Identification of Novel Antimicrobial Compounds Targeting Mycobacterium tuberculosis S-Adenosyl-L-Homocysteine Hydrolase Using Dual Hierarchical In Silico Structure-Based Drug Screening.

The emergence of multidrug-resistant and extensively drug-resistant Mycobacterium tuberculosis (M. tuberculosis) has become a major medical problem. S-adenosyl-L-homocysteine hydrolase (MtSAHH) was selected as the target protein for the identification of novel anti-TB drugs. Dual hierarchical in silico Structure-Based Drug Screening was performed using a 3D compound structure library (with over 150 thousand synthetic chemicals) to identify compounds that bind to MtSAHH's active site. In vitro experiments were conducted to verify whether the nine compounds selected as new drug candidates exhibited growth-inhibitory effects against mycobacteria. Eight of the nine compounds that were predicted by dual hierarchical screening showed growth-inhibitory effects against Mycobacterium smegmatis (M. smegmatis), a model organism for M. tuberculosis. Compound 7 showed the strongest antibacterial activity, with an IC50 value of 30.2 µM. Compound 7 did not inhibit the growth of Gram-negative bacteria or exert toxic effects on human cells. Molecular dynamics simulations of 40 ns using the MtSAHH-Compound 7 complex structure suggested that Compound 7 interacts stably with the MtSAHH active site. These in silico and in vitro results suggested that Compound 7 is a promising lead compound for the development of new anti-TB drugs.

YY1 Contributes to the Inflammatory Responses of Mycobacterium tuberculosis-Infected Macrophages Through Transcription Activation-Mediated Upregulation TLR4.

Tuberculosis (TB) is a chronic respiratory infectious disease and is induced by Mycobacterium tuberculosis (M.tb) infection. Macrophages serve as the cellular home in immunoreaction against M.tb infection, which is tightly regulated through Toll-like receptor 4 (TLR4) expression. Therefore, this study is designed to explore the role and mechanism of TLR4 in mycobacterial injury in human macrophages (THP-1 cells) after M.tb infection. Cell proliferation and apoptosis were assessed using MTT, EdU, and flow cytometry assays. ELISA kits were utilized to assess the levels of Interleukin-6 (IL-6), IL-1ß, and tumor necrosis factor α (TNF-α). The binding between Yin-Yang-1 (YY1) and TLR4 promoter was predicted by JASPAR and verified using Chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays. M.tb infection might repress THP-1 cell proliferation, and induce cell apoptosis and inflammatory response in a multiplicity of infection (MOI)-dependent manner. Moreover, M.tb infection increased the expression of TLR4 in HTP-1 cells in an MOI-dependent way, and its downregulation might overturn M.tb infection-mediated HTP-1 cell damage and inflammatory response. At the molecular level, YY1 was a transcription factor of TLR4 and promoted TLR4 transcription via binding to its promoter region. Besides, YY1 might activate the NF-kB signaling pathway via regulating TLR4. Meanwhile, TLR4 inhibitor BAY11-7082 might overturn the repression effect of TLR4 on M.tb-infected HTP-1 cell damage. YY1-activated TLR4 might aggravate mycobacterial injury in human macrophages after M.tb infection by the NF-kB pathway, providing a promising therapeutic target for TB treatment.

Indole Propionic Acid Disturbs the Normal Function of Tryptophanyl-tRNA Synthetase in Mycobacterium tuberculosis.

