Multidrug-resistant Tuberculosis Research Articles

Integrated virtual screening and MD simulation study to discover potential inhibitors of mycobacterial electron transfer flavoprotein oxidoreductase.

Tuberculosis (TB) continues to be a major global health burden, with high incidence and mortality rates, compounded by the emergence and spread of drug-resistant strains. The limitations of current TB medications and the urgent need for new drugs targeting drug-resistant strains, particularly multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB, underscore the pressing demand for innovative anti-TB drugs that can shorten treatment duration. This has led to a focus on targeting energy metabolism of Mycobacterium tuberculosis (Mtb) as a promising approach for drug discovery. This study focused on repurposing drugs against the crucial mycobacterial protein, electron transfer flavoprotein oxidoreductase (EtfD), integral to utilizing fatty acids and cholesterol as a carbon source during infection. The research adopted an integrative approach, starting with virtual screening of approved drugs from the ZINC20 database against EtfD, followed by molecular docking, and concluding with molecular dynamics (MD) simulations. Diacerein, levonadifloxacin, and gatifloxacin were identified as promising candidates for repurposing against TB based on their strong binding affinity, stability, and interactions with EtfD. ADMET analysis and anti-TB sensitivity predictions assessed their pharmacokinetic and therapeutic potential. Diacerein and levonadifloxacin, previously unexplored in anti-tuberculous therapy, along with gatifloxacin, known for its efficacy in drug-resistant TB, have broad-spectrum antimicrobial properties and favorable pharmacokinetic profiles, suggesting potential as alternatives to current TB treatments, especially against resistant strains. This study underscores the efficacy of computational drug repurposing, highlighting bacterial energy metabolism and lipid catabolism as fruitful targets. Further research is necessary to validate the clinical suitability and efficacy of diacerein, levonadifloxacin, and gatifloxacin, potentially enhancing the arsenal against global TB.

Time to Cure and Predictive Factors Among Patients with Multi-Drug Resistance Tuberculosis in Puntland, Somalia: A Retrospective Cohort Study

Background: Multi-drug-resistant tuberculosis, also known as MDR-TB, is caused by bacteria that are resistant to the most effective first-line anti-tuberculosis medications, which are rifampicin and isoniazid. MDR-TB is an increasing global concern, and its spread has varying cure times for patients affected. Thus, this study was intended to investigate the median time to cure and identify predictive factors for patients with MDR-TB in Puntland, Somalia. Methods: A retrospective cohort study was carried out at the MDR-TB center in Galkayo, Puntland, Somalia between the years of July 2017 and August 2023. The study utilized data that were collected from the inquiry form and monitoring cards of a randomly selected sample of 130 patients over a 6-year period. The data were entered into Epi-Data version 4.3 and analyzed using R Programming version 4.4.0. Non-parametric methods were used to estimate the median time to cure for patients with MDR-TB. Semi-parametric and parametric models were employed to determine predictive factors that influence the time to cure for MDR-TB patients. The Akaike Information Criteria (AIC) and Bayesian Information Criteria (BIC) of different survival models were compared to select the model that offers the best fit. Results: Out of the total of MDR-TB patients, 109(83.85%) were cured and 21(16.15%) were censored during the follow-up period. The median time to cure from MDR-TB was found to be 619 days which is approximately 20 months. In accordance with the AIC and BIC, the Log-logistic accelerated failure time model was the best fit for the data as compared to the other AFT models. The result of the Log-logistic AFT model revealed that age, sex, disease site, and comorbidities significantly affect the time to cure for MDR-TB. According to this study, older age with MDR-TB patients, male MDR-TB patients, MDR-TB patients with comorbid conditions, and extrapulmonary MDR-TB patients had a longer time to cure than their reference categories. Conclusion: Based on the findings of the study, the median time to cure for patients with MDR-TB in Puntland was found to be 20 months. Sex, disease site, comorbidities and age were predictive factors of time to cure from MDR-TB.

