First-line Antituberculosis Research Articles

Variations of Serum Oxidative Stress Biomarkers under First-Line Antituberculosis Treatment: A Pilot Study.

Tuberculosis (TB) is one of the highest infectious burdens worldwide, and pathogenesis is yet incompletely elucidated. Bacilli dissemination is due to poor antioxidant defense mechanisms and intensified oxidative stress. There are few recent studies that analyzed and compared free radicals or antioxidant status before and after anti-TB treatment. Hence, the present study underlines the need to identify oxidative stress as it could be a useful tool in TB monitorisation. Thirty newly diagnosed patients with pulmonary TB were included after signing an informed consent. Blood was collected before receiving first-line anti-tubercular therapy (T0) and after 60 days (T2). Spectrophotometric methods were used to quantify oxidative parameters (TBARS—thiobarbituric acid reactive species); enzymatic antioxidants such as SOD (superoxide dismutase), CAT (catalase), GPx (glutathione peroxidase), and TAC (total antioxidant capacity); and non-enzymatic antioxidants such as GSH (reduced glutathione). A moderate positive correlation was found between GSH and TAC (r = 0.63, p-value = 0.046) and GSH and SOD (r = 0.64, p-value = 0.041) at T2. Increased values of GSH, CAT, and SOD were noted at T2 in comparison with T0, while GPx, TAC, and TBARS decreased at T2. A better monitorisation in TB could be based on oxidative stress and antioxidant status. Nevertheless, restoring redox host balance could reduce TB progression.

Magnitude of Phenotypic and MTBDRplus Line Probe Assay First-Line Anti-Tuberculosis Drug Resistance Among Tuberculosis Patients; Northwest Ethiopia.

BackgroundMycobacterium tuberculosis (Mtb) drug resistance is a key challenge in ending TB.ObjectiveThe study aimed to determine anti-TB drug resistance and compare the discordance between phenotypic and genotypic drug-susceptibility testing (DST).MethodsProspective enrollment and sputum collection from patients suspected of active pulmonary TB from May 2018 to December 2019 at the University of Gondar Hospital. Phenotypic DST study for streptomycin, isoniazid, rifampin, and ethambutol was done by MGIT 360 SIRE Kit. Genotypic resistance for isoniazid and rifampin was performed by MTBDRplus v2 line probe assay (LPA) and compared to phenotypic drug resistance.ResultsA total of 376 patients, median age 32 years, and 53.7% male were enrolled. Mtb was isolated from 126 patients. 106/126 (84%) patients were newly diagnosed with TB and 20 patients with prior TB treatment. Seventy (66.0%) were susceptible to all anti‐TB drugs tested. Twenty-five (19.8%) of the isolates were resistant to isoniazid, 12 (9.5%) to rifampicin and six (5%) were multidrug resistant. Among previously treated TB patients, 4 (20.0%) and 5 (25.0%) were mono-resistant and poly-resistant, respectively. The sensitivity and specificity of LPA resistance for isoniazid were 94.4% and 100%, and for rifampin was 75.0% and 100%, respectively.ConclusionThe frequency of mono- and poly-drug resistance among both newly diagnosed and previously treated TB patients was high to the rest of the nation. MTBDRplus showed excellent concordance for isoniazid and rifampin. We concluded that DST should be performed for all patients to improve management and decrease spread of drug-resistant Mtb strains in the community.

