Search Results (407)

Background: Resistance to first-line anti-tuberculosis drugs in Mycobacterium tuberculosis represents a significant public health challenge, particularly in high-burden tuberculosis (TB) settings such as Pakistan, where multidrug-resistant (MDR) forms further complicate disease control efforts. Drug resistance is primarily associated with mutations in rpoB, inhA, katG, embA, embB, embC, and pncA. The emergence of novel, region-specific variants underscores the urgent need for integrating genomic surveillance into routine TB diagnostics and regional control programs. This study aimed to identify the spectrum of mutations contributing to first-line drug resistance in MDR-TB isolates from Khyber Pakhtunkhwa, Pakistan. Methods: Whole-genome sequencing was performed on 16 clinical isolates (12 MDR and 4 drug-susceptible) to identify resistance-associated mutations in rpoB, inhA, katG, embA, embB, embC, and pncA. Detected variants were interpreted using the World Health Organization (WHO) mutation catalogue to determine their association with drug resistance. Phylogenetic relationships were inferred using the Bacterial and Viral Bioinformatics Resource Center (BV-BRC) platform. Results: A total of 16 M. tuberculosis isolates were analyzed to evaluate resistance to first-line anti-tuberculosis drugs. In rpoB, 76 distinct variants were identified, including canonical mutations such as Ser450Leu and His445Arg, as well as a potentially novel substitution, Ser431Phe, predicted to confer high-level rifampicin resistance. The katG and inhA genes harbored 24 and 27 mutations, respectively, including well-characterized substitutions such as Ser315Thr and Ala114Glu, which are strongly associated with isoniazid resistance. Mutations in embA and embB were linked to ethambutol resistance, with several variants localized within conserved transmembrane domains critical for drug interaction. Phylogenetic analysis revealed substantial genetic diversity and evidence of local transmission among MDR-TB isolates. Conclusions: This study suggests that the genetic landscape of drug resistance in M. tuberculosis is highly dynamic in endemic regions. The findings highlight the importance of integrating region-specific mutation profiles into molecular diagnostic frameworks to enhance early detection, guide individualized therapeutic interventions, and strengthen strategies aimed at controlling the transmission of MDR-TB. Full article

Background: Drug-resistant tuberculosis (DR-TB) remains a major public health challenge in South Africa, particularly in rural settings with high HIV co-infection rates. Understanding predictors of treatment response among people living with HIV is essential for improving clinical management and programmatic outcomes. This study aimed to identify socio-demographic and clinical predictors of treatment outcomes among HIV-positive individuals diagnosed with multidrug-resistant (MDR) and extensively drug-resistant tuberculosis (XDR-TB) in rural Eastern Cape Province, South Africa. Methods: A retrospective cohort study was conducted using routinely collected clinical records of DR-TB patients initiated on treatment between January 2020 and December 2024 at two public healthcare facilities. A total of 239 patients with complete treatment outcome data were included. Treatment outcomes were classified as favourable (cured or treatment completed) or unfavourable (death, treatment failure, or loss to follow-up). Descriptive statistics were used to summarise patient characteristics, while univariate and multivariable logistic regression analyses were performed to identify factors associated with treatment outcomes. Results: Most participants were aged ≤ 39 years (58%), male (60%), unemployed (90%), and without income (80%). MDR-TB accounted for 40% of cases, rifampicin-resistant-TB (RR-TB) for 53%, and XDR-TB for 7.1%. Multivariable analysis showed that XDR-TB was the strongest independent predictor of unfavourable treatment outcome (AOR = 0.18; 95% CI: 0.06–0.58; p = 0.004). Income status was also significantly associated with outcome, with participants reporting some incomes having lower odds of favourable outcomes (AOR = 0.46; 95% CI: 0.23–0.92; p = 0.036). The model demonstrated modest predictive performance (AUC = 0.67). Conclusions: These findings highlight the dominant influence of resistance phenotype, particularly XDR-TB, on treatment prognosis among HIV-positive DR-TB patients in rural Eastern Cape. Integrating early resistance profiling, intensified clinical management of XDR-TB, and socioeconomic support mechanisms may improve treatment outcomes in high-burden rural settings. Full article

