Multidrug-resistant Tuberculosis Research Articles

Multidrug-resistant tuberculosis clusters and transmission in Taiwan: a population-based cohort study.

Multidrug-resistant tuberculosis (MDR-TB) remains a challenge in the TB program of Taiwan, where 0.5% of new cases and 2.1% of previously treated cases were resistant to at least rifampin (RIF) and isoniazid (INH). Since >80% of our MDR-TB are new cases, genotyping of MDR Mycobacterium tuberculosis is implemented to facilitate contact investigation, cluster identification, and outbreak delineation. This is a population-based retrospective cohort study analyzing MDR-TB cases from 2019 to 2022. Whole genome sequencing (WGS) was performed using the Illumina MiSeq and analyzed using the TB Profiler. A single nucleotide polymorphism (SNP) threshold of ≤ 12 and phylogenetic methods were used to identify putative transmission clusters. An outbreak was confirmed using genomic data and epidemiologic links. Of the 297 MDR-TB cases, 246 (82.8%), 45 (15.2%), and 6 (2.0%) were simple MDR, extensively drug-resistant tuberculosis (pre-XDR-TB) and extensively drug-resistant tuberculosis (XDR-TB), respectively. The sublineage 2.2 modern Beijing was the predominant (48.8%) MDR-TB strain in Taiwan. Phylogenetic analysis identified 25.3% isolates in 20 clusters, with cluster sizes ranging from 2 to 13 isolates. Nevertheless, only 2 clusters, one household and one community, were confirmed as outbreaks. In this study, we found that males had a higher risk of MDR-TB transmission compared to females, and those infected with the sublineage 2.1-proto-Beijing genotype isolates were at a higher risk of transmission. Furthermore, 161 (54.2%) isolates harbored compensatory mutations in the rpoC and non-rifampicin resistant determinant region (non-RRDR) of the rpoB gene. MDR-TB strains containing rpoB S450L and other compensatory mutations concurrently were significantly associated with clusters, especially the proto-Beijing genotype strains with the compensatory mutation rpoC E750D or the modern Beijing genotype strains with rpoC D485Y/rpoC E1140D. Routine and continuous surveillance using WGS-based analysis is recommended to warn of risks and delineate transmission clusters of MDR-TB. We proposed the use of compensatory mutations as epidemiological markers of M. tuberculosis to interrupt putative MDR-TB transmission.

A network pharmacology-based approach to understand the mechanism of action of anti-mycobacterial activity of Acacia nilotica: a modelling and experimental study.

The rapid rise in drug-resistant tuberculosis poses a serious threat to public health and demands the discovery of new anti-mycobacterial agents. Medicinal plants are a proven potential source of bioactive compounds; however, identifying those responsible for the putative anti-mycobacterial action still remains a challenging task. In this study, we undertook a systematic network pharmacology approach to identify and evaluate anti-mycobacterial compounds from a traditional plant, Acacia nilotica, as a model system. The protein-protein interaction network revealed 17 key pathways in M. tuberculosis encompassing 40 unique druggable targets that are necessary for its growth and survival. The phytochemicals of A. nilotica were preferentially found to interfere with the cell division and cell wall biogenesis proteins, especially FtsZ and Mur. Notably, the compounds epigallocatechin, ellagic acid, chlorogenic acid, and D-pinitol were found to exhibit a potential polypharmacological effect against multiple proteins. Further, in vitro studies confirmed that the selected candidates, chlorogenic acid, and ellagic acid exhibited potent anti-mycobacterial activity (against M. smegmatis) with specific inhibition of purified M.tb FtsZ enzyme. Taken together, the present study demonstrates that network pharmacology combined with molecular docking can be utilized as an efficient approach to identify potential bioactive phytochemicals from natural products along with their mechanism of action. Hence, the compounds identified in this study can be potential lead candidates for developing novel anti-mycobacterial drugs, while the key proteins identified here can be potential drug targets.

Concomitant Rifampicin-Sensitive Pulmonary Tuberculosis With Pre-extremely Drug-Resistant Neuro-Tuberculosis in Child With Steroid-Resistant Nephrotic Syndrome.