Anti-Tuberculosis Drug Induced Hepatotoxicity and Associated Factors among Tuberculosis Patients at Selected Hospitals, Ethiopia

BackgroundTuberculosis caused by susceptible mycobacterium tuberculosis strains is effectively treated by the first-line anti-tuberculosis drugs. However, most antibacterial drugs are known to induce hepatotoxicity which may limit their adherence and hence lead to the development of mycobacterial drug resistance.ObjectiveThe aim of this study was to assess the incidence of anti-tuberculosis drug induced hepatotoxicity and associated factors among tuberculosis patients of Debre Markos, Mota, and Bichena Hospitals.MethodsThe prospective cross sectional-study was conducted in three hospitals of East Gojjam zone by taking blood samples of new tuberculosis patients every 2 weeks for 2 months to measure the elevation of liver proteins indicating liver toxicity from the onset of starting therapy. A semi-structured questionnaire was also used to collect the socio-demographic data and factors of anti-tubeculosis drug induced liver toxicity. To identify factors associated with drug induced hepatotoxicity, binary logistic regression followed by multivariate analysis was applied at a statistically significant level of P<0.05.ResultsThe incidence of hepatotoxicity among tuberculosis patients is 7.9%. Diagnosis of extrapulmonary tuberculosis, having comorbid disease, and old age are significantly associated (P<0.05) with first-line antituberculosis drugs induced hepatotoxicity.ConclusionThe incidence of hepatotoxicity is relatively high among tuberculosis patients taking first-line anti-tuberculosis drugs. Therefore, the liver function of patients with old age, comorbid diseases, and extrapulmonary tuberculosis should be regularly monitored to reduce the severity of drug-induced hepatotoxicity.

Dokuz Eylül Üniversitesi Hastanesi, Mycobacterium tuberculosis Kompleks İzolatlarının İlk Sıra Antitüberküloz İlaçlara Duyarlılıkları

Objective: Tuberculosis retains its importance as the only infectious disease in the world that affects 10 million people and causes 1.5 million deaths per se. The major obstacle in the elimination and control of tuberculosis is the emergence and spread of resistant tuberculosis cases. It was aimed to determine the current Mycobacterium tuberculosis complex and its susceptibility to antituberculosis drugs at Dokuz Eylül University Hospital. Method: In our study, the results of all samples sent between January 2013 and November 2019 were examined retrospectively for the presence of M. tuberculosis complex and drug susceptibility results. The samples were cultured in Löwenstein Jensen media and BACTEC MGIT 960 system. Drug susceptibility testing was performed with the BACTEC MGIT 960 SIRE kit in accordance with the recommendations of the manufacturer. Results: In a total of 473 (2.2%) of 21620 specimens M. tuberculosis complex was reproduced. The samples were classified as pulmonary (n:300; 63.4%) and extrapulmonary (n:173; 36.6%), samples. When repeated samples of the same patient, were excluded, positive culture test results were determined in a total of 365 patients. Susceptibility to all primary antituberculosis drugs was shown in 275 of 321 (85.7%) patients, while total rates of resistance to streptomycin, isoniazid, rifampicin and ethambutol were found in respective number of patients as follows: (n:24 (7.5%), 22 (6.8%), (n:7; 2.2%) and (n:2; 0.6%). The rate of MDR was 0.6% in 2 patients. Conclusion: In our hospital, streptomycin is the first-line antituberculosis drug with the highest resistance rate. All susceptibility rates were seen lower than the data reported in Turkey Tuberculosis Control Report and other studies of Turkey. Implementing drug surveillance program plays an important role for maintaining these low rates and for the management of tuberculosis.

Antimycobacterial Activity, In Silico ADME Evaluation, and Docking Study of Novel Thiazolidinedione and Imidazolidinone Conjugates

A series of new thiazolidine-2,4-dione and hydantoin derivatives were synthesized by Knoevenagel condensation.. The compounds were identified by their melting points, 1H NMR, 13C NMR, and HR-MS spectral data. The in vitro antimycobacterial activity was evaluated against reference strain Mycobacterium tuberculosis H37Rv and compared to that of the first-line antituberculosis drugs isoniazid (INH) and ethambutol (EMB). The new compounds showed promising antimycobacterial activity (MIC ranging from 0.75 to 1.54 µM) and low cytotoxicity in the human embryonic kidney cell line HEK-293T (IC50 > 200 µM). The most potent compounds (IIIa) and (V) could be promising drug candidates for further development. In silico ADME screening revealed the biological potential of all synthesized compounds using SwissADME online biological activity prediction software. Molecular docking studies were carried out as well to confirm the groove mode of binding and receptor-complex interactions.

