Search Results (294)

Understanding the heterogeneous spread of tuberculosis (TB), particularly multidrug-resistant (MDR) forms and the role of subclinical infection, is critical for achieving the WHO End TB strategy. This study develops a novel compartmental model that explicitly incorporates incipient and subclinical TB together with MDR forms, and links them to case detection and treatment pathways. The key innovation lies in integrating a sensitivity-based identifiability analysis with a Bayesian MCMC framework to quantify parameter uncertainty and correlations directly from regional surveillance data. Applied to five high-burden regions of the Russian Federation (2009–2020), the approach reveals strong heterogeneity in epidemic drivers: wide credible intervals for contagiousness, the rate of progression to bacterio-positive (BE+) states, and detection rates. The probabilistic forecasts up to 2025 are validated against 2021–2023 data. The region-specific differences in these correlated parameters dictate transmission dynamics, and improving detection of BE+ cases is the most effective lever for control. Full article

The Bacillus Calmette–Guérin (BCG) vaccine, originally developed for tuberculosis (TB) prevention, has recently attracted attention due to its broader immunomodulatory properties. In addition to its role in TB control, BCG induces trained immunity, a process involving epigenetic and metabolic reprogramming of innate immune cells that leads to altered systemic inflammatory responses. Increasing evidence suggests that these long-term immune adaptations may influence the central nervous system by modulating microglial activation and neuroinflammatory pathways implicated in neurodegenerative diseases. In parallel, chronic infections such as TB are associated with persistent systemic inflammation and immune dysregulation, which may contribute to microglial priming and increased vulnerability to neurodegeneration. This narrative review, based on a targeted literature search of PubMed, Scopus, Web of Science, Embase, and relevant preprint servers, synthesizes current evidence on the relationships between BCG vaccination, trained immunity, and neuroimmune interactions. We focus on studies addressing systemic immune reprogramming, microglial responses, and neuroinflammatory mechanisms relevant to neurodegenerative disorders. The available data suggest that BCG-induced immune modulation may exert context-dependent effects on the brain, with potential neuroprotective implications under certain conditions. However, the evidence remains heterogeneous and largely observational, and causality cannot yet be established. Further mechanistic and prospective studies are required to clarify whether BCG-induced trained immunity can modify the risk or progression of age-related neurodegenerative diseases. Full article

Background/Objectives: Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), remains a major global health problem. Drug resistance and the limitations of sputum-based diagnostic methods highlight the need for additional host-response biomarkers. Protein tyrosine phosphatase receptor type O (PTPRO) has been implicated in inflammatory signaling and macrophage immune regulation, but its relationship with TB-related host transcriptional responses remains unclear. This study aimed to identify and preliminarily evaluate a PTPRO-related blood transcriptional signature with potential relevance to TB discrimination and treatment-response assessment. Methods: Genes correlated with PTPRO expression were first screened using TCGA-LUSC as a large human transcriptomic discovery resource. The resulting candidate genes were then filtered in TB-related whole-blood datasets by intersecting genes upregulated in TB compared with healthy controls, pneumonia, and lung cancer. This strategy yielded a five-gene PTPRO-related signature, termed PO5. The signature was evaluated in independent GEO cohorts and further explored by RT-qPCR in H37Ra-infected THP-1-derived macrophages and in a small clinical blood cohort. A PO5-derived TB risk score was calculated for each sample, and receiver operating characteristic analysis was used to assess discriminatory performance. Changes in TB risk scores during anti-TB treatment were also examined. Results: PTPRO expression was increased in TB whole-blood transcriptomic data and in H37Ra-infected macrophages. In public datasets, PO5 showed potential for distinguishing TB from healthy controls, latent TB, pneumonia, and lung cancer. PO5-derived TB risk scores also decreased after anti-TB treatment. In the exploratory clinical cohort, several PO5 genes showed expression changes in the same general direction as those observed in the public datasets, although the small sample size limited the strength of this evidence. Conclusions: PO5 represents a preliminary PTPRO-related blood transcriptional signature with potential relevance to TB discrimination and treatment-response assessment. These findings remain exploratory and require validation in larger prospective multicenter cohorts, together with further mechanistic studies. Full article

