Strategies to Combat Multi-Drug Resistance in Tuberculosis

Coumarin-Triazole-Thiazole hybrids: A new avenue in Antitubercular agents

The present work reports the design and synthesis of a series of 2-(4-(((2-oxo-2H-chromen-4-yl)oxy)methyl)-1H-1,2,3-triazol-1-yl)-N-(thiazol-2-yl)acetamide derivatives (4a-4k), which were investigated for their potential against tubercular activities. The well-known click cycloaddition reaction of azido derivatives (3a-3k) and 4-(prop-2-yn-1-yloxy)-2H-chromen-2-one (2) in the presence of catalytic amount of CuSO4 in H2O and DMF was employed. Notably, compounds 4c, 4d, and 4g showed the most promising results with MIC values against tuberculosis are 7.81 μg/mL, 2.61 μg/mL, and 7.81 μg/mL, respectively. Compounds (4a-4k) exhibited moderate to excellent antioxidant activities and low cytotoxicities. In addition, molecular docking studies were performed to investigate the binding interaction modes of the compounds (4a-4k) with various proteins and ligand sites.

Towards a unified approach in managing resistance to vaccines, drugs, and pesticides

Everywhere, pests and pathogens evolve resistance to our control efforts, impairing human health and welfare. Developing sustainable solutions to this problem requires working with evolved immune and ecological systems, rather than against these evolutionary forces. We advocate a transdisciplinary approach to resistance based on an evolutionary foundation informed by the concepts of integrated pest management and One Health. Diverse, multimodal management approaches create a more challenging environment for the evolution of resistance. Given our permanent evolutionary and ecological relationships with pests and pathogens, responses to most biological threats to health and agriculture should seek sustainable harm reduction rather than eradication.

Diverse impacts of different rpoB mutations on the anti-tuberculosis efficacy of capreomycin

BACKGROUND

Since the discovery of streptomycin in the 1940s, more than a dozen drugs have been continuously introduced into tuberculosis (TB) therapy. However, limited attention has been paid to the collateral effects of drug resistance evolution in Mycobacterium tuberculosis (Mtb). Recently, we observed a clear discordance between the capreomycin (CAP) susceptibility of rifampicin-resistant (RR) Mtb clinical isolates and the adverse outcomes associated with CAP treatment, indicating potential collateral effects between rpoB mutations and CAP. To explore this relationship, we integrated clinical isolate data, experimental evolution data, phenotypic data, sequencing data, and genome-wide association studies (GWAS).

METHODS

We analysed the correlations between CAP resistance and rpoB mutations at various loci based on phenotypic drug susceptibility testing (pDST) profiles and rpoB sequencing data from 565 RR Mtb isolates collected in southwestern China. To validate the clinical observations, we screened RR mutants of Mtb H37Rv and conducted rpoB sequencing to characterise the mutation sites. Additionally, we constructed various rpoB mutants in Mycobacterium smegmatis (Ms). We then examined the impact of these mutations on the efficacy of CAP through minimum inhibitory concentration (MIC) tests and time-kill assays in both Mtb and Ms rpoB mutants. Furthermore, we investigated the influence of three major rpoB mutations on the frequency of occurrence of rrs A1401G-associated with CAP resistance-using a GWAS of 607 Mtb genomes from a global dataset.

FINDINGS

By analysing 565 clinical isolates from southwestern China, we found that the CAP resistance in isolates with a single mutation at rpoB site 445 was significantly lower than in those with a single mutation at other sites (P < 0.05, Pearson chi-square test and Fisher exact test; odds ratio = 0.272). In contrast, the opposite trend was observed in isolates with a single mutation at rpoB site 435 (P < 0.001, Pearson chi-square test and Fisher exact test; odds ratio = 3.067). Subsequently, using laboratory-evolved RR mutants, we demonstrated that mutations at rpoB site 445 or site 441 enhanced the bactericidal effect of CAP. However, the opposite result was observed in mutants with mutations at rpoB site 435. Furthermore, we found that the occurrence frequency of the rrs A1401G mutation was significantly lower in clinical isolates with rpoB mutations at site 445, but significantly higher in those with mutations at site 435.

INTERPRETATION

Although rpoB mutations in Mtb did not affect the MIC of CAP, they influenced its bactericidal effect, highlighting the need for time-kill assays when investigating collateral effects. Different rpoB mutations may exert diverse impacts on the bactericidal effect of CAP-or CAP tolerance-underscoring the complexity of collateral effects and supporting the use of targeted sequencing in the molecular diagnosis of RR Mtb. As RNA polymerase plays a central role in bacterial RNA transcription, it regulates most metabolic processes in Mtb. Thus, different rpoB mutations may elicit distinct gene expression profiles upon CAP treatment, a hypothesis warranting further investigation. Additional clinical studies are needed to verify whether the adverse outcomes of CAP treatment are associated with infections caused by strains harbouring rpoB mutations at site 435. If so, such outcomes could be mitigated through rational drug regimens guided by precise molecular diagnosis. This study provides insights into the collateral effects of drug resistance mutations and advances the case for precision medicine in treating infections caused by drug-resistant bacteria.

FUNDING

Funding for this study was provided by the National Key Research and Development Program of China (Grant no. 2021YFA1300901).

Mitophagy-mtROS axis contributes to anti-tuberculosis-induced liver injury through activation of the cGAS-STING pathway in rat hepatocytes

Tuberculosis (TB) remains a major worldwide healthcare issue, with anti-TB drugs playing a pivotal role in its treatment. However, the emergence of anti-TB drug-induced liver injury (ATB-DILI) poses a considerable challenge, undermining treatment efficacy and patient survival. This study investigates the underlying mechanisms of ATB-DILI, focusing on reactive oxygen species (ROS), mitophagy, lysosomal function, and the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) signaling pathway. A rat hepatocyte model treated with standard anti-TB drugs was established to assess liver inflammation, oxidative stress biomarkers, mitochondrial function, and mitophagy processes. The results indicate that anti-TB drug administration induced significant inflammatory injury, characterized by elevated IL-6 and reduced IL-4 and IL-10 levels. ROS overproduction predominantly originates in the mitochondrial level, consequently resulting in oxidative stress and impaired mitochondrial function. A noticeable decline in both the oxygen consumption rate and ATP production is indicative of this phenomenon. Although mitophagy was activated, impaired lysosomal function hindered mitophagic flux, leading to the buildup of damaged mitochondria and ROS. Pharmacological intervention with mitoTEMPO alleviated mitochondrial dysfunction, while clioquinol restored lysosomal function and improved mitophagy. Additionally, the cGAS-STING signaling pathway was found to regulate inflammation in ATB-DILI, with both mitoTEMPO and clioquinol alleviating its effects. These findings elucidate the crucial impact of lysosome-mediated mitophagy dysfunction and mitochondrial ROS in ATB-DILI, highlighting potential therapeutic targets to enhance liver protection during anti-TB treatment.

Targeting type II NADH dehydrogenase in tuberculosis treatment: A review

Tuberculosis (TB), a critical global health issue, continues to impose significant harm on human populations worldwide, and the increasing prevalence of drug-resistant TB strains has exacerbated the challenges in effective treatment, underscoring an urgent need for the development of new therapeutic agents with innovative mechanisms of action. The introduction of bedaquiline highlights targeting Mycobacterium tuberculosis (Mtb) energy metabolism as a novel anti-TB strategy. Among the various targets within Mtb's metabolic pathways, type II NADH dehydrogenase (NDH-2) is of particular significance due to its critical function in bacterial respiration and its absence from human cells, rendering it an appealing candidate for selective inhibition. Recent advances have led to the identification of numerous NDH-2 inhibitors, some of which exhibit potent antibacterial activity at nanomolar concentrations, demonstrating their potential as lead compounds for future drug development. This review explores the biochemical function and molecular structure of NDH-2, underscoring its potential as a target for anti-TB therapies. It also discusses the progress made in discovering and optimizing NDH-2 inhibitors, offering insights into their mechanisms of action, efficacy, and pharmacological properties, with the aim of providing an overview that could inform and guide future research efforts towards developing more effective treatments against TB.

Vγ9Vδ2 T cells expanded with vitamin C combined with HMBPP in vitro inhibit intracellular Mycobacterium tuberculosis growth

Background

Mycobacterium tuberculosis (Mtb) presents a significant global health threat, and the existing treatments have notable limitations. Vγ9Vδ2 T cells activated by HMBPP can inhibit the growth of intracellular Mtb. Additionally, vitamin C (VC) promotes the differentiation and proliferation of related T cells. However, it remains uncertain whether VC can enhance the expansion of Vγ9Vδ2 T cells within PBMCs activated by HMBPP and rIL-2, and the underlying mechanism of the inhibitory effect of the expanded T cells on intracellular Mtb has not been elucidated.