Emergence of resistance to bedaquiline

Resistance to first-line anti-tuberculosis (TB) drugs continues to threaten global TB control with over 500 000 cases of rifampicin resistant (RR)-TB being reported in 2018. Treatment of RR-TB requires the use of toxic drugs often leading to adverse events, poor adherence and poor treatment outcomes. In order to address the toxicity of treatment and to improve treatment outcomes the World Health Organization has promoted the use of injection free regimens which include new and repurposed drugs: bedaquiline (BDQ), linezolid (LZD) and clofazimine (CFZ). In 2017, South Africa rolled out the inclusion of BDQ in the treatment of all pre-XDR- and XDR-TB cases as well as patients experiencing adverse events from kanamycin. In late 2018, South Africa included BDQ into three injection free regimens for treating RR-TB. This was done before routine drug susceptibility testing for BDQ could be implemented. Resistance to BDQ occurs primarily through mutations in Rv0678 (mmpR), pepQ and atpE. Understanding which mutations confer resistance and why they arise in a patient will be critical for early diagnosis as well as for preventing the emergence of resistance thereby ensuring successful treatment. Collation of the mutations identified in Rv0678 shows that BDQ resistance is largely driven by small insertions/deletions which disrupt the function of the repressor thereby leading to over expression of the efflux pump mmpL5 responsible for extruding BDQ from the cell. Understanding the association between gene mutation and phenotypic resistance remains critical for the development of new molecular diagnostics to rapidly diagnose resistance thereby affording the clinician the opportunity to adjust the regimen. Analysis of serial isolates collected from patients receiving BDQ (Access program pre-2017) has shown the emergence of mutations in Rv0678, atpE and pepQ during treatment in patients who remain culture positive after three months of treatment. Using targeted deep sequencing it is now possible to track the emergence of resistant sub-populations at the sub-phenotypic level (i.e., micro-heteroresistance) thereby affording the opportunity to study the association of the emergence of resistance with drug regimens, MIC distributions, PK and PD data and treatment outcomes. Our analysis showed that mutations conferring resistance occurred soon after the introduction of BDQ into the regimen and that clones harbouring these mutations were subsequently selected. Most surprising was the observation that different resistant sub-populations emerged during the period after the cessation of BDQ in the regimen. This demonstrates the continuing selective pressure as a result of the long half-life of BDQ. Although the origin of the distinct resistant clones is unknown, we hypothesize that resistance evolved independently in spatially separated lesions subsequently rupturing into the airways. A surprising observation was that concomitant emergence of different variants of the rpoC gene suggesting a compensatory mechanism to overcome the fitness cost of Rv0678 mutations.

Laboratory Evaluation of a Lateral-Flow Cell for Molecular Detection of First-Line and Second-Line Antituberculosis Drug Resistance.

Despite the WHO's call for universal drug susceptibility testing for all patients being evaluated for tuberculosis (TB), a lack of rapid diagnostic tests which can fully describe TB resistance patterns is a major challenge in ensuring that all persons diagnosed with drug-resistant TB are started on an appropriate treatment regime. We evaluated the accuracy of the Akonni Biosystems XDR-TB TruArray and lateral-flow cell (XDR-LFC), a novel multiplex assay to simultaneously detect mutations across seven genes that confer resistance to both first- and second-line anti-TB drugs. The XDR-LFC includes 271 discrete three-dimensional gel elements with target-specific probes for identifying mutations in katG, inhA promoter, and ahpC promoter (isoniazid), rpoB (rifampin), gyrA (fluoroquinolones), rrs and eis promoter (kanamycin), and rrs (capreomycin and amikacin). We evaluated XDR-LFC performance with 87 phenotypically and genotypically characterized clinical Mycobacterium tuberculosis isolates. The overall assay levels of accuracy for mutation detection in specific genes were 98.6% for eis promoter and 100.0% for the genes katG, inhA promoter, ahpC promoter, rpoB, gyrA, and rrs The sensitivity and specificity against phenotypic reference were 100% and 100% for isoniazid, 98.4% and 50% for rifampin (specificity increased to 100% once the strains with documented low-level resistance mutations in rpoB were excluded), 96.2% and 100% for fluoroquinolones, 92.6% and 100% for kanamycin, 93.9% and 97.4% for capreomycin, and 80% and 100% for amikacin. The XDR-LFC solution appears to be a promising new tool for accurate detection of resistance to both first- and second-line anti-TB drugs.