Tuberculosis–diabetes mellitus (TB-DM) is increasingly recognized as a syndemic in which chronic metabolic dysregulation amplifies tuberculosis severity, delays treatment response, and increases relapse and mortality. However, conventional systemic correlates soluble cytokines and bulk whole-blood transcriptomic signatures often appear broadly similar between TB and TB-DM. This highlights a key gap: clinically meaningful immune dysfunction in TB-DM likely resides in specific lung and blood cell states that are poorly resolved by bulk assays. Small extracellular vesicles (EVs) in plasma and bronchoalveolar lavage (BAL) provide a tractable “liquid biopsy” layer because their RNA and protein cargo can integrate information from infected macrophages, neutrophils, and epithelial/endothelial compartments, and may also include pathogen-derived components. Yet most EV studies remain bulk and cell-agnostic, and interpretation is constrained by heterogeneous vesicle mixtures, selective cargo packaging, and co-isolated non-vesicular contaminants, issues that are especially problematic for nucleic-acid claims without rigorous controls. In this targeted narrative review (2010–2026), we argue that single-cell and multimodal immune reference atlases, including scRNA-seq/CITE-seq, provide a needed scaffold to link EV cargo patterns to specific immune cell states, pathways, and anatomic compartments in TB-DM, enabling prioritized candidates and testable hypotheses. We outline three complementary frameworks: reference-atlas anchoring to project EV cargo modules onto atlas-defined immune states; orthogonal triangulation combining computational inference with immunoaffinity enrichment, targeted validation, and functional assays; and cautious use of “droplet-era” extracellular signals as hypothesis-generating priors for EV-producing states. Implemented in longitudinal, clinically annotated cohorts with standardized EV workflows, atlas-guided EV profiling could yield cell-of-origin–resolved biomarkers of TB-DM immunopathology and treatment response, while prioritizing mechanistically plausible targets for host-directed intervention. Full article

This study develops an integrated mathematical model to investigate the interaction between tuberculosis (TB) transmission and childhood stunting, which is aligned with the United Nations Sustainable Development Goals (SDG 3). The population is structured into two age groups (0–5 years and ≥5 years), with stunting explicitly incorporated into the pediatric population to capture its potential influence on TB dynamics. The model is formulated as a system of ordinary differential equations and analyzed using equilibrium and stability analysis, with the basic reproduction number, $R_0$. The disease-free equilibrium is locally asymptotically stable when $R_0<1$, while an endemic equilibrium exists when $R_0>1$. Sensitivity analysis indicates that the transmission rate ($\beta$), progression rate from latent to active infection ($\sigma$), and recovery rate ($\gamma$) are the most influential parameters affecting $R_0$. These parameters are therefore selected as control variables in an optimal control framework to design effective intervention strategies. Numerical simulations show that the combined control strategy significantly reduces TB transmission, resulting in a reduction of more than $80\%$ in active TB cases within a relatively short intervention period. The results suggest that integrated interventions targeting transmission, disease progression, and recovery are substantially more effective than single-measure strategies. This study provides a quantitative framework to support integrated public health policies addressing TB and childhood stunting simultaneously. Full article

Understanding the gross lesion distribution associated with bovine tuberculosis (bTB) and the relationship between antemortem test results is important for optimizing surveillance activities. Antemortem diagnostic test results and postmortem examination results from animals infected with bTB in the United States are routinely collected during surveillance and outbreak response. From 2017 to 2022, data were compiled and analyzed from 403 infected animals, representing both beef and dairy cattle from a variety of herds with different levels of disease prevalence. Overall, 95.3% of cattle infected with Mycobacterium bovis presented with gross lesions. Most cattle had lesions in one anatomic region. Lesions of the thorax and head were most common with 42.4% of infected cattle having lesions in only the thorax, 18.4% having lesions only in the head, and 15.6% having lesions in both the head and thorax. The most frequently affected tissues were the mediastinal, tracheobronchial, and medial retropharyngeal lymph nodes. Results of antemortem skin tests were not found to be associated with lesion count or location. This analysis presents an updated look at the current state and presentation of bTB in the U.S., makes use of data collected in the field, and can help guide future bTB surveillance and control strategies. Full article