Mixed tuberculosis occurs with multiple clonally distinct mycobacterium tuberculosis strains in an individual. We present a 12-year-old girl with steroid-resistant nephrotic syndrome and drug-sensitive pulmonary tuberculosis (Xpert MTB/Rif) and preextensively drug-resistant tuberculosis neuro-tuberculosis (Line Probe Assay). Mixed tuberculosis involving drug-susceptible and drug-resistant strains can hinder treatment. This case highlights the challenges in diagnosing mixed tuberculosis to ensure effective management.

Efficiency of Treatment of Tuberculosis Patients: Realities, Problems and Perspectives (Review)

An analysis of data from global experience and professional publications on modern treatment of tuberculosis patients and its effectiveness was carried out.The analysis of literary sources of recent years indicates an urgent problem regarding tuberculosis in Ukraine (especially in the conditions of martial law and the conduct of active hostilities). With early diagnosis and timely treatment, the number of patients decreases by 8 %.The effectiveness of the treatment of patients with pulmonary tuberculosis and the influence of various factors on it were evaluated. The effectiveness of treatment of newly diagnosed pulmonary tuberculosis in Ukraine does not exceed 70 %.An increase in the level of resistance of tuberculosis mycobacteria to anti-tuberculosis drugs was noted, and its treatment efficiency was not high. The effectiveness of treatment of such patients in Ukraine does not exceed 40—45 %. The inclusion of second-line drugs in the treatment regimen of patients with iso­niazid-­resistant tuberculosis increases the effectiveness of treatment by 11.8 %. The overall effectiveness of treatment of patients with multidrug-resistant tuberculosis (MDR-TB) in the world is 52 %, and only 10 % of patients are cured. The treatment of MRTB is three times longer (20 months) than that of the sensitive form and is significantly more expensive. Antimycobacterial drugs (AMBs) were used according to an individual regimen (18—20 months), then new AMBs were used (6 months), later versions of modified standardized short-term regimens (9 months). The BPaL regimen (bedaquiline, linezolid, pretomanide) was implemented for patients with multiple and extensively drug-resistant tuberculosis for 6 months (26 weeks or 182 doses), resulting in a cure rate of 90 % [35].The methods of optimizing the management of patients with pulmonary tuberculosis (including correction of treatment) in the conditions of martial law, which can be achieved by improving antimycobacterial and pathogenetic therapy, revealing new mechanisms and deepening the known regularities of the course of the disease, are evaluated.

Accessibility of Finding Tuberculosis Case Actively, Separate Safely and Treat Effectively (FAST) Strategy for Early Detection of Suspected and Symptomatic Tuberculosis Patients: A Hospital Based Quantitative Study

Introduction: Tuberculosis is a contagious disease which has always been a challenge over the course of human history. It is known to spread mostly from persons with undiagnosed and suspected tuberculosis cases. Diagnosing tuberculosis in an early stage with effective treatment is one of the best ways to reduce the burden of tuberculosis. Finding cases Actively, Separate safely and Treat effectively (FAST) Strategy in Nepal, is a rapid diagnostic tool for rapid tuberculosis case detection. Aims: To access tuberculosis case Actively, Separate safely and Treat effectively (FAST) strategy for suspected and symptomatic tuberculosis patients coming to the hospital for early case detection and also to identify patient’s health care behaviour, technical barrier during surveillance. Methods: An observational quantitative study of active cough surveillance was carried at an entry point of FAST corner of Nepalgunj Medical College Teaching Hospital, Banke from April 2023 to December 2023. Scrutinized data was obtained by purposive sampling method with sample size 128 from FAST corner. Results: Maximum cases belonged to the aged group 65 and above having lower middle to lower socioeconomic status. Most of them were from joint family with contact history of tuberculosis in 35 (27.3) % of total cases. Out of total cases, 72 (56.25) % were confirmed with tuberculosis. Among those confirmed tuberculosis cases, multi drug resistance TB was found in 6 (4.7) %. Uses of mask was found significant (P< 0.05) in our study although number of these health care behaviour were less appropriate. Pneumonia was a significant association 17 (P = 0.004) with tuberculosis patient. Insufficient volunteers, and limited Gene xpert machine were major barriers to implement FAST strategy screening in Hospital. Conclusion: FAST strategy is feasible tool in high tuberculosis burden healthcare settings in Nepal. However, the technical and behavioral factors should be managed to ensure an effective approach.