Miliary pattern, a classic pulmonary finding of tuberculosis disease

IntroductionThe increase in age of the population and in the use of immunosuppressive treatment makes tuberculosis (TB) with hematogenous or lymphatic dissemination a current problem. MethodsWe collected all the patients diagnosed with tuberculosis with miliary pulmonary pattern at the Santiago de Compostela University Teaching Hospital (NW Spain) from 1 January 2006 to 31 December 2015. ResultsA total of 27 patients were included, 70.4% women, with a median age of 69.0 years old. A cause of immunosuppression was observed only in 51.9% of patients. The majority of the cases (65.0%) presented pulmonary affectation. The most frequently isolated species was Mycobacterium tuberculosis (88.9%). Multiresistance to first-line antituberculosis drugs was observed only in 3.7%. 92.6% of the patients received treatment with Isoniazid, Rifampicin and Pyrazinamine, associated in 48.1% of them with Ethambutol. Two patients died during admission and there were no recurrences in the 2-years follow-up. ConclusionsMiliary tuberculosis remains a current pathology. Most patients do not have a known cause of immunosuppression. The response to the typical treatment is usually good.

Benefits of Therapeutic Drug Monitoring of First Line Antituberculosis Drugs

Abstract Tuberculosis is an airborne infectious disease that remains a huge global health-related issue nowadays. Despite constant approvals of newly developed drugs, the use of first-line antituberculosis medicines seems reasonable in drug-susceptible Mycobacterium tuberculosis strains. Therapeutic drug monitoring presents a useful technique for the determination of plasma drug concentration to adjust appropriate dose regimes. In tuberculosis treatment, therapeutic drug monitoring is aiding clinicians in selecting an optimal therapeutic level, which is essential for the personalisation of therapy. This review is aimed at clarifying the use of therapeutic drug monitoring of the first-line antituberculosis drugs in routine clinical practice.

Development and Application of a LC-MS/MS Method for Simultaneous Quantification of Four First-Line Antituberculosis Drugs in Human Serum.

A simple, rapid, and sensitive liquid chromatography (LC)/mass spectrometry (MS) method was established and validated for simultaneous quantitation of pyrazinamide, isoniazid, rifampicin, and ethambutol in human blood sample. Samples were pretreated by a single-step precipitation with acetonitrile. Chromatographic separation was achieved on XSelecT HSS T3 column by gradient elution with a total run time of 5.0 min. MS detection was performed by a triple quadrupole tandem mass spectrometer in the multiple reaction monitoring mode with a positive electrospray ionization source. Isotope-labeled internal standard, especially rifampicin-D8, was applied to adjust for the loss during sample treatment. The established LC-MS/MS method showed a wide analytical range (pyrazinamide: 1.02∼60.0 μg/mL, isoniazid: 0.152∼10.0 μg/mL, rifampicin: 0.500∼30.0 μg/mL, and ethambutol: 0.0998∼5.99 μg/mL) and a good linearity (r > 0.99 for the four analytes) with acceptable accuracy and precision (90.15%∼104.62% and 94.00%∼104.02% for intra- and interaccuracy, respectively; RSD%: <12.46% and <6.43% for intra- and interprecision, respectively). It also showed excellent recoveries (79.24%∼94.16% for all analytes) and absence of significant matrix effect. This method was successfully applied to the quantification of four first-line antituberculosis (anti-TB) drugs, suggesting its suitability for therapeutic drug monitoring in the clinical practices.

