Tuberculosis

BackgroundTuberculous meningitis (TBM) is the most sinister form of extrapulmonary tuberculosis (EPTB), associated with high mortality due to delayed diagnosis and limited sensitivity of conventional and molecular tests. Current study evaluated the diagnostic utility of Lipoarabinomannan antigen (LAM) detection in CSF and urine and explored host inflammatory biomarkers for diagnosis and prognosis of TBM. MethodsThis prospective observational study enrolled 80 patients with presumptive TBM at a tertiary care centre. CSF samples were subjected to AFB microscopy, liquid culture(MGIT-960), GeneXpert MTB/RIF (GX), and LAM lateral flow assay. Urine LAM was performed at baseline. Serum and CSF levels of IL-1{beta}, IL-6, TNF-, IFN-{gamma}, IL-17A, and IP-10 were measured at baseline and after 1 month treatment. ResultsAmong 80 participants, 23 (28.7%) had definite TBM and 46 (57.5%) had probable TBM. CSF LAM sensitivity and specificity against microbiological reference standards was 43.5% and 80.7%, while urine LAM sensitivity (60.9%) and specificity 82.5% was higher. Against composite reference standards, both CSF and urine LAM showed reduced sensitivity but achieved 100% specificity. Serum IL-1{beta} showed the best diagnostic performance (AUC 0.943; sensitivity 88.9%, specificity 90.9%). Elevated serum and CSF IP-10 levels were associated with poor outcomes, whereas declining IL-6 and TNF- levels correlated with treatment response. ConclusionLAM detection in CSF and urine may serve as a highly specific, rapid rule-in test for TBM. Host inflammatory biomarkers, especially IL-1{beta} and IP-10, show additional diagnostic and prognostic value. Combining LAM testing with cytokine biomarkers may improve early diagnosis and efficient clinical management of TBM.

Background: Without tuberculosis preventive therapy (TPT), approximately 5% of individuals infected with M. tuberculosis progress to active tuberculosis (TB) disease. Recent studies have identified body mass index (BMI) < 25 kg/m2 as a predictor of TB progression, but additional markers are needed to better identify persons at increased risk. Methods: Close contacts of patients with culture-confirmed pulmonary TB were enrolled in the Regional Prospective Observational Research in Tuberculosis (RePORT)-Brazil cohort from 2015 to 2019 and followed for up to 24 months. Analyses were restricted to interferon-{gamma} release assay (IGRA)-positive contacts who did not receive TPT or received <30 days of isoniazid. Prediction models to identify close contacts at increased TB risk were constructed using two complementary approaches: incremental models used BMI as the base predictor and evaluated whether baseline whole-blood transcriptomic signatures, human genetic polymorphism risk scores derived from low-pass whole-genome sequencing, and BMI-related plasma biomarkers improved model discrimination. Agnostic models did not impose BMI in the model and used penalized regression for predictor selection. Results: Among 285 close contacts, 15 (5%) progressed to TB. The model with BMI as unique predictor had a C-index of 0.66 (95% confidence interval [CI] 0.55; 0.77). Adding Rajan5 or Duffy9 transcriptomic signature scores to BMI improved discrimination compared with BMI alone, with C-indices of 0.78 (95% CI 0.62; 0.99) and 0.75 (95% CI 0.61; 0.89), respectively, but did not further improve discrimination after accounting for adiponectin. Adding adiponectin to BMI increased the C-index to 0.80 (95% CI 0.68; 0.91), while adiponectin alone captured most of the discriminatory performance in agnostic models (C-index, 0.80, 95% CI 0.69; 0.91). Genetic risk scores, leptin, and the adiponectin:leptin ratio did not improve model discrimination compared with the BMI-only model. In exploratory post hoc analyses, higher adiponectin was associated with increased risk of progression to TB, with each two-fold increase associated with a higher hazard of TB (HR 2.91, 95% CI 1.73; 4.91, p < 0.001). Conclusions: Baseline adiponectin strongly predicted progression to TB among close contacts and captured most of the discriminatory information contained in epidemiological and transcriptomic variables. Its consistent selection across modelling approaches supports adiponectin as a promising biomarker for TB risk stratification.