Methods

Venous blood was collected from healthy individuals, and PBMCs were subsequently isolated. In vitro, Vγ9Vδ2 T cells were selectively expanded with HMBPP, rIL-2, and VC. Flow cytometry was utilized to analyze the purities and phenotypes of Vγ9Vδ2 T cells, while cell counts were performed to determine the total number of viable cells. Magnetic bead sorting was employed to purify Vγ9Vδ2 T cells. Mtb strains were cultured, and macrophage infection models derived from THP1 cells were established. Co-culture experiments were conducted with Mtb-infected macrophages and Vγ9Vδ2 T cells, and the number of intracellular bacteria was quantified through CFU counting. The levels of cytokines were measured using the CBA method and flow cytometry. Statistical analysis was carried out using GraphPad Prism and SPSS software.

Results

VC (70 μM) significantly enhances the expansion of Vγ9Vδ2 T cells within PBMCs during primary HMBPP activation in the presence of rIL-2, with higher induction rates and total cell proliferation. By day 14 of induction, Vγ9Vδ2 T cells expanded with HMBPP, VC, and rIL-2 exhibited the central memory (10-20%) and the effector memory phenotypes (75-90%). Furthermore, these expanded T cells effectively inhibited the growth of intracellular virulent Mtb strain (H37Rv) in a cell-contact-dependent manner. The inhibitory effect was associated with an up-regulated production of TNF-α and IFN-γ, and a down-regulated expression of IL-10 and IL-17A during Mtb infection.

Conclusion

This study demonstrates that VC enhances the proliferative expansion of Vγ9Vδ2 T cells in PBMCs primarily stimulated with HMBPP and rIL-2. The expanded Vγ9Vδ2 T cells are capable of effectively inhibiting the growth of virulent H37Rv strain, likely through the secretion of TNF-α and IFN-γ. These findings provide a novel direction for tuberculosis treatment research.

Geospatial mapping of drug-resistant tuberculosis prevalence in Africa at national and sub-national levels

OBJECTIVES

To map subnational and local prevalence of drug-resistant tuberculosis (DR-TB) across Africa.

METHODS

We assembled a geolocated dataset from 173 sources across 31 African countries, comprising drug susceptibility test results and covariate data from publicly available databases. We used Bayesian model-based geostatistical framework with multivariate Bayesian logistic regression model to estimate DR-TB prevalence at lower administrative levels.

RESULTS

We estimated 148,239 DR-TB cases (95% uncertainty interval: 17,499-313,683) in Africa, showing significant variation by country. Eswatini and South Africa had highest case numbers, while Algeria and Egypt had the lowest. The highest DR-TB prevalence was estimated in Eswatini (53.26; 95% uncertainty interval 13.13-66.12), Morocco, Tunisia, and South Africa, while the lowest prevalence was found in Gabon, the Republic of Congo, Sierra Leone, and Mali. Marked subnational variation in DR-TB prevalence was noted, where 91 subnational areas across 12 countries had prevalence rates higher than their respective national averages. Factors such as mean temperature (β = 2.01; 95% CrI: 1.21, 3.42), population density (β = 0.41; 95% CrI: 0.19, 0.95), and fine particulate matter (β = 0.66; 95% CrI: 0.20, 0.80) were positively associated with DR-TB prevalence.

CONCLUSION

The study highlights substantial national and subnational variability in DR-TB prevalence across Africa, aiding policymakers in designing localized TB control interventions.

Deciphering insights into the binding mechanism and plasticity of Telacebec with M. tuberculosis cytochrome bcc-aa3 supercomplex through an unbiased molecular dynamics simulation, free-energy analysis, and DFT study

The cytochrome bcc-aa3 supercomplex, a key component in the electron transport chain pathway involved in bacterial energy production and homeostasis, is a clinically validated target for tuberculosis (TB), leading to Telacebec (Q203). Telacebec is a potent candidate drug under Phase II clinical development for the treatment of drug-sensitive and drug-resistant TB. Recently, the cryo-electron microscopy structure of this supercomplex from Mycobacterium tuberculosis (Mtb) complexed with Q203 was resolved at 6.9 Å resolution (PDB ID: 7E1W). To understand the binding site (QP site) flexibility and Q203's stability at the QP site of the Mtb cytochrome bcc complex, we conducted molecular dynamics (MD) simulation and free energy analysis on this complex in an explicit hydrated lipid bilayer environment for 500 ns. Through this study, the persistence of a range of direct and indirect interactions was observed over the course of the simulation. The significance of the interactions with His375, Tyr161, Ala178, Ala179, Ile183, His355, Leu356, and Thr313 is underlined. Electrostatic energy was the primary source of the net binding free energy, regardless of the important interacting residues. The overall binding free energy for Q203 was -112.84 ± 7.73 kcal/mol, of which the electrostatic and lipophilic energy contributions were -116.31 ± 1.14 and -21.32 ± 2.35 kcal/mol, respectively. Meanwhile, DFT calculations were utilized to elucidate Q203's molecular properties. Overall, this study deciphers key insights into the cytochrome bcc-aa3 supercomplex with Q203 on the ground of molecular mechanics and quantum mechanics that may facilitate structure-based drug design and optimization for the discovery of the next-generation antitubercular drug(s).

3D-QSAR and ADMET studies of morpholino-pyrimidine inhibitors of DprE1 from Mycobacterium tuberculosis

DprE1 is involved in the synthesis of Mycobacterium tuberculosis cell wall and is a potent drug target for Tuberculosis (TB) treatment. The structure and dynamics of the loops L-I and L-II flanking the inhibitor binding site was studied using molecular dynamics (MD) simulation and MMPBSA in Amber v18. Docking and three-dimensional quantitative structure-activity relationship (3D-QSAR) of 55 Morpholino-pyrimidine (MP) inhibitors was carried out using Autodock v1.2.0 and Forge v10. ADMET analysis was done using SwissADME and pkCSM. All MP inhibitors docked in the DprE1 binding pocket, making contacts with L-II residues. MD studies showed that L-I and L-II unfold in the absence of the inhibitor but fold stably structure with reduced protein motions in the presence of MP-38, the highest affinity inhibitor. This was confirmed by k-means clustering and secondary structure analysis. L-II residues, L317, F320 and R325 contributed most towards the MMPBSA binding free energy of MP-38. A robust field-based 3D-QSAR model showed values of r2train = 0.982, r2test = 0.702 and q2 = 0.516. The MP inhibitor field points were broadly divided into negative electrostatics near the A, B rings and hydrophobic electrostatics near the D, E rings. Addition of negative groups at methanone position and ring B as well as addition of hydrophobic and bulky groups at ring E will improve activity. Highly active compounds 47, 49 and 50 of MP series exhibited highly favourable drug-like properties. SAR and ADMET insights attained from this model will help in the development of active DprE1 inhibitors in future.

Outdoor particulate matter and risk of drug resistance for workers and farmers with pulmonary tuberculosis: a population-based time-series study in Suzhou, China

OBJECTIVES

The detrimental effects of particulate matter (PM) on human health have been widely corroborated. We aimed to examine the association between outdoor PM and the drug resistance risk among workers and farmers with pulmonary tuberculosis (PTB).

DESIGN

We performed a population-based time-series study using routinely collected meteorological and TB surveillance data.

SETTING

We selected Suzhou City, China, as the study area. Data on patients with PTB and meteorological factors were extracted from the National Tuberculosis Online Registration System and the China Meteorological Data Sharing Center.

PARTICIPANTS

This study included 7868 patients with PTB diagnosed from January 2017 to December 2021 in Suzhou.

METHODS

The generalised additive model was used to estimate the effects of outdoor PM on the drug resistance risk of TB among workers and farmers who typically work outdoors. Moreover, subgroup analyses were carried out to evaluate the associations in different populations and seasons.

RESULTS

Although there was no significant association between PM with an aerodynamic diameter≤10 µm (PM10) and drug-resistant risk in the overall analysis, subgroup analysis revealed a significant positive association in the winter season. Similarly, PM with an aerodynamic diameter≤2.5 µm (PM2.5) was significantly associated with drug resistance risk among males with a lag of 0-3 days, people ≤60 years with a lag of 0-7 days and in the winter season with a lag of 0-7 days, 0-15 days, 0-90 days or 0-180 days.

CONCLUSIONS

Outdoor PM10 and PM2.5 were positively related to the drug resistance risk of workers and farmers with PTB. Reducing ambient PM pollution might reduce the burden of TB. Further research is required to verify the association through in vitro experiments and extensive cohort studies.