Implementation strategies for decentralized management of multidrug-resistant tuberculosis: insights from community health systems in Zambia

BackgroundDecentralized management approaches for multi-drug-resistant tuberculosis (MDR TB) have shown improved treatment outcomes in patients. However, challenges remain in the delivery of decentralized MDR TB services. Further, implementation strategies for effectively delivering the services in community health systems (CHSs) in low-resource settings have not been fully described, as most strategies are known and effective in high-income settings. Our research aimed to delineate the specific implementation strategies employed in managing MDR TB in Zambia.MethodsOur qualitative case study involved 112 in-depth interviews with a diverse group of participants, including healthcare workers, community health workers, patients, caregivers, and health managers in nine districts. We categorized implementation strategies using the Expert Recommendations for Implementing Change (ERIC) compilation and later grouped them into three CHS lenses: programmatic, relational, and collective action.ResultsThe programmatic lens comprised four implementation strategies: (1) changing infrastructure through refurbishing and expanding health facilities to accommodate management of MDR TB, (2) adapting and tailoring clinical and diagnostic services to the context through implementing tailored strategies, (3) training and educating health providers through ongoing training, and (4) using evaluative and iterative strategies to review program performance, which involved development and organization of quality monitoring systems, as well as audits. Relational lens strategies were (1) providing interactive assistance through offering local technical assistance in clinical expert committees and (2) providing support to clinicians through developing health worker and community health worker outreach teams. Finally, the main collective action lens strategy was engaging consumers; the discrete strategies were increasing demand using community networks and events and involving patients and family members.ConclusionThis study builds on the ERIC implementation strategies by stressing the need to fully consider interrelations or embeddedness of CHS strategies during implementation processes. For example, to work effectively, the programmatic lens strategies need to be supported by strategies that promote meaningful community engagement (the relational lens) and should be attuned to strategies that promote community mobilization (collective action lens).

The catalogue of Mycobacterium tuberculosis mutations associated with drug resistance to 12 drugs in China from a nationwide survey: a genomic analysis

WHO issued the first edition catalogue of Mycobacterium tuberculosis complex (MTBC) mutations associated with drug resistance in 2021. However, country-specific issues might lead to arising complex and additional drug-resistant mutations. We aimed to fully reflect the characteristics of drug resistance mutations in China. We analysed MTBC isolates from the nationwide drug-resistant tuberculosis surveillance with 70counties in 31provinces, municipalities, and autonomous regions in China. Three types of MYCOTB plates were used to perform drug susceptibility testing for 12antibiotics (rifampicin, isoniazid, ethambutol, levofloxacin, moxifloxacin, amikacin, kanamycin, ethionamide, clofazimine, linezolid, delamanid, and bedaquiline). Mutations were divided into five groups according to their odds ratios, positive predictive values, false discovery rate-corrected p values, and 95% CIs: (1) associated with resistance; (2) associated with resistance-interim; (3) uncertain significance; (4) not associated with resistance-interim; and (5) not associated with resistance. The Wilcoxon rank-sum and Kruskal-Wallis tests were used to quantify the association between mutations and minimum inhibitory concentrations (MICs). Our dataset was compared with the first edition of the WHO catalogue. We analysed 10 146MTBC isolates, of which 9071 (89·4%) isolates were included in the final analysis. 744(8·2%) isolates were resistant to rifampicin and 1339 (14·8%) to isoniazid. 208 (1·9%) of 11 065mutations were classified as associated with resistance or associated with resistance-interim. 33 (97·1%) of 34mutations in group 1and 92 (52·9%) of 174in group 2also appeared in groups 1or 2of the WHO catalogue. Of 81indel mutations in group 2, 15 (18·5%) were in the WHO catalogue. The newly discovered mutation gyrA_Ala288Asp was associated with levofloxacin resistance. MIC values for rifampicin, isoniazid, moxifloxacin, and levofloxacin corresponding to resistance mutations in group 1were significantly different (p<0·0001), and 12 high-level resistance mutations were detected. 61mutations in group 3occurred as solo in at least five phenotypically susceptible isolates, but with MIC values moderately higher than other susceptible isolates. Among 945phenotypically resistant but genotypically susceptible isolates, 433 (45·8%) were mutated for at least one efflux pump gene. Our analysis reflects the complexity of drug resistance mutations in China and suggests that indel mutations, efflux pump genes, protein structure, and MICs should be fully considered in the WHO catalogue, especially in countries with a high tuberculosis burden. National Key Research and Development Program of China and the Science and Technology Major Project of Tibetan Autonomous Region of China.