Tuberculosis (TB) is the leading infectious disease caused by Mycobacterium tuberculosis and the second-most contagious killer after COVID-19. The emergence of drug-resistant TB has caused a great need to identify and develop new anti-TB drugs with novel targets. Indole propionic acid (IPA), a structural analog of tryptophan (Trp), is active against M. tuberculosis in vitro and in vivo. It has been verified that IPA exerts its antimicrobial effect by mimicking Trp as an allosteric inhibitor of TrpE, which is the first enzyme in the Trp synthesis pathway of M. tuberculosis. However, other Trp structural analogs, such as indolmycin, also target tryptophanyl-tRNA synthetase (TrpRS), which has two functions in bacteria: synthesis of tryptophanyl-AMP by catalyzing ATP + Trp and producing Trp-tRNATrp by transferring Trp to tRNATrp. So, we speculate that IPA may also target TrpRS. In this study, we found that IPA can dock into the Trp binding pocket of M. tuberculosis TrpRS (TrpRSMtb), which was further confirmed by isothermal titration calorimetry (ITC) assay. The biochemical analysis proved that TrpRS can catalyze the reaction between IPA and ATP to generate pyrophosphate (PPi) without Trp as a substrate. Overexpression of wild-type trpS in M. tuberculosis increased the MIC of IPA to 32-fold, and knock-down trpS in Mycolicibacterium smegmatis made it more sensitive to IPA. The supplementation of Trp in the medium abrogated the inhibition of M. tuberculosis by IPA. We demonstrated that IPA can interfere with the function of TrpRS by mimicking Trp, thereby impeding protein synthesis and exerting its anti-TB effect.

Quinoline Derivatives as Promising Scaffolds for Antitubercular Activity: A Comprehensive Review.

BACKGROUND: Heterocyclic compounds and their derivatives play a significant role in the design and development of novel quinoline drugs. Among the various pharmacologically active heterocyclic compounds, quinolines stand out as the most significant rings due to their broad pharmacological roles, specifically antitubercular activity, and their presence in plant-based compounds. Quinoline is also known as benzpyridine, benzopyridine, and 1-azanaphthalene. It has a benzene ring fused with a pyridine ring, and both rings share two carbon atoms. The importance of quinoline lies in its incorporation as a key component in various natural compounds found in medicinal plant families like Fumariaceae, Berberidaceae, Rutaceae, Papavaraceae, and others. OBJECTIVE: This article is expected to have a significant impact on the advancement of effective antitubercular drugs. Through harnessing the potent activity of quinoline derivatives, the research aims to make valuable contributions to combating tuberculosis more efficiently and ultimately reducing the global burden of this infectious disease. METHODS: Numerous nitrogen-containing heterocyclic compounds exhibit significant potential as antitubercular agents. These chemicals have fused aromatic nitrogen-heterocyclic nuclei that can change the number of electrons they have, which can change their chemical, physical, and biological properties. This versatility comes from their ability to bind with the receptors in multiple modes, a critical aspect of drug pharmacological screening. Among these compounds, quinoline stands out as it incorporates a stable fusion of a benzene ring with a pyridine nucleus. Quinolines have demonstrated a diverse range of pharmacological activities, including but not limited to anti-tubercular, anti-tumor, anticoagulant, anti-inflammatory, antioxidant, antiviral, antimalarial, anti-HIV, and antimicrobial effects. RESULTS: Some molecules, such as lone-paired nitrogen species, include pyrrole, pyrazole, and quinoline. These molecules contain nitrogen and take part in metabolic reactions with other molecules inside the cell. However, an excessive accumulation of reactive nitrogen species can lead to cytotoxicity, resulting in damage to essential biological macromolecules. Among these compounds, quinoline stands out as the oldest and most effective one, exhibiting a wide range of significant properties such as antitubercular, antimicrobial, anti-inflammatory, antioxidant, analgesic, and anticonvulsant activities. Notably, naturally occurring quinoline compounds, such as quinine, have proven to be potent antimalarial drugs. CONCLUSION: This review highlights quinoline derivatives' antitubercular potential, emphasizing recent research advancements. Utilizing IC50 values, the study emphasizes the efficacy of various quinoline substitutions, hybrids, and electron-withdrawing groups against MTB H37Rv. Continued research is essential for developing potent, low-toxicity quinoline derivatives to combat tuberculosis.

Bilateral hand dactylitis: An unusual presentation of the great imitator: Tuberculosis.