Purpose: Central nervous system tuberculosis (CNS TB) presenting with vasculitis or arachnoiditis causes significant morbidity and mortality. The purpose of this study was to characterise the clinical spectrum and outcomes of patients diagnosed with TB arachnoiditis and TB-associated CNS vasculitis Methods A retrospective study was conducted between October 2020 and September 2023, screening patients admitted with suspected CNS TB to a tertiary care hospital. Patients diagnosed with proliferative arachnoiditis, and TB-associated CNS vasculitis were recruited. Their clinical details, follow-up records, and outcomes were assessed. Results Among 318 patients admitted with suspected CNS TB, 87 patients had complications, with follow-up data available for 69 patients. Vasculitis, spinal arachnoiditis (SA), and optochiasmatic arachnoiditis (OCA) was diagnosed in 66 (76%), 41 (47%), and 26 (30%) patients respectively. Median duration of follow-up was 490 days. Median mRS at discharge was 4. 18 (69%) OCA patients and 14 (35%) SA patients received pulse methylprednisolone. Intrathecal hyaluronidase was administered in 14 patients and thalidomide was given to 9 patients. 30 (46%) patients with vasculitis were treated with aspirin. 69 patients completed follow-up, 49% died. Among the remaining, 88.6% had improvement with treatment with a median mRS of 2 (1-3). Among patients with OCA, 3(23.1%) showed complete improvement with a median improvement of 3 points on Likert scale. In the SA patients, 19 (55.9%, 34) patients were alive on follow-up, with a median mRS of 1. Aspirin use was not associated with better mRS or survival in patients with vasculitis. A multivariable Cox proportional model showed age at diagnosis to be the only predictor of mortality (HR 1.04, 95% CI (1.01- 1.08), p =0.012). Conclusions TB arachnoiditis and CNS vasculitis are severe complications of CNS TB, and management remains a challenge. The poor therapeutic response to intrathecal hyaluronidase, thalidomide, and aspirin highlights need for further larger prospective trials and search for alternative agents.

Adjunctive therapies that enhance the efficacy of existing antitubercular drugs are needed for drug-resistant tuberculosis. We evaluated the efficacy of intranasally administered recombinant D29 LysB, a mycobacteriophage-derived mycolylarabinogalactan esterase, in murine and guinea pig models of pulmonary tuberculosis. BALB/c mice and guinea pigs were aerosol-infected with Mycobacterium tuberculosis H37Rv and treated for 4 weeks with LysB alone or with standard antitubercular therapy (ATT: rifampicin, isoniazid, pyrazinamide). Outcomes included pulmonary and extrapulmonary bacterial burden (CFU), lung and spleen histopathology, cytokine profiling, and humoral immune responses. LysB monotherapy produced modest pulmonary CFU reductions. When given adjunctively with ATT, LysB produced an additional 0.6-0.7 log10 reduction in lung CFU compared with ATT alone and decreased splenic dissemination in both species. Combination therapy improved tissue pathology, reducing granulomatous involvement and preserving pulmonary architecture. LysB treatment increased TNF- with a moderate rise in IL-10, a profile consistent with enhanced antibacterial immunity without excessive inflammatory damage. Repeated intranasal administration was well tolerated; no IgE-mediated hypersensitivity was detected. LysB-specific IgG developed but did not diminish therapeutic efficacy. These results show that intranasal D29 LysB augments the bactericidal and histopathological effects of standard ATT in vivo and support further development of inhaled phage-derived lysins as adjunctive therapies for drug-resistant tuberculosis. ImportanceTuberculosis remains a major cause of infectious mortality worldwide, and the increasing burden of multidrug-resistant and extensively drug-resistant disease continues to challenge effective treatment. New therapeutic approaches that complement conventional antibiotics are urgently needed. In this study, intranasally delivered recombinant mycobacteriophage-derived LysB was well tolerated and enhanced treatment efficacy in experimental pulmonary tuberculosis. Adjunctive LysB improved bacterial clearance, reduced tissue pathology, and modulated host immune responses in both murine and guinea pig models. These findings highlight phage-derived endolysins as promising inhalable adjunctive therapeutics for drug-resistant tuberculosis.

Phage therapy offers promise to combat antimicrobial resistance, including drug-resistant tuberculosis (TB). Understanding phage activity against Mycobacterium tuberculosis (Mtb) adapted to physiologic microenvironments, such as hypoxia and acidity in granulomas, is essential since these conditions induce non-replicating states. We evaluated a phage combination against Mtb under hypoxic, acidic (pH 5.5), and stationary-phase conditions in vitro. In planktonic Mtb growth conditions, phage concentrations increased around day seven followed by a significant reduction in Mtb H37Rv load, which was maintained over 31 days. Phage addition prevented regrowth was observed with rifampicin and isoniazid alone. Individual phage stability was differentially affected by acidic media conditions, resulting in variability of antimycobacterial activity. In hypoxic conditions and stationary growth experiments, phage titers remained stable over time with no change in mycobacterial load compared to controls. Model-based predictions were able to adequately capture phage-mycobacterial interactions with and without rifampicin. The lack of antimycobacterial activity in assays with non-replicating mycobacteria suggest that phages need actively replicating mycobacteria to exert lytic activity. Stable phage concentrations in assays with non-replicating mycobacteria suggests low grade phage replication in these conditions. Established models can support future study design through simulations of different experimental scenarios.