Identification of Chemical Scaffolds That Inhibit the Mycobacterium tuberculosis Respiratory Complex Succinate Dehydrogenase.

Drug-resistant Mycobacterium tuberculosis is a significant cause of infectious disease morbidity and mortality for which new antimicrobials are urgently needed. Inhibitors of mycobacterial respiratory energy metabolism have emerged as promising next-generation antimicrobials, but a number of targets remain unexplored. Succinate dehydrogenase (SDH), a focal point in mycobacterial central carbon metabolism and respiratory energy production, is required for growth and survival in M. tuberculosis under a number of conditions, highlighting the potential of inhibitors targeting mycobacterial SDH enzymes. To advance SDH as a novel drug target in M. tuberculosis, we utilized a combination of biochemical screening and in-silico deep learning technologies to identify multiple chemical scaffolds capable of inhibiting mycobacterial SDH activity. Antimicrobial susceptibility assays show that lead inhibitors are bacteriostatic agents with activity against wild-type and drug-resistant strains of M. tuberculosis. Mode of action studies on lead compounds demonstrate that the specific inhibition of SDH activity dysregulates mycobacterial metabolism and respiration and results in the secretion of intracellular succinate. Interaction assays demonstrate that the chemical inhibition of SDH activity potentiates the activity of other bioenergetic inhibitors and prevents the emergence of resistance to a variety of drugs. Overall, this study shows that SDH inhibitors are promising next-generation antimicrobials against M. tuberculosis.

Development and Evaluation of Bis-benzothiazoles as a New Class of Benzothiazoles Targeting DprE1 as Antitubercular Agents.

Benzothiazole-bearing compounds have emerged as potential noncovalent DprE1 (decaprenylphosphoryl-β-d-ribose-2'-epimerase) inhibitors active against Mycobacterium tuberculosis. Based on structure-based virtual screening (PDB ID: 4KW5), a focused library of thirty-one skeletally diverse benzothiazole amides was prepared, and the compounds were assessed for their antitubercular activity against M.tb H37Ra. Most potent compounds 3b and 3n were further evaluated against the M.tb H37Rv strain by the microdilution assay method. Among the compounds evaluated, bis-benzothiazole amide 3n emerged as a hit molecule and demonstrated promising antitubercular activity with minimum inhibitory concentration (MIC) values of 0.45 μg/mL and 8.0 μg/mL against H37Ra and H37Rv, respectively. Based on the preliminary hit molecule (3n), a focused library of 12 more bis-benzothiazole amide derivatives was further prepared by varying the substituents on either side to obtain new leads and generate a structure-activity relationship (SAR). Among these compounds, 6a, 6c, and 6d demonstrated remarkable antitubercular activity with MIC values of 0.5 μg/mL against H37Ra and 1.0, 2.0, and 8.0 μg/mL against H37Rv, respectively. The most active compound, 6a, also displayed significant efficacy against four drug-resistant tuberculosis strains. Compound 6a was assessed for in vitro cytotoxicity against the HepG2 cell line, and it displayed insignificant cytotoxicity. Furthermore, time-kill kinetic studies demonstrated time- and dose-dependent bactericidal activity of this compound. The GFP release assay revealed that compound 6a targets the inhibition of a cell wall component. SNPs in dprE-1 gene assessment revealed that compound 6a binds to tyrosine at position 314 of DprE1 and replaces it with histidine, causing resistance similar to that of standard TCA1. In silico docking studies further suggest that the strong noncovalent interactions of these compounds may lead to the development of potent noncovalent DprE1 inhibitors.

Exploring the therapeutic and prophylactic potential of bedaquiline in leprosy.

Leprosy remains a significant public health concern despite major strides in treatment and control efforts. The Global Leprosy Strategy 2021-2030 and the National Strategic Plan for Leprosy 2023-2027 majorly focus on facilitating action to reach the goal of zero leprosy. Exploration of new treatment regimens is emphasized as one of the verticals of the multipronged approach for reaching the aforementioned goals. This becomes particularly pertinent in the wake of growing evidence for resistance to the drugs currently being used in the management of leprosy. Repurposed molecules present a very good approach in this direction. The present review aims to explore the potential of bedaquiline, a drug used for multidrug-resistant tuberculosis, as a potential addition to the therapeutic armamentarium of leprosy. Through this narrative review, the authors attempt to look into the available proof of concept, clinical evidence, potential risks, and possible ways forward with bedaquiline in leprosy.