The incidence of tuberculosis in developed countries has decreased over the years due to the use of effective tuberculosis drugs and improvements in socio-economic conditions. However, with the ease of global transport and increased travel to countries with high tuberculosis prevalence, the reduction in extrapulmonary tuberculosis cases has been less significant compared with the overall decrease in tuberculosis cases. Extrapulmonary tuberculosis can manifest in a variety of ways. Tuberculous dactylitis, a rare form of tuberculous osteomyelitis, was first described by Rankin in 1886. It mainly affects the short tubular bones in the hands and feet of children and is sometimes called 'spina ventosa'. A 42-year-old male patient initially presented to an external centre reporting swelling and pain in the hand joints of one year's duration. Despite one year of treatment with leflunomide and methylprednisolone (16 mg) and a history of methotrexate use during this period, he experienced no improvement. The patient's condition worsened after the start of sulfasalazine. Dermatological examination was performed due to the presence of haemorrhagic crusted papules and plaques on the ventral surface of both hands. A wound culture was taken, but no bacterial growth was observed. One week after the initial evaluation, the patient complained of persistent foul-smelling nasal discharge, which led to an evaluation by the infectious disease department. At this time, the Quantiferon test was positive. Mycobacterial culture on Days 1 and 3 showed growth of the Mycobacterium tuberculosis complex.

Whole genome sequencing reveals candidate genes involving in PAS resistance in M. Tuberculosis isolated from patients in Thailand.

Para-amino salicylic acid (PAS) was first reported by Lehmann in 1946 and used for tuberculosis treatment. However, due to its adverse effects, it is now used only as a second line anti-tuberculosis drug for treatment of multidrug resistant or extensively drug resistant M. tuberculosis. The structure of PAS is similar to para-amino benzoic acid (pABA), an intermediate metabolite in the folate synthesis pathway. The study has identified mutations in genes in folate pathway and their intergenic regions for their possibilities in responsible for PAS resistance. Genomic DNA from 120 PAS-resistant and 49 PAS-sensitive M. tuberculosis isolated from tuberculosis patients in Thailand were studied by whole genome sequencing. Twelve genes in the folate synthesis pathway were investigated for variants associated with PAS resistance. Fifty-one SNVs were found in nine genes and their intergenic regions (pabC, pabB, folC, ribD, thyX, dfrA, thyA, folK, folP). Functional correlation test confirmed mutations in RibD, ThyX, and ThyA are responsible for PAS resistance. Detection of mutation in thyA, folC, intergenic regions of thyX, ribD, and double deletion of thyA dfrA are proposed for determination of PAS resistant M. tuberculosis.

Deciphering drug discovery and microbial pathogenesis research in tuberculosis during the two decades of postgenomic era using entity mining approach.

We examined literature on Mycobacterium tuberculosis (Mtb) subsequent to its genome release, spanning years 1999-2020. We employed scientometric mapping, entity mining, visualization techniques, and PubMed and PubTator databases. Most popular keywords, most active research groups, and growth in quantity of publications were determined. By gathering annotations from the PubTator, we determined direction of research in the areas of drug hypersensitivity, drug resistance (AMR), and drug-related side effects. Additionally, we examined the patterns in research on Mtb metabolism and various forms of tuberculosis, including skin, brain, pulmonary, extrapulmonary, and latent tuberculosis. We discovered that 2011 had the highest annual growth rate of publications, at 19.94%. The USA leads the world in publications with 18,038, followed by China with 14,441, and India with 12,158 publications. Studies on isoniazid and rifampicin resistance showed an enormous increase. Non-tuberculous mycobacteria also been the subject of more research in effort to better understand Mtb physiology and as model organisms. Researchers also looked at co-infections like leprosy, hepatitis, plasmodium, HIV, and other opportunistic infections. Host perspectives like immune response, hypoxia, and reactive oxygen species, as well as comorbidities like arthritis, cancer, diabetes, and kidney disease etc. were also looked at. Symptomatic aspects like fever, coughing, and weight loss were also investigated. Vitamin D has gained popularity as a supplement during illness recovery, however, the interest of researchers declined off late. We delineated dominant researchers, journals, institutions, and leading nations globally, which is crucial for aligning ongoing and evolving landscape of TB research efforts. Recognising the dominant patterns offers important information about the areas of focus for current research, allowing biomedical scientists, clinicians, and organizations to strategically coordinate their efforts with the changing priorities in the field of tuberculosis research.

Finding and treating both tuberculosis disease and latent infection during population-wide active case finding for tuberculosis elimination.