Tuberculosis (TB) remains a leading cause of infectious disease mortality, and the continued emergence of drug-resistant Mycobacterium tuberculosis (MTB) strains threatens the effectiveness of standard treatment regimens. Culture-based antibiotic susceptibility testing (AST) remains the clinical reference standard for resistance determination but typically requires six to eight weeks, delaying initiation of optimized therapy for patients with drug-resistant disease. Whole-genome sequencing (WGS)-based approaches provide a rapid alternative for predicting antimicrobial resistance directly from genomic data and are increasingly being incorporated into diagnostic workflows. This survey reviews computational approaches for genomic resistance prediction in MTB, focusing on two major classes of methods: catalog-based tools that identify established resistance-conferring variants, and de novo machine learning approaches that infer resistance from genome-wide sequence features. We examine the strengths and limitations of these approaches with respect to interpretability, scalability, computational requirements, and concordance with phenotypic testing. We further discuss emerging directions in quantitative minimum inhibitory concentration (MIC) prediction, challenges in pyrazinamide susceptibility testing, and the limited availability of resistant isolates for newer and repurposed drugs used in multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) treatment regimens. Continued expansion of paired phenotypic and genomic datasets, standardized MIC testing protocols, and rigorous lineage-aware evaluation frameworks will be essential for improving the clinical reliability and global deployment of genomic resistance prediction for tuberculosis diagnostics.

Background: Tuberculosis (TB) treatment outcomes remain suboptimal, and standard clinical diagnostics cannot reliably identify patients at high risk of treatment failure or relapse at the time of diagnosis. While within-host Mycobacterium tuberculosis genetic diversity is hypothesized to reflect the viable bacterial burden and adaptive capacity of the infection, its clinical prognostic value remains unknown. Methods: We conducted a prospective cohort study of 364 patients with newly diagnosed, rifampicin-susceptible pulmonary TB in South Africa. Patients received standard 6-month therapy and were monitored for up to two years to ascertain composite unfavorable outcomes (treatment failure, death, or relapse). To accurately detect low-frequency (unfixed) genetic variants and eliminate reference bias artifacts, we mapped medium to high depth short-read sequences against matched, patient-specific long-read assemblies. The association between baseline pathogen genetic diversity and clinical outcomes was evaluated using multivariable Cox proportional-hazards models. Results: After bioinformatic filtering, true unfixed variants were relatively rare but significantly enriched in genes mediating pathogen adaptation and drug tolerance, including transporter proteins and two-component regulatory systems. Within-host bacterial genetic diversity (i.e., the total number of unfixed variants) ranged from 0-20, with a median of 1 per patient. In survival analysis adjusting for known clinical risk factors--including HIV status, prior TB, baseline smear positivity, and radiographic lung involvement--baseline within-host genetic diversity emerged as a strong, independent predictor of unfavorable treatment outcomes. For patients with greater than 3 unfixed variants at diagnosis, each increase of 5 unfixed variants was associated with more than double the risk of a composite unfavorable outcome (adjusted Hazard Ratio, 2.36; 95% CI, 1.27 to 4.39; p=0.007). Conclusions: Baseline within-host pathogen genetic diversity is an independent predictor of unfavorable TB treatment outcomes. As sequencing becomes increasingly integrated into routine diagnostics, quantifying unfixed variants is an accessible approach that promises to risk-stratify patients and guide the duration of individualized regimens.

BackgroundAccess to tuberculosis (TB) diagnostics remains limited in high-burden countries, partly due to centralised and complex testing. We evaluated MiniDock MTB, a low-complexity near point-of-care (nPOC) assay, in sputum for diagnostic accuracy and agreement with Xpert MTB/RIF Ultra (Xpert). MethodsFrom September 2024 to April 2025, presumptive pulmonary TB cases aged >28 days were consecutively enrolled at 15 community health centres, a lung clinic, and a lung hospital in Bandung, Indonesia. Sputum was tested with MiniDock MTB on sputum swab, Xpert, and liquid culture. We assessed diagnostic accuracy against microbiological and composite reference standards (CRS) and agreement with Xpert. ResultsFrom 3051 individuals screened, 671 were eligible and included; 533 were adults (aged [&ge;]15 years), 138 were children. Overall, 126 were Xpert-positive and 132 culture-positive. In adults, MiniDock MTB sensitivity was 86.2% (110/116; 95% CI 78.8 - 91.3) and 55.8% (110/197; 95% CI 48.9 - 62.6) against liquid culture and CRS, respectively; small numbers of positive results precluded estimation in children. Specificity ranged from 96.8% to 98.8%. Overall agreement between MiniDock MTB and Xpert (excluding trace positive) was 94.8% (95% CI 92.6 - 96.3; K = 0.84). Positive percent agreement was 82.8% (95% CI 75.1 - 88.4) and 25% (95% CI 4.6 - 69.9) in adults and children, respectively, and reduced with lower bacillary burden (p = 0.004). ConclusionsSensitivity of MiniDock MTB in sputum against liquid culture exceeded the WHO threshold for a sputum-based nPOC TB test in adults. There was high agreement with Xpert but reduced sensitivity in low-bacillary burden TB disease.