Innovative Strategies for Combating Multidrug-Resistant Tuberculosis: Advances in Drug Delivery Systems and Treatment

Multidrug-resistant tuberculosis (MDR-TB) is a significant public health challenge globally, exacerbated by the limited efficacy of existing therapeutic approaches, prolonged treatment duration, and severe side effects. As drug resistance continues to emerge, innovative drug delivery systems and treatment strategies are critical to combating this crisis. This review highlights the molecular mechanisms underlying resistance to drugs in Mycobacterium tuberculosis, such as genetic mutation, efflux pump activity, and biofilm formation, contributing to the persistence and difficulty in eradicating MDR-TB. Current treatment options, including second-line drugs, offer limited effectiveness, prompting the need for innovation of advanced therapies and drug delivery systems. The progression in drug discovery has resulted in the approval of innovative therapeutics, including bedaquiline and delamanid, amongst other promising candidates under investigation. However, overcoming the limitations of traditional drug delivery remains a significant challenge. Nanotechnology has emerged as a promising solution, with nanoparticle-based drug delivery systems offering improved bioavailability and targeted and controlled release delivery, particularly for pulmonary targeting and intracellular delivery to macrophages. Furthermore, the development of inhalable formulations and the potential of nanomedicines to bypass drug resistance mechanisms presents a novel approach to enhancing drug efficacy. Moreover, adjunctive therapies, including immune modulation and host-directed therapies, are being explored to improve treatment outcomes. Immunotherapies, such as cytokine modulation and novel TB vaccines, offer complementary strategies to the use of antibiotics in combating MDR-TB. Personalized medicine approaches, leveraging genomic profiling of both the pathogen and the host, offer promise in optimizing treatment regimens and minimizing drug resistance. This review underscores the importance of multidisciplinary approaches, combining drug discovery, advanced delivery system development, and immune modulation to address the complexities of treating MDR-TB. Continued innovation, global collaboration, and improved diagnostics are essential to developing practical, accessible, and affordable treatments for MDR-TB.

A Streamlined Point-of-Care CRISPR Test for Tuberculosis Detection Directly from Sputum

Mycobacterium tuberculosis (Mtb) is a major threat to global health and is responsible for over one million deaths each year. To stem the tide of cases and maximize opportunities for early interventions, there is an urgent need for affordable and simple means of tuberculosis diagnosis in under-resourced areas. We sought to develop a CRISPR-based isothermal assay coupled with a compatible, straightforward sample processing technique for point-of-care use. Here, we combine Recombinase Polymerase Amplification (RPA) with Cas13a and Cas12a, to create two parallelised one-pot assays that detect two conserved elements of Mtb (IS6110 and IS1081) and an internal control targeting human DNA. These assays were shown to be compatible with lateral flow and can be readily lyophilized. Our finalized assay exhibited sensitivity over a wide range of bacterial loads (105 to 102 CFU/mL) in sputum. The limit of detection (LoD) of the assay was determined to be 69.0 (51.0 - 86.9) CFU/mL for Mtb strain H37Rv spiked in sputum and 80.5 (59.4 - 101.6) CFU/mL for M. bovis BCG. Our assay showed no cross reactivity against a wide range of bacterial/fungal isolates. Clinical tests on 13 blinded sputum samples revealed 100% (6/6) sensitivity and 100% (7/7) specificity compared to culture. Our assay exhibited comparable sensitivity in clinical samples to the microbiological gold standard, TB culture, and to the nucleic acid state-of-the-art, GeneXpert MTB/RIF Ultra. This technology streamlines TB diagnosis from sample extraction to assay readout in a rapid and robust format, making it the first test to combine amplification and detection while being compatible with both lateral flow and lyophilization.

Host-Mediated Antimicrobial Effects and NLRP3 Inflammasome Modulation by Caulerpin and Its Derivatives in Macrophage Models of Mycobacterial Infections

Caulerpin, a bis-indole alkaloid isolated from Caulerpa racemosa, has several documented pharmacological activities, including antineoplastic and antiviral properties. This study aimed to evaluate the anti-inflammatory and anti-tubercular potentials of caulerpin and its analogues in RAW 264.7 macrophages infected with Mycobacterium spp. Additionally, we evaluated cytokine production and NLRP3 expression in this infection model. Toxicity tests were performed using Vero E6 and HepG2 cell lines and Artemia salina. Pre-incubation of RAW 264.7 cells with caulerpin and its analogues decreased internalized M. smegmatis and M. tuberculosis H37Ra. Furthermore, treatment of M. smegmatis-infected macrophages with caulerpin and its analogues reduced bacterial loads. Caulerpin reduced the CFU count of internalized bacilli in the M. tuberculosis H37Ra infection model. In addition, caulerpin and its diethyl derivative were notably found to modulate IL-1β and TNF-α production in the M. smegmatis infection model after quantifying pro-inflammatory cytokines and NLRP3. Caulerpin and its derivates did not affect the viability of Vero E6 and HepG2 cell lines or nauplii survival in toxicity studies. These findings demonstrate that caulerpin and its analogues exhibit anti-inflammatory activity against Mycobacterium spp. infection in RAW 264.7 macrophages and show promising potential for further efficacy and safety evaluation.

Recent advances in nanomaterials for the detection of mycobacterium tuberculosis (Review)

The world's leading infectious disease killer tuberculosis (TB) has >10 million new cases and ~1.5 million mortalities yearly. Effective TB control and management depends on accurate and timely diagnosis to improve treatment, curb transmission and reduce the burden on the medical system. Current clinical diagnostic methods for tuberculosis face the shortcomings of limited accuracy and sensitivity, time consumption and high cost of equipment and reagents. Nanomaterials have markedly enhanced the sensitivity, specificity and speed of TB detection in recent years, owing to their distinctive physical and chemical features. They offer several biomolecular binding sites, enabling the simultaneous identification of multiple TB biomarkers. Biosensors utilizing nanomaterials are often compact, user‑friendly and well‑suited for detecting TB on location and in settings with limited resources. The present review aimed to review the advances that have occurred during the last five years in the application of nanomaterials for TB diagnostics, focusing on their detection capabilities, structures, working principles and the significance of key nanomaterials. The current review addressed the limitations and challenges of nanomaterials‑based TB diagnostics, along with potential solutions.

Trends in tuberculosis and inequality-adjusted Human Development Index in Brazil, 2018-2022

Tuberculosis (TB) remains a significant global health concern, causing 1.5 million deaths annually. We conducted an ecological analysis to examine TB prevalence in Brazil from 2018 to 2022, focusing on its relationship with the Human Development Index (HDI) and its inequality-adjusted version HDI (IHDI). We determined significant correlation between HDI and TB prevalence for the period of 2018-2021 (P = 0.044 in 2018, P = 0.041 in 2019, P = 0.044 in 2020, and P = 0.043 in 2021). However, an unexpected rise in TB cases in 2022, despite an increase in HDI, disrupted this trend (P = 0.12), indicating additional influencing factors. The IHDI showed correlation with TB prevalence, underscoring the importance of addressing socio-economic inequalities. These findings suggest the need for targeted interventions, particularly for vulnerable populations.

Advancements and challenges in tuberculosis drug discovery: A comprehensive overview

Tuberculosis continues to pose a health challenge causing the loss of millions of lives despite the existence of multiple drugs, for treatment. The emergence of drug-resistant strains has made the situation more complex making it increasingly difficult to fight against this disease. This review outlines the challenges associated with TB drug discovery, the nature of Mycobacterium tuberculosis shedding light on the mechanisms that lead to treatment failure and antibiotic resistance. We explore promising drug targets, encompassing inhibition of mycolyarabinogalactan peptidoglycan (MAGP) assembly, mycolic acid biosynthesis, DNA replication, transcription, translation, protein synthesis, and bioenergetics/metabolism pathways. A comprehensive overview of the global pipeline of anti-tuberculosis drugs at various stages of clinical trials, the diverse strategies being pursued to tackle this complex disease. By gaining an understanding of the mechanisms that contribute to resistance development and identifying suitable targets, we can pave the way for more effective treatments and contribute to global efforts to combat drug-resistant tuberculosis.

Furamidine-induced autophagy exerts an anti-mycobacterial effect in a SIRT1-pAMPK-FOXO3a-dependent manner by elevation of intracellular Ca2+ level expression

Mycobacterium tuberculosis (M. tb), the etiological agent of tuberculosis (TB), continues to be a major contributor to global mortality rates. To effectively combat this pandemic, TB control has to be enhanced in several areas, including point-of-care diagnostics, shorter and safer drug regimens, and preventative vaccination. The latest findings have highlighted autophagy as a host-defense mechanism that eradicates many invading bacteria, including M. tb. Thus, novel approaches like the stimulation of autophagy using various pharmaceutical drugs can be undertaken to deal with this noxious pathogen. The present study has been formulated to evaluate the anti-mycobacterial potential of Furamidine, a DNA minor groove binder (MGB). Initially, a non-cytotoxic concentration of Furamidine (10 µM) was used to assess its impact on the intracellular persistence of mycobacteria in differentiated THP-1 (dTHP-1) cells. Furamidine treatment compromised intracellular mycobacterial growth compared to control cells. Autophagy, a well-known host-defensive strategy, was investigated as a possible contributor to revealing the mechanism of action. Multiparametric approaches such as LC3-I to II conversion, protein level expression of different autophagic markers, and MDC staining were employed to study autophagic response that conclusively suggested the autophagy induction potential of Furamidine in dTHP-1 cells. Further, elevated LC3-II expression and increased autophagic vacuole accumulation under Baf-A1 treatment demonstrated the positive regulation of autophagic flux upon Furamidine treatment. Mechanistic investigations showed increased intracellular calcium (Ca2+) level expression, SIRT1, pAMPK, and FOXO3a activation upon its treatment. Inhibition of Ca2+ level expression suppressed Ca2+-mediated-FOXO3a level in Furamidine-treated cells. Furthermore, administering various inhibitors hampered the Furamidine-induced autophagy that impacted intracellular mycobacteria clearance. These results conclude that Furamidine triggered the Ca2+/pAMPK/SIRT1/FOXO3a pathway, causing less mycobacterial load in dTHP-1 cells.