3-(5-Nitrofuran-2-yl)prop-2-en-1-one Derivatives, with Potent Antituberculosis Activity, Inhibit A Novel Therapeutic Target, Arylamine N-acetyltransferase, in Mycobacteria.

In this study, the inhibitory potential of 3-(5-nitrofuran-2-yl)prop-2-en-1-one derivatives was evaluated against a panel of bacteria, as well as mammalian cell lines to determine their therapeutic index. In addition, we investigated the mechanism of antibiotic action of the derivatives to identify their therapeutic target. We discovered compound 2 to be an extremely potent inhibitor of Mycobacterium tuberculosis H37Rv growth (MIC: 0.031 mg/L) in vitro, performing better than the currently used first-line antituberculosis drugs such as isoniazid, rifampicin, ethambutol, and pretomanid in vitro. Furthermore, compound 3 was equipotent to pretomanid against a multidrug-resistant M. tuberculosis clinical isolate. The derivatives were selective and bactericidal towards slow-growing mycobacteria. They showed low cytotoxicity towards murine RAW 264.7 and human THP-1 cell lines, with high selectivity indices. Compound 1 effectively eliminated the intracellular mycobacteria in a mycobacteria-infected macrophage model. The derivatives were assessed for their potential to inhibit mycobacterial arylamine N-acetyltransferase (NAT) and were identified as good inhibitors of recombinant mycobacterial NAT, a novel target essential for the intracellular survival of M. tuberculosis. This study provided hits for designing new potent and selective antituberculosis leads, having mycobacterial NAT inhibition as their possible endogenous mechanisms of action.

Probing the Molecular Mechanism of Rifampin Resistance Caused by the Point Mutations S456L and D441V on Mycobacterium tuberculosis RNA Polymerase through Gaussian Accelerated Molecular Dynamics Simulation.

Rifampin is the first-line antituberculosis drug, with Mycobacterium tuberculosis RNA polymerase as the molecular target. Unfortunately, M. tuberculosis strains that are resistant to rifampin have been identified in clinical settings, which limits its therapeutic effects. In clinical isolates, S531L and D516V (in Escherichia coli) are two common mutated codons in the gene rpoB, corresponding to S456L and D441V in M. tuberculosis However, the resistance mechanism at the molecular level is still elusive. In this work, Gaussian accelerated molecular dynamics simulations were performed to uncover the resistance mechanism of rifampin due to S456L and D441V mutations at the atomic level. The binding free energy analysis revealed that the reduction in the ability of two mutants to bind rifampin is mainly due to a decrease in electrostatic interaction, specifically, a decrease in the energy contribution of the R454 residue. R454 acts as an anchor and forms stable hydrogen bond interaction with rifampin, allowing rifampin to be stably incorporated in the center of the binding pocket. However, the disappearance of the hydrogen bond between R454 and the mutated residues increases the flexibility of the side chain of R454. The conformation of R454 changes, and the hydrogen bond interaction between it and rifampin is disrupted. As result, the rifampin molecule moves to the outside of the pocket, and the binding affinity decreases. Overall, these findings can provide useful information for understanding the drug resistance mechanism of rifampin and also can give theoretical guidance for further design of novel inhibitors to overcome the drug resistance.

