The aim of this study was to determine if malnourished and control individuals had differences in gene expression, immune pathways and TB risk signatures., Methods: We utilized data from 50 tuberculin skin test positive household contacts of persons with TB - 18 malnourished participants (body mass index [BMI] < 18.5 kg/m2) and 32 controls (individuals with BMI ≥ 18.5 kg/m2). Whole blood RNA-sequencing was conducted to identify differentially expressed genes (DEGs). Ingenuity Pathway Analysis was applied to the DEGs to identify top canonical pathways and gene regulators. Gene enrichment methods were then employed to score the performance of published gene signatures associated with progression from LTBI to TB., Results: Malnourished individuals had increased activation of inflammatory pathways, including pathways involved in neutrophil activation, T-cell activation and proinflammatory IL-1 and IL-6 cytokine signaling. Consistent with known association of inflammatory pathway activation with progression to TB disease, we found significantly increased expression of the RISK4 (area under the curve [AUC] = 0.734) and PREDICT29 (AUC = 0.736) progression signatures in malnourished individuals., Conclusion: Malnourished individuals display a peripheral immune response profile reflective of increased inflammation and a concomitant increased expression of risk signatures predicting progression to TB. With validation in prospective clinical cohorts, TB risk biomarkers have the potential to identify malnourished LTBI for targeted therapy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 VanValkenburg, Kaipilyawar, Sarkar, Lakshminarayanan, Cintron, Prakash Babu, Knudsen, Joseph, Horsburgh, Ellner, Narasimhan, Johnson, Hochberg and Salgame.)

Introduction: Tuberculosis (TB) is a common opportunistic infection among people living with HIV. Diagnostic tests such as culture, Xpert-MTB-RIF, and ULTRA have low sensitivity in paucibacillary TB disease; a blood biomarker could improve TB diagnostic capabilities. We assessed soluble factors to identify biomarkers associated with TB among persons with advanced HIV., Methods: A case-control (1:1) study was conducted, with participants from Rio de Janeiro and Manaus, Brazil. People living with HIV presenting with CD4 count ≤100 cells/mm3 were eligible to participate. Cases had culture-confirmed TB (N=15) (positive for Mycobacterium tuberculosis [Mtb]); controls had HIV-infection only (N=15). Study visits included baseline, month 2 and end of TB therapy, during which samples of peripheral blood were obtained. A panel containing 29 biomarkers including cytokines, chemokines and growth factors was utilized to assess candidate biomarkers using Luminex technology in cryopreserved EDTA plasma samples. We used neural network analysis, based on machine learning, to identify biomarkers (single or in combination) that best distinguished cases from controls. Additional multi-dimensional analyses provided detailed profiling of the systemic inflammatory environment in cases and controls., Results: Median CD4 count and HIV-1 RNA load values were similar between groups at all timepoints. Persons with TB had lower body mass index (BMI) (median=19.6, Interquartile Range [IQR]=18.6-22.3) than controls (23.7; IQR: 21.8 = 25.5, p=0.004). TB coinfection was also associated with increased frequency of other comorbidities. The overall profile of plasma cytokines, chemokines and growth factors were distinct between the study groups at all timepoints. Plasma concentrations of IL-15 and IL-10 were on average lower in TB cases than in controls. When used in combination, such markers were able to discriminate between TB cases and controls with the highest degree of accuracy at each study timepoint., Conclusion: Among persons with advanced HIV, plasma concentrations of IL-15 and IL-10 can be used in combination to identify TB disease regardless of time on anti-TB treatment., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Queiroz, Araújo-Pereira, Barreto-Duarte, Gomes-Silva, Costa, Andrade, Miguez-Pinto, Spener-Gomes, Souza, Benjamin, Sant’Anna, Figueiredo, Mave, Salgame, Ellner, Sterling, Cordeiro-dos-Santos, Andrade and Rolla.)

Patients who complete a standard course of anti-tuberculous treatment (ATT) for pulmonary tuberculosis and are declared cured according to the current standard of care commonly have residual metabolic activity (RMA) in their lungs on fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PER/CT) imaging. RMA seen in this setting has been shown to be associated with relapse of tuberculosis. The routine clinical use of FDG PET/CT imaging for treatment response assessment in tuberculosis is hindered by cost and availability. CT is a more readily available imaging modality. We sought to determine the association between CT features suggestive of active tuberculosis and RMA on FDG PET/CT obtained in patients who completed a standard course of ATT for pulmonary tuberculosis. We prospectively recruited patients who completed a standard course of ATT and declared cured based on negative sputum culture. All patients had FDG PET/CT within 2 weeks of completing ATT. We determined the presence of RMA on FDG PET images. Among the various lung changes seen on CT, we considered the presence of lung nodule, consolidation, micronodules in tree-in-bud pattern, FDG-avid chest nodes, and pleural effusion as suggestive of active tuberculosis. We determine the association between the presence of RMA on FDG PET and the CT features of active tuberculosis. We include 75 patients with a mean age of 36.09 ± 10.49 years. Forty-one patients (54.67%) had RMA on their FDG PET/CT while 34 patients (45.33%) achieved complete metabolic response to ATT. There was a significant association between four of the five CT features of active disease, p < 0.05 in all cases. Pleural effusion (seen in two patients) was the only CT feature of active disease without a significant association with the presence of RMA. This suggests that CT may be used in lieu of FDG PET/CT for treatment response assessment of pulmonary tuberculosis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Lawal, Mokoala, Mathebula, Moagi, Popoola, Moeketsi, Nchabeleng, Hikuam, Ellner, Hatherill, Fourie and Sathekge.)