In recognition of the high rates of undetected tuberculosis in the community, the World Health Organization (WHO) encourages targeted active case finding (ACF) among "high-risk" populations. While this strategy has led to increased case detection in these populations, the epidemic impact of these interventions has not been demonstrated. Historical data suggest that population-wide (untargeted) ACF can interrupt transmission in high-incidence settings, but implementation remains lacking, despite recent advances in screening tools. The reservoir of latent infection-affecting up to a quarter of the global population -complicates elimination efforts by acting as a pool from which future tuberculosis cases may emerge, even after all active cases have been treated. A holistic case finding strategy that addresses both active disease and latent infection is likely to be the optimal approach for rapidly achieving sustainable progress toward TB elimination in a durable way, but safety and cost effectiveness have not been demonstrated. Sensitive, symptom-agnostic community screening, combined with effective tuberculosis treatment and prevention, should eliminate all infectious cases in the community, whilst identifying and treating people with latent infection will also eliminate tomorrow's tuberculosis cases. If real strides toward global tuberculosis elimination are to be made, bold strategies are required using the best available tools and a long horizon for cost-benefit assessment.

Spina Ventosa of the Left Index Finger in an Indian Girl With No Pulmonary Involvement: A Rare Case.

Mycobacterium tuberculosis is a significant issue in endemic countries. The most common manifestation of skeletal tuberculosis in children is spondylitis, also known as Pott disease, but it may rarely involve small bones. Usually, a pulmonary focus is present from where the bacteria reach the extremities, but an isolated tuberculous involvement of the left index finger in a child without any pulmonary seeding is rare. It is a challenging diagnosis due to a lack of awareness among primary care physicians, the paucibacillary nature of the disease, and overlapping clinical features with other musculoskeletal disorders. A 13-year-old girl was brought in with complaints of pain, swelling, and discharging sinuses from her left index finger. A diagnosis was achieved after a histopathological correlation of clinical and radiological findings. She was started on anti-tubercular treatment for 12 months.

Molecular diversity of Mycobacterium tuberculosis isolates in Treatment-experienced Patients from Andhra Pradesh, India.

INTRODUCTION: To get a comprehensive idea about the transmission and epidemiology of TB globally and locally, the use of molecular typing methods has become imperative not only for understanding genetic diversity but also the population structure of Mycobacterium tuberculosis complex (MTBC). We aimed to investigate the drug resistance pattern and genetic diversity of MTBC among previously treated patients with sputum smear-positive pulmonary tuberculosis in a South Indian population. METHODOLOGY: 104 patients with sputum smear positivity and who had previously undergone treatment were selected. Drug susceptibility testing, Spoligotyping, MIRU-VNTR, and SNP typing were performed. RESULTS: Mono-resistance to isoniazid 16 (15.38%) was the highest among all drugs. Out of 104 isolates, 24 (23%) isolates were classified as MDR strains. The distributions of most common lineages were: EAI3-Ind-20 (19.23%), EAI5-13 (12.50%), Beijing-12 (11.54%), CAS1-Delhi- 9 (8.65%), and 7 (6.73%) each of T-H37rv, Unknown and Orphan types. MIRU-VNTR-based analysis revealed that there are two major groups: CAS1-Delhi and Beijing groups. Out of 104 isolates, 82 belonged to well-defined lineages and 6 clusters, and the remaining 22 were singletons. SNP analysis showed no mutations associated with five sets of genes in 33 strains. CONCLUSIONS: The occurrence of 11.54% Beijing strains in South India is an important finding. High frequency of Isoniazid mono resistance noticed. Spoligotyping along with MIRU-VNTR and SNP typing is the best approach to the identification of strain lineages. No mutation with Antigen85C gene represents, can be used for vaccine candidates.

Liposomal Glutathione Supplementation Mitigates Extrapulmonary Tuberculosis in the Liver and Spleen.