Small Molecule Inhibitors of Mycobacterium tuberculosis Topoisomerase I Identified by Machine Learning and In Vitro Assays

Tuberculosis (TB) caused by Mycobacterium tuberculosis is a leading infectious cause of death globally. The treatment of patients becomes much more difficult for the increasingly common multi-drug resistant TB. Topoisomerase I is essential for the viability of M. tuberculosis and has been validated as a new target for the discovery of novel treatment against TB resistant to the currently available drugs. Virtual high-throughput screening based on machine learning was used in this study to identify small molecules that target the binding site of divalent ion near the catalytic tyrosine of M. tuberculosis topoisomerase I. From the virtual screening of more than 2 million commercially available compounds, 96 compounds were selected for testing in topoisomerase I relaxation activity assay. The top hit that has IC50 of 7 µM was further investigated. Commercially available analogs of the top hit were purchased and tested with the in vitro enzyme assay to gain further insights into the molecular scaffold required for topoisomerase inhibition. Results from this project demonstrated that novel small molecule inhibitors of bacterial topoisomerase I can be identified starting with the machine-learning-based virtual screening approach.

Assessing the Impact of Bedaquiline, Clofazimine, and Linezolid on Mycobacterial Genome Integrity

Tuberculosis (TB) presents significant medical challenges, largely due to the genetic diversity of Mycobacterium tuberculosis, which enhances the resilience and resistance of the pathogen to first-line treatments. In response to the global rise of drug-resistant TB, second-line antitubercular drugs like bedaquiline (BDQ), linezolid (LZD), and clofazimine (CFZ) have become critical treatment options. Understanding the molecular changes these drugs induce is essential for optimizing TB therapy. To contribute to this effort, we investigated their impact on genome maintenance and stability using Mycobacterium smegmatis as a model organism. Using mutation accumulation assays and whole-genome sequencing, we found that the second-line antibiotics did not significantly increase mutation rates, unlike the positive control UV treatment. However, upon BDQ treatment, we detected mutations in transporter proteins and transcription factors without any increase in the minimal inhibitory concentration. Additionally, BDQ and CFZ were found to alter DNA repair pathways and reduce cellular dNTP levels, particularly CFZ, which depleted dGTP, impacting DNA synthesis. CFZ also upregulated DNA repair enzymes, enhancing error-free repairs. Despite minimal mutagenic effects, both drugs displayed distinct impacts on cellular mechanisms, suggesting additional modes of action.

Treatment outcomes and associated factors among patients with multidrug-resistant tuberculosis in Southwestern Oromia, Ethiopia: ten-year retrospective analysis.

Treatment of rifampicin-resistant or multidrug-resistant tuberculosis (RR/MDR-TB) requires the use of second-line anti-TB drugs, which are less effective and more toxic. This study assessed treatment outcomes and factors associated with unfavorable treatment outcomes among RR/MDR-TB patients in Southwestern Oromia, Ethiopia. A multicenter retrospective study was conducted on 226 RR/MDR-TB patients (six extrapulmonary and 220 pulmonary) treated under a national TB program between 2013 and 2022 at five treatment facilities in Southwestern Oromia, Ethiopia. RR/MDR-TB patient data, such as sociodemographic, clinical, and laboratory results and treatment outcomes, were collected from the RR/MDR-TB registry using a standard data extraction form between April and June 2023. Logistic regression analysis was used to explore the associations between risk factors and unfavorable treatment outcomes. Among 220 pulmonary RR/MDR-TB patients, 181 (82.3%) achieved favorable treatment outcomes (161 cured and 20 treatment completed). However, 39 (17.7%) patients had unfavorable treatment outcomes (12 were lost to follow-up, seven experienced treatment failure, and 20 died). Of the six extrapulmonary RR/MDR-TB patients, five (83.3%) had favorable treatment outcomes, and one (16.7%) was lost to follow-up. Pulmonary RR/MDR-TB patients with HIV infection (AOR = 4.85, 95% CI: 1.90 to 12.39), history of previous TB treatment (AOR = 3.09, 95% CI: 1.21 to 7.86), and low baseline BMI (AOR = 2.86, 95% CI: 1.06 to 7.72) had increased risk of unfavorable treatment outcomes. Although the majority of RR/MDR-TB patients have favorable treatment outcomes, a significant proportion of patients still experienced unfavorable outcomes. Patients with HIV infection, history of previous TB treatment, and low baseline BMI require special attention to improve pulmonary RR/MDR-TB treatment outcomes. Future studies with larger sample sizes are required to evaluate treatment outcomes and associated factors among patients with extrapulmonary RR/MDR-TB.