Mechanisms underlying variability in transmission of Mycobacterium tuberculosis strains remain undefined. By characterizing high and low transmission strains of M.tuberculosis in mice, we show here that high transmission M.tuberculosis strain induce rapid IL-1R-dependent alveolar macrophage migration from the alveolar space into the interstitium and that this action is key to subsequent temporal events of early dissemination of bacteria to the lymph nodes, Th1 priming, granulomatous response and bacterial control. In contrast, IL-1R-dependent alveolar macrophage migration and early dissemination of bacteria to lymph nodes is significantly impeded in infection with low transmission M.tuberculosis strain; these events promote the development of Th17 immunity, fostering neutrophilic inflammation and increased bacterial replication. Our results suggest that by inducing granulomas with the potential to develop into cavitary lesions that aids bacterial escape into the airways, high transmission M.tuberculosis strain is poised for greater transmissibility. These findings implicate bacterial heterogeneity as an important modifier of TB disease manifestations and transmission., (© 2022. The Author(s).)

Background: Comorbidities such as undernutrition and parasitic infections are widespread in India and other tuberculosis (TB)-endemic countries. This study examines how these conditions as well as food supplementation and parasite treatment might alter immune responses to Mycobacterium tuberculosis (Mtb) infection and risk of progression to TB disease., Methods: This is a 5-year prospective clinical trial at Jawaharlal Institute of Post Graduate Medical Education and Research in Puducherry, Tamil Nadu, India. We aim to enroll 760 household contacts (HHC) of adults with active TB in order to identify 120 who are followed prospectively for 2 years: Thirty QuantiFERON-TB Gold Plus (QFT-Plus) positive HHCs ≥ 18 years of age in four proposed groups: (1) undernourished (body mass index [BMI] < 18.5 kg/m 2 ); (2) participants with a BMI ≥ 18.5 kg/m 2 who have a parasitic infection (3) undernourished participants with a parasitic infection and (4) controls-participants with BMI ≥ 18.5 kg/m 2 and without parasitic infection. We assess immune response at baseline and after food supplementation (for participants with BMI < 18.5 kg/m 2 ) and parasite treatment (for participants with parasites). Detailed nutritional assessments, anthropometry, and parasite testing through polymerase chain reaction (PCR) and microscopy are performed. In addition, at serial time points, these samples will be further analyzed using flow cytometry and whole blood transcriptomics to elucidate the immune mechanisms involved in disease progression., Conclusions: This study will help determine whether undernutrition and parasite infection are associated with gene signatures that predict risk of TB and whether providing nutritional supplementation and/or treating parasitic infections improves immune response towards this infection. This study transcends individual level care and presents the opportunity to benefit the population at large by analyzing factors that affect disease progression potentially reducing the overall burden of people who progress to TB disease. Trial registration ClinicalTrials.gov; NCT03598842; Registered on July 26, 2018; https://clinicaltrials.gov/ct2/show/NCT03598842., (© 2021. The Author(s).)

Tuberculosis (TB) treatment regimens are lengthy, causing non-adherence to treatment. Inadequate treatment can lead to relapse and the development of drug resistance TB. Furthermore, patients often exhibit residual lung damage even after cure, increasing the risk for relapse and development of other chronic respiratory illnesses. Host-directed therapeutics are emerging as an attractive means to augment the success of TB treatment. In this study, we used C3HeB/FeJ mice as an experimental model to investigate the potential role of rapamycin, a mammalian target of rapamycin inhibitor, as an adjunctive therapy candidate during the treatment of Mycobacterium tuberculosis infection with moxifloxacin. We report that administration of rapamycin with or without moxifloxacin reduced infection-induced lung inflammation, and the number and size of caseating necrotic granulomas. Results from this study strengthen the potential use of rapamycin and its analogs as adjunct TB therapy, and importantly underscore the utility of the C3HeB/FeJ mouse model as a preclinical tool for evaluating host-directed therapy candidates for the treatment of TB., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2021. Published by The Company of Biologists Ltd.)