Tuberculosis (TB) continues to pose a significant global public health challenge with substantial patient morbidity and mortality. Current TB patient biomarkers lack sufficient resolution to inform treatment response and patient stratification. This necessitates the development of sensitive and reliable host biomarkers. We previously demonstrated the efficacy of TruCulture whole blood stimulation for differentiating asymptomatic TB from active pulmonary TB disease patients in endemic regions. Our systems immunology study expands upon this previous work by evaluating the potential of TruCulture to monitor longitudinal responses to TB treatment in patients from the Predict-TB trial before, during, and after 6 months of antibiotic therapy. We stimulated whole blood from TB patients (n=40) using TruCulture under four conditions (Null, Mycobacterium tuberculosis-antigen, LPS, and IL-1{beta}) at baseline (week 0), during treatment (weeks 16 and 24), and one-year follow-up post- treatment (week 72). 20/25 measured cytokines exhibited significant changes throughout treatment, with several continuing to evolve during post-therapy follow-up. Machine learning based analysis identified Mtb-Ag-induced IL-1RA (AUC = 0.90, 0.92, 0.95 at weeks 16, 24, 72) and LPS-induced NLRP3 (AUC = 0.94 at week 16) as the best protein and transcriptional biomarkers for distinguishing treated from untreated patients, strongly implicating the inflammasome response. Combining these results with the extent of lung disease assessed by FDG PET/CT scans, we showed direct disease relevance for these blood-based biomarkers. The identified biomarker profiles hold promise for improving TB patient care through early prediction of treatment responses, real-time therapy monitoring, and informed development of host-directed therapeutic strategies for clinical decision-making. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=146 HEIGHT=200 SRC="FIGDIR/small/723467v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@14a32eforg.highwire.dtl.DTLVardef@55f3d4org.highwire.dtl.DTLVardef@fb0137org.highwire.dtl.DTLVardef@10cf39e_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstractC_FLOATNO Predict-TB clinical study overview and summary of TB-specific biomarkers identified from TruCulture whole blood stimulation system. C_FIG

BackgroundThe World Health Organisation (WHO) recommends digital chest radiography (dCXR) with computer-aided detection (CAD) for tuberculosis (TB) screening of individuals >15 years of age. MethodologyAdults ([&ge;]18 years) were enrolled (March 2021-December 2022) in South Africa into a community-based Screening Cohort (household contacts) and a facility-based Triage Cohort (symptomatic clinic attendees). Microbiologically-confirmed pulmonary TB required positive sputum culture and/or Xpert Ultra. Asymptomatic TB was diagnosed in participants without TB symptoms. dCXR were read by blinded human readers and qXR CAD (0.5 threshold; Qure.AI, India). ResultsdCXR from 1,353 participants (886 Screening Cohort; 467 Triage Cohort) were analysed. Microbiologically-confirmed TB occurred in 48 (5.4%) Screening Cohort [9 symptomatic (19%) and 39 asymptomatic (81%)]; and 116 (24.8%) Triage Cohort (all symptomatic) participants. dCXR sensitivity (human readers) for asymptomatic TB in the Screening Cohort was 56.4%, vs. 72.4% for symptomatic TB in the Triage Cohort (difference -16%; 95%CI -2.9 to -29.1); with specificities 94.1% and 81.2%, respectively. Corresponding qXR CAD sensitivities were 69.2% vs. 83.6% (difference -14.4%; 95%CI -26 to -2.8), with specificities 89.3% and 73.5%, respectively. The difference in dCXR sensitivity and specificity for asymptomatic TB between qXR CAD and human readers was 12.8% (95%CI -0.48 to 26.1) and -4.8% (95%CI -12.4 to 28.2), respectively. ConclusionSensitivity of community-based dCXR screening for microbiologically-confirmed asymptomatic TB among household contacts was lower than for facility-based triage of symptomatic TB, but approached 70% with CAD. Neither human reader nor qXR CAD evaluation met WHO targets for a TB screening test (90% sensitivity; 80% specificity). Research in contextO_ST_ABSEvidence before this studyC_ST_ABSThe World Health Organisation (WHO) recommends digital chest radiography (dCXR) with computer-aided detection (CAD) for tuberculosis (TB) screening of individuals >15 years of age, based on data from prevalence surveys and facility-based studies. Performance data for community-based screening of asymptomatic TB are lacking. We searched PubMed for literature published in English between January 1, 2000, and November 1, 2025, for community-based, active case-finding studies of adolescents and adults aged 15 years and older that used dCXR CAD for asymptomatic TB screening. We used the following search terms: "Tuberculosis" AND ("asymptomatic" OR "subclinical") AND ("computer aided diagnosis" OR "artificial intelligence") AND "community-based screening" AND "chest radiography" AND ("diagnostic performance" OR "sensitivity"). We identified five studies reporting on microbiologically-confirmed asymptomatic TB and dCXR CAD performance. Three of five studies tested sputum only in those who were symptomatic and/or had abnormal CXR. One study did measure prevalence of asymptomatic TB by universal sputum testing of all participants, but did not report sensitivity and specificity for asymptomatic TB separately. One case-control study of CAD4TB (v7), which pooled data from five active case-finding cohorts, reported sensitivity of 61.4% and specificity of 86.7% for asymptomatic TB. However, the case-control design and inclusion of two cohorts using prevalence survey methodology and three cohorts enrolling high TB risk groups, two of which did not perform CXR on all participants, suggest potential for selection bias. Added value of this studyWe evaluated discriminatory performance of dCXR screening for asymptomatic TB among adult household contacts of TB patients, using human readers and qXR CAD (QURE.AI, India), in three communities in South Africa (Screening Cohort). Performance was benchmarked against that for symptomatic TB among adult clinic attendees (Triage Cohort), to enable comparison with traditional published approaches. All participants underwent universal sputum testing, regardless of symptom status or dCXR results. Sensitivity of human readers for asymptomatic TB in the Screening Cohort was 56.4%, compared to 72.4% for symptomatic TB in the Triage Cohort, with specificity 94.1% and 81.2%, respectively. The corresponding sensitivity of qXR CAD for asymptomatic TB, using the manufacturers 0.5 threshold score, was 69.2%, compared to 83.6% for symptomatic TB, with specificity 89.3% and 73.5%, respectively. The difference in dCXR sensitivity and specificity for asymptomatic TB between qXR CAD and human readers was 12.8% and -4.8%, respectively. The adjusted qXR threshold score (0.007) required to achieve 90% sensitivity for asymptomatic TB reduced specificity to 18.9%; and did not meet the WHO Target Product Profile (TPP) for a high sensitivity (90%), high specificity (80%) TB screening test. Implications of all the available evidenceSensitivity of community-based dCXR screening of household contacts for asymptomatic TB was low, compared to facility-based triage of symptomatic TB. Neither human reader nor qXR CAD evaluation of dCXR met the minimal WHO TPP for a high sensitivity (90%), high specificity (80%) TB screening test. Although dCXR CAD community screening would detect more than two-thirds of all people with previously undiagnosed, microbiologically-confirmed asymptomatic TB, the significant proportion of people with TB that would remain undetected, and untreated, might allow ongoing Mycobacterium tuberculosis transmission and hinder elimination efforts.