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 mycobacterialATP synthase. However, themechanisms 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 mechanisticallyinduce collateral antimicrobial drug sensitivity and reveal druggable vulnerabilities in antimicrobial resistant pathogens.

Population-level frequency of fluoroquinolone resistance by whole-genome sequencing drug predictions in Mycobacterium tuberculosis complex isolates in England from 2017-2023.

Fluoroquinolones are an important component of anti-tuberculosis treatment and identifying fluoroquinolone resistance is essential. We present the first survey of fluoroquinolone resistance in England from sequencing of over 16,000 unselected isolates. Fluoroquinolone resistance was 1.4% overall and 23.9% in multidrug-resistant TB. Routine sequencing allows resistance surveillance and should be widely adopted.

Arenicolide Family Macrolides Provide a New Therapeutic Lead Combating Multidrug-Resistant Tuberculosis.

The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Mycobacterium tuberculosis (Mtb) poses a significant threat to health globally. During searching for new chemical entities regulating MDR- and XDR-Mtb, chemical investigation of the black oil beetle gut bacterium Micromonospora sp. GR10 led to the discovery of eight new members of arenicolides along with the identification of arenicolide A (Ar-A, 1), which was a previously reported macrolide with incomplete configuration. Genomic analysis of the bacterial strain GR10 revealed their putative biosynthetic pathway. Quantum mechanics-based computation, chemical derivatizations, and bioinformatic analysis established the absolute stereochemistry of Ar-A and arenicolides D-K (Ar-D-K, 2-9) completely for the first time. Biological studies of 1-9 revealed their antimicrobial activity against MDR and XDR strains of Mtb. Ar-A had the most potent in vitro antimicrobial efficacy against MDR- and XDR-Mtb. Mechanistically, Ar-A induced ATP depletion and destabilized Mtb cell wall, thereby inhibiting growth. Notably, Ar-A exerted a significant antimicrobial effect against Mtb in macrophages, was effective in the treatment of Mtb infections, and showed a synergistic effect with amikacin (AMK) in a mouse model of MDR-Mtb lung infection. Collectively, our findings indicate Ar-A to be a promising drug lead for drug-resistant tuberculosis.

A CT-based radiomics analyses for differentiating drug‑resistant and drug-sensitive pulmonary tuberculosis.

To explore the value of computed tomography based radiomics in the differential diagnosis of drug-sensitive and drug-resistant pulmonary tuberculosis. The clinical and computed tomography image data of 177 patients who were diagnosed with pulmonary tuberculosis through sputum culture and completed drug-susceptibility testing from April 2018 to December 2020 at the Second Hospital of Nanjing were retrospectively analyzed. Patients with drug-resistant pulmonary tuberculosis (n = 78) and drug-sensitive pulmonary tuberculosis (n = 99) were randomly divided into a training set (n = 124) and a validation set (n = 53) at a ratio of 7:3. Regions of interest were drawn to delineate the lesions and radiomics features were extracted from non-contrast computed tomography images. A radiomics signature based on the valuable radiomics features was constructed and a radiomics score was calculated. Demographic data, clinical symptoms, laboratory results and computed tomography imaging characteristics were evaluated to establish a clinical model. Combined with the Rad-score and clinical factors, a radiomics-clinical model nomogram was constructed. Thirteen features were used to construct the radiomics signature. The radiomics signature showed good discrimination in the training set (area under the curve (AUC), 0.891; 95% confidence interval (CI), 0.832-0.951) and the validation set (AUC, 0.803; 95% CI, 0.674-0.932). In the clinical model, the AUC of the training set was 0.780(95% CI, 0.700-0.859), while the AUC of the validation set was 0.692 (95% CI, 0.546-0.839). The radiomics-clinical model showed good calibration and discrimination in the training set (AUC, 0.932;95% CI, 0.888-0.977) and the validation set (AUC, 0.841; 95% CI, 0.719-0.962). Simple radiomics signature is of great value in differentiating drug-sensitive and drug-resistant pulmonary tuberculosis patients. The radiomics-clinical model nomogram showed good predictive, which may help clinicians formulate precise treatments.

In vitro monitoring of drug resistance emergence during stepwise induction of bedaquiline and clofazimine, alone and in combination: a phenotypic and genotypic analysis.