Background: Undernutrition impairs immunity to Mycobacterium tuberculosis and is a risk factor for tuberculosis disease (TB). We aim to investigate if severe undernutrition affects the tuberculin skin test (TST) response among household contacts (HHCs) of pulmonary TB cases., Methods: We analyzed data from HHCs (> five years) of pulmonary TB cases in Southern India. Undernutrition was defined as per World Health Organization based on body mass index (BMI) for adults (undernutrition 16-18.4 and severe undernutrition <16 kg/m2) and BMI relative to the mean for children (undernutrition 2SD-3SD and severe undernutrition < 3SDs below mean). Univariate and multivariate models of TST positivity (> five mm) were calculated using logistic regression with generalized estimating equations., Results: Among 1189 HHCs, 342 were children (age 5-17 years) and 847 were adults. Prevalence of TST positivity in well-nourished, undernourished and severely undernourished children was 135/251 (53.8%), 32/68 (47.1%), and 7/23 (30.4%) respectively; among adults, prevalence of TST positivity was 304/708 (42.9%), 43/112 (38.4%) and 12/26 (46.2%), respectively. Severe undernutrition in children was associated with decreased odds of TST positivity (adjusted odds ratio 0.3; 95%CI 0.1-0.9)., Conclusion: Severe undernutrition in children was associated with decreased odds of TST positivity. False-negative TSTs may result from undernutrition; caution is warranted when interpreting negative results in undernourished populations., Competing Interests: The authors have declared that no competing interests exist.

Setting: Alcohol use increases the risk of tuberculosis (TB) disease and is associated with worse outcomes., Objective: To determine whether alcohol use affects TB severity at diagnosis in a high-burden setting., Design: Participants were smear-positive people living with TB (PLWTB) in India. Disease severity was assessed as 1) high versus low smear grade, 2) time to positivity (TTP) on liquid culture, 3) chest radiograph cavitation, and 4) percent lung affected. Alcohol use and being at-risk for alcohol use disorders (AUD) were assessed using the AUDIT-C. Univariable and multivariable analyses were conducted., Results: Of 1166 PLWTB, 691 (59.3%) were drinkers; of those, 518/691 (75.0%) were at-risk for AUD. Drinkers had more lung affected than non-drinkers (adjusted mean difference 10.8%, p<0.0001); this was not significant for those at-risk for AUD (adjusted mean difference 3.7%, p = 0.11). High smear grade (aOR 1.0, 95%CI: 0.7-1.4), cavitation (aOR 0.8, 95%CI 0.4-1.8), and TTP (mean difference 5.2 hours, p = 0.51) did not differ between drinkers and non-drinkers, nor between those at-risk and not at-risk for AUD., Conclusions: A large proportion of PLWTB were drinkers and were at-risk for AUD. Alcohol drinkers had more lung affected than non-drinkers. Studies are needed to explore mechanisms of this association., Competing Interests: The authors have declared that no competing interests exist.

Background: People with advanced human immunodeficiency virus (HIV) (CD4 < 50) remain at high risk of tuberculosis (TB) or death despite the initiation of antiretroviral therapy (ART). We aimed to identify immunological profiles that were most predictive of incident TB disease and death., Methods: The REMEMBER randomized clinical trial enrolled 850 participants with HIV (CD4 < 50 cells/µL) at ART initiation to receive either empiric TB treatment or isoniazid preventive therapy (IPT). A case-cohort study (n = 257) stratified by country and treatment arm was performed. Cases were defined as incident TB or all-cause death within 48 weeks after ART initiation. Using multiplexed immunoassay panels and ELISA, 26 biomarkers were assessed in plasma., Results: In total, 52 (6.1%) of 850 participants developed TB; 47 (5.5%) died (13 of whom had antecedent TB). Biomarkers associated with incident TB overlapped with those associated with death (interleukin [IL]-1β, IL-6). Biomarker levels declined over time in individuals with incident TB while remaining persistently elevated in those who died. Dividing the cohort into development and validation sets, the final model of 6 biomarkers (CXCL10, IL-1β, IL-10, sCD14, tumor necrosis factor [TNF]-α, and TNF-β) achieved a sensitivity of 0.90 (95% confidence interval [CI]: .87-.94) and a specificity of 0.71(95% CI: .68-.75) with an area under the curve (AUC) of 0.81 (95% CI: .78-.83) for incident TB., Conclusion: Among people with advanced HIV, a parsimonious inflammatory biomarker signature predicted those at highest risk for developing TB despite initiation of ART and TB preventive therapies. The signature may be a promising stratification tool to select patients who may benefit from increased monitoring and novel interventions., Clinical Trials Registration: NCT01380080., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Serial interval (SI), defined as the time between symptom onset in an infector and infectee pair, is commonly used to understand infectious diseases transmission. Slow progression to active disease, as well as the small percentage of individuals who will eventually develop active disease, complicate the estimation of the SI for tuberculosis (TB). In this paper, we showed via simulation studies that when there is credible information on the percentage of those who will develop TB disease following infection, a cure model, first introduced by Boag in 1949, should be used to estimate the SI for TB. This model includes a parameter in the likelihood function to account for the study population being composed of those who will have the event of interest and those who will never have the event. We estimated the SI for TB to be approximately 0.5 years for the United States and Canada (January 2002 to December 2006) and approximately 2.0 years for Brazil (March 2008 to June 2012), which might imply a higher occurrence of reinfection TB in a developing country like Brazil., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Tuberculosis (TB) is a major public health problem worldwide. Contamination rate and poor recovery of Mycobacterium tuberculosis complex (MTBC) in MGIT960 culture may affect the early diagnosis of TB. Evidence is needed to determine the factors associated with contamination rates and MTBC recovery in MGIT960. Hence, we undertook this study to compare the factors influencing MTBC culture positivity and contamination rates in MGIT960 in patients with Pulmonary tuberculosis (PTB)., Methods: A total of 849 sputum samples from newly diagnosed smear-positive TB cases enrolled into the Regional Prospective Observational Research for Tuberculosis India cohort between May 2014 to March 2017 were analyzed. Samples were inoculated into MGIT960 and positive cultures were examined for the presence of MTBC by immunochromatographic test for detection of MPT64 antigen., Results: Of the 849 cases, 811 (95.5%) were culture positive for MTBC, 23 (2.7%) were culture negative and 15 (1.8%) were contaminated. Salivary sputum showed significantly less culture yield compared to mucopurulent/blood stained samples (p = 0.021). Sputum from individuals <20 or ≥60 years showed lower culture yield of 93.9%, compared to those aged 20-59years (98.2%) (p = 0.002). Based on smear grading, culture isolation of MTBC by MGIT960 was 86.1%, 93.6% and 99.5% for negative, scanty and positive (1+/2+/3+) samples, respectively (p ≤ 0.0001). Sputum from HIV negative patients showed higher culture yield, compared to HIV positive patients (p ≤ 0.0001). Chest X-Ray revealed that patient with cavity showed higher culture isolation of MTBC compared to patients without cavity (p = 0.035). Contamination rates were higher in smear negatives (6.0%), compared to scanty (2.1%) and smear positives (1.1%) (p = 0.007). However, delay in transport of the specimen to the laboratory was the only independent factor significantly associated with increase in culture contamination., Conclusion: Our results highlight that extremes of age, smear negativity, HIV infection, sputum quality and cavitation significantly influence the culture yield of MTBC, whereas transport duration and smear grading affected the contamination rates in MGIT960. Hence, addressing these factors may improve the diagnostic performance of MGIT960., Competing Interests: Declaration of competing interest All authors have none to declare., (Copyright © 2020 Tuberculosis Association of India. All rights reserved.)