Tracking multidrug resistant tuberculosis: a 30-year analysis of global, regional, and national trends.

To provide valuable insights for targeted interventions and resource allocation, our analysis delved into the multifaceted burden, trends, risks, and projections of multi drug resistant tuberculosis (MDR-TB). This research employed data from the Global Burden of Disease (GBD) 2019 dataset, which used a comparative risk assessment to quantify the disease burden resulting from risk factors. Initially, this database was utilized to extract details concerning the disability-adjusted life years (DALYs), mortality, incidence, and the number of individuals afflicted by MDR-TB. Subsequently, regression analyses were conducted using the Joinpoint program to figure average annual percent change (AAPC) to ascertain the trend. Thirdly, the age-period-cohort model (APCM) was adopted to analyze evolutions in incidence and mortality. Finally, utilizing the Nordpred model within R software, we projected the incidence and mortality of MDR-TB from 2020 to 2030. MDR-TB remained a pressing global health concern in regions with lower socio-demographic indexes (SDI), where the AAPC in DALYs topped 7% from 1990 to 2019. In 2019, the cumulative DALYs attributed to MDR-TB tallied up to 4.2 million, with India, the Russian Federation, and China bearing the brunt. Notably, the incidence rates have shown a steadfast presence over the past decade, and a troubling forecast predicts an uptick in these areas from 2020 to 2030. Additionally, the risk of contracting MDR-TB grew with advancing age, manifesting most acutely among men aged 40+ in lower SDI regions. Strikingly, alcohol consumption had been identified as a significant contributor, surpassing the impacts of smoking and high fasting plasma glucose, leading to 0.7 million DALYs in 2019. A robust strategy is needed to end tuberculosis (TB) by 2030, especially in lower SDI areas.

HIV and body mass index are associated with prolonged corrected QT interval among people with drug-resistant tuberculosis on bedaquiline-containing regimen in Uganda

ObjectivesPeople with drug-resistant tuberculosis (DR-TB) on bedaquiline-containing regimens are at risk for a prolonged corrected QT (QTc) interval but this problem is understudied in low-resource countries. We determined the magnitude and risk factors for QTc interval prolongation among people with DR-TB on bedaquiline-containing regimens at three referral hospitals in Uganda. MethodsUsing retrospectively collected data, we designed a matched case-control study, with cases as participants with prolonged QTc interval and controls as those with normal QTc interval in 1:1. QTc interval prolongation was defined as an increase in QTc interval by 60 milliseconds in electrocardiogram from the baseline or ≥500 milliseconds during follow-up for men and women. Factors associated with cases compared with controls were identified using a multivariable conditional regression analysis at a 5% significance level, reported using odds ratio (OR) and the 95% confidence interval (CI). ResultsOf 153 participants, 39 (25.5%) had a prolonged QTc interval. We matched 30 participants with prolonged QTc interval (cases) with 30 participants with normal QTc interval (controls). Cases and controls were similar in several sociodemographic and clinical characteristics but different regarding the baseline body mass index (BMI), baseline weight, and HIV infection. Increasing BMI (adjusted OR 1.29, 95% CI 1.02-1.63) and HIV infection (adjusted OR 0.27, 95% CI 0.08-0.96) were associated with the cases compared with the controls. ConclusionsWe found a relatively high prevalence of QTc interval prolongation among people with DR-TB on a bedaquiline-containing regimen compared with the prevalence in healthy individuals, with a higher likelihood in those with increasing BMI and a lower likelihood in those with HIV. We recommend routine anthropometric measurements to identify individuals with DR-TB at a high risk for QTc interval prolongation. In addition, tuberculosis/HIV treatment guidelines for people with DR-TB on bedaquiline-containing regimens should include risk assessment for prolonged QTc intervals.