The co-resistance between bedaquiline and clofazimine raises significant concerns, as they are commonly co-administered as core drugs in drug-resistant TB regimens. The present study aimed to monitor drug resistance-associated gene mutations and the phenotypic change in Mycobacterium tuberculosis (Mtb) under a stepwise drug resistance induction in vitro using bedaquiline, clofazimine or combined drugs. Drug-resistant Mtb strains were gradually induced in vitro on a drug-containing solid medium with a 2-fold increasing concentration of bedaquiline, clofazimine and their combination. The MIC of the induced drug-resistant Mtb strains was determined. The drug resistance-associated genes, including Rv0678, Rv1979c, atpE and pepQ, were sequenced and analysed. Unlike exposure to bedaquiline alone or the combination of these two drugs, clofazimine alone resulted in drug resistance gene mutations occurring later, specifically in the fourth round of induction as opposed to the second round of induction. Besides, nucleotide deletion or insertion in Rv0678 was the main mutation type for induction under the two-drug combination, while single-nucleotide polymorphisms (SNPs) in Rv0678 were the major mutation types when induced by bedaquiline or clofazimine alone. Rv0678 mutation happened at a relatively lower bedaquiline concentration exposure alone, while atpE mutation occurred at a higher bedaquiline concentration. Regardless of the drug exposure manner, a strong correlation between bedaquiline MICs and clofazimine MICs was observed in all drug resistance strains. Combined exposure to bedaquiline and clofazimine developed Rv0678 mutation as early as exposure to bedaquiline alone. However, rather than SNPs, deletion and insertion were the dominant mutation types in dual-drug exposure strain.

Features of the pathogen and efficacy of drug-resistant tuberculosis treatment

According to the World Health Organization (WHO), nearly 10.6 million new cases of tuberculosis were detected in 2022, indicating an increase of 3.5 % from the reported 10.3 million in 2021. After the COVID-19 pandemic, the incidence of tuberculosis increased by 3.9 % from 2020 to 2022. According to the latest regulatory documents, multidrug-resistant pathogen is diagnosed when any bacteriologic or molecular genetic methods reveal drug resistance of M. Tuberculosis complex at least to isoniazid and rifampicin regardless of resistance to other antituberculosis drugs.With a wide range of virulence genes, the tuberculosis pathogen expresses genes in different phases of infection. Some genes are “switched on” in the early phases and are important for overcoming immune defenses and spreading the pathogen in the host, while others are important for survival in the latent phase. These characteristics of Mycobacterium tuberculosis determine the need for correct and adequate selection of therapy. The problem of diagnostics and treatment of drug-resistant tuberculosis remains extremely urgent. Despite the introduction of new tests for rapid determination of drug susceptibility spectrum of Mycobacterium tuberculosis, the problem of timely and adequate prescription of chemotherapy regimen remains. When selecting therapy, the problem of prescribing a combination of antituberculosis drugs with proven efficacy against M. tuberculosis remains. The need to assess the patient’s comorbid status, which affects the effectiveness of treatment and the occurrence of relapses, remains relevant.Despite the introduction of new tests for rapid determination of the drug susceptibility spectrum of Mycobacterium tuberculosis, the problem of timely and adequate prescription of chemotherapy remains relevant. The problem of prescribing a combination of antituberculosis drugs with proven efficacy against M. tuberculosis remains in the selection of therapy. Currently, the introduction of bedaquiline in therapy regimens is important for improving the effectiveness of tuberculosis treatment. In addition, studies are underway to shorten the duration of therapy for MDR-TB and XDR-TB, which is particularly important for maintaining patient adherence to treatment.

Case Report: Multi drug resistant tuberculosis in an 18-month-old boy with seizure, vomiting, and loss of vision