Biological Applications of Isoniazid Derived Schiff Base Complexes: An Overview

Antibiotic resistance has been growing at an alarming rate and consequently the activity of antibiotics against Gram-negative and Gram-positive bacteria has dropped dramatically day by day. In this sense there is a strong need to synthesis new substances that not only have good field of activity, but having new appliances of action. Inorganic compounds particularly metal complexes have played a significant role in the development of new metal based drugs. Like few compounds, isonicotinic acid hydrazide (Isoniazid INH) is well known as first-line anti-tuberculosis (TB) drug to treat TB infection worldwide for more than 60 years. Unfortunately, people are only dependent on this drug and consequently, the rate of use of this drug has been increasing day by day. As the bacterial strains resistant to isoniazid are getting same for the long-term extensive use and even abuse so there is an urgent need to synthesis new drugs not only for anti-tuberculosis properties but also for having significant activity in various biological areas with mechanisms of action. Isoniazid derivatives and their metal complexes, particularly medicinal inorganic metal complexes have been considered as new drugs for their antimicrobial activities like anti-bacterial, anti-fungal, anti-tuberculosis, DNA binding, antioxidant, cytotoxic, scavenging and antiviral activities. In this review, we have focused on the various synthesized metal complexes of isoniazid and its hydrazones and have compared their biological activities which are more or less strong against microorganisms. It is found that INH has moderate to strong antimicrobial activity.

Bile acids, lipid and purine metabolism involved in hepatotoxicity of first-line anti-tuberculosis drugs

ABSTRACT Objectives Rifampin (RIF), isoniazid (INH) and pyrazinamide (PZA) are essential components of the short-term first-line anti-tuberculosis (anti-TB) chemotherapy regimen and can cause hepatotoxicity. However, the mechanism of anti-TB drug-induced hepatotoxicity (ATDH) is currently unclear. We investigate the relevant contributions to liver injury and the pathway of the above-mentioned drugs administered alone or in combination. Methods UPLC-Q-TOF/MS-based metabolomics, bile acids (BAs) analysis and FXR/SHP detection were used to evaluate the toxicity of these drugs and clarify the underlying metabolism-related pathway. Results In C57BL/6 mice administered the corrected clinical doses, RIF, INH and PZA could induced hepatotoxicity; with less toxicity in the combination therapy than RIF. The pathological biochemistry, BAs concentration and metabolically regulated FXR/SHP gene expression analyzes in mice were consistent with the metabolomics results. FXR played a role in the hepatotoxicity of anti-tuberculosis drugs in the obeticholic acid treated and FXR-/- mice. Additionally, the purine and lipid metabolic pathways were involved in ATDH. Conclusion ATDH was involved in bile acids and lipid and purine metabolism. The BAs metabolic pathway involvement in mice was validated in TB patients. The noninvasive metabolomics approach is more systemic than routine toxicity evaluation and can be used to assess compound toxicity and the underlying mechanism.

Direct Determination of Pyrazinamide (PZA) Susceptibility by Sputum Microscopic Observation Drug Susceptibility (MODS) Culture at Neutral pH: the MODS-PZA Assay.

Pyrazinamide (PZA) is considered the pivot drug in all tuberculosis treatment regimens due to its particular action on the persistent forms of Mycobacterium tuberculosis However, no drug susceptibility test (DST) is considered sufficiently reliable for routine application. Although molecular tests are endorsed, their application is limited to known PZA resistance associated mutations. Microbiological DSTs for PZA have been restricted by technical limitations, especially the necessity for an acidic pH. Here, for the first time, MODS culture at neutral pH was evaluated using high PZA concentrations (400 and 800 μg/ml) to determine PZA susceptibility directly from sputum samples. Sputum samples were cultured with PZA for up to 21 days at 37°C. Plate reading was performed at two time points: R1 (mean, 10 days) and R2 (mean, 13 days) for each PZA concentration. A consensus reference test, composed of MGIT-PZA, pncA sequencing, and the classic Wayne test, was used. A total of 182 samples were evaluated. The sensitivity and specificity for 400 μg/ml ranged from 76.9 to 89.7 and from 93.0 to 97.9%, respectively, and for 800 μg/ml ranged from 71.8 to 82.1 and from 95.8 to 98.6%, respectively. Compared to MGIT-PZA, our test showed a similar turnaround time (medians of 10 and 12 days for PZA-sensitive and -resistant isolates, respectively). In conclusion, MODS-PZA is presented as a fast, simple, and low-cost DST that could complement the MODS assay to evaluate resistance to the principal first-line antituberculosis drugs. Further optimization of test conditions would be useful in order to increase its performance.