BACKGROUND: Extrapulmonary tuberculosis (EPTB) accounts for a fifth of all Mycobacterium tuberculosis (M. tb) infections worldwide. The rise of multidrug resistance in M. tb alongside the hepatotoxicity associated with antibiotics presents challenges in managing and treating tuberculosis (TB), thereby prompting a need for new therapeutic approaches. Administration of liposomal glutathione (L-GSH) has previously been shown to lower oxidative stress, enhance a granulomatous response, and reduce the burden of M. tb in the lungs of M. tb-infected mice. However, the effects of L-GSH supplementation during active EPTB in the liver and spleen have yet to be explored. METHODS: In this study, we evaluated hepatic glutathione (GSH) and malondialdehyde (MDA) levels, and the cytokine profiles of untreated and L-GSH-treated M. tb-infected wild type (WT) mice. Additionally, the hepatic and splenic M. tb burdens and tissue pathologies were also assessed. RESULTS: L-GSH supplementation increased total hepatic levels and reduced GSH. A decrease in the levels of MDA, oxidized GSH, and interleukin (IL)-6 was also detected following L-GSH treatment. Furthermore, L-GSH supplementation was observed to increase interferon-gamma (IFN-γ) and tumor necrosis factor (TNF)-α production and decrease IL-10 levels. M. tb survival was significantly reduced in the liver and spleen following L-GSH supplementation. L-GSH treatment also provided a host-protective effect in the liver and spleen of M. tb-infected mice. CONCLUSIONS: Overall, L-GSH supplementation elevated the levels of total and reduced forms of GSH in the liver and reduced the burden of M. tb by decreasing oxidative stress, enhancing the production of immunosupportive cytokines, and reducing the levels of immunosuppressive cytokines. These observed benefits highlight the potential of L-GSH supplementation during active EPTB and provide insight into novel therapeutic interventions against M. tb infections.

Determination of anti-tuberculosis activity of biosynthesized gold nanocompounds against M. tuberculosis H37RV.

BACKGROUND: The biosynthesis of gold nanoparticles using medicinal plants as reducing and stabilizing agent for synthesis is an emerging area of research due to their cost effectiveness and further diversified applications in various fields. People with HIV are prone to these opportunistic infections like TB due to the immunocompromised condition. In the present study, the nanoparticles and nanoconjugates were screened for effective anti-mycobacterial efficiency against opportunistic infections. METHODS: Incidentally, the nanoparticles were biosynthesized using single plant extract. The biosynthesized nanoparticles were initially screened for effective anti-tuberculosis activity against Mycobacterium tuberculosis. Based on the effective antimicrobial activity, a nanoconjugate was biosynthesized combining three plant extracts for a cumulative activity. RESULTS: The biosynthesized gold nanoparticles and nanoconjugates showed MIC demonstrating for 99% inhibition and MIC99 was found to be 6.42 µg/ml. Among all the 15 nanoparticles tested, seven NPs showed exceptional anti-TB activities NP1, NP2, NP6, NP7, NP10, NP12 and NP15 and the other nanoparticles exhibited varying degrees of inhibition - anti-TB activities. In the 12 nanoconjugate tested, seven nanoconjugate demonstrated exceptional anti-TB activities such as NCC1, NCC2, NCC5, NCC6, NCV1, NCV6 and NCV4. CONCLUSION: The objective of the study was to identify the nanoparticles and nanoconjugates which demonstrated potential activity against M. tuberculosis so that a single nanoparticle or nanoconjugate can be targeted to treat patients with TB. Minimum Inhibitory Concentration (MIC) of the biosynthesized gold nanoparticles and nanoconjugates were determined against M. tuberculosis H37Rv.

Deciphering the emerging role of phytocompounds: Implications in the management of drug-resistant tuberculosis and ATDs-induced hepatic damage.