Unveiling the Antimycobacterial Potential of Novel 4-Alkoxyquinolines: Insights into Selectivity, Mechanism of Action, and In Vivo Exposure

This work presents a comprehensive investigation into the design, synthesis, and evaluation of a novel series of 4-alkoxyquinolines as potential antimycobacterial agents. The design approach, which combined molecular simplification and chain extension, resulted in compounds with potent and selective activity against both drug-susceptible and multidrug-resistant Mycobacterium tuberculosis strains. The lead molecule, targeting the cytochrome bc1 complex, exhibited favorable kinetic solubility and remarkable chemical stability under acidic conditions. Despite in vitro ADME evaluations showing low permeability and high metabolism in rat microsomes, the lead compound exhibited bacteriostatic activity in a murine macrophage model of TB infection and demonstrated promising in vivo exposure following gavage in mice, with an AUC0-t of 127.5 ± 5.7 μM h. To the best of our knowledge, for the first time, a simplified structure from 2-(quinolin-4-yloxy)acetamides has shown such potential. These findings suggest a new avenue for exploring this chemical class as a source of antituberculosis drug candidates.

Multi-omics Analysis of Klebsiella pneumoniae Revealed Opposing Effects of Rutin and Luteolin on Strain Growth

The emergence of pathogenic bacteria resistant to conventional antibiotics is becoming increasingly challenging. Plant-derived flavonoids are potential alternatives to antibiotics, owing to their antimicrobial properties. However, the molecular mechanisms through which they inhibit the growth of pathogenic microorganisms remain unclear. Therefore, Klebsiella pneumoniae ATCC700603 was separately incubated in two flavonoids to elucidate their inhibitory mechanism. Metabolomic and transcriptomic analyses were performed after 4-h incubation. In total, 5483 genes and 882 metabolites were identified. Compared to the untreated control, rutin and luteolin activated 507 and 374 differentially expressed genes (DEGs), respectively. However, the number of differential abundant metabolites (DAMs) remained the same. The top 10 correlated DEGs and DAMs were identified within each comparative group after a correlation analysis. Rutin induced the accumulation of unique metabolites and suppressed gene expression whereas luteolin did not. Our results explain the disparate effects of these two flavonoids and demonstrate the inhibitory mechanism of rutin on strain growth.

Cloning and Functional Analysis of Skin Host Defense Peptides from Yakushima Tago's Brown Frog (Rana tagoi yakushimensis) and Development of Serum Endotoxin Detection System

Background/Objective: Amphibian skin is a valuable source of host defense peptides (HDPs). This study aimed to identify HDPs with novel amino acid sequences from the skin of Rana tagoi yakushimensis and analyze their functions. Methods: cDNAs encoding HDP precursors were cloned and sequenced using RT-PCR and 3'-RACE. The novel HDPs were synthesized to evaluate their antimicrobial activity, antioxidant activity, and cytotoxicity. Antimicrobial activity was evaluated by way of broth microdilution and endotoxin- and β-glucan-binding capacity using an enzyme-linked endotoxin binding assay (ELEBA) and a modified ELEBA, respectively. Results: Nine cDNAs encoding precursors for various HDP families, including temporin, ranatuerin-2, brevinin-1, amurin-9, and a novel yakushimin peptide, were identified. Brevinin-1TYa exhibited antibacterial activity against Staphylococcus aureus, and brevinin-1TYa and amurin-9TYa induced morphological changes in Escherichia coli and S. aureus. Yakushimin-TYa, amurin-9TYa, and brevinin-1TYa showed concentration-dependent antibacterial effects against the plant pathogens Xanthomonas oryzae pv. oryzae and Clavibacter michiganensis subsp. michiganensis. Amurin-9TYa demonstrated strong binding affinity to lipopolysaccharide, lipoteichoic acid, and β-glucan, exhibited antioxidant activity, and lacked cytotoxicity, making it a promising therapeutic candidate. Moreover, brevinin-1TYa showed strong cytotoxicity, whereas yakushimin-TYa exhibited weak cytotoxicity. Conclusions: These findings highlight the potential of these peptides, particularly amurin-9TYa, for future applications as antimicrobial and therapeutic agents.

Characterizing the immune response to Mycobacterium tuberculosis: a comprehensive narrative review and implications in disease relapse

Introduction

Tuberculosis remains the leading cause of death from infectious diseases among adults worldwide. To date, an overarching review of the immune response to Mtb in humans has not been fully elucidated, with innate immunity remaining poorly understood due to historic focus on adaptive immunity. Specifically, there is a major gap concerning the contribution of the immune system to overall bacterial clearance, particularly residual bacteria. This review aims to describe the time course of interactions between the host immune system and Mtb, from the start of the infection to the development of the adaptive response. Concordantly, we aim to crystallize the pathogenic effects and immunoevasive mechanisms of Mtb. The translational value of animal data is also discussed.

Methods

The literature search was conducted in the PubMed, ScienceDirect, and Google Scholar databases, which included reported research from 1990 until 2024. A total of 190 publications were selected and screened, of which 108 were used for abstraction and 86 were used for data extraction. Graphical summaries were created using the narrative information (i.e., recruitment, recognition, and response) to generate clear visual representations of the immune response at the cellular and molecular levels.

Results

The key cellular players included airway epithelial cells, alveolar epithelial cells, neutrophils, natural killer cells, macrophages, dendritic cells, T cells, and granulomatous lesions; the prominent molecular players included IFN-γ, TNF-α, and IL-10. The paper also sheds light on the immune response to residual bacteria and applications of the data.

Discussion

We provide a comprehensive characterization of the key immune players that are implicated in pulmonary tuberculosis, in line with the organs or compartments in which mycobacteria reside, offering a broad vignette of the immune response to Mtb and how it responds to residual bacteria. Ultimately, the data presented could provide immunological insights to help establish optimized criteria for identifying efficacious treatment regimens and durations for relapse prevention in the modeling and simulation space and wider fields.

The homodimerization domain of the Stl repressor is crucial for efficient inhibition of mycobacterial dUTPase

The dUTPase is a key DNA repair enzyme in Mycobacterium tuberculosis, and it may serve as a novel promising anti-tuberculosis target. Stl repressor from Staphylococcus aureus was shown to bind to and inhibit dUTPases from various sources, and its expression in mycobacterial cells interfered with cell growth. To fine-tune and optimize Stl-induced inhibition of mycobacterial dUTPase, we aimed to decipher the molecular details of this interaction. Structural background of the complex between dUTPase and a truncated Stl lacking the repressor C-terminal homodimerization domain has been described, however, the effects of this truncation of Stl on enzyme binding and inhibition are still not known. Using several independent biophysical, structural and enzyme kinetic methods, here we show that lack of the repressor homodimerization domain strongly perturbs both enzyme binding and inhibition. We also investigated the role of a mycobacteria-specific loop in the Stl-interaction. Our results show that removal of this loop leads to a ten-fold increase in the apparent inhibition constant of Stl. We present a high-resolution three-dimensional structure of mycobacterial dUTPase lacking the genus-specific loop for structural insight. Our present data suggest that potent inhibition of mycobacterial dUTPase by Stl requires the wild-type full-length protein context.

Cell-autonomous targeting of arabinogalactan by host immune factors inhibits mycobacterial growth

Deeper understanding of the crosstalk between host cells and Mycobacterium tuberculosis (Mtb) provides crucial guidelines for the rational design of novel intervention strategies against tuberculosis (TB). Mycobacteria possess a unique complex cell wall with arabinogalactan (AG) as a critical component. AG has been identified as a virulence factor of Mtb which is recognized by host galectin-9. Here, we demonstrate that galectin-9 directly inhibited mycobacterial growth through AG-binding property of carbohydrate-recognition domain 2. Furthermore, IgG antibodies with AG specificity were detected in the serum of TB patients. Based on the interaction between galectin-9 and AG, we developed a monoclonal antibody (mAb) screening assay and identified AG-specific mAbs which profoundly inhibit Mtb growth. Mechanistically, proteomic profiling and morphological characterizations revealed that AG-specific mAbs regulate AG biosynthesis, thereby inducing cell wall swelling. Thus, direct AG-binding by galectin-9 or antibodies contributes to protection against TB. Our findings pave the way for the rational design of novel immunotherapeutic strategies for TB control.