Synthesis of SPIONs-CNT Based Novel Nanocomposite for Effective Amperometric Sensing of First-Line Antituberculosis Drug Rifampicin.

It is necessary to study the possible interactions among various chemical surfaces and analytes before applying them to biological systems. We report the synthesis of carbon nanotubes-iron oxide (SPIONs-CNT) nanocomposite material by using lecithin stabilized superparamagnetic iron oxide nanoparticles (SPIONs) obtained by facile hydrothermal technique. Various characterizations of the obtained nanocomposite were carried out and electrochemical studies were performed further to study the interaction capabilities of the nanocomposite with anti-TB drug Rifampicin. Obtained results by cyclic voltammetric studies of SPIONs-CNT nanocomposite with limit of detection (LOD) of 1.178 μM showed the enhanced electrochemical sensitivity and selectivity of anti-tuberculosis (anti-TB) drug Rifampicin (RIF).

Stability Study of Isoniazid and Rifampicin Oral Solutions Using Hydroxypropyl-Β-Cyclodextrin to Treat Tuberculosis in Paediatrics.

(1) Background: First-line antituberculosis treatment in paediatrics entails the administration of Isoniazid, Pyrazinamide, and Rifampicin. This study examines the possibility of developing a combined dose liquid formulation for oral use that would facilitate dose adjustment and adherence to treatment for younger children. (2) Methods: The active pharmaceutical ingredients stability under in vitro paediatric digestive pH conditions have been checked. The samples were studied as individual or fixed combined paediatric dosages to determine the pH of maximum stability. The use of hydroxypropyl-β-cyclodextrin to improve Rifampicin solubility and the use of ascorbic acid to increase the stability of the formulation have been studied. (3) Results: Maximum stability of combined doses was determined at pH 7.4, and maximum complexation at pH 8.0. Taking this into account, formulations presented the minimum dose of two active pharmaceutical ingredients dissolved. The addition of ascorbic acid at 0.1% w/v enables the detection of a higher remaining quantity of both drugs after three days of storage at 5 °C. (4) Conclusions: a formulation which combines the minimum paediatric dosages dissolved recommended by WHO for Isoniazid and Rifampicin has been developed. Future assays are needed to prolong the stability of the formulation with the aim of incorporating Pyrazinamide to the solution.

Sagittaria sagittifolia polysaccharide, a chinese herbal extract, protects against isoniazid- and rifampicin-induced hepatotoxicity in in-vitro model

Background: Isoniazid (INH) and rifampicin (RFP) are first-line antituberculosis drugs; however, one of the most common adverse effects of their use is hepatotoxicity. Sagittaria sagittifolia polysaccharide (SSP) is the primary component of S. sagittifolia. Our previous research has confirmed the protective effect of SSP against INH and RFP-induced hepatic injury in in vivo model system. Objectives: In this study, we aimed to investigate the protective effect and the underlying mechanisms of SSP in cultured HepG2 cells after induction with INH and RFP. Materials and Methods: The study was designed as follows: normal (without any treatment), model (injury induced by INH + RFP), and SSP group (treated with SSP followed by INH + RFP). Cell viability, catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH), along with malondialdehyde (MDA), as well as alanine aminotransferase, aspartate transaminase, and lactate dehydrogenase, were assessed by corresponding kits. Real-time polymerase chain reaction and Western blot were used to evaluate the mRNA and protein expression of Bcl-2, Bax, Nrf2, and Keap1. Results: SSP had a potential protective effect as it increased the cell viability and reduced the intracellular levels of hepatic injury markers. SSP reduced the intracellular content of MDA and increased the activity of SOD, CAT, and GSH. It is noteworthy that the optimum protective effect was observed with a 0.5 mg/mL SSP at 24 h after treatment. In addition, the protection appears to be associated with its activation of nuclear factor E2-related factor 2 signaling pathway. Conclusion: SSP protected against INH + RFP-induced hepatotoxicity in HepG2 cells and this protection might via Nrf2 signaling pathway.