BackgroundTimely diagnosis of tuberculosis and drug resistance remains a cornerstone of effective disease control. Multiplex open molecular platforms capable of simultaneously detecting Mycobacterium tuberculosis complex (MTBc), non-tuberculous mycobacteria (NTM), and resistance to first-line anti-tuberculosis drugs could streamline diagnostic pathways. MethodsWe conducted a laboratory-based evaluation of two multiplex real-time PCR assays (MTBc/NTM R-Gene(R) and MTB-RIF/INH R-Gene(R)) using 300 well-characterized samples, including 150 MTBc-positive culture isolates (including rifampicin-resistant, isoniazid-resistant, and drug-susceptible strains) and 150 MTBc-negative samples (50 NTM isolates and 100 mycobacteria-negative specimens). Composite reference standards included culture, MPT64 antigen testing, and line probe assay corroborated by phenotypic drug susceptibility testing for resistance profiling, with NTM speciation performed using a dedicated line probe assay. DNA extraction was performed using the QIAamp DNA Mini Kit (QIAGEN, Germany), followed by amplification on a real-time PCR platform according to manufacturer instructions. The diagnostic performance was assessed against composite reference standards. ResultsThe analytical performance for detecting MTBc demonstrated 100% sensitivity and specificity (150/150). NTM detection showed 70{middle dot}0% sensitivity (35/50) and a specificity of 100%, highlighting limitations in coverage of NTM species. Rifampicin resistance was detected with a sensitivity of 96{middle dot}0% (48/50) and specificity of 100%, whereas isoniazid resistance detection was 100% sensitive and specific (50/50). Agreement with established reference standards was high ({kappa}=0{middle dot}76-1{middle dot}00) within this analytical context. InterpretationThis analytical validation demonstrates that multiplex open real-time PCR assays can accurately and simultaneously detect MTBc, NTM, and rifampicin and isoniazid resistance using culture isolates. While these platforms offer potential advantages in flexibility and expanded resistance profiling, additional studies on clinical diagnostic accuracy, cost-effectiveness analyses, and operational feasibility are required to determine their practical utility and programmatic impact in high-burden settings

