Multidrug-resistant Mycobacterium Tuberculosis Research Articles

Occupational Rehabilitation Following Surgery for Multidrug-Resistant and Extensively Drug-Resistant Tuberculosis

Objective: To assess the level of occupational rehabilitation among patients who underwent surgery for multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis in the long-term period compared with patients who refused surgery and opted solely for conservative management.Material and methods: We analyzed long-term outcomes of surgical treatment for destructive pulmonary tuberculosis caused by MDR and XDR Mycobacterium tuberculosis in 976 patients (group 1). Furthermore, we evaluated long-term outcomes of 888 patients (group 2) who had an ineffective main chemotherapy course (regimens IV and V) or relapses after an initially effective chemotherapy course and were managed conservatively because they refused surgery.Results: One year after the surgery or surgery consultation, the complete clinical response, ie, cavity closure and elimination of bacilli (CV-, MBT-), was achieved in 99.5% of the operated patients, in contrast to only 5.3% among those who refused surgery. At the 5-year mark after the surgery/consultation, we observed the sustained effectiveness in 97.7% of the operated patients compared with only 3.2% among those who refused surgery. During the 12 years of follow-up, tuberculosis-related deaths occurred in 9 operated patients (0.8%) and 643 patients (72.4%) who refused surgery. Furthermore, 78.9% of the patients treated surgically were able to return to work in the long-term period, in contrast to only 2.6% of those who refused surgery.Conclusions: Our analysis revealed that the complete clinical response one year after the surgery/surgery consultation was 18.8 times more common in the patients who underwent surgery compared with those who refused it. Similarly, the complete clinical response 5 years after the surgery/consultation was 30.5 times higher in the operated patients. Tuberculosis-related deaths during the follow-up were 90.5 times more common among the patients who refused surgery. Furthermore, the 5-year survival rate among the operated patients was 3.3 times higher, and occupational rehabilitation was 30.3 times more common compared with those who refused surgery.

Catalase activity deficiency sensitizes multidrug-resistant Mycobacterium tuberculosis to the ATP synthase inhibitor bedaquiline

Multidrug-resistant tuberculosis (MDR-TB), defined as resistance to the first-line drugs isoniazid and rifampin, is a growing source of global mortality and threatens global control of tuberculosis disease. The diarylquinoline bedaquiline has recently emerged as a highly efficacious drug against MDR-TB and kills Mycobacterium tuberculosis by inhibiting mycobacterial ATP synthase. However, the mechanisms underlying bedaquiline’s efficacy against MDR-TB remain unknown. Here we investigate bedaquiline hyper-susceptibility in drug-resistant Mycobacterium tuberculosis using systems biology approaches. We discovered that MDR clinical isolates are commonly sensitized to bedaquiline. This hypersensitization is caused by several physiological changes induced by deficient catalase activity. These include enhanced accumulation of reactive oxygen species, increased susceptibility to DNA damage, induction of sensitizing transcriptional programs, and metabolic repression of several biosynthetic pathways. In this work we demonstrate how resistance-associated changes in bacterial physiology can mechanistically induce collateral antimicrobial drug sensitivity and reveal druggable vulnerabilities in antimicrobial resistant pathogens.

Discovery of benzo[c]phenanthridine derivatives with potent activity against multidrug-resistant Mycobacterium tuberculosis.