Little is known about the physiology of latent Mycobacterium tuberculosis infection. We studied the mutational rates of 24 index tuberculosis (TB) cases and their latently infected household contacts who developed active TB up to 5.25 years later, as an indication of bacterial physiological state and possible generation times during latent TB infection in humans. Here we report that the rate of new mutations in the M. tuberculosis genome decline dramatically after two years of latent infection (two-sided p < 0.001, assuming an 18 h generation time equal to log phase M. tuberculosis, with latency period modeled as a continuous variable). Alternatively, assuming a fixed mutation rate, the generation time increases over the latency duration. Mutations indicative of oxidative stress do not increase with increasing latency duration suggesting a lack of host or bacterial derived mutational stress. These results suggest that M. tuberculosis enters a quiescent state during latency, decreasing the risk for mutational drug resistance and increasing generation time, but potentially increasing bacterial tolerance to drugs that target actively growing bacteria.

Identifying predictors of loss to follow-up (LTFU; treatment lapse ≥ 2 months) among people with tuberculosis (TB) may assist programmatic efforts in controlling the spread of TB. Newly diagnosed smear-positive TB patients were enrolled in the Regional Prospective Observational Research for TB study in Puducherry and Tamil Nadu, India. Treatment records were used to identify LTFU of those who were enrolled from May 2014 through December 2017. This nested case-control study evaluated male TB patients. Predictors were assessed using multivariable logistic regression. Of 425 men with TB, 82 (19%) were LTFU. In the adjusted analyses of males, divorced/separated marital status (adjusted odds ratio [aOR] 3.80; 95% CI: 1.39-10.38) and at-risk alcohol use (aOR 1.92; 95% CI: 1.12-3.27) were significant predictors for increased risk of LTFU, and diabetes was a significant predictor for decreased risk of LTFU (aOR 0.52; 95% CI: 0.29-0.92). Of 53 men with recorded date of last treatment visit, 23 (43%) and 43 (81%) had LTFU within the first 2 and first 4 months of treatment, respectively. Addressing at-risk alcohol use and providing more intensive follow-up could lead to improved treatment completion.