Tuberculosis is a disease of poverty, discrimination, and socioeconomic burden. Epidemiological studies suggest that the mortality and incidence of tuberculosis are unacceptably higher worldwide. Genomic mutations in embCAB, embR, katG, inhA, ahpC, rpoB, pncA, rrs, rpsL, gyrA, gyrB, and ethR contribute to drug resistance reducing the susceptibility of Mycobacterium tuberculosis to many antibiotics. Additionally, treating tuberculosis with antibiotics also poses a serious risk of hepatotoxicity in the patient's body. Emerging data on drug-induced liver injury showed that anti-tuberculosis drugs remarkably altered levels of hepatotoxicity biomarkers. The review is an attempt to explore the anti-mycobacterial potential of selected, commonly available, and well-known phytocompounds and extracts of medicinal plants against strains of Mycobacterium tuberculosis. Many studies have demonstrated that phytocompounds such as flavonoids, alkaloids, terpenoids, and phenolic compounds have antibacterial action against Mycobacterium species, inhibiting the bacteria's growth and replication, and sometimes, causing cell death. Phytocompounds act by disrupting bacterial cell walls and membranes, reducing enzyme activity, and interfering with essential metabolic processes. The combination of these processes reduces the overall survivability of the bacteria. Moreover, several phytochemicals have synergistic effects with antibiotics routinely used to treat TB, improving their efficacy and decreasing the risk of resistance development. Interestingly, phytocompounds have been presented to reduce isoniazid- and ethambutol-induced hepatotoxicity by reversing serum levels of AST, ALP, ALT, bilirubin, MDA, urea, creatinine, and albumin to their normal range, leading to attenuation of inflammation and hepatic necrosis. As a result, phytochemicals represent a promising field of research for the development of new TB medicines.

In-silico and in-vitro assessments of some fabaceae, rhamnaceae, apocynaceae, and anacardiaceae species against Mycobacterium tuberculosis H37Rv and triple-negative breast cancer cells.

Medicinal plants play a huge role in the treatment of various diseases in the Limpopo province (South Africa). Traditionally, concoctions used for treating tuberculosis and cancer are sometimes prepared from plant parts naturally occurring in the region, these include (but not limited to) Schotia brachypetala, Rauvolfia caffra, Schinus molle, Ziziphus mucronate, and Senna petersiana. In this study, the aim was to evaluate the potential antimycobacterial activity of the five medicinal plants against Mycobacterium smegmatis mc2155, Mycobacterium aurum A + , and Mycobacterium tuberculosis H37Rv, and cytotoxic activity against MDA-MB 231 triple-negative breast cancer cells. Phytochemical constituents present in R. caffra and S. molle were tentatively identified by LC-QTOF-MS/MS as these extracts showed antimycobacterial and cytotoxic activity. A rigorous Virtual Screening Workflow (VSW) of the tentatively identified phytocompounds was then employed to identify potential inhibitor/s of M. tuberculosis pantothenate kinase (PanK). Molecular dynamics simulations and post-MM-GBSA free energy calculations were used to determine the potential mode of action and selectivity of selected phytocompounds. The results showed that plant crude extracts generally exhibited poor antimycobacterial activity, except for R. caffra and S. molle which exhibited average efficacy against M. tuberculosis H37Rv with minimum inhibitory concentrations between 0.25-0.125 mg/mL. Only one compound with a favourable ADME profile, namely, norajmaline was returned from the VSW. Norajmaline exhibited a docking score of -7.47 kcal/mol, while, pre-MM-GBSA calculation revealed binding free energy to be -37.64 kcal/mol. All plant extracts exhibited a 50% inhibitory concentration (IC50) of < 30 µg/mL against MDA-MB 231 cells. Flow cytometry analysis of treated MDA-MB 231 cells showed that the dichloromethane extracts from S. petersiana, Z. mucronate, and ethyl acetate extracts from R. caffra and S. molle induced higher levels of apoptosis than cisplatin. It was concluded that norajmaline could emerge as a potential antimycobacterial lead compound. Validation of the antimycobacterial activity of norajmaline will need to be performed in vitro and in vivo before chemical modifications to enhance potency and efficacy are done. S. petersiana, Z. mucronate, R.caffra and S. molle possess strong potential as key contributors in developing new and effective treatments for triple-negative breast cancer in light of the urgent requirement for innovative therapeutic solutions.

Chemical analysis and antitubercular activity evaluation of the dried mycelial powders of the basidiomycete Ganoderma australe TBRC-BCC 22314.