Mycobacterium tuberculosis (Mtb), the pathogen responsible for tuberculosis (TB), is the leading cause of bacterial disease-related death worldwide. Current antibiotic regimens for the treatment of TB remain dated and suffer from long treatment times as well as the development of drug resistance. As such, the search for novel chemical modalities that have selective or potent anti-Mtb properties remains an urgent priority, particularly against multidrug-resistant (MDR) Mtb strains. Herein, we design and synthesize 35 novel benzo[c]phenanthridine derivatives (BPDs). The two most potent compounds, BPD-6 and BPD-9, accumulated within the bacterial cell and exhibited strong inhibitory activity (MIC90 ~2 to 10 µM) against multiple Mycobacterium strains while remaining inactive against a range of other Gram-negative and Gram-positive bacteria. BPD-6 and BPD-9 were also effective in reducing Mtb survival within infected macrophages, and BPD-9 reduced the burden of Mycobacterium bovis BCG in the lungs of infected mice. The two BPD compounds displayed comparable efficacy to rifampicin (RIF) against non-replicating Mtb (NR-Mtb). Importantly, BPD-6 and BPD-9 inhibited the growth of multiple MDR Mtb clinical isolates. Generation of BPD-9-resistant mutants identified the involvement of the Mmr efflux pump as an indirect resistance mechanism. The unique specificity of BPDs to Mycobacterium spp. and their efficacy against MDR Mtb isolates suggest a potential novel mechanism of action. The discovery of BPDs provides novel chemical scaffolds for anti-TB drug discovery.IMPORTANCEThe emergence of drug-resistant tuberculosis (TB) is a serious global health threat. There remains an urgent need to discover new antibiotics with unique mechanisms of action that are effective against drug-resistant Mycobacterium tuberculosis (Mtb). This study shows that novel semi-synthetic compounds can be derived from natural compounds to produce potent activity against Mtb. Importantly, the identified compounds have narrow spectrum activity against Mycobacterium species, including clinical multidrug-resistant (MDR) strains, are effective in infected macrophages and against non-replicating Mtb (NR-Mtb), and show anti-mycobacterial activity in mice. These new compounds provide promising chemical scaffolds to develop potent anti-Mtb drugs of the future.

Nano Revolution: Harnessing Nanoparticles to Combat Antibiotic-resistant Bacterial Infections.

Nanoparticles, defined as particles ranging from 1 to 100 nanometers in size, are revolutionizing the approach to combating bacterial infections amid a backdrop of escalating antibiotic resistance. Bacterial infections remain a formidable global health challenge, causing millions of deaths annually and encompassing a spectrum from common illnesses like Strep throat to severe diseases such as tuberculosis and pneumonia. The misuse of antibiotics has precipitated the rise of resistant strains like methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant Mycobacterium tuberculosis (MDR-TB), and carbapenem-resistant Enterobacteriaceae (CRE), underscoring the critical need for innovative therapeutic strategies. Nanotechnology offers a promising avenue in this crisis. Nanoparticles possess unique physical and chemical properties that distinguish them from traditional antibiotics. Their high surface area to volume ratio, ability to be functionalized with various molecules, and distinctive optical, electronic, and magnetic characteristics enable them to exert potent antibacterial effects. Mechanisms include physical disruption of bacterial membranes, generation of Reactive Oxygen Species (ROS), and release of metal ions that disrupt bacterial metabolism. Moreover, nanoparticles penetrate biofilms and bacterial cell walls more effectively than conventional antibiotics and can be precisely targeted to minimize off-target effects. Crucially, nanoparticles mitigate the development of bacterial resistance by leveraging multiple simultaneous mechanisms of action, which make it challenging for bacteria to adapt through single genetic mutations. As research advances, nanotechnology holds immense promise in transforming antibacterial treatments, offering effective solutions that address current infections and combat antibiotic resistance globally. This review provides a comprehensive overview of nanoparticle applications in antibacterial therapies, highlighting their mechanisms, advantages over antibiotics, and future directions in healthcare innovation.

Analysis of genetic characteristics associated with reduced bedaquiline susceptibility in multidrug-resistant Mycobacterium tuberculosis

Bedaquiline (BDQ) has shown efficacy in shortening treatment duration and enhancing treatment success rates for multidrug-resistant tuberculosis (MDR-TB), thereby prompting widespread adoption. However, resistance to BDQ has emerged. This study aimed to identify genetic characteristics associated with decreased susceptibility to BDQ, using a public database to aid in the detection of resistant strains. Seventy-one BDQ-resistant and 929 BDQ-susceptible isolates from the open-source CRyPTIC database were selected for analysis. Variant calling was conducted via the clockwork pipeline. Univariate logistic regression was performed for each gene mutation, followed by LASSO regression for further variant selection. Ultimately, a multiple linear regression model was developed using log2-transformed Minimum Inhibitory Concentration values as the dependent variable, with variant selection refined through stepwise regression based on the Akaike Information Criterion. Ten gene mutations were significantly associated with reduced BDQ susceptibility, including two key gene mutations: Rv0678_141_ins_1 and Rv1979c_D249E, with effect estimates of 1.76 (95 % CI: 0.67–2.84) and 1.69 (95 % CI: 0.22–3.17), respectively. Other implicated genes included Rv2699c_-84_del_1, hsaB_I179T, mmpL9_T241A, pncA_C14R, Rv0373c_G621S, Rv0893c_L27F, Rv1770_A4D, and Rv3428c_S327C. This study identified ten gene mutations linked to decreased susceptibility to BDQ, providing a reference for developing a comprehensive catalog of BDQ-resistant genes.