Background: Drug-resistant tuberculosis remains a major challenge in resource-limited settings, particularly in rural regions of the Eastern Cape Province, where limited laboratory infrastructure, constrained access to advanced molecular diagnostics, shortages of specialized healthcare personnel, and prolonged diagnostic turnaround times can delay appropriate treatment initiation. This study examined whether routinely detectable genomic resistance markers could be integrated with parsimonious machine learning approaches to support early risk stratification for isoniazid (INH) and/or rifampicin (RIF) resistance and multidrug-resistant tuberculosis (MDR-TB). Methods: We conducted a retrospective analysis of clinical, demographic, and genomic data from 207 Mycobacterium tuberculosis isolates representing 207 unique patients. Resistance was classified as INH and/or RIF resistance or MDR-TB (concurrent resistance to both drugs). Predictors included age, sex, and canonical resistance-associated mutations (katG S315T, inhA −15C>T, and rpoB codon substitutions). Logistic regression was used to estimate adjusted odds ratios (aORs), while Random Forest models were applied to assess non-linear feature importance. Internal validation was performed using 10-fold cross-validation. A systems network analysis mapped the integration of model-derived risk bands into Clinical Governance structures and Community-Engaged Education pathways, including interventions delivered by Community Health Workers (CHWs). Results: INH and/or RIF resistance was identified in 58.9% of isolates, with 21.7% classified as MDR-TB. The most frequently detected mutations were katG S315T (29.0%) and rpoB S450L (26.6%). Logistic regression identified rpoB S450L (aOR 4.20; 95% CI: 2.10–8.45) and katG S315T (aOR 2.85; 95% CI: 1.40–5.80) as the strongest independent predictors, while age and sex were not statistically significant. Models demonstrated strong internal discrimination (AUCs of 0.96 for INH and/or RIF resistance and 0.99 for MDR-TB). Risk stratification categorized 18% of patients as high risk. Scenario-based modelling suggested that prioritizing high-risk patients for reflex Line Probe Assay testing could reduce the median time to appropriate treatment from 14 to 3 days and may reduce progression from isoniazid-resistant TB to MDR-TB under specified operational assumptions. Conclusions: Mutation-informed predictive modelling demonstrates strong internally validated discrimination and provides a structured framework for risk-stratified intervention. Integrating probability-based risk thresholds within Clinical Governance systems and community-level support structures, including CHW-led adherence and education strategies, may support earlier treatment optimization in high-burden rural settings. External validation and prospective implementation studies are required before broader programmatic adoption. Full article

Structure-based strategies are widely used in tuberculosis drug discovery; however, their translational impact remains limited. This review examines how structure-based virtual screening (SBVS) is applied in practice to Mycobacterium tuberculosis targets and explores why docking-derived predictions frequently fail to translate into measurable biological activity. Rather than treating docking scores as quantitative predictors of potency, representative case studies are analyzed to demonstrate that SBVS is most effective when employed as a prioritization framework integrated with appropriate target preparation, physicochemical filtering, and early experimental validation. Across diverse targets, molecular dynamics simulations emerge as a critical discriminator, enabling the identification of binding instability and false-positive hits that persist after static docking. Tuberculosis-specific constraints—including cofactor-dependent catalysis, resistance-associated mutations, membrane-rich environments, and permeability barriers—are discussed as key factors decoupling in silico affinity from whole-cell efficacy. Collectively, these observations support a workflow-oriented view of computational drug discovery in tuberculosis, in which iterative integration of structural modeling and experimental validation is required for meaningful lead identification. Full article