Recognition of infected macrophages by CD4+ T cells is essential to immune protection against Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). However, not all infected macrophage subsets successfully elicit T cell activation. We recently discovered that M2-like macrophages fail to efficiently activate memory CD4+ T cells when infected with Mtb, yet successfully elicit T cell activation when loaded with peptides, {gamma}-irradiated bacteria, or Mtb whole cell lysate. Since the mechanisms underlying CD4+ T cell evasion by infected M2 but not M1-like macrophages remain underexplored, we sought to determine the genes and pathways unique to Mtb infection of M2-like cells, including alveolar macrophages. RNA sequencing of human macrophages infected with virulent Mtb identified enrichment of IL-10 and type I interferon (IFN) signaling genes, including IL10RA and HERC5, respectively, in infected M2-like monocyte-derived and alveolar macrophages. However, genes involved in MHC-II trafficking, such as AP1M2, were higher in infected M1-like macrophages. In complementary experiments using fluorescence microscopy and flow cytometry, we observed impaired trafficking of newly synthesized MHC-II to the plasma membrane of Mtb-infected M2-like macrophages despite high total surface MHC-II levels. Neutralization of IL-10 or knockdown of HERC5 restored MHC-II trafficking to the cell surface among infected M2-like macrophages and significantly enhanced activation of memory CD4+ T cells in an MHC-II-dependent manner. These findings identify coordinated IL-10 and type I IFN signaling as key mechanisms that restrict MHC-II trafficking to the plasma membrane in Mtb-infected M2-like macrophages, thereby limiting antigen presentation and CD4+ T cell activation. We propose that host-directed therapies targeting these pathways in infected alveolar macrophages will facilitate T cell recognition for the prevention or treatment of active TB. Author SummaryRecognition of infected macrophages by CD4+ T cells is essential to immune protection against Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). However, not all infected macrophage subsets successfully elicit T cell activation. We recently discovered that M2-like macrophages fail to efficiently activate memory CD4+ T cells when infected with Mtb, yet they successfully elicit T cell activation when treated with peptides, {gamma}-irradiated bacteria, or Mtb whole cell lysate. In this study, we identified genes and pathways uniquely upregulated in Mtb-infected M2-like macrophages that are linked to inefficient CD4+ T cell activation, including IL-10 signaling and type I interferon (IFN) pathways. These pathways were linked to reduced MHC-II trafficking to the plasma membrane in Mtb-infected M2-like macrophages. Neutralization of IL-10 or knockdown of HERC5 restored MHC-II trafficking and augmented memory CD4+ T cell activation. Our study demonstrates that IL-10 signaling and type I IFN pathways play detrimental roles in macrophages during Mtb infection, impairing MHC-II trafficking and CD4+ T cell activation. Since lung-resident alveolar macrophages express a dominant M2-like phenotype, these findings suggest that targeting IL-10 and type I IFN signaling may offer a strategy to enhance CD4+ T cell-mediated immunity and improve TB outcomes.

Background High-risk subgroups among household contacts of persons with tuberculosis (TB) might benefit from additional interventions. However, the significance of an abnormal baseline chest radiograph (CXR) suggestive of TB, despite negative sputum microbiology, is uncertain. Methods Adults ([&ge;]18 years) with recent household TB exposure were enrolled at three South African sites (April 2021-September 2022). All participants underwent symptom screening, CXR, and sputum Xpert Ultra and MGIT culture. Pulmonary TB diagnosis was microbiologically-confirmed. Participants without prevalent TB were followed for symptomatic incident TB through 12 months. Multivariable logistic regression identified factors associated with abnormal CXR suggestive of TB. Poisson regression estimated adjusted incidence rate ratios (aIRR) with 95% confidence intervals (95%CI). Results Baseline CXR were available for 795/846 (94.0%) participants without prevalent TB and were abnormal in 157/795 (19.7%); associated with older age (adjusted odds ratio, aOR=1.04, 95%CI 1.02-1.05); prior TB (aOR=6.39, 95%CI 4.18-9.78); and current smoking (aOR=1.61, 95%CI 1.00-2.62). Symptomatic incident TB developed in 8/795 (1.0%) participants, including 7/8 (87.5%) who were asymptomatic and 4/8 (50.0%) with abnormal CXR at baseline. TB incidence was higher in those with abnormal versus normal CXR (aIRR=4.11, 95%CI 1.29-13.09), but after median 12.1 (IQR 11.1-13.1) months follow-up, 153/157 (97.5%) had not progressed to incident TB. Conclusions Adult household contacts with CXR abnormalities, but without prevalent TB, had a four-fold higher incidence of TB within one year, compared to those with normal CXR. This additional risk warrants targeted preventive treatment and extended surveillance, but since most remained TB-free, therapeutic TB treatment is not justified.