Background: Tuberculosis (TB) remains a major global health challenge, with Mycobacterium tuberculosis (M. tuberculosis) causing significant morbidity and mortality mainly in high-burden countries. Following exposure to M. tuberculosis, individuals may become infected, developing TB infection (TBI) through inhalation of the bacillus: this affects approximately one-fourth of the global population and serves as a critical reservoir for potential disease reactivation and transmission. The risk of being infected with M. tuberculosis is shaped by bacterial load of people with TB, contact patterns, environmental factors, and host susceptibility, particularly in high-risk congregate settings. Elucidating these determinants is instrumental for optimising TB prevention and control strategies. Methods: A preliminary PubMed search was conducted on 25 August 2024, using the keywords “latent tuberculosis infection,” “risk factors,” and “systematic review.” Targeted reviews were then performed in November 2024 to examine factors influencing progression from exposure to M. tuberculosis to TBI. Systematic reviews published between January 2000 and November 2024 were included. Results: The scoping review analysed eight systematic reviews, grouping findings into three key themes: (1) proximity and behavioural risk factors; (2) environmental risk factors; and (3) host immune vulnerabilities. Close contact with people with TB in crowded settings, such as dormitories, healthcare facilities, and prisons, was strongly associated with an elevated risk of TBI. Healthcare workers travelling from low- to high-incidence regions faced the highest risk due to frequent exposure to M. tuberculosis, while military personnel and general travellers had lower risks. Environmental exposures, including second-hand smoke and inadequate ventilation, further heightened susceptibility among children and adults. Host immune risk factors, such as advanced age, low body mass index, lack of BCG vaccination, and metabolic disorders such as diabetes, markedly increase susceptibility to TBI. The interplay between proximity, behavioural and environmental risk factors, and host immune vulnerabilities highlights the multifactorial nature of TBI risk. Conclusion: Effective TBI control demands a multifaceted approach, combining robust infection prevention and control measures, comorbidity management, and mitigation of behavioural risk factors like smoking. Tailored strategies are crucial for high-risk settings such as healthcare facilities and prisons. Multisectoral collaboration is essential to address key risk factors and protect vulnerable populations from progressing to TBI. Full article

The lack of reliable diagnostic tools and relapse monitoring for latent tuberculosis infection (LTBI) constitutes a major obstacle to global tuberculosis (TB) control. This highlights an urgent need for robust animal models and predictive biomarkers. To address this, we report the successful establishment of a rapid murine model of recapitulating the active, latent, and relapse phases of TB within a compressed ten-week timeframe—hence termed the rapid multi-stage TB murine model. In this model, mice were first intravenously infected with Mycobacterium tuberculosis, followed by a four-week isoniazid (INH) regimen starting at two weeks post-infection. By week six, pulmonary bacterial loads in most mice dropped below the detection limit, signifying the establishment of latency. Reactivation was subsequently triggered by a four-week administration of anti-TNF-α (Tumor Necrosis Factor-α) monoclonal antibody. Leveraging this reproducible and time-efficient model, we performed transcriptomic profiling of peripheral blood and identified a distinct sixteen-gene signature (including Ets2, Fam111a, Fosl2, Gadd45b, Nfkbid, Rgs1, Bhlhe40, Il1r2, Clec2d, Kmo, Lynx1, Papd4, Trim34a, Wrb, Nlrp12, Spns1) that dynamically tracks disease progression. Collectively, these findings not only provide a valuable and efficient preclinical tool but also deliver transformable candidate biomarkers with immediate potential to guide the development of novel diagnostic strategies for LTBI surveillance and management. Full article

Approximately 25% of the global population is estimated to have latent tuberculosis infection (LTBI), with a 5–10% lifetime risk of progression to active disease. Although interferon-gamma release assays (IGRAs) are widely used for LTBI diagnosis, their high cost and operational complexity limit large-scale implementation in resource-limited settings. This study evaluated the diagnostic performance of a low-complexity, rapid, fluorescence-based point-of-care assay, ichroma IGRA-TB, for LTBI detection. A total of 300 participants enrolled at TB Screening and Treatment Centers and the Dhaka Hospital of icddr,b were categorized as healthy controls (n = 130), household contacts of TB patients (n = 70), GeneXpert MTB/RIF Ultra-positive active TB patients (n = 80), or individuals with a previous history of TB (n = 20). ichroma IGRA-TB was compared with QuantiFERON-TB Gold Plus (QFT-Plus) across all groups. Overall agreement between ichroma IGRA-TB and QFT-Plus was 91.9%, with a Cohen’s kappa of 0.83, indicating almost perfect concordance. Using culture as a surrogate reference standard, QFT-Plus demonstrated higher sensitivity (74.6%) than ichroma IGRA-TB (69.0%). Overall, ichroma IGRA-TB demonstrates high agreement with QFT-Plus and acceptable sensitivity, supporting its potential as a near-point-of-care tool for LTBI screening in resource-constrained settings. Full article