Multi drug resistant tuberculosis (MDR-TB) in children is rare and requires tremendous skill and knowledge of clinicians for early detection and treatment. This case highlights the complexities in diagnosing and treating MDR-TB in young children. An 18-month-old immunocompetent boy presented with prolonged fever, sudden onset of vision loss, vomiting, and seizures, which led to a suspicion of meningitis. Given his family history of treated pulmonary TB (TB) in the father and uncle one year ago, the initial treatment followed the Nepali national protocol for non-MDR tuberculous meningitis (TBM). However, the child's lack of response to this treatment raised concerns about MDR-TB, particularly after discovering on close questioning that the uncle, who lived with the boy’s family, had actually been diagnosed with MDR-TB. The diagnosis was confirmed by molecular tests of cerebrospinal fluid (CSF) and customized treatment for MDR TBM administered. The boy then slowly improved and became less irritable, afebrile, seizure-free, developed spontaneous movements of all four limbs, and was discharged after one month. Delays in suspicion, confirmation, and treatment of MDR TBM led to complications of leptomeningitis with non-communicating hydrocephalus and bilateral optic atrophy, which was confirmed by magnetic resonance imaging (MRI) scan of the brain. This case highlights the importance of taking a very thorough and proper history and considering the possibility of MDR, especially in countries like Nepal where TB in general is rampant so that timely diagnosis and treatment is possible and complications are avoided.

Tuberculosis in Times of War and Peace

This chapter provides a comprehensive analysis of tuberculosis (TB) across different historical contexts of war and peace, underscoring the disease’s resilience and adaptability. It highlights the exacerbation of TB transmission due to war-related factors such as mass displacement, malnutrition, and compromised healthcare systems, while also noting periods of peace as opportunities for advancing TB control measures. The chapter examines the impact of major conflicts on TB incidence and management, including World Wars I and II and more recent conflicts like the Ukraine war. It also discusses the evolution of TB control efforts, from the discovery of Mycobacterium tuberculosis to modern strategies against drug-resistant TB, emphasizing the importance of international collaboration and integrated public health strategies to combat this enduring global health challenge.

PECULIARITIES OF FATAL CASES IN HIV-INFECTED PATIENTS WITH CENTRAL NERVOUS SYSTEM LESIONS IN TUBERCULOSIS INPATIENT SETTINGS FOR 2014-2023

Aim of the work is to study the peculiarities of fatal cases of CNS lesions in patients with tuberculosis against the background of HIV infection.Materials and methods. A retrospective analysis of 68 medical histories of tuberculosis patients with HIV infection who died in the CNE "Zaporizhia Regional Phthisiopulmonology Clinical Treatment and Diagnostic Center" for the years 2014-2023 was carried out. An analysis of the anamnesis, clinical and radiological data, laboratory indicators, final clinical and pathological diagnoses was carried out.Results. The mortality rate among HIV-infected people in TB hospitals has a steady downward trend. In 2014-2023, 1234 patients with HIV infection were treated at the CNE "Zaporizhia Regional Phthisiopulmonology Clinical Treatment and Diagnostic Center", 214 (17.3%) died. In 2014, 33 (24.6%) out of 134 HIV-positive patients died, and in 2023, 3 (6.8%) out of 44 HIV-positive patients died. Central nervous system (CNS) lesions among the dead were noted in 68 (31.8%) patients. The study of medical records found that among those who died with CNS lesions, men prevailed - 55 (80.9%), women - 13 (19.1%), young patients - 53 (77.9%), and 15 (22.1%) patients over 45 years of age. In the structure of central nervous system lesions in patients with active tuberculosis, tuberculous meningoencephalitis prevails in fatal cases - 35 (51.5%), a significant share of cryptococcal meningoencephalitis - 18 (26.5%) and progressive multifocal leukoencephalopathy - 9 (13.2%). The main reason that leads to fatal consequences is the late diagnosis of HIV infection - in 26 (38.2%) the number of CD4<50 cl./μl, 36 (52.9%) patients did not receive antiretroviral therapy (ART), 18 (26 .5%) of patients had been taking ART for a year. Improvement of tuberculosis microbiological diagnosis due to the introduction of the Xpert MTB/RIF® (Ultra) test at all levels of the laboratory network, the introduction of a mandatory test for cryptococci, free CT, MRI examination for the diagnosis in HIV-infected patients, improvement of drug-resistant tuberculosis treatment regimens contributed to the reduction of mortality in case of HIV and tuberculosis combination, which was 24.6% in 2014, and 6.8% in 2023.Conclusions. Diagnosis and treatment of CNS diseases in patients with active tuberculosis against the background of HIV infection requires a comprehensive approach: early diagnosis of HIV infection, tuberculosis and lesions of the CNS, improvement of treatment.