Tuberculosis (TB) is prevalent in Uganda and overlaps with a high rate of HIV/TB coinfection. While nearly all hospital-based TB cases in Kampala, the capital of Uganda, show clear TB symptoms, 30% or more of undiagnosed TB cases found through active screening are asymptomatic. Additionally, the host risk factors for TB in Kampala cannot be distinguished from environmental risk factors. These TB-specific challenges are just part of the complexity, especially in areas with high HIV/AIDS burden. Data science techniques, especially Artificial Intelligence (AI) and Machine Learning (ML) algorithms, could help untangle this complexity by identifying factors related to the host, pathogen, and environment, which are difficult to explain or predict with traditional/conventional methods. In this project, we will use health data science approaches (AI/ML) to identify factors driving TB transmission within households and reasons for anti-TB treatment failure. We will utilize the computational resources at Makerere University and available demographic, clinical, and laboratory data from TB patients and their contacts to develop AI and ML algorithms. These will aim to: (1) identify patients at baseline (month 0) unlikely to convert their sputum or culture results by months 2 and 5, thus at risk of failing TB treatment; (2) identify household contacts of TB cases who are at risk of developing TB disease, as well as contacts who may resist TB infection despite repeated exposure to M. tuberculosis. Achieving these objectives will provide evidence that data science methods are effective for early detection of potential TB cases and high-risk patients, thereby helping to reduce TB transmission in the community. The study protocol received approval from the School of Biomedical Sciences IRB, protocol number SBS-2023-495.

Background: Tuberculosis (TB) remains the leading infectious cause of death worldwide, with India accounting for nearly one-fourth of global TB cases. Ni-kshay, the countrys digital case-based TB notification platform is rich in data pertaining to the continuum of care of TB patients. This study aims to develop a standardized analytical approach to programmatic data to identify predictors of unfavourable treatment outcomes and mortality among adult drug-sensitive TB patients at the state level for Maharashtra during 2021 and 2022. Methods: Two separate analyses were undertaken comparing treatment success with: (1) unfavourable outcomes (death, treatment failure, loss to follow-up, regimen change, or not evaluated); and (2) mortality. Multivariate logistic regression was used to compute adjusted odds ratios (aOR) for key risk factors, adjusting for age, gender, and weight. Results: The final cohort included 323,124 cases for unfavourable outcome analysis and 315,579 cases for mortality analysis. Increasing age, male gender, lower body weight, known HIV and diabetes comorbidities, tobacco and alcohol consumption, and "unknown" status for behavioural risks and comorbidity status were significantly associated with increased odds of both unfavourable outcomes and mortality. Conclusions: This study highlights the utility of programmatic data in identifying high-risk TB patients and offers a reproducible analytic framework.

Although spread of internalized Mtb from the initial infected alveolar macrophages (AMs) is a crucial determinant of infection outcomes, the role of cell death in facilitating this spread, and how it is regulated by Mtb remains poorly understood. Ferroptosis, a lipid peroxidation-mediated form of necrotic cell death, contributes to pathology during later stages of infection. However, the role of ferroptosis in early AM cell death remains inadequately defined, and its induction during infection has been primarily studied with the laboratory strain, H37Rv. Using gene set variation analysis of single cell RNAseq data profiling Mtb-infected murine lungs, we found that the hypervirulent Beijing sublineage clinical strain SA161 is associated with an elevated pro-ferroptotic transcriptional response in AMs compared to H37Rv by 17 days post infection. Consistent with these transcriptional profiles, we found that SA161 induced increased lipid peroxidation in comparison to H37Rv during infection in vitro and in vivo. Administration of the lipid peroxidation inhibitor, ferrostatin-1 (Fer-1), reduces this Mtb-induced lipid peroxidation. Notably, we found that administration of Fer-1 to Mtb-infected mice significantly reduced bacterial burden for SA161 at 14 dpi while having no effect on H37Rv. Microscopic analysis of SA161-infected lung lesions at 14 dpi suggests that inhibition of ferroptosis-driving lipid peroxidation results in a greater proportion of AMs amongst infected cells and decreased neutrophil-associated IFN signaling. Collectively, these findings reveal that ferroptosis plays an important role during early infection with virulent clinical strains of Mtb by influencing bacterial spread and signaling of immune cell responders, potentially informing host-directed intervention strategies.

Introduction: Household contacts (HHCs) of pulmonary TB patients remain at high risk for TB infection and disease progression, yet many remain asymptomatic and are missed by symptom-screening pathways. While India expanded its TB preventative guidelines to include all HHCs in 2021, chest X-ray (CXR) screening continues to be used selectively, representing a missed opportunity in early case detection. Methods: The analysis uses programmatic data from Project JEET 2.0 (Joint Effort for Elimination of Tuberculosis), implemented by the William J. Clinton Foundation in India, between October 2021 and March 2024. Eligible HHCs (>=5 years) were offered CXR screening as part of TB preventive therapy (TPT) evaluation. Descriptive and multivariable analyses examined predictors of CXR uptake and TB yield. A two-stage logistic regression model estimated potential TB yield under universal CXR coverage. Model performance was evaluated using the area under the curve (AUC), and bootstrap simulations generated counterfactual estimates of missed TB cases. Results: Among 1,034,621 HHCs, 1.02% individuals were found positive for TB, which includes 7,786 HHCs who were on TB treatment already, while an additional 2,812 were identified during pre-TPT evaluation. Among eligible HHCs (n = 1,026,835), 70% were screened with CXR, of which 2.4% had suggestive TB findings. Of these, 79% went for further TB assessment. Symptomatic HHCs were more likely to be CXR screened (84% vs 69%) and assessed for TB, yet two-thirds of all detected TB cases were asymptomatic. It is estimated that universal CXR coverage and TB testing for suggestive cases can increase TB detection by at least 87%. Conclusion: The study provides a scalable approach to expand CXR coverage through public-private partnerships, enabling early TB detection among HHCs, especially among asymptomatic contacts. Future implementations will benefit from integrating AI-enabled reading, along with systematic follow up for those with suggestive findings.