The introduction of significantly shorter, all-oral regimens has significantly shifted the management of drug-resistant tuberculosis (DR-TB) towards a more tolerable and patient-centred therapeutic approach that aims to enhance treatment adherence, clinical outcomes, and quality of life among patients. Nigeria has gradually adopted this all-oral, shorter regimen, but the impact of this regimen in programmatic settings has not yet been studied. In 2022, a longitudinal, two-armed cohort study was conducted to explore the effectiveness, safety, and feasibility of the all-oral shorter regimen in the programmatic management of RR/MDR-TB in Nigeria. Consenting and eligible RR/MDR-TB patients receiving the all-oral regimen (intervention group) in four states were consecutively enrolled and compared to those receiving the standard of care (SOC). Treatment effectiveness, proportion, and 95% confidence intervals of favourable and unfavourable outcomes were measured at the end of treatment and during follow-up (six and 12 months post-treatment). In total 383 Participants were followed monthly throughout the 9–12-month treatment phase and then reassessed at 6 and 12 months after treatment completion, giving a total possible observation period of up to 24 months (185 received the intervention and 198 the standard of care). At the end of follow-up, there was a higher but non-significant proportion of favourable outcomes among the intervention vs. SOC group (80% vs. 69.7%); a higher proportion of favourable outcomes was also noted at the end of treatment among intervention participants (81.1 vs. 76.8%). Around one third of patients reported at least one serious adverse event (SAE), with no significant differences between arms, and none were deemed related to the use of medication. Intervention participants reported greater improvements in health-related quality of life between baseline and four months compared to those receiving the SOC. These findings support the programmatic use of all-oral shorter treatment for RR/MDR-TB as a regimen that is effective, tolerable, safe, and associated with enhanced health-related quality of life for patients in Nigeria. Full article

Background: Bedside manipulation of adult anti-tuberculosis tablets for paediatric dosing is common in low-resource settings, yet it can compromise drug stability. This study investigated how grinding and multi-drug co-suspension affect the supramolecular organisation, thermal stability, and dissolution of isoniazid (INH). Methods: INH raw, INH branded tablets (whole and ground), and multi-drug combination mixtures (MCMs) that simulate paediatric multi-drug-resistant tuberculosis (MDR-TB) regimens were assessed. Samples were analysed as solids and aqueous suspensions using hot-stage microscopy (HSM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Raman spectroscopy, FTIR-ATR, USP dissolution, and HPLC (LOD 0.0015 mg mL⁻¹; LOQ 0.005 mg mL⁻¹). Results: Grinding and co-mixing lowered melting points and masked typical INH events. Spectroscopy revealed the broadening and shifting of OH/NH and pyridine-ring bands, consistent with the formation of new hydrogen-bonding networks, correlative with supramolecular rearrangements. In multi-drug suspensions, INH fell below the HPLC quantification limit in both pH 1.2 and 6.8 media, despite visible residue, suggesting the formation of non-dissociable supramolecular complexes. Using a validated HPLC assay, no quantifiable INH was detected from the crushed multi-drug suspensions in either pH 1.2 or pH 6.8, whereas intact API/tablets showed measurable release. Conclusions: Co-suspension of INH with companion tuberculosis (TB) drugs disrupts its supramolecular integrity, leading to pre-administration degradation and a loss of quantifiable drug. Dissolution testing showed minimal INH release at pH 1.2 and none at pH 6.8, contrasting with intact tablets/API. These observations highlight that converting an immediate-release tablet into an aqueous suspension fundamentally alters its physicochemical environment and requires rational formulation design to preserve molecular stability, differentiating true resistance from formulation failure. Full article

Background: Antimicrobial resistance is a threat that increases morbidity and mortality. This cross-sectional study aimed to describe the profile of priority antimicrobial-resistant pathogens and to analyze the behavior of multidrug-resistant tuberculosis (MDR-TB) in the Santiago de Cali District, Colombia. Methods: researchers compiled information from data provided by healthcare institutions, the National Public Health Surveillance System, and laboratory-based surveillance using the World Health Organization’s WHONET v.5.6 software. Univariate statistical analysis described trends in pathogen resistance, and multivariate analysis analyzed the behavior of MDR-TB. Results: Among Gram-negative bacteria, high levels of carbapenem resistance were observed in A. baumannii (84% aztreonam resistance) and in K. pneumoniae (63%). P. aeruginosa exhibited elevated multidrug resistance, consistent with extensive antimicrobial selective pressure. MDR-TB exhibited a high burden of resistance, reaching 96%, with projections indicating a potential increase driven by monoresistance and resistance to rifampicin. Patients with drug-resistant tuberculosis who were HIV-positive or experiencing homelessness had a significantly higher likelihood of hospitalization (OR 5.59; 95% CI 3.09–10.11 and OR 2.94; 95% CI 1.48–5.81, respectively) and mortality (OR 3.34; 95% CI 1.72–6.49 and OR 2.59; 95% CI 1.16–5.79, respectively). Conclusions: The expansion of resistance mechanisms suggests sustained selective pressure, underscoring the need for strategies to optimize antibiotics. Full article