The isolation of lanostane triterpenoids possessing significant anti-tuberculosis (anti-TB) activity from mycelial cultures of the basidiomycete Ganoderma australe strain TBRC-BCC 22314 was previously reported. To demonstrate the potential of the dried mycelial powder for utilization in anti-TB medicinal products, its authentic chemical analysis was performed. Considering the possibility of the changes in the lanostane compositions and anti-TB activity by sterilization, both autoclave treated and non-autoclaved mycelial powder materials were chemically investigated. The study led to the identification of the lanostanes responsible for the activity of the mycelial extract against Mycobacterium tuberculosis H37Ra. The anti-TB activity of the extracts from autoclaved and non-autoclaved mycelial powders were the same (MIC 3.13 µg/mL). However, the analytical results revealed several unique chemical conversions of the lanostanes under the sterilization conditions. The most potent major lanostane, ganodermic acid S (1), was shown to be significantly active also against the extensively drug-resistant (XDR) strains of M. tuberculosis.

Multi-drug resistant and rifampin-resistant tuberculosis in transplant recipients.

BACKGROUND: Management of multidrug-resistant (MDR) and rifampin-resistant (RR) tuberculosis is challenging. Data on transplant recipients is limited. We reviewed published literature to examine treatment choices, outcomes, and adverse effects from MDR-TB/RR-TB treatment in transplant recipients. METHODS: Multiple databases from inception to 12/2022 were reviewed using the keywords "drug-resistant TB" or "drug-resistant tuberculosis" or "multidrug-resistant TB" or "multidrug-resistant tuberculosis". MDR-TB was defined as resistance to isoniazid (H) and rifampin (R), and RR if resistant to rifampin alone. Cases without patient-level data and reports which did not describe treatment and/or outcomes for MDR-TB were excluded. RESULTS: A total of 12 patients (10 solid organ transplants and two hematopoietic cell transplants) were included. Of these, 11 were MDR-TB and one was RR-TB. Seven recipients were male. The median age was 41.5 (range 16-60) years. Pre-transplant evaluation for the majority (8/12, 66.7%) did not reveal a prior history of TB or TB treatment, but 9/12 were from TB intermediate or high-burden countries. Seven patients were initially treated with the quadruple first-line anti-TB regimen. Those who had early RR confirmation (5/12) via Xpert MTB/RIF assay were initiated on alternative therapies. Final regimens were individualized based on susceptibility profiles and tolerability. Adverse events were reported in seven recipients, including acute kidney injury (n = 3), cytopenias (n = 3), and jaundice (n = 2). Four recipients died, with two deaths attributable to TB. The remaining eight patients who survived had functioning allografts at the last follow-up. CONCLUSIONS: MDR-TB treatment in transplant recipients is associated with many complications. Xpert MTB/RIF detected RR early and guided early empiric therapy.

[Treatment of tuberculosis: what is new?] / Therapie der Tuberkulose: Was gibt es Neues?

Never before have so many people around the world been simultaneously affected by tuberculosis. Tuberculosis is the leading cause of death from a bacterial infectious disease worldwide. The World Health Organization's ambitious goal from 2014 of achieving global elimination of tuberculosis does not seem realistic, but on current trends, tuberculosis could be eliminated in the European Union by 2040. Since the beginning of 2022, there have been more innovations for the treatment of tuberculosis than in no other comparable time period before. One month of rifapentine and isoniazid is effective in treating latent tuberculosis infection. However, rifapentine is licensed in the USA but not in the EU and must be imported for individual cases. The duration of the standard treatment for tuberculosis can be shortened to four months but this treatment regimen is also based on rifapentine, in addition to isoniazid, pyrazinamide, and moxifloxacin. The approval of rifapentine in Europe is a much-needed step towards shortening the treatment of tuberculosis. With new drugs an even shorter standard treatment of only 2 months is possible. The treatment of multidrug-resistant/rifampicin-resistant tuberculosis (MDR-/RR-TB) has been shortened to six months, the same length as the standard treatment available in Germany. The combination of bedaquiline, pretomanid, linezolid ± moxifloxacin, cured around 90% of affected patients were cured in studies with a treatment duration of six months. With 19 drugs in clinical trials, the treatment of tuberculosis is expected to continue to improve rapidly in the coming years.

Identification of novel antimicrobial compounds targeting Mycobacterium tuberculosis shikimate kinase using in silico hierarchical structure-based drug screening.