The goal of this study was to identify individuals at risk of progression and reactivation among household contacts (HHC) of pulmonary TB cases in Vitoria, Brazil. We first evaluated the predictive performance of six published signatures on the transcriptional dataset obtained from peripheral blood mononuclear cell samples from HHC that either progressed to TB disease or not (non-progressors) during a five-year follow-up. The area under the curve (AUC) values for the six signatures ranged from 0.670 to 0.461, and the PPVs did not reach the WHO published target product profiles (TPPs). We therefore used as training cohort the earliest time-point samples from the African cohort of adolescents (GSE79362) and applied an ensemble feature selection pipeline to derive a novel 29-gene signature (PREDICT29). PREDICT29 was tested on 16 progressors and 21 non-progressors. PREDICT29 performed better in segregating progressors from non-progressors in the Brazil cohort with the area under the curve (AUC) value of 0.911 and PPV of 20%. This proof of concept study demonstrates that PREDICT29 can predict risk of progression/reactivation to clinical TB disease in recently exposed individuals at least 5 years prior to disease development. Upon validation in larger and geographically diverse cohorts, PREDICT29 can be used to risk-stratify recently infected for targeted therapy., Competing Interests: Declaration of competing interest The authors have declared that no conflict of interest exists., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Household contact studies of tuberculosis (TB) are a common way to study disease transmission dynamics. However these studies lack a mechanism for accounting for community transmission, which is known to be significant, particularly in high burden settings. We illustrate a statistical approach for estimating both the correlates with transmission of TB in a household setting and the probability of community transmission using a modified Bayesian mixed-effects model. This is applied to two household contact studies in Vitória, Brazil from 2008-2013 and Kampala, Uganda from 1995-2004 that enrolled households with an individual that was recently diagnosed with pulmonary TB. We estimate the probability of community transmission to be higher in Uganda (ranging from 0.21 to 0.69, depending on HHC age and HIV status of the index case) than in Brazil (ranging from 0.13 for young children to 0.50 in adults). These estimates are consistent with a higher overall burden of disease in Uganda compared to Brazil. Our method also estimates an increasing risk of community-acquired TB with age of the household contact, consistent with existing literature. This approach is a useful way to integrate the role of the community in understanding TB disease transmission dynamics in household contact studies., Competing Interests: The authors have declared that no competing interests exist.

Background: Malnutrition and diabetes are risk factors for active tuberculosis (TB), possible risk factors for latent TB infection (LTBI), and may interact to alter their effect on these outcomes. Studies to date have not investigated this interaction., Methods: We enrolled 919 newly diagnosed active TB patients and 1113 household contacts at Primary Health Centres in Puducherry and Tamil Nadu, India from 2014 to 2018. In cross-sectional analyses, we used generalized estimating equations to measure additive and multiplicative interaction of body mass index (BMI) and diabetes on two outcomes, active TB and LTBI., Results: Among overweight or obese adults, active TB prevalence was 12-times higher in diabetic compared to non-diabetic participants, 2.5-times higher among normal weight adults, and no different among underweight adults (P for interaction < 0.0001). Diabetes was associated with 50 additional active TB cases per 100 overweight or obese participants, 56 per 100 normal weight participants, and 17 per 100 underweight participants (P for interaction < 0.0001). Across BMI categories, screening 2.3-3.8 active TB patients yielded one hyperglycemic patient. LTBI prevalence did not differ by diabetes and BMI*diabetes interaction was not significant., Conclusions: BMI and diabetes are associated with newly diagnosed active TB, but not LTBI. Diabetes conferred the greatest risk of active TB in overweight and obese adults whereas the burden of active TB associated with diabetes was similar for normal and overweight or obese adults. Hyperglycemia was common among all active TB patients. These findings highlight the importance of bi-directional diabetes-active TB screening in India.

Background: Epidemiologic data suggests that only a minority of tuberculosis (TB) patients are infectious. Cough aerosol sampling is a novel quantitative method to measure TB infectiousness., Methods: We analyzed data from three studies conducted in Uganda and Brazil over a 13-year period. We included sputum acid fast bacilli (AFB) and culture positive pulmonary TB patients and used a cough aerosol sampling system (CASS) to measure the number of colony-forming units (CFU) of Mycobacterium tuberculosis in cough-generated aerosols as a measure for infectiousness. Aerosol data was categorized as: aerosol negative (CFU = 0) and aerosol positive (CFU > 0). Logistic regression models were built to identify factors associated with aerosol positivity., Results: M. tuberculosis was isolated by culture from cough aerosols in 100/233 (43%) TB patients. In an unadjusted analysis, aerosol positivity was associated with fewer days of antituberculous therapy before CASS sampling ( p = .0001), higher sputum AFB smear grade ( p = .01), shorter days to positivity in liquid culture media ( p = .02), and larger sputum volume ( p = .03). In an adjusted analysis, only fewer days of TB treatment (OR 1.47 per 1 day of therapy, 95% CI 1.16-1.89; p = .001) was associated with aerosol positivity., Conclusion: Cough generated aerosols containing viable M. tuberculosis, the infectious moiety in TB, are detected in a minority of TB patients and rapidly become non-culturable after initiation of antituberculous treatment. Mechanistic studies are needed to further elucidate these findings.

Background: The relationship between malnutrition and tuberculosis (TB) severity is understudied. We investigated the effect of malnutrition on radiographic findings and mycobacterial burden., Methods: Subjects included newly diagnosed, smear-positive, culture-confirmed, pulmonary TB cases enrolled in the Regional Prospective Observational Research for TB (RePORT) cohort. Multivariate regression models were used to evaluate the relationship at start of treatment between body mass index (BMI) and chest radiograph (CXR) findings of cavitation and percentage of lung affected and mycobacterial growth indicator tube (MGIT) time to positive (TTP). Severe malnutrition was defined as BMI<16 kg/m2, moderate malnutrition as 16-18.4kg/m2, and "normal"/overweight as ≥18.5 kg/m2., Results: Of 173 TB cases with chest x-ray data, 131 (76%) were male. The median age was 45 years (range 16-82); 42 (24%) had severe malnutrition and 58 (34%) moderate malnutrition. Median percentage of lung affected was 32% (range 0-95), and 132 (76%) had cavitation. Individuals with severe malnutrition had, on average, 11.1% [95% CI: 4.0-13.3] more lung affected, compared to those with normal BMI, controlling for diabetes and cavitation. In multivariable analyses, cases with severe malnutrition had a 4.6-fold [95% CI, 1.5-14.1] increased odds of cavitation compared to those with normal BMI, controlling for smoking. Median MGIT TTP was 194.5 hours. Neither severe (aRR 0.99; 95% CI, 0.9-1.2) nor moderate (aRR 0.97; 95% CI, 0.8-1.1) malnutrition was associated with MGIT TTP., Conclusion: We found that malnutrition was associated with increased extent of disease and cavitation on CXR. These findings may reflect the immunomodulatory effect of malnutrition on pulmonary pathology., Competing Interests: The authors have declared that no competing interests exist.