Drug-resistant tuberculosis (DR-TB), particularly multidrug-resistant TB (MDR-TB), remains a significant public health challenge in rural South Africa, where diagnostic and treatment infrastructure is limited. This study aimed to assess resistance patterns, bacillary load, treatment outcomes, and predictors of MDR-TB in the O.R. Tambo District of the Eastern Cape Province. Although isoniazid monoresistant TB (Hr-TB) was identified, its analysis was descriptive due to the limited sample size. A retrospective cohort analysis was conducted on bacteriologically confirmed TB cases (n = 477) diagnosed between 2020 and 2022. The data collected included demographic and clinical variables, smear and culture results, resistance patterns, and treatment outcomes. Drug resistance was categorized as MDR-TB, Hr-TB, or fully susceptible. Outcomes were classified as favorable, unfavorable, lost to follow-up, or ongoing. Logistic regression identified predictors of MDR-TB. DR-TB prevalence was 11.3% (n = 54), with MDR-TB accounting for 10.7% (n = 51) and Hr-TB for 0.6% (n = 3). Prior TB treatment was significantly associated with MDR-TB (adjusted odds ratio [aOR] 4.45, 95% CI: 1.89–10.48). Smear positivity was associated with MDR-TB in univariate analysis (OR 5.0), although its effect diminished in multivariable analysis (aOR 0.40, 95% CI: 0.12–1.36), suggesting confounding by bacillary load. Culture positivity was a strong independent predictor (aOR 27.71, 95% CI: 8.84–86.85), indicating a higher mycobacterial burden among MDR-TB cases. MDR-TB patients had significantly poorer treatment outcomes, with a high rate of unfavorable outcomes and loss to follow-up. MDR-TB dominates the resistance landscape in this rural district, primarily driven by prior treatment and high bacillary loads. The study highlights the need for targeted interventions, including enhanced diagnostic capacity, improved clinical governance, and community-based support systems, to optimize the detection and management of MDR-TB. Full article

Multidrug-resistant tuberculosis is a major global health concern. Newer agents, including bedaquiline (BDQ), delamanid (DLM), pretomanid (PMD), and linezolid (LZD), are essential for treatment; however, the resistance mechanisms of these drugs remain poorly understood in South Korea. This study aimed to investigate correlations between phenotypic and genotypic resistance to these drugs using 49 clinical Mycobacterium tuberculosis isolates collected in South Korea between 2017 and 2022. The minimum inhibitory concentrations were determined using the 7H9 broth microdilution method, and whole-genome sequencing (WGS) results were compared with the May 2024 World Health Organization (WHO) mutation catalogue. Phenotypic drug susceptibility testing (pDST) revealed elevated MICs to BDQ in 12 isolates (24.5%), DLM in nine (18.4%), and PMD and LZD in two each (4.1%). No Group 1 or 2 resistance-associated mutations were detected in BDQ-, PMD-, or LZD-elevated-MIC isolates. A Group 2 mutation (fbiC_LoF) was observed in one DLM-elevated-MIC isolate, whereas fbiC_p.Ala855fs (WHO Group 2) mutations occurred in four susceptible isolates. These findings suggest resistance mechanisms beyond the current WHO catalog. Discrepancies between pDST and WGS highlight the need for integrated diagnostics and reinforce the importance of ongoing surveillance and refinement of mutation classification systems to improve genotypic resistance prediction. Full article

Tuberculosis, caused by Mycobacterium tuberculosis, remains a global health challenge, particularly due to multidrug-resistant strains. Photodynamic therapy using porphyrin-based photosensitizers offers a promising alternative by targeting the trehalose-rich cell wall of the bacillus. Motivated by prior experimental observations that shorter linkers improve efficacy, this study probes the molecular basis of linker-length-dependent activity in trehalose–porphyrin glycoconjugates. Here, we show that shorter linker lengths are consistent with improved activity in vitro and, in an Ag85B docking model, constrain conformational flexibility, reduce solvent exposure, and promote tighter packing consistent with stronger predicted interactions. Using computational docking, we analyzed binding scores, RMSD variability, steric clashes, and protein–ligand interactions for conjugates docked into Ag85B, a key enzyme in cell wall synthesis. Shorter linkers (0–2 carbons) were found to exhibit superior binding scores, lower RMSD variability, and stronger interactions with residues such as ARG 43, including unique π–cation interactions. In contrast, longer linkers displayed increased flexibility, reduced binding specificity, and greater solvent exposure. These findings, which support our experimental observations, suggest a molecular basis for linker-dependent efficacy and provide a framework for designing next-generation porphyrin-based therapeutics for tuberculosis treatment. Full article