Exploring gene mutations and multidrug resistance in Mycobacterium tuberculosis: a study from the Lung Hospital in Vietnam.

Drug-resistant tuberculosis not only diminishes treatment efficacy but also heightens the risk of transmission and mortality. Investigating Mycobacterium tuberculosis resistance to first-line antituberculosis drugs is essential to tackle a major global health challenge. Using Sanger sequencing, this study investigates gene mutations associated with multidrug resistance in drug-resistant M. tuberculosis strains. Among 30 samples, mutations were found in genes linked to first-line anti-tuberculosis drug resistance. Rifampicin resistance was observed in 46.67% of the samples, with the most frequent mutation in the rpoB gene at codon 450 (S450L) occurring in 23.33% of cases. Similarly, isoniazid resistance was found in 86.67% of samples, with 33.33% of cases indicating the katG gene mutation at codon 315 (S315T). Additionally, streptomycin resistance was present in 76.67% of samples, and 30% of these cases were mainly linked to the rpsL gene mutation at codon 43 (K43R). These findings illuminate the genetic mechanisms behind drug resistance in M. tuberculosis. By identifying specific genetic markers, this research enhances our ability to diagnose and treat drug-resistant Tuberculosis more accurately and efficiently.

Drug-resistance characteristics, genetic diversity, and transmission dynamics of multidrug-resistant or rifampicin-resistant Mycobacterium tuberculosis from 2019 to 2021 in Sichuan, China

BackgroundMultidrug- or rifampicin-resistant tuberculosis (TB; MDR/RR-TB) is a significant public health threat. However, the mechanisms involved in its transmission in Sichuan, China are unclear. To provide a scientific basis for MDR/RR-TB control and prevention, we investigated the drug-resistance characteristics, genetic diversity, and transmission dynamics and analyzed the demographic and clinical characteristics of patients to identify risk factors for the acquisition of MDR/RR-TB in Sichuan, Western China.MethodsWhole-genome sequencing was performed using a sample comprised of all MDR/RR-TB strains isolated from patients with pulmonary TB (≥ 15 years) at the 22 surveillance sites in Sichuan province between January 2019 and December 2021, to analyze genotypic drug resistance and genetic diversity. Moreover, we performed statistical analyses of the epidemiological characteristics and risk factors associated with the transmission dynamics of MDR/RR-TB.ResultsThe final analysis included 278 MDR/RR TB strains. Lineage 2.2, the major sub-lineage, accounted for 82.01% (228/278) of isolates, followed by lineage 4.5 (9.72%, 27/278), lineage 4.4 (6.83%, 19/278), and lineage 4.2 (1.44%, 4/278). The drug resistance rates, ranging from high to low, were as follows: isoniazid (229 [82.37%]), streptomycin (177 [63.67%]), ethambutol (144 [51.80%]), pyrazinamide (PZA, 119 [42.81%]), fluoroquinolones (FQs, 93 [33.45%]). Further, the clofazimine, bedaquiline, and delamanid resistance rates were 2.88, 2.88, and 1.04%, respectively. The gene composition cluster rate was 32.37% (90/278). In addition, 83.81% (233/278) of MDR/RR-TB cases were determined to be likely caused by transmission. Finally, patients infected with lineage two strains and strains with the KatG S315T amino acid substitution presented a higher risk of MDR/RR-TB transmission.ConclusionTransmission plays a significant role in the MDR/RR-TB burden in Sichuan province, and lineage 2 strains and strains harboring KatG S315T have a high probability of transmission. Further, high levels of FQ and PZA drug resistance suggest an urgent need for drug susceptibility testing prior to designing therapeutic regimens. New anti-TB drugs need to be used standardly and TB strains should be regularly monitored for resistance to these drugs.