Tuberculosis (TB) has been a leading cause of death from a single infectious agent for decades. Bacille Calmette-Guerin (BCG) remains both the primary TB vaccine strategy and the oldest vaccine in circulation, with severe limitations in adult populations. Recently, live attenuated vaccine strategies, or generating safe strains of Mycobacterium tuberculosis (Mtb) through genetic engineering, have shown considerable promise. We previously developed an attenuated strain of Mtb lacking the nucleoid-associated protein Lsr2 ({Delta}lsr2) which is also phthiocerol dimycocerosates (PDIM) deficient and induces an immune response that represents an intermediate stage between the parental Mtb strain and BCG. In this study we examined the immune response of {Delta}lsr2 vaccinated mice in comparison to BCG and found a substantially stronger CD4 and CD8 T cell responses from {Delta}lsr2 vaccinated mice. Complementary, we conducted Mtb protection studies in {Delta}lsr2 and BCG vaccinated mice and guinea pigs, where we found that {Delta}lsr2 provided superior protection in both animals. This improved protection is shown with reduced bacterial burden and improved organ pathology in the lungs and spleen. Taken together, our work shows {Delta}lsr2 serves as a promising vaccine candidate for continued preclinical development.

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides (Mmm), remains a major burden to cattle health and the agricultural industry. Mmm is an atypical bacterial pathogen that appears to lack classical virulence factors that cause direct tissue injury (i.e. toxins), and little is known about the mechanisms driving its pathogenicity. The host immune response is believed to be implicated in CBPP pathology, though the molecular mechanisms underlying lesion initiation, progression and chronicity are poorly defined. Classical pathology describes a continuum of lung lesions starting from early inflammation to more mature necrotic lesions and formation of fibrotic sequestra. However, the host transcriptional response driving this potentially immunopathological progression during Mmm infection has never been resolved in vivo. Here, we performed lesion-stage-resolved transcriptomic profiling of pathological lung tissue collected from experimentally infected animals and compared to healthy lung tissue collected from unchallenged controls. Differential gene expression and functional enrichment analyses were used to identify biological pathways relevant to Mmm infection and pathological lesion formation. Early infection was dominated by interferon-stimulated genes and cytokine-responsive pathways, creating a primarily antiviral-like response environment despite the bacterial etiology. Red hepatization showed strong induction of neutrophil chemoattractants, epithelial remodeling markers, and early matrix-remodeling enzymes. Consolidation, spanning red and grey stages, was enriched for innate immune activation, leukocyte adhesion, extracellular matrix organization, and persistent interferon signaling. Grey hepatization reflected late-stage consolidation with heightened neutrophil effector activity, oxidative and proteolytic injury, and macrophage and fibroblast-linked collagen processing. Necrosis/Sequestra lesions showed reduced inflammatory signaling, robust extracellular matrix organization, adhesion, and morphogenetic pathways consistent with encapsulation and sequestrum formation. Our data indicate that the dynamic continuum of CBPP lung pathology is initiated by interferon-primed myeloid recruitment and amplified by neutrophil-driven injury and macrophage- and fibroblast-mediated matrix remodeling. These data further substantiate the role of dysregulated immunity in the development of disease during Mmm infection.

Infection by Mycobacterium tuberculosis (Mtb) is characterized by pathogen persistence in lung cells derived from blood monocytes. Since monocyte-derived lung subsets differ in their ability to restrict the growth of intracellular Mtb in mice, understanding the ontogeny of these subsets can inform development of host-directed therapies. Circulating monocytes are proposed to be heterogeneous, arising from distinct bone marrow or spleen progenitors that direct local differentiation. However, the role of the Mtb-infected lung environment in this process has not been addressed. We found that infected and uninfected mice had similar bone marrow monopoiesis, resulting in equivalent monocyte differentiation within the infected lung. While pulmonary Mtb infection also induced splenic monopoiesis, we found no impact on lung monocyte differentiation in splenectomized mice. However, when wildtype monocytes were transferred into Mtb-infected Sp140-/- recipients, in which excess Type I interferons and neutrophils alter the lung environment, we observed that donor-derived lung subsets resembled recipient-derived cells. In the lungs of Mtb-infected mice, we identified monocyte-derived lung subsets with unique gene expression, associated with specific spatial distributions and cell neighborhoods. These findings suggest that the local lung environment has a larger influence on the phenotypic diversity of monocyte-derived lung cells than does the peripheral environment.