Peripheral blood MR1 tetramer-positive mucosal-associated invariant T-cell function is modulated by mammalian target of rapamycin complex 1 in patients with active tuberculosis

Tuberculosis (TB) is still an urgent global public health problem. Notably, mucosal-associated invariant T (MAIT) cells play an important role in early anti-TB immune response. Targeted control of them may be an effective method to improve vaccine efficacy and TB treatment. However, the biology and signal regulation mechanisms of MAIT cells in TB patients are still poorly understood. Previous studies have been limited by the lack of reagents to specifically identify MAIT cells. In addition, the use of alternative markers may subsume non-MAIT cell into MAIT cell populations. In this study, the human MR1 tetramer which can specifically identify MAIT cells was used to further explore the effect and mechanism of MAIT cells in anti-TB immune response. Our results showed that the tetramer+ MAIT cells in peripheral blood of TB patients were mainly CD8+ or CD4-CD8- cells, and very few were CD4+ cells. After BCG infecting autologous antigen-presenting cells, MAIT cells in patients produced significantly higher levels of cytokines, lysis and proliferation compared with healthy controls. After suppression of mTORC1 by the mTORC1-specific inhibitor rapamycin, the immune response of MAIT cells in patients was significantly reduced. This study demonstrates that peripheral blood tetramer+ MAIT cells from TB patients have significant anti-TB immune effect, which is regulated by mTORC1. This could provide ideas and potential therapeutic targets for the development of novel anti-TB immunotherapy.

Halogenated chalcones against Mycobacterium tuberculosis targeting InhA: Rational design, in silico and in vitro evaluation

A library of 25-series compounds was designed against Mycobacterium Tuberculosis (M.tb) to identify novel antitubercular drugs. In silico inhibition of InhA, an essential component of FAS-II, was successfully achieved. The drug ability, lead-likeness, and toxicity of the compounds were assessed using Swiss ADME, pkCSM, and Osiris Property Explorer, which revealed the potential for drug development of chalcone compounds. Through in silico research, it was confirmed that toxic-free compounds could bind to InhA. It was found that all of the compounds bind to InhA with binding affinities ranging from -7.78 to -10.29 kcal/mol-1 which is higher than the reference standard Isoniazid and Pyrazinamide. The top five compounds were synthesized from 15 toxic-free compounds. The structural characteristics of the compounds were determined using IR, NMR, and mass spectrometry techniques. These findings indicate that these substances are competitive, reversible, and specific InhA inhibitors of InhA. using the Alamar Blue assay method (H37RV, ATCC No. 27294), the in vitro anti-mycobacterial activity of each of the synthesized compounds against M.tb was evaluated. The two most powerful compounds were (2E)-3-[4-(benzyloxy)-3,5-dimethylphenyl] and (2E)-1-(3,5-dibromophenyl)-3-(3-phenoxyphenyl) prop-2-en-1-one. In the MABA Assay, the MIC for 1-(3,5-dibromophenyl) prop-2-en-1-one was 6.25 μg/ml.

Identifying risk factors for recurrent multidrug resistant tuberculosis based on patient's record data from 2016 to 2021: retrospective study

Globally, the prevalence of multidrug-resistant tuberculosis (MDR-TB) has been increasing recently. This is a major public health concern, as MDR-TB is more difficult to treat and has poorer outcomes compared to drug-sensitive tuberculosis. The main objective of the study was to identify risk factors for recurrent multidrug-resistant tuberculosis, at Alert Specialized Hospital, Addis Ababa, by using different parametric shared frailty models. From January 2016 to December 2021, a retrospective study was conducted on MDR-TB patients at Alert Specialized Hospital in Addis Ababa. The data for the study were collected from the medical records of MDR-TB patients at the hospital during this time period. Gamma and inverse-Gaussian shared frailty models were used to analyze the dataset, with the exponential, Weibull, and lognormal distributions included as baseline hazard functions. The data were analyzed using R statistical software. The median recurrence time of the patients was 12 months, and 149 (34.3%) had recurrences. The clustering effect was statistically significant for multiple drug-resistant tuberculosis patients' recurrence. According to the Weibull-Inverse-Gaussian model, factors that reduced time to MDR-TB recurrence included lower weight (ɸ = 0.944), smoking (ɸ = 0.045), alcohol use (ɸ = 0.631), hemoptysis (ɸ = 0.041), pneumonia (ɸ = 0.564), previous anti-TB treatment (ɸ = 0.106), rural residence (ɸ = 0.163), and chronic diseases like diabetes (ɸ = 0.442) were associated with faster recurrence. While, higher education (ɸ = 3.525) and age (ɸ = 1.021) extended time to recurrence. For weight increment, smokers and alcohol users, clinical complications of hemoptysis and pneumonia, patients with pulmonary disease who had a history of previous anti-TB treatment, and being rural residents are prognostic factors. There was a significant clustering effect at the Alert Specialized Hospital in Addis Ababa, Ethiopia. The Weibull-Inverse Gaussian Shared Frailty Model was chosen as the best model for predicting the time to recurrence of MDR-TB.

Advancing Roles and Therapeutic Potentials of Pyroptosis in Host Immune Defenses against Tuberculosis

Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis (Mtb) infection, remains a deadly global public health burden. The use of recommended drug combinations in clinic has seen an increasing prevalence of drug-resistant TB, adding to the impediments to global control of TB. Therefore, control of TB and drug-resistant TB has become one of the most pressing issues in global public health, which urges the exploration of potential therapeutic targets in TB and drug-resistant TB. Pyroptosis, a form of programmed cell death characterized by cell swelling and rupture, release of cellular contents and inflammatory responses, has been found to promote pathogen clearance and adopt crucial roles in the control of bacterial infections. It has been demonstrated that Mtb can cause host cell pyroptosis, and these host cells, which are infected by Mtb, can kill Mtb accompanied by pyroptosis, while, at the same time, pyroptosis can also release intracellular Mtb, which may potentially worsen the infection by exacerbating the inflammation. Here, we describe the main pathways of pyroptosis during Mtb infection and summarize the identified effectors of Mtb that regulate pyroptosis to achieve immune evasion. Moreover, we also discuss the potentials of pyroptosis to serve as an anti-TB therapeutic target, with the aim of providing new ideas for the development of TB treatments.

The Mycobacterium tuberculosis Cell Wall: An Alluring Drug Target for Developing Newer Anti-TB Drugs-A Perspective

The Mycobacterium cell wall is a capsule-like structure comprising of various layers of biomolecules such as mycolic acid, peptidoglycans, and arabinogalactans, which provide the Mycobacteria a sort of cellular shield. Drugs like isoniazid, ethambutol, cycloserine, delamanid, and pretomanid inhibit cell wall synthesis by inhibiting one or the other enzymes involved in cell wall synthesis. Many enzymes present across these layers serve as potential targets for the design and development of newer anti-TB drugs. Some of these targets are currently being exploited as the most druggable targets like DprE1, InhA, and MmpL3. Many of the anti-TB agents present in clinical trials inhibit cell wall synthesis. The present article covers a systematic perspective of developing cell wall inhibitors targeting various enzymes involved in cell wall biosynthesis as potential drug candidates for treating Mtb infection.

Anti-mutagenic agent targeting LexA to combat antimicrobial resistance in mycobacteria

Antimicrobial resistance (AMR) is a serious global threat demanding innovations for effective control of pathogens. The bacterial SOS response, regulated by the master regulators, LexA and RecA, contributes to AMR through advantageous mutations. Targeting the LexA/RecA system with a novel inhibitor could suppress the SOS response and potentially reduce the occurrence of AMR. RecA presents a challenge as a therapeutic target due to its conserved structure and function across species, including humans. Conversely, LexA which is absent in eukaryotes, can be potentially targeted, due to its involvement in SOS response which is majorly responsible for adaptive mutagenesis and AMR. Our studies combining bioinformatic, biochemical, biophysical, molecular, and cell-based assays present a unique inhibitor of mycobacterial LexA, wherein we show that the inhibitor interacts directly with the catalytic site residues of LexA of Mycobacterium tuberculosis (Mtb), consequently hindering its cleavage, suppressing SOS response thereby reducing mutation frequency and AMR.

The rv2820c K114N mutation is related with capreomycin tolerance

As one of the factors affecting the treatment outcomes, drug tolerance in mycobacteriosis has not been paid due attention. Genome-wide association studies on 607 Mycobacterium tuberculosis clinical isolates with phenotypic drug susceptibility test data revealed that a K114N mutation on the rv2820c gene was highly enriched in capreomycin-resistant isolates (32/213, 15.02%). However, the mutation was also observed in capreomycin-sensitive isolates (10/394, 2.53%). In most cases (31/42, 73.81%), the rv2820c K114N mutation occurred in isolates with the known capreomycin resistance conferring mutation rrs A1401G. In contrast, the general frequency of the rv2820c K114N mutation was low in 7061 genomes downloaded from the National Center for Biotechnology Information database. To determine the impact of this mutation on the antimycobacterial activity of capreomycin, the intact rv2820c gene and the rv2820c K114N mutant were over-expressed in Mycobacterium smegmatis (Ms), and the results of susceptibility tests showed that the rv2820c K114N mutation did not affect the minimum inhibition concentration (MIC) of capreomycin. Subsequently, the data of time-kill assays showed that, it took only 2 h of capreomycin treatment (40 μg/ml, 5 × MIC) to kill 99.9% bacterial cells of Ms MC2155 pMV261::rv2820cH37Rv, while it took 6 h to achieve that for Ms MC2155 pMV261::rv2820cK114N. Taken together, these data suggested that the rv2820c K114N mutation is related with capreomycin tolerance, which merits further investigation.