In a study of household contacts (HHC), households were categorized into High (HT) and Low (LT) transmission groups based on the proportion of HHC with a positive tuberculin skin test. The Mycobacterium tuberculosis (Mtb) strains from HT and LT index cases of the households were designated Mtb-HT and Mtb-LT, respectively. We found that C3HeB/FeJ mice infected with Mtb-LT strains exhibited significantly higher bacterial burden compared to Mtb-HT strains and also developed diffused inflammatory lung pathology. In stark contrast, a significant number of mice infected with Mtb-HT strains developed caseating granulomas, a lesion type with high potential to cavitate. None of the Mtb-HT infected animals developed diffused inflammatory lung pathology. A link was observed between increased in vitro replication of Mtb-LT strains and their ability to induce significantly high lipid droplet formation in macrophages. These results support that distinct early interactions of Mtb-HT and Mtb-LT strains with macrophages and subsequent differential trajectories in pathological disease may be the mechanism underlying their transmission potential., Competing Interests: The authors have declared that no competing interests exist.

Background: Mycobacterium tuberculosis (TB) infection induces systemic inflammation that could impact HIV-1 persistence., Setting: HIV-1-seropositive individuals either with or without pulmonary TB disease were recruited in Kampala, Uganda., Methods: Plasma cytokines, HIV-1 DNA, and cell-associated (ca)-RNA were compared among those coinfected with TB (cases) to those without TB (controls). TB-coinfected cases and controls were compared at presentation (n = 15 and n = 16, respectively) and at around 6 months after HIV-1 treatment initiation among those who had achieved virologic suppression (n = 6 and n = 8, respectively). At follow-up, the TB-coinfected cases had also finished TB treatment., Results: Before treatment, the TB-coinfected cases as compared to the controls had higher levels of soluble(s)-CD163 (P = 0.0002) and interleukin-6 (P = 0.006) but lower levels of macrophage chemoattractant protein-1 (P = 0.04). After treatment, the TB-coinfected cases as compared to controls still had higher plasma s-CD163 levels (P = 0007). Controls as compared to the coinfected cases had higher ca-RNA per DNA template both at baseline (P = 0.03) and at follow-up (P = 0.07). Levels of ca-RNA per DNA copy at follow-up showed a negative correlation with baseline plasma s-CD163 (P = 0.008) and interleukin-6 (P = 0.05) levels., Conclusions: TB disease is associated with inflammation and decreased HIV-1 RNA expression relative to the number of infected cells, both before and after viral suppression. Infections present before antiretroviral initiation impact HIV-1 latency.

Background: Mycobacterium tuberculosis cultures of cough-generated aerosols from patients with pulmonary tuberculosis (TB) are a quantitative method to measure infectiousness and to predict secondary outcomes in exposed contacts. However, their reproducibility has not been established., Objective: To evaluate the predictive value of colony-forming units (CFU) of M. tuberculosis in cough aerosols on secondary infection and disease in household contacts in Brazil., Methods: Adult sputum smear+ and culture+ pulmonary TB cases underwent a standard evaluation and were categorized according to aerosol CFU. We evaluated household contacts for infection at baseline and at 8 weeks with TST and IGRA, and secondary disease., Results: We enrolled 48 index TB cases; 40% had negative aerosols, 27% low aerosols (<10 CFU) and 33% high aerosols (≥10 CFU). Of their 230 contacts, the proportion with a TST ≥10 mm at 8 weeks was 59%, 65% and 75%, respectively (p = 0.34). Contacts of high aerosol cases had greater IGRA readouts (median 4.6 IU/mL, IQR 0.02-10) when compared to those with low (0.8, 0.2-10) or no aerosol (0.1, 0-3.7; p = 0.08). IGRA readouts in TST converters of high aerosol cases (median 20 IU/mL, IQR 10-24) were larger than those from aerosol-negative (0.13, 0.04-3; p = o.o2). 8/9 (89%) culture+ secondary TB cases occurred in contacts of aerosol+ cases., Conclusion: Aerosol CFU predicts quantitatively IGRA readouts among household contacts of smear positive TB cases. Our results strengthen the argument of using cough aerosols to guide targeted preventive treatment strategies, a necessary component of current TB elimination projections., Competing Interests: One of our co-authors, Dr. Jones-López, is a co-founder and shareholder of a small startup company created in 2013 to develop and commercialize a molecular assay for tuberculosis diagnosis. This does not alter our adherence to PLOS ONE policies on sharing data and materials. All other authors declare that no competing interests exist.