Dynamic changes of respiratory microbiota associated with treatment outcome in drug-sensitive and drug-resistant pulmonary tuberculosis

BackgroundRespiratory microbiota is closely related to tuberculosis (TB) initiation and progression. However, the dynamic changes of respiratory microbiota during treatment and its association with TB progression remains unclear.MethodsA total of 16 healthy individuals and 16 TB patients (10 drug-sensitive TB (DS-TB) and 6 drug-resistant TB (DR-TB)) were recruited. Sputum samples were collected at baseline for all anticipants and after anti-TB treatment at Month-6 for TB patients. High throughput 16 S RNA sequencing was used to characterize the respiratory microbiota composition.ResultsCompared to the healthy individuals, TB patients exhibited lower respiratory microbiota diversity (p < 0.05). This disruption was alleviated after anti-TB treatment, especially for DS-TB patients. Parvimonas spp. numbers significantly increased after six months of anti-TB treatment in both DS-TB and DR-TB patients (p < 0.05). Rothia spp. increase during treatment was associated with longer sputum-culture conversion time and worse pulmonary lesion absorption (p < 0.05). Besides, Moraxella spp. prevalence was associated with longer sputum-culture conversion time, while Gemella spp. increase was associated with worsening resolving of pulmonary lesions (p < 0.05).ConclusionDynamic changes of respiratory microbiota during anti-TB treatment is closely related to TB progression. The involvement of critical microorganisms, such as Parvimonas spp., Rothia spp., Moraxella, and Gemella spp., appears to be associated with pulmonary inflammatory conditions, particularly among DR-TB. These microorganisms could potentially serve as biomarkers or even as targets for therapeutic intervention to enhance the prognosis of tuberculosis patients.

Design and Synthesis of Isatin-Tagged Isoniazid Conjugates with Cogent Antituberculosis and Radical Quenching Competence: In-vitro and In-silico Evaluations.

In pursuit of potential chemotherapeutic alternates to combat severe tuberculosis infections, novel heterocyclic templates derived from clinically approved anti-TB drug isoniazid and isatin have been synthesized that demonstrate potent inhibitory action against Mycobacterium tuberculosis, and compound 4i with nitrophenyl motif exhibited the highest anti-TB efficacy with a MIC value of 2.54 μM/ml. Notably, the same nitro analog 4i shows the best antioxidant efficacy among all the synthesized compounds with an IC50 value of 37.37 μg/ml, suggesting a synergistic influence of antioxidant proficiency on the anti-TB action. The titled compounds exhibit explicit binding affinity with the InhA receptor. The befitting biochemical reactivity and near-appropriate pharmacokinetic proficiency of the isoniazid conjugates is reflected in the density functional theory (DFT) studies and ADMET screening. The remarkable anti-TB action of the isoniazid cognates with marked radical quenching ability may serve as a base for developing multi-target medications to confront drug-resistant TB pathogens.

Critical assessment of infants born to mothers with drug resistant tuberculosis

There have been no detailed descriptions of infants born to mothers treated for drug resistant TB in pregnancy. Critical case history assessment is important to identify risks and guide clinical practice. In a cohort of pregnant women with multidrug or rifampicin resistant (MDR/RR)-TB enrolled between 1 January 2013 and 31 December 2022, we followed mother-infant pairs until the infant was 12 months old. We performed critical case history assessments to explore potential mechanisms of Mycobacterium tuberculosis transmission to the infant, and to describe the clinical presentation and disease trajectories observed in infants diagnosed with TB. Among 101 mother-infant pairs, 23 (23%) included infants diagnosed with TB disease; 16 were clinically diagnosed and seven had microbiological confirmation (five MDR/RR-TB, two drug-susceptible TB). A positive maternal sputum culture at the time of delivery was significantly associated with infant TB risk (p=0.023). Of the 12 infants diagnosed with TB in the first three months of life, seven (58%) of the mothers were culture positive at delivery; of whom four reported poor TB treatment adherence. However, health system failures, including failing to diagnose and treat maternal MDR/RR-TB, inadequate screening of newborns at birth, not providing appropriate TB preventive therapy (TPT), and M.tuberculosis transmission from non-maternal sources also contributed to TB development in infants. Infants born to mothers with MDR/RR-TB are at greatest risk if maternal adherence to MDR/RR-TB treatment or antiretroviral therapy (ART) is sub-optimal. In a high TB incidence setting, infants are also at risk of non-maternal household and community transmission. Ensuring maternal TB diagnosis and appropriate treatment, together with adequate TB screening and prevention in all babies born to mothers or households with TB will minimise the risk of infant TB disease development. South African Medical Research Council.