Recent advances in the biosynthesis of ZnO nanoparticles using floral waste extract for water treatment, agriculture and biomedical engineering

Flowers are often discarded after cultural and religious events, making it worthwhile to explore the utilization of this floral waste for material production. Floral extracts contain a diverse array of phytochemicals such as polyphenols, flavonoids, and reducing sugars, which play a significant role in the formation and influencing the properties of zinc oxide (ZnO) nanoparticles. In this review, we delve into the importance of floral extract, methodology, mechanism, and influencing factors in the production of ZnO nanoparticles. Additionally, the role of green ZnO nanoparticles as an adsorbent and photocatalyst for water treatment is discussed. These floral extract-mediated ZnO nanoparticles exhibit advantages in agricultural and biomedical applications, including promoting seed germination and demonstrating antibacterial, anticancer, and antifungal properties. Cost analysis reveals that while various expenses are associated with ZnO production, scaling up processes can help reduce these costs. This review underscores the potential of floral waste extract for the synthesis of green ZnO nanoparticles, thereby contributing to waste-to-wealth strategies and adhering to green chemistry principles.

Drug resistance profiles of Mycobacterium tuberculosis clinical isolates by genotype MTBDRplus line probe assay in Zambia: findings and implications

Background

The emergence of drug resistance is a threat to global tuberculosis (TB) elimination goals. This study investigated the drug resistance profiles of Mycobacterium tuberculosis (M. tuberculosis) using the Genotype MTBDRplus Line Probe Assay at the National Tuberculosis Reference Laboratory (NTRL) in Zambia.

Methods

A cross-sectional study was conducted between January 2019 and December 2020. GenoType MTBDRplus line probe assay records for patients at the NTRL were reviewed to investigate drug susceptibility profiles of M. tuberculosis isolates to rifampicin and isoniazid. Data analysis was done using Stata version 16.1.

Results

Of the 241 patient records reviewed, 77% were for females. Overall, 44% of patients were newly diagnosed with TB, 29% had TB relapse, 10% treatment after failure and 8.3% treatment after loss to follow-up. This study found that 65% of M. tuberculosis isolates were susceptible to rifampicin and isoniazid. Consequently, 35% of the isolates were resistant to rifampicin and/or isoniazid and 21.2% were multidrug-resistant (MDR). Treatment after failure [relative risk ratios (RRR) = 6.1, 95% CI: 1.691-22.011] and treatment after loss to follow-up (RRR = 7.115, 95% CI: 1.995-25.378) were significantly associated with MDR-TB. Unknown HIV status was significantly associated with isoniazid mono-resistance (RRR = 5.449, 95% CI: 1.054-28.184).

Conclusions

This study found that 65% of M. tuberculosis isolates were susceptible to rifampicin and isoniazid while 35% were resistant. Consequently, a high prevalence of MDR-TB is of public health concern. There is a need to heighten laboratory surveillance and early detection of drug-resistant TB to prevent the associated morbidity and mortality.

Prediction of Mycobacterium tuberculosis cell wall permeability using machine learning methods

Tuberculosis (TB) caused by the bacteria Mycobacterium tuberculosis (M. tb), continues to pose a significant worldwide health threat. The advent of drug-resistant strains of the disease highlights the critical need for novel treatments. The unique cell wall of M. tb provides an extra layer of protection for the bacteria and hence only compounds that can penetrate this barrier can reach their targets within the bacterial cell wall. The creation of a reliable machine learning (ML) model to predict the mycobacterial cell wall permeability of small molecules is presented in this work and four ML algorithms, including Random Forest, Support Vector Machines (SVM), k-nearest Neighbour (k-NN) and Logistic Regression were trained on a dataset of 5368 compounds. RDKit and Mordred toolkits were used to calculate features. To determine the most effective model, various performance metrics were used such as accuracy, precision, recall, F1 score, and area under the receiver operating characteristic curve. The best-performing model was further refined with hyperparameter tuning and tenfold cross-validation. The SVM model with filtering outperformed the other machine learning models and demonstrated 80.26% and 81.13% accuracy on the test and validation datasets, respectively. The study also provided insights into the molecular descriptors that play the most important role in predicting the ability of a molecule to pass the M. tb cell wall, which could guide future compound design. The model is available at https://github.com/PGlab-NIPER/MTB_Permeability .

Prediction of Concomitant Nosocomial Infection in Patients Previously Colonized Colorectally by Multidrug-Resistant Bacteria in an SDD Setting

BACKGROUND

Antibiotic resistance is a worldwide concern. This study retrospectively analyzed patients admitted to the ICU of a tertiary hospital over a period of 7 months who were rectally colonized by multidrug-resistant microorganisms. The incidence of concomitant nosocomial infections was estimated, thus providing the risk of a colonizing microorganism producing a nosocomial infection.

METHODS

Infections with the same microorganism (concomitant) or different microorganisms (non-concomitant) were analyzed in order to adjust the empirical antibiotic treatment. Patients with rectal colonization by at least one multidrug-resistant bacterium (MDRB) on admission or after ICU admission were included. All patients had complete selective digestive decontamination (SDD) prophylaxis. For univariate analysis, categorical variables are expressed as frequencies and percentages and continuous variables as means and standard deviations, or as medians and interquartile ranges. For multivariate analysis, the model is summarized with p-values and hazard ratios with 95% confidence intervals. Survival analysis was conducted using the Kaplan-Meier method, which was performed to evaluate the time elapsed from colonization to infection by the same bacteria. Statistical significance was considered at p < 0.05.

RESULTS

Of the 130 patients with MDRB bacterial colonization analyzed, 98 remained free of infection, while 22 developed non-concomitant infections and 10 had infections concomitant to rectal colonizing bacteria. OXA-48-producing bacteria and MDR-Pseudomonas spp. incidences were 18.9% (95% CI: 7.96-35.2) and 44.4% (CI: 13.7-78.8), respectively.

CONCLUSIONS

OXA-48-producing bacteria and MDR-Pseudomonas spp. were the only bacteria associated with the development of infections concomitant to rectal colonization in an SDD setting. The incidence of MDRB infections was low.

Inhibition of DXR in the MEP pathway with lipophilic N-alkoxyaryl FR900098 analogs

In Mycobacterium tuberculosis (Mtb) and Plasmodium falciparum (Pf), the methylerythritol phosphate (MEP) pathway is responsible for isoprene synthesis. This pathway and its products are vital to bacterial/parasitic metabolism and survival, and represent an attractive set of drug targets due to their essentiality in these pathogens but absence in humans. The second step in the MEP pathway is the conversion of 1-deoxy-d-xylulose-5-phosphate (DXP) to MEP and is catalyzed by 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR). Natural products fosmidomycin and FR900098 inhibit DXR, but are too polar to reach the desired target inside some cells, such as Mtb. Synthesized FR900098 analogs with lipophilic substitution in the position α to the phosphorous atom showed promise, resulting in increased activity against Mtb and Pf. Here, an α substitution, consisting of a 3,4-dichlorophenyl substituent, in combination with various O-linked alkylaryl substituents on the hydroxamate moiety is utilized in the synthesis of a novel series of FR900098 analogs. The purpose of the O-linked alkylaryl substituents is to further enhance DXR inhibition by extending the structure into the adjacent NADPH binding pocket, blocking the binding of both DXP and NADPH. Of the initial O-linked alkylaryl substituted analogs, compound 6e showed most potent activity against Pf parasites at 3.60 μM. Additional compounds varying the phenyl ring of 6e were synthesized. The most potent phosphonic acids, 6l and 6n, display nM activity against PfDXR and low μM activity against Pf parasites. Prodrugs of these compounds were less effective against Pf parasites but showed modest activity against Mtb cells. Data from this series of compounds suggests that this combination of substituents can be advantageous in designing a new generation of antimicrobials.

Exploring the potential of Lactocaseibacillus rhamnosus PMC203 in inducing autophagy to reduce the burden of Mycobacterium tuberculosis

Mycobacterium tuberculosis, a lethal pathogen in human history, causes millions of deaths annually, which demands the development of new concepts of drugs. Considering this fact, earlier research has explored the anti-tuberculosis potential of a probiotic strain, Lactocaseibacillus rhamnosus PMC203, leading to a subsequent focus on the molecular mechanism involved in its effect, particularly on autophagy. In this current study, immunoblotting-based assay exhibited a remarkable expression of autophagy marker LC3-II in the PMC203 treated group compared to an untreated group. A remarkable degradation of p62 was also noticed within treated cells compared to control. Furthermore, the immunofluorescence-based assay showed significant fold change in fluorescence intensity for alexa-647-LC3 and alexa-488-LC3, whereas p62 was degraded noticeably. Moreover, lysosomal biogenesis generation was elevated significantly in terms of LAMP1 and acidic vesicular organelles. As a result, PMC203-induced autophagy played a vital role in reducing M. tuberculosis burden within the macrophages in treated groups compared to untreated group. A colony -forming unit assay also revealed a significant reduction in M. tuberculosis in the treated cells over time. Additionally, the candidate strain significantly upregulated the expression of autophagy induction and lysosomal biogenesis genes. Together, these results could enrich our current knowledge of probiotics-mediated autophagy in tuberculosis and suggest its implications for innovatively managing tuberculosis.