Eco-friendly Biosynthesis of Silver Nanoparticles Using Elephantorrhiza elephantina: Characterization and Antimicrobial Activity against Mycobacterium tuberculosis Surrogate Models

The emergence of multidrug-resistant (MDR) and extensively-drug resistant (XDR) Mycobacterium tuberculosis (MTB) strains have scampered efforts to arrest the tuberculosis (TB) pandemic due to treatment failures based on current drugs. The need for novel therapeutics has never been more urgent. Research is leaning towards alternative composite antimicrobials such as silver nanoparticles (AgNPs). Elephantorrhiza elephantina (E. elephantina) is an indigenous Southern African rhizomatous plant which has been used for eons in African traditional medicine for the management of TB. The purpose of this study was to biosynthesize and characterize AgNps using E. elephantina, and to evaluate their antimicrobial effectiveness against surrogate MTB species. The study also sought to screen for the participating secondary metabolites in E. elephantina acting as bio reducing, capping and stabilising agents; and to determine the toxicity of the lyophilised root extract in vivo. Qualitative phytochemical screening techniques confirmed the presence of bioactive secondary metabolites with functional groups capable of mediating in the biosynthesis of AgNPs. UV-Vis spectrometry established the identity of the nanostructures as AgNPs. Transmission electron microscopy and dynamic light scattering confirmed the AgNPs to have an average size of 44 nm, with spherical and cubic morphologies. The biosynthesised AgNPs were potent inhibitors of the model MTB species with an MIC of 19.53 µg/mL, and inhibition zones of 20mm and 18mm against Mycolicibacterium aurum and Mycolicibacterium smegmatis respectively at their MICs. Oral toxicity evaluations based on OECD guideline 425 determined the LD50 of the lyophilised E. elephantina root extract to be safe above 4000mg/kg body weight. The study concluded that biosynthesized AgNPs from E. elephantina root extract, using a one-pot green-synthesis technique, were both safe and effective, offering a promising alternative therapeutic strategy for combating multidrug-resistant TB.

Synthesis and antitubercular activities of acetamide-substituted benzazole derivatives

Multidrug-resistant Mycobacterium tuberculosis strains' increasing emergence and rapid spread necessitate the urgent development of innovative antimycobacterial agents. In pursuit of novel agents, a series of N-(benzazole-2-ylmethyl)-2-substituted phenylacetamide or N-(benzazole-2-ylmethyl)-2-(thiophen-2-yl)acetamide compounds (6-11) were synthesized. Their efficacy against multidrug-resistant Mycobacterium tuberculosis was assessed. Compounds exhibited potent antimycobacterial activity with minimum inhibitory concentrations (MIC) ranging from 1.05 to 4.10 µM and demonstrated low cytotoxicity towards fibroblast cell line (L929). ADMET predictions suggested that these synthesized compounds possess drug-like properties. Our findings offer a promising starting point for designing more selective and potent antimycobacterial agents.

Bioinformatic Approaches Identify Hybrid Antibiotics against Tuberculosis via d-Amino Acid-Activating Adenylation Domains from Cordyceps militaris.

The development of tuberculosis (TB) therapy has been marked by the discovery of natural-product-derived streptomycin, followed by the introduction of NP-derived rifampicin, representing a significant milestone in the history of TB management. However, TB remains a global challenge, with the emergence of multidrug-resistant Mycobacterium tuberculosis highlighting the need for novel therapeutic agents. In this study, a bioinformatic approach was employed to investigate d-amino acid-activating adenylation domains, leading to the identification of cordysetin A (1), a novel trans-decalin tetramic acid antibiotic from the ascomycete fungi Cordyceps militaris. Cordysetin A (1) exhibits considerable activity against M. tuberculosis in vitro and in vivo while maintaining low cytotoxicity. These results reveal that the d-configuration of the amino acid within this hybrid polyketide-nonribosomal antibiotic is crucial for preserving its anti-tuberculosis efficacy. These findings emphasize the significant translational potential of cordysetin A as a promising candidate for TB treatment, furthering our understanding of bioinformatic approaches in the development of effective anti-tuberculosis agents.