The development of new anti-TB drugs to prevent the spread of multidrug-resistant Mycobacterium tuberculosis (Mtb) strains is imperative. Mtb shikimate kinase (MtSK) was selected as the target protein to screen for new anti-TB drugs. We performed hierarchical in silico screening using a library of 154,118 compounds to search for novel compounds that could bind to the active site of MtSK. The growth-inhibitory effects of the candidate compounds on Mycobacterium smegmatis were evaluated in vitro. Nine of the 11 candidate compounds exhibited inhibitory effects against mycobacteria in vitro. The inhibitory activity of Compound 2 (IC50 = 1.39 µM) was higher than that of isoniazid, the first-line drug for TB treatment. Moreover, Compound 2 did not exhibit toxicity against mammalian cells and Escherichia coli. Molecular dynamics simulations using the MtSK-Compound 2 complex structure in a timeframe of 100 ns suggested that Compound 2 could stably bind to MtSK. The binding free energy of Compound 2 was estimated to be -37.96 kcal/mol using the MM/PBSA method, demonstrating that Compound 2 can stably bind to MtSK. These in silico and in vitro results indicated that Compound 2 is a promising hit compound for the development of novel anti-TB drugs.

The impact of genotype on the phenotype of Mycobacterium tuberculosis ΔsufR mutants.

Iron-sulphur (FeS) cluster biogenesis is a tightly regulated process in vivo. In Mycobacterium tuberculosis (Mtb), SufR functions as a transcriptional repressor of the operon encoding the primary FeS cluster biogenesis system. Previously, three independently isolated mutants (ΔRv1460stop_1.19, ΔRv1460stop _5.19 and ΔRv1460stop _5.20) harbouring the same deletion in sufR, displayed different growth kinetics in OADC supplemented 7H9 media. To investigate this discrepancy, we performed whole genome sequencing of the 3 mutants and the wild-type progenitor. Single nucleotide polymorphisms (SNPs) were identified in 3 genes in the ΔRv1460stop_1.19 mutant and one gene in the ΔRv1460stop_5.20 mutant. Phenotyping of the ΔRv1460stop_5.19 mutant, which had no additional SNPs, revealed increased susceptibility to clofazimine, DMNQ and menadione, while uptake and survival in THP-1 cells were not significantly different from the wild-type strain. Given that these results differ from those reported for other sufR deletion mutants (ΔSufRMTB and MtbΔSufR), they suggest that the position of the sufR deletion and the genotype of the progenitor strain impact the resulting phenotype.

The mutational signatures of poor treatment outcomes on the drug-susceptible Mycobacterium tuberculosis genome.

Drug resistance is a known risk factor for poor tuberculosis (TB) treatment outcomes, but the contribution of other bacterial factors to poor outcomes in drug-susceptible TB is less well understood. Here, we generate a population-based dataset of drug-susceptible Mycobacterium tuberculosis (MTB) isolates from China to identify factors associated with poor treatment outcomes. We analyzed whole-genome sequencing (WGS) data of MTB strains from 3196 patients, including 3105 patients with good and 91 patients with poor treatment outcomes, and linked genomes to patient epidemiological data. A genome-wide association study (GWAS) was performed to identify bacterial genomic variants associated with poor outcomes. Risk factors identified by logistic regression analysis were used in clinical models to predict treatment outcomes. GWAS identified fourteen MTB fixed mutations associated with poor treatment outcomes, but only 24.2% (22/91) of strains from patients with poor outcomes carried at least one of these mutations. Isolates from patients with poor outcomes showed a higher ratio of reactive oxygen species (ROS)-associated mutations compared to isolates from patients with good outcomes (26.3% vs 22.9%, t-test, p=0.027). Patient age, sex, and duration of diagnostic delay were also independently associated with poor outcomes. Bacterial factors alone had poor power to predict poor outcomes with an AUC of 0.58. The AUC with host factors alone was 0.70, but increased significantly to 0.74 (DeLong's test, p=0.01) when bacterial factors were also included. In conclusion, although we identified MTB genomic mutations that are significantly associated with poor treatment outcomes in drug-susceptible TB cases, their effects appear to be limited.