Efficacy and Safety of Bufei Jiedu Granules in Treating Multidrug-Resistant Pulmonary Tuberculosis: A Multi-center, Double-Blinded and Randomized Controlled Trial

OBJECTIVE

To assess the efficacy and safety of Bufei Jiedu (BFJD) ranules as adjuvant therapy for patients with multidrug-resistant pulmonary tuberculosis (MDR-PTB).

METHODS

A large-scale, multi-center, double-blinded, and randomized controlled trial was conducted in 18 sentinel hospitals in China from December 2012 to December 2016. A total of 312 MDR-PTB patients were randomly assigned to BFJD Granules or placebo groups (1:1) using a stratified randomization method, which both received the long-course chemotherapy regimen for 18 months (6 Am-Lfx-P-Z-Pto, 12 Lfx-P-Z-Pto). Meanwhile, patients in both groups also received BFJD Granules or placebo twice a day for a total of 18 months, respectively. The primary outcome was cure rate. The secondary outcomes included time to sputum-culture conversion, changes in lung cavities and quality of life (QoL) of patients. Adverse reactions were monitored during and after the trial.

RESULTS

A total of 216 cases completed the trial, 111 in the BFJD Granules group and 105 in the placebo group. BFJD Granules, as an adjuvant treatment, increased the cure rate by 13.6% at the end of treatment, compared with the placebo (58.4% vs. 44.8%, P=0.02), and accelerated the median time to sputum-culture conversion (5 months vs. 11 months). The cavity closure rate of the BFJD Granules group (50.6%, 43/85) was higher than that of the placebo group (32.1%, 26/81; P=0.02) in patients who completed the treatment. At the end of the intensive treatment, according to the 36-item Short Form, the BFJD Granules significantly improved physical functioning, general health, and vitality of patients relative to the placebo group (all P<0.01). Overall, the death rates in the two groups were not significantly different; 5.1% (8/156) in the BFJD Granules group and 2.6% (4/156) in the placebo group.

CONCLUSIONS

Supplementing BFJD Granules with the long-course chemotherapy regimen significantly increased the cure rate and cavity closure rates, and rapidly improved QoL of patients with MDR-PTB (Registration No. ChiCTR-TRC-12002850).

The Nitrofuran-Warhead-Equipped Spirocyclic Azetidines Show Excellent Activity against Mycobacterium tuberculosis

A series of 21 new 7'H-spiro[azetidine-3,5'-furo [3,4-d]pyrimidine]s substituted at the pyrimidine ring second position were synthesized. The compounds showed high antibacterial in vitro activity against M. tuberculosis. Two compounds had lower minimum inhibitory concentrations against Mtb (H37Rv strain) compared with isoniazid. The novel spirocyclic scaffold shows excellent properties for anti-tuberculosis drug development.

TB/FLU-06E Influenza Vector-Based Vaccine in the Complex Therapy of Drug-Susceptible and Drug-Resistant Experimental Tuberculosis

The steady rise of drug-resistant tuberculosis (TB), which renders standard therapy regimens ineffective, necessitates the development of innovative treatment approaches. Immunotherapeutic vaccines have the potential to effectively regulate the anti-TB immune response and enhance the efficacy of anti-TB treatment. In the present study, we aimed to evaluate the potency of the mucosal vector vaccine TB/FLU-06E as part of a complex treatment regimen for drug-susceptible (DS) or drug-resistant (DR) tuberculosis in C57BL/6 mice. Incorporating TB/FLU-06E into the treatment protocol significantly increased the effectiveness of therapy for both forms of tuberculosis. It was evidenced by higher survival rates and reduced pulmonary bacterial load (1.83 lg CFU for DS tuberculosis and 0.93 lg CFU for DR tuberculosis). Furthermore, the treatment reduced pathomorphological lesions in the lungs and stimulated the local and systemic T-helper 1 (Th1) and cytotoxic T-lymphocyte (CTL) anti-TB immune responses. Thus, therapeutic immunization with the TB/FLU-06E vaccine significantly enhances the efficacy of tuberculosis treatment, which is particularly important in DR tuberculosis.

A consensus reverse docking approach for identification of a competitive inhibitor of acetyltransferase enhanced intracellular survival protein from Mycobacterium tuberculosis

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb), which remains a significant global health challenge. The emergence of multidrug-resistant (MDR) Mtb strains imposes the development of new therapeutic strategies. This study focuses on the identification and evaluation of potential inhibitors against Mtb H37Ra through a comprehensive screening of an in-house chemolibrary. Subsequently, a promising pyrimidine derivative (LQM495) was identified as promising and then further investigated by experimental and in silico approaches. In this context, computational techniques were used to elucidate the potential molecular target underlying the inhibitory action of LQM495. Then, a consensus reverse docking (CRD) protocol was used to investigate the interactions between this compound and several Mtb targets. Out of 98 Mtb targets investigated, the enhanced intracellular survival (Eis) protein emerged as a target for LQM495. To gain insights into the stability of the LQM495-Eis complex, molecular dynamics (MD) simulations were conducted over a 400 ns trajectory. Further insights into its binding modes within the Eis binding site were obtained through a Quantum mechanics (QM) approach, using density functional theory (DFT), with B3LYP/D3 basis set. These calculations shed light on the electronic properties and reactivity of LQM495. Subsequently, inhibition assays and kinetic studies of the Eis activity were used to investigate the activity of LQM495. Then, an IC50 value of 11.0 ± 1.4 µM was found for LQM495 upon Eis protein. Additionally, its Vmax, Km, and Ki parameters indicated that it is a competitive inhibitor. Lastly, this study presents LQM495 as a promising inhibitor of Mtb Eis protein, which could be further explored for developing novel anti-TB drugs in the future.

In vitro Antibacterial Effect Study of Plasma-Activated Saline on Mycobacterium Tuberculosis

Purpose

This study aimed to investigate the antibacterial effects of plasma-activated saline (PAS) on My-cobacterium tuberculosis (Mtb).

Methods

We conducted a growth assay on 3 strains of Mtb and an antibiotic sensitivity test on 4 strains of Mtb. Both tests included groups treated with normal saline (NS), PAS, and hydrochloric acid (HCl). The test of antibiotic sensitivity consisted of parallel tests with two concentrations of bacteria suspension: 10-2 and 10-4. The selected antibiotics were rifampicin (RIF), isoniazid (INH), ethambutol (EMB), and streptomycin (SM). The number of bacteria was determined after one month of culture under different conditions. The Kruskal-Wallis test was used to analyze the differences in grouping factors at representative time points.

Results

The growth assay indicated that PAS significantly inhibited the growth of 3 strains of Mtb compared with NS and HCl treatment groups. Furthermore, except for the initial observation time point, the remaining three observation time points consistently demonstrate no significant differences between the NS group and the HCl group. The antibiotic sensitivity test of INH, SM, and RIF indicated that PAS could inhibit the growth of antibiotic-resistant Mtb, and the antibiotic sensitivity test of INH and SM with bacterial suspension concentration of 10-2 and SM with bacterial suspension concentration of 10-4 showed statistically different results. The antibiotic sensitivity test of EMB indicated that the growth of Mtb in PAS was slower than that in NS and HCl in both antibiotic-resistant and sensitive Mtb, but there was no statistical difference.

Conclusion

The study indicates that PAS contains a significant amount of active substances and exhibits high oxidizability and an acidic pH state. The unique physicochemical properties of PAS significantly delayed the growth of Mtb, compared to the NS and the HCl. PAS not only inhibited the growth of drug-sensitive strains but also significantly enhanced the sensitivity of drug-resistant strains to anti-tuberculosis drugs, which may provide a new therapeutic strategy for the treatment of tuberculosis.

Improving the treatment of bacterial infections caused by multidrug-resistant bacteria through drug repositioning

Drug repurposing (repositioning) is a dynamically-developing area in the search for effective therapy of infectious diseases. Repositioning existing drugs with a well-known pharmacological and toxicological profile is an attractive method for quickly discovering new therapeutic indications. The off-label use of drugs for infectious diseases requires much less capital and time, and can hasten progress in the development of new antimicrobial drugs, including antibiotics. The use of drug repositioning in searching for new therapeutic options has brought promising results for many viral infectious diseases, such as Ebola, ZIKA, Dengue, and HCV. This review describes the most favorable results for repositioned drugs for the treatment of bacterial infections. It comprises publications from various databases including PubMed and Web of Science published from 2015 to 2023. The following search keywords/strings were used: drug repositioning and/or repurposing and/or antibacterial activity and/or infectious diseases. Treatment options for infections caused by multidrug-resistant bacteria were taken into account, including methicillin-resistant staphylococci, multidrug-resistant Mycobacterium tuberculosis, or carbapenem-resistant bacteria from the Enterobacteriaceae family. It analyses the safety profiles of the included drugs and their synergistic combinations with antibiotics and discusses the potential of antibacterial drugs with antiparasitic, anticancer, antipsychotic effects, and those used in metabolic diseases. Drug repositioning may be an effective response to public health threats related to the spread of multidrug-resistant bacterial strains and the growing antibiotic resistance of microorganisms.