Background: Effective tuberculosis vaccines capable of inducing durable pulmonary immunity remain an unmet need. Mucosal vaccination strategies and rational antigen selection are increasingly recognized as critical for improving protection against aerosol Mycobacterium tuberculosis (Mtb) infection. Objective: The objective of this study was to establish an intranasal recombinant adeno-associated virus (rAAV) platform and evaluate SapM (Rv3310) as a mucosal TB vaccine antigen in mice. Methods: We established and optimized an rAAV production and purification platform suitable for intranasal immunization and applied it to deliver Mtb antigen SapM. Immunogenicity was assessed by lung mucosal T-cell responses (CD69/CD103) and IFN-γ production in the lungs and spleen after mycobacterial antigen stimulation. Protective efficacy was evaluated after aerosol H37Rv challenge by quantifying pulmonary bacterial burden and lung pathology compared with vector controls and BCG. Results: rAAV6-SapM was successfully produced and efficiently transduced antigen-presenting cells without inducing phenotypic maturation. Intranasal immunization in mice induced mucosal T-cell responses in the lungs and increased expression of tissue residency-related markers (CD69 and CD103). It also elicited a Th1-biased cellular immune response characterized by enhanced IFN-γ production in both the lungs and spleen in response to mycobacterial antigen stimulation. Upon aerosol challenge with virulent Mtb H37Rv, rAAV6-SapM-immunized mice exhibited a significant reduction in pulmonary bacterial burden and attenuated lung pathology compared with vector-immunized controls. Conclusions: These findings provide proof-of-concept evidence that intranasal delivery of an AAV-based vaccine encoding SapM can induce antigen-responsive Th1 immunity and confer significant protection against early pulmonary TB, supporting further exploration of SapM as a vaccine antigen and AAV-based mucosal gene vaccination as a platform for TB vaccine development. Full article

Pulmonary tuberculosis (TB) remains a major global health challenge. The molecular and metabolic responses of monocyte-derived macrophages (MDMs), which are critical for host defense against Mycobacterium tuberculosis (Mtb), are not fully characterized. A murine pulmonary TB model was established by intravenous injection of BALB/c mice with the attenuated Mtb strain H37Ra; controls received saline. After 8 weeks, lung MDMs were isolated for integrated transcriptomic and untargeted metabolomic profiling. Transcriptomic analysis identified 3970 differentially expressed genes (DEGs) in infected MDMs, including upregulated Ptpn1, Dgat2, and Alox5ap and downregulated Cyld, Zfp61, and Mapk11. Metabolomic profiling revealed 113 differentially accumulated metabolites (DAMs). Taurocholic acid and linoleic acid were identified as potential diagnostic biomarkers, both achieving an area under the curve (AUC) of 1.0 in ROC analysis. Integrated omics analysis showed a positive correlation between linoleic acid levels and the expression of Tbxas1, Acaa1b, and Acox1, implicating lipid metabolic pathways in the host response to TB. This multi-omics study delineates key molecular and metabolic alterations in lung MDMs during TB infection. The identified metabolites, taurocholic acid and linoleic acid, show promise as biomarkers, while dysregulated linoleic acid metabolism represents a potential target for novel diagnostic and therapeutic strategies against TB. Full article

Background/Objectives: An important diagnostic problem is to differentiate between active tuberculosis (TB) and latent TB infection (LTBI). Furthermore, the current biomarkers also offer minimal insight into disease pathogenesis to direct treatment. This triggered us to design a two-mode biomarker signature based on the multicohort analysis using a transcriptomic and stringent machine learning pipeline. Methods: When analyzing active TB, latent TB, and healthy control samples, a rigorous filter (ANOVA, p < 0.001) was used, followed by the selection of features with the help of Boruta-XGBoost and LASSO regression. This determined a small four-gene signature (TAP2, SORT1, WARS, and ANKRD22), which was selectively and highly upregulated in the active TB clinical state (p < 0.001). An ensemble staking classifier based on this signature (Random Forest and XGBoost) had a very high diagnostic performance (ROC-AUC = 0.991 (95% CI: 0.983–0.997)) in the stratification of infection phases, which was strongly confirmed in another cohort (GSE19444). Results: Importantly, the analysis of the functional pathways showed that all the genes are mapped to core dysregulated host pathways in active TB: antigen presentation (TAP2), lipid trafficking (SORT1), interferon response (WARS), and inflammasome signaling (ANKRD22). In such a way, the signature has a dual advantage: (1) high specificity, non-sputum transcriptional diagnostic of active TB, and (2) a mechanistic map of key host pathways, which describes targets of intervention. Conclusions: Thus, the signature provides a two-fold response: a biomarker panel aligned with WHO performance targets for TB triage and a mechanistic plan of therapy, which provides an easy way to implement transcriptomic discovery into clinical action against TB. Full article