Globally, the prevalence of tuberculosis (TB) disease is higher in males. This study examined the effect of sex and age on Mycobacterium tuberculosis (Mtb) infection. Demographic and exposure data were collected on household contacts of sputum smear-positive pulmonary TB patients in Brazil. Contacts with tuberculin skin test induration ⩾10 mm at baseline or 12 weeks were considered Mtb infected. The study enrolled 917 household contacts from 160 households; 508 (55.4%) were female, median age was 21.0 years (range 0.30-87.0) and 609 (66.4%) had Mtb infection. The proportion infected increased with age from 63.3% in girls <5 years to 75.4% in women ⩾40 years and from 44.9% in boys <5 years to 73.6% in men ⩾40 years. Multivariable modelling showed the odds of infection increased between age 5 and 14 years among female contacts (OR 1.5 per 5-year age increase; 95% CI 1.1-2.2; P = 0.02) and between ages 0-4 and 15-39 years among male contacts (OR 2.7, 95% CI 0.83-8.9 and 1.1, 95% CI 0.99-1.3 per 5-year age increase; P = 0.10, 0.07, respectively). The study suggests that the age at which Mtb infection increases most is different in females compared with males. Studies are needed to explore whether these findings are due to differences in host susceptibility, exposure outside the household or other factors.

Host-directed therapy in tuberculosis is a potential adjunct to antibiotic chemotherapy directed at Mycobacterium tuberculosis Ambroxol, a lead compound, emerged from a screen for autophagy-inducing drugs. At clinically relevant doses, ambroxol induced autophagy in vitro and in vivo and promoted mycobacterial killing in macrophages. Ambroxol also potentiated rifampin activity in a murine tuberculosis model., (Copyright © 2018 American Society for Microbiology.)

Objective: Mycobacterium tuberculosis infection leads to latent or active tuberculosis (TB). Increased uptake on 18 F-fluoro-2-deoxy-glucose-positron emission tomography/computed tomography (FDG-PET/CT) has been reported in the lungs and lymph nodes of individuals with recent infection and active TB, but not in individuals without known recent exposure or suggestive symptoms. We describe five patients with lung nodules not suspected to be due to TB in whom abnormalities on FDG-PET/CT scans ultimately were attributed to TB infection., Results: Patient records were searched using the words "positron emission tomography/computed tomography" and 24 codes for TB between 2004 and 2013. Patients with a diagnosis of TB and a PET/CT scan were included. Clinical and radiographic data were retrieved. PET/CT images were reviewed by an experienced radiologist. FDG-PET/CT scans revealed elevated FDG-uptake in lungs of five patients subsequently diagnosed with active (n = 3) or clinically inactive (n = 2) tuberculosis. Uptake magnitude was unrelated to disease activity. These findings suggest that tuberculosis latency may include periods of percolating inflammation of uncertain relationship to future disease risk.

Background: Tuberculosis (TB) is the major cause of death in Human Immunodeficiency Virus (HIV)-infected individuals. However, diagnosis of TB in HIV remains challenging particularly when HIV infection is advanced. Several gene signatures and serum protein biomarkers have been identified that distinguish active TB from latent infection. Our study was designed to assess if gene expression signatures and cytokine levels would distinguish active TB in advanced HIV., Methods: We conducted a case-control study of whole blood RNA-Seq and plasma cytokine/chemokine analysis in HIV-infected with CD4 + T cell count of ≤ 100 cells/μl, with and without active TB. Next, the overlap of the differentially expressed genes (DEG) with the published signatures was performed and then receiver operator characteristic (ROC) analysis was done on small gene discriminators to determine their performance in distinguishing TB in advanced HIV. ELISA was performed on plasma to evaluate cytokine and chemokine levels., Results: Hierarchical clustering of the transcriptional profiles showed that, in general, HIV-infected individuals with TB (TB-HIV) clustered separately from those without TB. IPA indicated that the TB-HIV signature was characterized by an increase in inflammatory signaling pathways. Analysis of overlaps between DEG in our data set with published TB signatures revealed that significant overlap was seen with one TB signature and one TB-IRIS signature. ROC analysis revealed that transcript levels of FcGR1A (AUC = 0.85) and BATF2 (AUC = 0.82), previously reported as consistent single gene classifiers of active TB irrespective of HIV status, performed successfully even in advanced HIV. Plasma protein levels of IFNγ, a stimulator of FcGR1A and BATF2, and CXCL10, also up-regulated by IFNγ, accurately classified active TB (AUC = 0.98 and 0.91, respectively) in advanced HIV. Neither of these genes nor proteins distinguished between TB and TB-IRIS., Conclusions: Gene expression of FcGR1A and BATF2, and plasma protein levels of IFNγ and CXCL10 have the potential to independently detect TB in advanced HIV. However, since other lung diseases were not included in this study, these final candidates need to be validated as specific to TB in the advanced HIV population with TB.