Multidrug-resistant tuberculosis

One of predominant contributors to global mortality is tuberculosis (TB), an infection caused by Mycobacterium tuberculosis (MTB). Inappropriate and ineffectual treatment can lead to the development of drug-resistant TB. One of the most common forms of drug-resistant TB is multidrug-resistant tuberculosis (MDR-TB), caused by mutations in the rpoB and katG genes that lead to resistance to anti-TB drugs, rifampicin (RIF) and isoniazid (INH), respectively. Although culturing remains the gold standard, it is not rapid thereby delaying potential treatment and potentially increasing the incidence of MDR-TB. In contrast, molecular techniques provide a highly sensitive and specific alternative. This review discusses the classification of biomarkers used to detect MDR-TB, some of the commonly used anti-TB drugs, and DNA mutations in MTB that lead to anti-TB resistance. The objective of this review is to increase awareness of the need for rapid and precise detection of MDR-TB cases to decrease morbidity and mortality of this infectious disease worldwide.

Numerous Asymptomatic Brain Tuberculomas Complicated by Fatal Tuberculous Meningitis

Tuberculosis (TB) is still one of the most challenging infectious diseases worldwide. Coinfection with HIV increases the likelihood of extrapulmonary involvement, including the tuberculosis of the central nervous system (CNS-TB). CNS-TB often presents as tuberculomas or tuberculous meningitis. Although tuberculomas can be single or multiple, asymptomatic carriage of numerous tuberculomas is seldom reported. We present a case of a 55-year-old man who carried at least 34 tuberculomas of different sizes asymptomatically before developing and succumbing to tuberculous meningitis. Furthermore, we highlight several possible public health challenges that might have complicated his clinical course, suggesting that future studies also focus on these variables alongside more traditional clinical issues.

High-throughput nanopore targeted sequencing for efficient drug resistance assay of Mycobacterium tuberculosis

Drug-resistant tuberculosis (TB), especially multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB), is one of the urgent clinical problems and public health challenges. Culture-based phenotypic drug susceptibility testing (pDST) is time-consuming, and PCR-based assays are limited to hotspot mutations. In this study, we developed and validated a convenient and efficient approach based on high-throughput nanopore sequencing technology combined with multiplex PCR, namely nanopore targeted sequencing (NTS), to simultaneously sequence 18 genes associated with antibiotic resistance in Mycobacterium tuberculosis (MTB). The analytical performance of NTS was evaluated, and 99 clinical samples were collected to assess its clinical performance. The NTS results showed that MTB and its drug resistance were successfully identified in approximately 7.5 h. Furthermore, compared to the pDST and Xpert MTB/RIF assays, NTS provided much more drug resistance information, covering 14 anti-TB drugs, and it identified 20 clinical cases of drug-resistant MTB. The mutations underlying these drug-resistant cases were all verified using Sanger sequencing. Our approach for this TB drug resistance assay offers several advantages, including being culture-free, efficient, high-throughput, and highly accurate, which would be very helpful for clinical patient management and TB infection control.

Tuberculosis treatment-shortening

Tuberculosis (TB) presents a significant global health concern, with ∼10 million people developing TB and 1.3 million people dying from the disease each year. The standard treatment regimen for drug-susceptible TB was between 6 and 9 months until recently, presenting a prolonged therapeutic duration compared with other infectious diseases. This is a long time for patients to adhere to the medication, consequently increasing the risk of developing drug-resistant Mycobacterium tuberculosis - a significant challenge in TB management globally. Therefore, the primary objective of contemporary TB drug development research is to shorten the treatment duration. This review comprehensively explores the strategies aimed at shortening TB treatment.

Novel strategies based on natural products and synthetic derivatives to overcome resistance in Mycobacterium tuberculosis

One of the biggest health challenges of today's world is the emergence of antimicrobial resistance (AMR), which renders conventional therapeutics insufficient and urgently demands the generation of novel antimicrobial strategies. Mycobacterium tuberculosis (M. tuberculosis), the pathogen causing tuberculosis (TB), is among the most successful bacteria producing drug-resistant infections. The versatility of M. tuberculosis allows it to evade traditional anti-TB agents through various acquired and intrinsic mechanisms, rendering TB among the leading causes of infectious disease-related mortality. In this context, researchers worldwide focused on establishing novel approaches to address drug resistance in M. tuberculosis, developing diverse alternative treatments with varying effectiveness and in different testing phases. Overviewing the current progress, this paper aims to briefly present the mechanisms involved in M. tuberculosis drug-resistance, further reviewing in more detail the under-development antibiotics, nanotechnological approaches, and natural therapeutic solutions that promise to overcome current treatment limitations.

Genomic analysis of seven mycobacteriophages identifies three novel species with differing phenotypic stabilities

Recently, case studies have been published regarding the application of mycobacteriophage (MP) therapy (MPT) in patients with multi-antibiotic-resistant infections. A major limitation in the development of MPT is the paucity of therapeutically useful MP. As there are approximately 10,000 MP that have yet to be sequenced, it is possible that characterization of this cohort would increase the repertoire of useful MP. This study aims to contribute to such a strategy, by characterizing a cohort of 7 mycobacteriophages. Sequencing analyses revealed that the MP have unique sequences, and subsequent gene annotation revealed differences in gene organization. Notably, MP LOCARD has the largest genome and operons encoding for glycosyltransferases. Taxonomic analysis executed with VIRIDIC, Gegenees and VICTOR revealed that LOCARD belongs to a different genus than the other phages and is the foundational member of one of three novel species identified in this study. LOCARD, LOCV2, and LOCV5 were selected as representative members of their species and subjected to phenotypic analyses to compare their stability under biologically and industrially relevant conditions. Again LOCARD stood out, as it was unaffected by the typical temperatures (37 °C) and salinity (0.9%) experienced in mammals, while the viability of LOCV2 and LOCV5 was significantly reduced. LOCARD was also tolerant to pH 10, low levels of antiviral detergent and was the least impacted by a single freeze-thaw cycle. When all these results are considered, it indicates that LOCARD in particular, has potential therapeutic and/or diagnostics applications, given its resilience towards physiological and storage conditions.

Molecular docking, molecular dynamics simulations and binding free energy studies of interactions between Mycobacterium tuberculosis Pks13, PknG and bioactive constituents of extremophilic bacteria

Mycobacterial pathogens present a significant challenge to disease control efforts globally due to their inherent resistance to multiple antibiotics. The rise of drug-resistant strains of Mycobacterium tuberculosis has prompted an urgent need for innovative therapeutic solutions. One promising way to discover new tuberculosis drugs is by utilizing natural products from the vast biochemical space. Multidisciplinary methods can used to harness the bioactivity of these natural products. This study aimed to evaluate the antimycobacterial efficacy of functional crude extracts from bacteria isolated from gold mine tailings in South Africa. Bacterial strains were identified using 16S rRNA sequencing. The crude extracts obtained from the bacteria were tested against Mycobacterium tuberculosis H37Rv, Mycobacterium smegmatis mc2155, and Mycobacterium aurum A+. Untargeted HPLC-qTOF and molecular networking were used to identify the functional constituents present in extracts that exhibited inhibitory activity. A virtual screening workflow (VSW) was used to filter compounds that were strong binders to Mycobacterium tuberculosis Pks13 and PknG. The ligands returned from the VSW were subjected to optimization using density functional theory (DFT) at M06-2X/6-311++ (d,p) level of theory and basis set implemented in Gaussian16 Rev.C01. The optimized ligands were re-docked against Mycobacterium tuberculosis Pks13 and PknG. Molecular dynamics simulation and molecular mechanics generalized born surface area were used to evaluate the stability of the protein-ligand complexes formed by the identified hits. The hit that showed promising binding characteristics was virtually modified through multiple synthetic routes using reaction-driven enumeration. Three bacterial isolates showed significant activity against the two strains of Mycobacterium, while only two, Bacillus subtilis and Bacillus licheniformis, exhibited activity against both Mycobacterium tuberculosis H37Rv, Mycobacterium smegmatis mc2155, and Mycobacterium aurum A+. The tentatively identified compounds from the bacterial crude extracts belonged to various classes of natural compounds associated with antimicrobial activity. Two compounds, cyclo-(L-Pro-4-OH-L-Leu) and vazabitide A, showed strong binding against PknG and Pks13, with pre-MD MM-GBSA values of - 42.8 kcal/mol and - 47.6 kcal/mol, respectively. The DFT-optimized compounds exhibited the same docking scores as the ligands optimized using the OPSL-4 force field. After modifying vazabitide A, its affinity to the Pks13 binding site increased to - 85.8 kcal/mol, as revealed by the post-MD MM-GBSA analysis. This study highlights the potential of bacteria isolates from gold mine tailings as a source of new scaffolds for designing and optimizing anti-Mycobacterium agents. These agents synthesized in-silico can be further tested in-vitro to evaluate their efficacy.