In the last three decades, 2-oxazolidinones have emerged as an important class of inhibitors of bacterial protein synthesis, effective in the treatment of multidrug-resistant (MDR) bacterial infections. From a public health perspective, the importance of 2-oxazolidinones is related to the treatment of tuberculosis (TB), primarily MDR-TB and extensively drug-resistant XDR-TB. Linezolid, the first oxazolidinone antibiotic approved by FDA, is still used in therapy despite common adverse events, such as myelosuppression and serotonergic toxicity, as well as the increasing percentage of linezolid-resistant bacteria (Staphylococcus aureus, enterococci and methicillin-resistant S. aureus). Tedizolid phosphate was the second commercially available oxazolidinone antibiotic approved, followed by other oxazolidinones (contezolid, radezolid, ranbezolid, sutezolid, delpazolid, cadazolid, TBI-233 and MK-7762) that are in clinical study. Contezolid is approved in China and cadazolid has entered phase III clinical trials. This comprehensive review intends to provide an overview of the compounds belonging to this class already in use in therapy and/or clinical studies and to portray the most significant and recent outcomes regarding new oxazolidinones under study. Three literature databases, i.e., PubMed/MEDLINE, Google Scholar and Scopus, were used for the literature search, particularly focusing on the last five years, and screened using different keywords. The design of new drugs belonging to this class may be of considerable interest to researchers and clinicians, contributing to the discovery of new antibiotics that retain antibacterial activity but have fewer side effects. Full article

Antimicrobial resistance (AMR) threatens global health, particularly through the rise of multidrug-resistant tuberculosis (MDR-TB) and other critical bacterial infections such as methicillin-resistant Staphylococcus aureus (MRSA). Rifamycins remain frontline antibiotics but are increasingly undermined by resistance. Here, we introduce a click-enabled platform for the synthesis of C8-functionalized rifamycins, which can be converted in a single additional step into efficacious 3′-hydroxy-5′-aminobenzoxazinorifamycins (bxRifs) and enzymatically into 25-deacetylated rifamycins (deAcRifs), providing access to novel antibacterial scaffolds that expand beyond the scope of traditional C8 modifications. Accordingly, we establish a modular strategy for late-stage analog development of the complex natural product rifamycin S, wherein azido and alkyne functionalities are installed via tailored core chemistry and converted into 1,2,3-triazoles through copper(I)-catalyzed click chemistry. Another key feature of this work is the development of systematic HPLC purification methods, enabling the isolation of analytically pure compounds despite structural complexity. The resulting analogs exhibit distinct antibacterial profiles, notably against Gram-positive bacteria including MRSA and Streptococcus mutans, informing structure–activity relationships and offering a foundation for further optimization. This approach supports the rapid diversification of rifamycin scaffolds to combat the escalating threat of AMR, while also establishing a foundation for future discovery through bioorthogonal applications. Full article

Background: To effectively manage tuberculosis (TB), it is essential to address the high incidence of the disease, as multidrug-resistant pulmonary TB (MDR-PTB) remains a significant concern to halt pre-extensive drug-resistant (pre-XDR) recrudescence. The objective of the current study was to examine and compare MDR-PTB patterns among adult PTB patients (>12 years) in Bangladesh’s urban and rural areas who had newly diagnosed and previously treated PTB. Methods: A total of 430 newly diagnosed and previously treated adult patients with PTB were randomly recruited during two study periods: the 1st period, from May 2010 to December 2010 (eight months), and the 2nd period, from January 2014 to January 2015 (thirteen months). Only the drug-resistant (DR) patients were included in the final analysis. Mycobacteriological tests, i.e., smear microscopy, culture, drug susceptibility testing (proportion method of Canetti), line-probe assay, and GeneXpert MTB/RIF were performed. Logistic regression analysis was used to determine the strength of associations between treatment outcomes and predictor variables. Results: Of the newly diagnosed patients, 156 cases were negative and drug-sensitive (DS) at diagnosis, and 274 patients exhibited various DR patterns. During the 1st period, MDR-PTB was 26% among newly diagnosed patients, while the proportion was 31% among previously treated patients in the 2nd period. The majority of MDR-PTB belonged to the age group of ≤45 years. Male patients consistently revealed a higher proportion of MDR-PTB compared to females in both the newly diagnosed and previously treated groups. Conclusion: The proportion of MDR-PTB was higher among the previously treated patients than among newly diagnosed patients. Regardless of demographic characteristics, a significant proportion of patients showed DR, particularly in previously treated groups, indicating a substantial burden of MDR-PTB. Full article