Apramycin kills replicating and non-replicating Mycobacterium tuberculosis

IntroductionMycobacterium tuberculosis (Mtb) has the capability to dodge the immune system by escaping into alternate physiological forms by forming drug tolerant populations under the immune pressure in the host. New drugs are urgently needed to treat these non-replicating persisters. In the past, aminoglycoside antibiotics have played a pivotal role in TB chemotherapy.MethodsHere, we explored the therapeutic potential of a monosubstituted deoxystreptamine aminoglycoside, apramycin (APR) which is different in its chemical structure from the other clinically relevant aminoglycoside antibiotics that are all disubstituted, e.g., amikacin (AMI). We determined the APR MIC as 0.25-1 µg/ml for sensitive and multidrug-resistant Mtb (MDRTB), including amikacin (AMI) resistant strains.ResultsIn standard time-kill kinetic assays, the bactericidal activity of APR was similar to that of AMI demonstrating dose-dependent killing of planktonic Mtb. However, in biofilm and macrophage intracellular killing assays, APR appeared significantly more potent than AMI. Further, APR monotherapy was efficacious in a mouse chronic TB lung infection model (~0.92 log10 CFU/lung reduction). APR combination therapy with the current 1st line standard of care (SoC) antibiotic combination of isoniazid (H), rifampicin (R), ethambutol (E), and pyrazinamide (Z) was found to be additive (HREZ=1.88 vs. HREZ-APR=2.78 log10CFU/lung reduction).DiscussionThe results indicate the potential of apramycin-based combinations for the treatment of human tuberculosis.

Dynamic PET reveals compartmentalized brain and lung tissue antibiotic exposures of tuberculosis drugs

Tuberculosis (TB) remains a leading cause of death, but antibiotic treatments for tuberculous meningitis, the deadliest form of TB, are based on those developed for pulmonary TB and not optimized for brain penetration. Here, we perform first-in-human dynamic 18F-pretomanid positron emission tomography (PET) in eight human subjects to visualize 18F-pretomanid biodistribution as concentration-time exposures in multiple compartments (NCT05609552), demonstrating preferential brain versus lung tissue partitioning. Preferential, antibiotic-specific partitioning into brain or lung tissues of several antibiotics, active against multidrug resistant (MDR) Mycobacterium tuberculosis strains, are confirmed in experimentally-infected mice and rabbits, using dynamic PET with chemically identical antibiotic radioanalogs, and postmortem mass spectrometry measurements. PET-facilitated pharmacokinetic modeling predicts human dosing necessary to attain therapeutic brain exposures. These data are used to design optimized, pretomanid-based regimens which are evaluated at human equipotent dosing in a mouse model of TB meningitis, demonstrating excellent bactericidal activity without an increase in intracerebral inflammation or brain injury. Importantly, several antibiotic regimens demonstrate discordant activities in brain and lung tissues in the same animal, correlating with tissue antibiotic exposures. These data provide a mechanistic basis for the compartmentalized activities of antibiotic regimens, with important implications for developing treatments for meningitis and other infections in compartments with unique antibiotic penetration.

New generation fluoroquinolone sitafloxacin could potentially overcome the majority levofloxacin and moxifloxacin resistance in multidrug-resistant Mycobacterium tuberculosis.