Background: Isoniazid preventive therapy (IPT) reduces mortality among people living with HIV (PLHIV) and is recommended for those without active tuberculosis (TB) symptoms. Heavy alcohol use, however, is contraindicated for liver toxicity concerns. We evaluated the risks and benefits of IPT at antiretroviral therapy (ART) initiation to ART alone for PLHIV who are heavy drinkers in 3 high TB-/HIV-burden countries., Methods: We developed a Markov simulation model to compare ART alone to ART with either 6 or 36 months of IPT for heavy drinking PLHIV enrolling in care in Brazil, India, and Uganda. Outcomes included nonfatal toxicity, fatal toxicity, life expectancy, TB cases, and TB death., Results: In this simulation, 6 months of IPT + ART (IPT6) extended life expectancy over both ART alone and 36 months of IPT + ART (IPT36) in India and Uganda, but ART alone dominated in Brazil in 51.5% of simulations. Toxicity occurred in 160/1000 persons on IPT6 and 415/1000 persons on IPT36, with fatal toxicity in 8/1000 on IPT6 and 21/1000 on IPT36. Sensitivity analyses favored IPT6 in India and Uganda with high toxicity thresholds., Conclusions: The benefits of IPT for heavy drinkers outweighed its risks in India and Uganda when given for a 6-month course. The toxicity/efficacy trade-off was less in Brazil where TB incidence is lower. IPT6 resulted in fatal toxicity in 8/1000 people, whereas even higher toxicities of IPT36 negated its benefits in all countries. Data to better characterize IPT toxicity among HIV-infected drinkers are needed to improve guidance.

Several studies have identified blood transcriptomic signatures that can distinguish active from latent Tuberculosis (TB). The purpose of this study was to assess how well these existing gene profiles classify TB disease in a South Indian population. RNA sequencing was performed on whole blood PAXgene samples collected from 28 TB patients and 16 latently TB infected (LTBI) subjects enrolled as part of an ongoing household contact study. Differential gene expression and clustering analyses were performed and compared with explicit predictive testing of TB and LTBI individuals based on established gene signatures. We observed strong predictive performance of TB disease states based on expression of known gene sets (ROC AUC 0.9007-0.9879). Together, our findings indicate that previously reported classifiers generated from different ethnic populations can accurately discriminate active TB from LTBI in South Indian patients. Future work should focus on converting existing gene signatures into a universal TB gene signature for diagnosis, monitoring TB treatment, and evaluating new drug regimens., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Household contacts of pulmonary tuberculosis (TB) patients are at increased risk of TB infection and disease. However, their risk in relation to the intensity of exposure remains unknown.We studied smear-positive TB cases and their household contacts in Vitória, Brazil. We collected clinical, demographic and radiographic information from TB cases, and obtained tuberculin skin test (TST) and QuantiFERON-TB Gold (QFT) results from household contacts. We measured intensity of exposure using a proximity score and sleep location in relation to the TB index case and defined infection by TST ≥10 mm or QFT ≥0.35 UI·mL -1 We ascertained secondary TB cases by reviewing local and nationwide case registries.We included 160 TB index cases and 894 household contacts. 464 (65%) had TB infection and 23 (2.6%) developed TB disease. Risk of TB infection and disease increased with more intense exposures. In an adjusted analysis, the proximity score was associated with TB disease (OR 1.61, 95% CI 1.25-2.08; p<0.000); however, its diagnostic performance was only moderate.Intensity of exposure increased risk of TB infection and disease among household contacts; however, its diagnostic performance was still suboptimal. A biomarker to target preventive therapy is urgently needed in this at-risk population., Competing Interests: Conflict of interest: Disclosures can be found alongside this article at erj.ersjournals.com, (Copyright ©ERS 2018.)

Background: Identification of the Mycobacterium tuberculosis immunoproteome and antigens associated with serologic responses in adults has renewed interest in developing a serologic test for childhood tuberculosis (TB). We investigated IgG antibody responses against M. tuberculosis antigens in children with well-characterized TB., Methods: We studied archived sera obtained from hospitalized children with suspected pulmonary TB, and classified as having confirmed TB (culture-confirmed), unlikely TB (clinical improvement without TB treatment), or unconfirmed TB (all others). A multiplexed bead-based assay for IgG antibodies against 119 M. tuberculosis antigens was developed, validated and used to test sera. The area under the curves (AUCs) of the empiric receiver-operator characteristic curves were generated as measures of predictive ability. A cross-validated generalized linear model was used to select the most predictive combinations of antigens., Results: For the confirmed TB versus unlikely TB comparison, the maximal single antigen AUC was 0.63, corresponding to sensitivity 0.60 and specificity 0.60. Older (age: 60+ months old) children's responses were better predictive of TB status than younger (age: 12-59 months old) children's, with a maximal single antigen AUC of -0.76. For the confirmed TB versus unlikely TB groups, the most predictive combinations of antigens assigned TB risk probabilities of 0.33 and 0.33, respectively, when all ages were considered, and 0.57 (interquartile range: 0.48-0.64) and 0.35 (interquartile range: 0.32-0.40) when only older children were considered., Conclusion: An antigen-based IgG test is unlikely to meet the performance characteristics required of a TB detection test applicable to all age groups.