Background/Objectives: Latent tuberculosis infection (LTBI) represents a critical reservoir for subsequent development of active tuberculosis (ATB) and poses significant challenges for early diagnosis and disease prevention. Traditional immunological assays, such as interferon-gamma release assays (IGRAs), are limited in their ability to reliably distinguish LTBI from ATB. Recent advances in high-throughput omics technologies and machine learning (ML) approaches offer new opportunities for precise, biomarker-based differential diagnostics. Methods: Transcriptomic and proteomic profiling of host immune responses has revealed reproducible gene and protein signatures associated with LTBI and ATB. The integration of ML techniques—including feature selection, dimensionality reduction, multimodal learning, and explainable AI—facilitates the construction of robust diagnostic models. Single-modality signatures, derived from RNA-seq, microarrays, or proteomic assays, are complemented by multimodal approaches that incorporate soluble mediators, immunological readouts, and imaging-derived features. Deep learning frameworks, such as convolutional neural networks and transformer-based architectures, enhance the extraction of complex molecular and structural patterns from high-dimensional datasets. Results: ML-driven analyses of transcriptomic and proteomic data consistently outperform conventional immunological tests in terms of sensitivity, specificity, and clinical applicability. Multimodal integration further improves diagnostic accuracy and robustness. These advances support the translational development of concise, quantitative reverse transcription PCR (qRT-PCR)-based biomarker panels suitable for routine clinical application, enabling early and reliable differentiation between LTBI and ATB. Overall, the combination of high-throughput omics and AI-based analytical frameworks provides a promising pathway for enhancing global tuberculosis diagnostics. Conclusions: This review provides a structured and critical synthesis of transcriptomic and proteomic biomarker research for LTBI and ATB discrimination, with a particular emphasis on machine learning–based analytical frameworks. Unlike previous narrative reviews, we systematically compare data-generating platforms, modelling strategies, validation approaches, and sources of heterogeneity across studies. We further identify key translational barriers, including cohort homogeneity, platform dependency, and limited external validation, and propose directions for future research aimed at improving clinical applicability. Full article

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a global health burden, particularly due to multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains. Rifampicin, a frontline anti-TB drug that inhibits RNA polymerase, has been central to therapy, but rpoB mutations compromise its efficacy. This highlights the need for Rifampicin analogues that target alternative enzymes to sustain therapeutic effectiveness. In this study, a structure-based computational approach was employed to screen Rifampicin analogues against enoylacyl carrier protein reductase (InhA), a validated enzyme in the biosynthesis of mycolic acids. A library of 399 analogues was retrieved from SwissSimilarity and evaluated using ADMET analysis, with the best candidates showing favourable pharmacokinetic profiles and compliance with Lipinski’s Rule of Five. Molecular docking identified ZINC000013629834 (−10.90 kcal/mol) and ZINC000253411694 (−10.36 kcal/mol) as superior to Rifampicin (−9.05 kcal/mol), with ILE21, SER20, and THR196 consistently stabilizing interactions. Molecular dynamics simulations confirmed the stability of the complexes, with RMSD values of 0.167 nm, 0.175 nm, and 0.297 nm for ZINC000013629834, ZINC000253411694, and Rifampicin, respectively. MM/PBSA analysis showed comparable binding free energies. These findings suggest that optimized Rifampicin analogues targeting InhA may overcome rpoB-associated resistance and serve as promising leads for next-generation anti-TB drug development. Full article