Introduction. Pre-existing fluoroquinolones (FQs) resistance is a major threat in treating multidrug-resistant (MDR) tuberculosis. Sitafloxacin (Sfx) is a new broad-spectrum FQ.Hypothesis. Sfx is more active against drug-resistant Mycobacterium tuberculosis (Mtb) isolates.Aim. To determine whether there is cross-resistance between Sfx and ofloxacin (Ofx), levofloxacin (Lfx) and moxifloxacin (Mfx) in MDR Mtb.Methods. A total of 106 clinical Mtb isolates, including 23 pan-susceptible and 83 MDR strains, were analysed for Sfx, Lfx and Mfx resistance using MIC assay. The isolates were also subjected to whole-genome sequencing to analyse drug-resistant genes.Results. Sfx exhibited the most robust inhibition activity against Mtb clinical isolates, with a MIC50 of 0.0313 µg ml-1 and MIC90 of 0.125 µg ml-1, which was lower than that of Mfx (MIC50 = 0.0625 µg ml-1, MIC90 = 1 µg ml-1) and Lfx (MIC50 = 0.125 µg ml-1, MIC90 = 2 µg ml-1). We determined the tentative epidemiological cut-off values as 0.5 µg ml-1 for Sfx. Also, 8.43% (7/83), 43.37% (36/83), 42.17% (35/83) and 51.81% (43/83) MDR strains were resistant to Sfx, Mfx, Lfx and Ofx, respectively. Cross-resistance between Ofx, Lfx and Mfx was 80.43% (37/46). Only 15.22% (7/46) of the pre-existing FQs resistance isolates were resistant to Sfx. Among the 30 isolates with mutations in gyrA or gyrB, 5 (16.67%) were Sfx resistant. The combination of Sfx and rifampicin could exert partial synergistic effects, and no antagonism between Sfx and six clinically important anti-Mtb antibiotics was evident.Conclusion. Sfx exhibited superior activity against MDR isolates comparing to Lfx and Mfx, and could potentially overcome the majority pre-existing FQs resistance in Mtb strains.

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.

Occurrence of multidrug-resistant Mycobacterium tuberculosis in upper Southern Thailand.

Mycobacterium tuberculosis causes global concern with tuberculosis (TB). Multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) pose additional challenges, as they resist to multiple first-line drugs. This study investigated the occurrence of TB, antibiotic resistance due to inhA and katG gene mutations, and multidrug resistance in M. tuberculosis during fiscal years 2020-2022. Samples were gathered from hospitals in seven provinces of upper Southern Thailand. The study investigated the correlation between inhA and katG gene mutations in M. tuberculosis and the development of antimicrobial resistance and isoniazid resistance. A total of 19,186 samples were sent to the Office of Disease Prevention and Control Region 11st, Nakhon Si Thammarat, Thailand. The results showed that 51% of the samples were obtained from patients located in Nakhon Si Thammarat, followed by Surat Thani provinces. Regarding the spatial distribution of TB-infected cases, the incidence of TB was high in the province, which has a moderate to high population density. The highest average occurrence of TB in this study was found in Phuket province (9.75/100,000 risk person-year). The detected isoniazid resistance was 394, 255, and 179 cases in 2020, 2021, and 2022, respectively. A total of 99 isolates were MDR, whereas four isolates were XDR. The antimicrobial resistance associated with the inhA mutation was 192, 142, and 105 isolates, respectively, whereas the resistance associated with the katG mutation was 249, 182, and 120 cases in 2020, 2021, and 2022, respectively. These findings contribute to the understanding of the occurrence of antibiotic-resistant TB that could lead to use as data for preventing MDR-TB.

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.

New synergistic benzoquinone scaffolds as inhibitors of mycobacterial cytochrome bc1 complex to treat multi-drug resistant tuberculosis

Through a comprehensive molecular docking study, a unique series of naphthoquinones clubbed azetidinone scaffolds was arrived with promising binding affinity to Mycobacterial Cytbc1 complex, a drug target chosen to kill multi-drug resistant Mycobacterium tuberculosis (MDR-Mtb). Five compounds from series-2, 2a, 2c, 2g, 2h, and 2j, showcased significant in vitro anti-tubercular activities against Mtb H37Rv and MDR clinical isolates. Further, synergistic studies of these compounds in combination with INH and RIF revealed a potent bactericidal effect of compound 2a at concentration of 0.39 μg/mL, and remaining (2c, 2g, 2h, and 2j) at 0.78 μg/mL. Exploration into the mechanism study through chemo-stress assay and proteome profiling uncovered the down-regulation of key proteins of electron-transport chain and Cytbc1 inhibition pathway. Metabolomics corroborated these proteome findings, and heightened further understanding of the underlying mechanism. Notably, in vitro and in vivo animal toxicity studies demonstrated minimal toxicity, thus underscoring the potential of these compounds as promising anti-TB agents in combination with RIF and INH. These active compounds adhered to Lipinski's Rule of Five, indicating the suitability of these compounds for drug development. Particular significance of molecules NQ02, 2a, and 2h, which have been patented (Published 202141033473).