Cryo-EM structures of a mycobacterial ABC transporter that mediates rifampicin resistance

Drug-resistant Tuberculosis (TB) is a global public health problem. Resistance to rifampicin, the most effective drug for TB treatment, is a major growing concern. The etiological agent, Mycobacterium tuberculosis (Mtb), has a cluster of ATP-binding cassette (ABC) transporters which are responsible for drug resistance through active export. Here, we describe studies characterizing Mtb Rv1217c-1218c as an ABC transporter that can mediate mycobacterial resistance to rifampicin and have determined the cryo-electron microscopy structures of Rv1217c-1218c. The structures show Rv1217c-1218c has a type V exporter fold. In the absence of ATP, Rv1217c-1218c forms a periplasmic gate by two juxtaposed-membrane helices from each transmembrane domain (TMD), while the nucleotide-binding domains (NBDs) form a partially closed dimer which is held together by four salt-bridges. Adenylyl-imidodiphosphate (AMPPNP) binding induces a structural change where the NBDs become further closed to each other, which downstream translates to a closed conformation for the TMDs. AMPPNP binding results in the collapse of the outer leaflet cavity and the opening of the periplasmic gate, which was proposed to play a role in substrate export. The rifampicin-bound structure shows a hydrophobic and periplasm-facing cavity is involved in rifampicin binding. Phospholipid molecules are observed in all determined structures and form an integral part of the Rv1217c-1218c transporter system. Our results provide a structural basis for a mycobacterial ABC exporter that mediates rifampicin resistance, which can lead to different insights into combating rifampicin resistance.

Clinical Characteristics and Outcome Predictors in Drug-Resistant Tuberculosis: A Comprehensive Analysis

Background: Drug-resistant tuberculosis (DR-TB) poses significant challenges to public health, with poor outcomes frequently observed in affected patients. This study aims to evaluate the characteristics and factors associated with poor outcomes in patients with drug-resistant pulmonary tuberculosis at Liwa Hospital from January 2018 to May 2023. Methods: A retrospective, cross-sectional single-center analysis was conducted on 408 patients admitted to Liwa Hospital. Among these, 28 patients diagnosed with drug-resistant tuberculosis (DR-TB) were selected for detailed analysis based on their treatment outcomes and clinical data. Inclusion criteria encompassed patients aged 18 years or older with confirmed drug-resistant TB, while patients younger than 18, those with latent tuberculosis, and those with extra-pulmonary tuberculosis were excluded. Results: The majority of patients were between 18-40 years old (60.7%), predominantly male (85.7%), and Asian (96.4%). Comorbidities included diabetes (46.4%) and hypertension (21.4%). Clinical characteristics revealed cough (28.6%) and fever with cough (7.1%) as common symptoms. Primary resistance was observed in 92.9% of cases, with 96.4% being newly diagnosed TB cases. Adverse drug events were minimal, with 7.1% experiencing nausea and vomiting. Radiological findings showed unilateral TB in 53.6% and cavitary TB in 57.1% of cases. Laboratory analysis indicated elevated HbA1c (9.83 ± 3.25), CRP (25.94 ± 5.16 mg/L), and white blood cell count (9.94 ± 4.59 x 10^9 cells/L). Rifampicin resistance was the most prevalent (42.9%), followed by isoniazid resistance (25.0%). Regarding treatment outcomes, age, hypertension, and diabetes mellitus were found to be significantly associated with poor outcomes in patients (p=0.05). Conclusion: The study identified significant associations between treatment outcomes and age, hypertension, and diabetes status, with higher proportions of poor outcomes observed in patients. Comprehensive management strategies targeting these factors are essential to improve outcomes in patients with drug-resistant TB. Further research is warranted to develop tailored interventions for this population.

A Genome-Focused Investigation Reveals the Emergence of a Mycobacterium tuberculosis Strain Related to Multidrug-Resistant Tuberculosis in the Amazon Region of Brazil.