Actor Sensemaking and its Role in Implementation of the Decentralized Drug-Resistant TB Policy in South Africa.

South Africa has a high burden of drug-resistant tuberculosis (DR-TB). A policy to decentralize DR-TB treatment from specialized central hospitals to more accessible district facilities was introduced in 2011, but to date implementation has been suboptimal, with variable pace, coverage and models of care emerging. This study explored multilevel policy implementation of DR-TB decentralization in two provinces of South Africa, Western Cape and KwaZulu-Natal. Applying interpretive policy analysis, this paper describes how actors across health system levels and geographies made sense of the DR-TB policy and how this shaped implementation. In an embedded qualitative case study, districts of the two provinces were compared, through data collected in 94 in-depth interviews, and analysed using Vickers' framework of reality, value and action judgements. Five district cases characterise variation in the pace of implementation and models of DR-TB care that emerged. Individual and collective attitudes for and against the policy were underpinned by different systems of meaning for interpreting policy problems and making decisions. These meaning systems were reflected in actor stances on whether DR-TB care needed to be specialized or generalized, nurse- or doctor-led, and institutionalized or ambulatory. Actors' stances influenced their actions and implementation strategies adopted. Resistance to decentralized DR-TB care related to perceived threats of budget cuts to and loss of authority of central facilities, and was often justified in fears of increased transmission, poor quality of care and inadequate resources at lower levels. New advances in diagnosis and treatment to address the growing burden of DR-TB in South Africa will have little impact unless implementation dynamics are better understood, and attention paid to the mindsets, interests and interpretations of policy by actors tasked with implementation. Deliberative policy implementation processes will enhance the quality of discourse, communication and cross-learning between policy actors, critical for reaching synthesis of meaning systems.

Supporting multidrug-resistant or rifampicin-resistant TB treatment adherence in people with harmful use of alcohol through person-centred care.

TB is concentrated in populations with complex health and social issues, including alcohol use disorders (AUD). We describe treatment adherence and outcomes in a person-centred, multidisciplinary, psychosocial support and harm reduction intervention for people with multidrug-resistant or rifampicin-resistant TB (MDR/RR-TB) with harmful alcohol use. An observational cohort study, including multilevel mixed-effects logistic regression and survival analysis with people living in Minsk admitted with MDR/RR-TB and AUD during January 2019-November 2021 who received this person-centred, multidisciplinary, psychosocial support and harm reduction intervention, was conducted. There were 89 participants enrolled in the intervention, with a median follow-up of 12.2 (IQR: 8.1-20.5) mo. The majority (n=80; 89.9%) of participants had AUD, 11 (12.4%) also had a dependence on other substances, six (6.7%) a dependence on opioids and three (3.4%) a personality disorder. Fifty-eight had a history of past incarceration (65.2%), homelessness (n=9; 10.1%) or unemployment (n=55; 61.8%). Median adherence was 95.4% (IQR: 90.4-99.6%) and outpatient adherence was 91.2% (IQR: 65.1-97.0%). Lower adherence was associated with hepatitis C, alcohol plus other substance use and outpatient facility-based treatment, rather than video-observed treatment, home-based or inpatient treatment support. This intervention led to good adherence to MDR/RR-TB treatment in people with harmful use of alcohol, a group usually at risk of poor outcomes. Poor outcomes were associated with hepatitis C, other substance misuse and outpatient facility-based treatment support.

Method development and validation of an analytical quality by design ultrafast liquid chromatographic method for the determination of bedaquiline from pharmaceutical bulk and nanoemulsions.

Bedaquiline (BDQ) is a drug used to treat multidrug-resistant tuberculosis (MDR-TB). It exhibits exposure-dependent efficacy in eliminating Mycobacterium tuberculosis (Mtb). An easy, efficient and precise reverse-phase ultrafast liquid chromatography (RP-UFLC) method was developed to validate the free base of the antitubercular medication BDQ. BDQ was separated using a 10:90 v/v mobile phase of ammonium acetate buffer solution (pH = 5.4) and high-performance liquid chromatography-grade methanol, with a flow rate of 1.5mL/min and a UV detection wavelength of 226 nm. By using the Box-Behnken design (BBD) and response surface methodology (RSM), the method was optimised by varying critical analytical attributes (CAA) and critical performance attributes (CPAs) namely ammonium acetate fraction (%), flow rate (ml/min), buffer system molarity (M) and pH. BDQ was eluted at 7.5min utilising isocratic elution. The method was linear in the concentration range of 0.5-300 μg/mL with limit of detection values of 0.039 μg/mL and limit of quantification of 0.12 μg/mL. The results indicate that this validated method can be used as an alternative method for assay of BDQ.