Drug Targets, Current and Future Therapeutics for the Treatment of Multi Drug Resistant Tuberculosis with their Clinical Applications: A Critical Review

Abstract: Multi drug-resistant or extensive drug resistance Mycobacterium tuberculosis poses numerous challenges for health care workers and for public health authorities. Treating multidrug resistant or extensive drug resistance tuberculosis continues to be a difficult task, as a longer regimen is associated with a higher number of adverse drug events and economic burden and has a significant negative effect on health care resources. Many trials and observational studies were conducted. Few studies are underway to develop the universal regimen and improve the outcomes related to multi or extensive drug resistance tuberculosis with a shorter regimen duration. The current review will discuss which drug inhibits what target, their synthesis, genetic aspects, repurposed drugs, novel drugs, and extensive trials for the treatment of multi or extensive drug resistance tuberculosis.

Exploring Genomic Patterns to Identify Drug-Resistant TB: A Comprehensive Study of Age, Gender, Lineage, and Outcome

Background: Tuberculosis (TB) is a prevalent bacterial infection caused by Mycobacterium tuberculosis (Mtb), primarily affecting the lungs, with rising incidence rates. Drug-resistant TB strains, including multidrug-resistant (MDR) and extensively drug-resistant (XDR) types, pose challenges with poor treatment success rates and increased mortality. Demographic factors and genomic patterns contribute to drug resistance, emphasizing the need for new drugs targeting specific genomic patterns.Methods: This study analyzes the impact of demographics, treatment outcomes, and genomic mutations on drug-resistant TB using pattern identification techniques and whole-genome sequencing to discover therapeutic targets. This study primarily focused on the identification and analysis of MDR and XDR strains, considering various demographic characteristics and treatment outcomes. A dataset comprising 2,602 observations was utilized, and pattern recognition techniques were employed to identify significant features. Additionally, the study employs the whole-genome sequencing (WGS) pipeline to identify single nucleotide polymorphisms (SNPs) that result in new mutations in drug-resistant Mtb strains.Results: The findings of the study revealed that XDR and MDR non-XDR TB were the most prevalent types of drug resistance, and they were associated with unfavorable treatment outcomes, including death or treatment failure. Males exhibited a higher susceptibility to both XDR and MDR non-XDR TB compared to females. The age of onset for both types of resistance was approximately 40 years. Among the observed variants in 31 commonly occurring genes,Conclusion: These findings introduce a novel set of therapeutic targets specific to MDR and XDR Mtb types, which warrant further investigation for potential therapeutic interventions.Keywords: Tuberculosis; Drug Resistance; Multidrug resistance; Demographics; Dataset; Gene; Mutations

Genetic analysis of pyrazinamide resistance: mutations in the pncA gene among clinical isolates of multi-drug resistant Mycobacterium Tuberculosis

Pyrazinamide (PZA) resistance presents a significant challenge in tuberculosis (TB) management, particularly in multi-drug resistant (MDR) cases. Understanding the genetic basis of PZA resistance is crucial for effective treatment strategies. This review provides a comprehensive overview of recent advancements in molecular characterization of PZA resistance, focusing on mutations in the pncA, rpsA, and panD genes. We discuss the prevalence of PZA resistance, mechanisms of resistance, and the utility of genetic analysis in early diagnosis. Key findings from studies investigating PZA resistance in clinical isolates are summarized, highlighting the predominant role of pncA mutations. Additionally, we explore the significance of mutations in rpsA and panD genes, elucidating alternative pathways to PZA resistance. Insights from genetic analysis have implications for personalized treatment approaches and TB control programs. Future directions in research and the potential of molecular methods in enhancing PZA susceptibility testing are also discussed.