Background: Tuberculosis (TB) remains a major global health challenge, with transmission influenced by the incidence of contagious people with TB, the duration of infectivity, and the probability of contact with susceptible individuals. This review synthesizes recent evidence on established and emerging risk factors influencing TB transmission, particularly in light of global trends such as migration, urbanization, and demographic shifts, to guide future prevention and control strategies. This scoping review maps and synthesizes evidence from systematic reviews on risk factors for Mycobacterium tuberculosis exposure. Methods: A preliminary general literature search was conducted in PubMed on 25 August 2024, using the keywords “tuberculosis,” “risk factors,” and “systematic review.” A subsequent targeted search focused on systematic reviews published since 2000 that examined social and environmental determinants of exposure to M. tuberculosis identified in the general search. Original research and reviews spanning pre-2000 were excluded. Data extraction and synthesis followed PRISMA-ScR guidelines. Results: Of the 344 systematic reviews identified, 14 met the eligibility criteria, reporting on key risk factors contributing to the incidence of contagious people with TB, the duration of infectivity, and the probability of contact. These risk factors included homelessness, migration, occupational exposure, urbanization, climate change, and air pollution. The findings emphasize the complex interrelated role of social and environmental determinants in driving TB transmission. Conclusion: This review highlights the need for a multi-sectoral approach to TB, as climate change, air pollution, overcrowding, stigma, and limited healthcare access exacerbate established risks related to poverty. Effective prevention and control require targeted interventions that address these interconnected factors. Full article

Background. Over the past decade, the World Health Organization has highlighted the need for rapid molecular diagnostics as first-line tools for detecting Mycobacterium tuberculosis complex (MTBC) to strengthen global tuberculosis control. At the same time, infections caused by non-tuberculous mycobacteria (NTM) have become increasingly prevalent, particularly in low TB-burden countries such as Italy. This changing epidemiological scenario underscores the necessity for fast and reliable methods capable of distinguishing NTM from MTBC, a critical step for guiding appropriate treatment. This study evaluated the diagnostic accuracy and potential applications of the STANDARD™ M10 MTB/NTM assay, which simultaneously detects and differentiates MTBC and NTM. Methods. A total of 155 clinical specimens (78.1% respiratory) from patients with suspected mycobacterial infection were tested by fluorescence microscopy, GeneXpert MTB/RIF Ultra (respiratory samples only), STANDARD™ M10 MTB/NTM and culture, used as the reference method. Results. Culture detected MTBC in 54% and NTM (predominantly slow-growing species) in 46% of samples. STANDARD™ M10 showed overall sensitivity and specificity of 70% and 100%, respectively. For MTBC, sensitivity was 85.1% with almost perfect agreement with culture (κ = 0.866), while for NTM, sensitivity was 50% with moderate agreement (κ = 0.566). Sensitivity decreased in microscopy-negative/culture-positive specimens, particularly for NTM. Compared with GeneXpert MTB/RIF Ultra, STANDARD™ M10 exhibited slightly lower sensitivity for MTBC but retained excellent specificity. Conclusions. STANDARD™ M10 MTB/NTM represents a rapid, fully automated tool to support early etiological diagnosis and MTB/NTM differentiation, mainly in selected samples or high-risk patients, but it does not replace culture or molecular tests providing species identification and MTBC drug-resistance profiling. Full article

Background: The Korea Disease Control and Prevention Agency classifies healthcare workers (HCWs) into five groups based on Mycobacterium tuberculosis exposure risk and potential transmission impact to guide TB screening strategies. However, data on actual exposure frequency and latent tuberculosis infection (LTBI) incidence across these classifications remain limited. Methods: We conducted a retrospective cohort study of HCWs at a tertiary hospital between 2023 and 2024. Baseline LTBI screening was performed for all staff, with annual follow-up testing for Groups 1–4 according to national guidelines. TB exposure history and frequency were investigated and documented by the infection prevention department. LTBI incidence was assessed among HCWs with a negative test in 2023 who underwent repeat testing in 2024. Results: Among 2116 HCWs (27.7% male; mean age, 33 years), TB exposure rates increased with higher risk classification (Group 1: 46.9%, Group 2: 31.3%, Group 3: 18.5%, Group 4: 1.2%, Group 5: 0.6%; p < 0.001), as did the mean number of exposure events per person (1.39, 0.74, 0.31, 0.01, and 0.01, respectively; p < 0.001). The incidence of LTBI was 13/1323 (1.0%). After adjustment, LTBI incidence was associated with ≥2 TB exposure events (adjusted OR, 7.03; 95% CI, 1.87–26.36; p = 0.005), but did not differ significantly by group classification. Conclusions: This study suggests that occupational classification effectively predicts the frequency of TB exposure among healthcare workers. However, LTBI incidence is more closely associated with multiple TB exposure events rather than occupational classification. Full article