Dynamic modelling of improved diagnostic testing for drug-resistant tuberculosis in high burden settings.

Limited diagnostic testing for drug-resistant TB (DR-TB) may lead to high rates of misdiagnosis and undertreatment. Current diagnostic tests focus only on detection of rifampicin-resistant TB (RR-TB). This study aims to determine the impact of improved diagnostic testing for a wider range of drug resistance on DR-TB outcomes in high-burden TB settings, using the Philippines and Thailand as case studies. A dynamic compartmental model was designed to simulate population level TB transmission, accounting for acquired drug resistance from treatment failure of drug susceptible TB. Three scenarios were analyzed: (1) Use of GeneXpert MTB/RIF on all presumptive TB cases (Status Quo); (2) GeneXpert MTB/RIF + GeneXpert XDR, (3) GeneXpert MTB/RIF + targeted Next Generation Sequencing (tNGS). Scenarios were modelled over a 10-year period, from 2025 to 2034. Compared to the status quo, Scenario 2 results in a fourfold increase in annual DR-TB cases diagnosed in the Philippines and a fivefold increase in Thailand. DR-TB treatment failure decreases by 20% in the Philippines and 23% in Thailand. Scenario 3 further increases DR-TB case detection, reducing DR-TB treatment failure by 26% in the Philippines and 29% in Thailand. Reductions in DR-TB incidence and mortality ranged from 3 to 6%. The use of GeneXpert XDR or tNGS as an additional diagnostic test for DR-TB significantly improves DR-TB case detection and reduces treatment failure, supporting their consideration for use in high burden settings. These findings highlight the importance of detecting a wider range of TB resistance in addition to RR-TB, the potential impact these improved diagnostic tests can have on DR-TB outcomes, and the need for additional research on cost-effectiveness of these interventions.

Association between toxin-antitoxin system mutations and global transmission of MDR-TB.

The emergence of Multidrug-Resistant Tuberculosis (MDR-TB) poses a significant threat to global tuberculosis control efforts. This study aimed to examine the influence of mutations in Toxin-Antitoxin system genes on the global transmission of MDR-TB caused by Mycobacterium tuberculosis (M. tuberculosis). Whole-genome sequencing was conducted on 13,518 M. tuberculosis isolates. Genes of the Toxin-Antitoxin system were obtained from the National Center for Biotechnology Information (NCBI) Gene database. Techniques such as Random Forest, Gradient Boosting Decision Tree, and Generalized Linear Mixed Models were employed to identify mutation sites in Toxin-Antitoxin system-related genes that facilitated the transmission of MDR-TB. 4,066 (30.08%) were identified as MDR-TB strains of all analyzed isolates. We found significant associations between specific gene mutations and MDR-TB transmission clusters including mutations in Rv0298 (G213A), Rv1959c (parE1, C88T), Rv1960c (parD1, C134T), Rv1991A (maze, G156A), Rv2547 (vapB, C54G), Rv2862A (vapB23, T2C), and Rv3385c (vapB46, G70A). Additionally, several gene mutations associated with MDR-TB transmission clades such as Rv1956 (higA, G445T), Rv1960c (parD1, C134T), and Rv1962A (vapB35, G99A) were noted. Certain gene mutations including vapB35 (G99A), higA (G445T), and parD1 (C134T) correlated with cross-regional transmission clades. This study highlights the significant association between specific gene mutations in the Toxin-Antitoxin system and the global transmission of MDR-TB, providing valuable insights for developing targeted interventions to control MDR-TB.

Comparative effectiveness of shorter regimen with oral bedaquiline or injectable on treatment outcomes and mortality among patients with multidrug-resistant tuberculosis in Guinea: A retrospective cohort study

Comparative effectiveness of shorter regimen with oral bedaquiline or injectable on treatment outcomes and mortality among patients with multidrug-resistant tuberculosis in Guinea: A retrospective cohort study