A previous study in Pará, Northern Brazil, described a strain of Mycobacterium tuberculosis with a unique genotype (SIT2517/T1) associated with multidrug-resistant tuberculosis (MDR-TB). To improve our understanding of MDR-TB transmission dynamics of these strains within this region, we performed phenotypic and genotypic drug susceptibility testing (pDST/gDST), 24-loci mycobacterial interspersed repetitive units (MIRU-VNTR) genotyping, whole-genome sequencing (WGS) and geo-epidemiology analysis. Of the 28 SIT2517/T1 isolates, 19 (67.9%) could be genotyped by 24-loci MIRU-VNTR and 15 by WGS. All belonged to sublineage 4.1.1.3, distinct from other representative Lineage 4 isolates identified in Brazil. The MDR phenotype determined by pDST was confirmed by gDST, the latter also demonstrating the presence of additional mutations conferring pre-extensively drug-resistance (pre-XDR). Discrepancies between gDST and pDST were observed for pyrazinamide and fluoroquinolones. Thirteen out of 15 isolates analyzed by WGS were clustered when applying a 12 single nucleotide polymorphisms (SNPs) cutoff. The SIT2517/T1 isolates were distributed across the metropolitan regions of Belém and Collares municipalities, showing no geographic clustering. WGS-transmission network analysis revealed a high likelihood of direct transmission and the formation of two closely linked transmission chains. This study highlights the need to implement TB genomic surveillance in the Brazilian Amazon region.

Drug resistance and genomic variations among Mycobacterium tuberculosis isolates from The Nile Delta, Egypt

Tuberculosis is a global public health concern. Earlier reports suggested the emergence of high rates of drug resistant tuberculosis in Egypt. This study included 102 isolates of Mycobacterium tuberculosis collected from two reference laboratories in Cairo and Alexandria. All clinical isolates were sub-cultured on Löwenstein–Jensen medium and analyzed using both BD BACTEC MGIT 960 SIRE Kit and standard diffusion disk assays to identify the antibiotic sensitivity profile. Extracted genomic DNA was subjected to whole genome sequencing (WGS) using Illumina platform. Isolates that belong to lineage 4 represented > 80%, while lineage 3 represented only 11% of the isolates. The percentage of drug resistance for the streptomycin, isoniazid, rifampicin and ethambutol were 31.0, 17.2, 19.5 and 20.7, respectively. Nearly 47.1% of the isolates were sensitive to the four anti-tuberculous drugs, while only one isolate was resistant to all four drugs. In addition, several new and known mutations were identified by WGS. High rates of drug resistance and new mutations were identified in our isolates. Tuberculosis control measures should focus on the spread of mono (S, I, R, E)- and double (S, E)-drug resistant strains present at higher rates throughout the whole Nile Delta, Egypt.

Audit of risk factors of drug-sensitive, drug-resistant tuberculosis disease, a case-control study of patients registered under NTEP, Gujarat.

Characterizing risk factors for drug-resistant tuberculosis (TB) is critical to guide targeted interventions in high-burden settings like India. We aimed to identify socioeconomic, lifestyle, and clinical factors associated with drug-sensitive and drug-resistant TB acquisition. A comparative cross-sectional study recruited 350 bacteriologically confirmed TB patients registered under the National Tuberculosis Elimination Program (NTEP) in Gujarat, India, and 300 matched participants without active/past TB. Multinomial logistic regression analyzed risk factors for 200 drug-sensitive and 150 drug-resistant TB cases compared to participants without active or past TB. Key factors independently associated with higher adjusted odds ratios (aOR) of both TB types included low socioeconomic status (SES) (drug-sensitive TB: aOR 1.7, 95% CI 1.2-2.5; drug-resistant TB: aOR 2.2, 95% CI 1.3-3.7), crowding (>5 persons/room) (drug-sensitive TB: aOR 1.6, 95% CI 1.1-2.3; drug-resistant TB: aOR 1.9, 95% CI 1.2-2.9), undernutrition (drug-sensitive TB: aOR 1.6, 95% CI 1.1-2.3; drug-resistant TB: aOR 2.0, 95% CI 1.2-3.2), smoking (drug-sensitive TB: aOR 1.5, 95% CI 1.0-2.3; drug-resistant TB: aOR 1.7, 95% CI 1.1-2.7), and indoor air pollution (drug-sensitive TB: aOR 1.5, 95% CI 1.0-2.2; drug-resistant TB: aOR 1.8, 95% CI 1.2-2.8). Marked social determinants and clinical risks drive heightened susceptibility for both TB types in India, while prior inadequate treatment and nosocomial exposures selectively enable additional drug resistance. Holistic prevention policies jointly targeting transmission, vulnerability, and curative factors are imperative.