Multidrug-resistant strains of Mycobacterium complex species in Egyptian farm animals, veterinarians, and farm and abattoir workers.

Background and Aim:Mycobacterium tuberculosis complex (MTBC) is a group of mycobacteria that are important human pathogens. Mycobacterium tuberculosis and Mycobacterium bovis cause serious chronic life-threatening disease and also significant economic losses in both production and remedication. Recently, emergence of multidrug-resistant tuberculosis (MDR-TB) complex has generated global recognition of the need for rapid and sensitive diagnosis and development of new treatments. The current study illustrates the isolation/identification of MTBC strains in specimens obtained from cows and humans by conventional and real-time polymerase chain reaction (RT-PCR) techniques. Further, the study assesses sensitivity to antituberculosis drugs in isolated MDR strains.Materials and Methods:A total of 1464 samples from cattle (1285 raw milk and 179 lymph node), and 149 human sputum samples, were collected from farms and abattoirs in Delta Egypt. Conventional methods (culture and Ziehl–Neelsen staining) were implemented as were RT-PCR using MTBC universal DNA. The effect of some antituberculosis drugs on obtained isolates was assayed using drug susceptibility proportion and qualitative suspension techniques.Results:The MBTC detection rate using the culture method was higher than for Ziehl–Neelsen staining; raw cow milk (2.56 vs. 1.63%), lymph nodes (51.59 vs. 48.04%), and human sputum (5.36 vs. 4.02%). A total of 135 isolates were obtained. Application of RT-PCR detected 138 isolates from the same set of samples. MBTC isolates were resistant to first-line antituberculosis drugs, such as pyrazinamide, isoniazid, rifampicin, and ethambutol by 78.5, 59.3, 40.7, and 31.8%, respectively, and could be highly resistant to kanamycin (82.3%) and amikacin (80.7%). However, isolates remained sensitive to ciprofloxacin (71.1%) and clarithromycin (73.3%) as second-line drugs.Conclusion:There is a growing risk for isolation of MDR-TB from raw milk and lymph nodes of field tuberculin positive cattle as well as sputum of veterinarians and workers existed in farms and abattoirs. PCR-based techniques have become the gold standard for the identification of mycobacterial species, showing high efficiency compared to bacteriological and microscopic examination. Application of the first- and second-line antituberculosis drugs in combination could counter the MDR-TB concern once infections are identified.

Uncovering the Resistance Mechanism of Mycobacterium tuberculosis to Rifampicin Due to RNA Polymerase H451D/Y/R Mutations From Computational Perspective.

Tuberculosis is still one of the top 10 causes of deaths worldwide, especially with the emergence of multidrug-resistant tuberculosis. Rifampicin, as the most effective first-line antituberculosis drug, also develops resistance due to the mutation on Mycobacterium tuberculosis (Mtb) RNA polymerase. Among these mutations, three mutations at position 451 (H451D, H451Y, H451R) are associated with high-level resistance to rifampicin. However, the resistance mechanism of Mtb to rifampicin is still unclear. In this work, to explore the resistance mechanism of Mtb to rifampicin due to H451D/Y/R mutations, we combined the molecular dynamics simulation, molecular mechanics generalized-Born surface area calculation, dynamic network analysis, and residue interactions network analysis to compare the interaction change of rifampicin with wild-type RNA polymerase and three mutants. The results of molecular mechanics generalized-Born surface area calculations indicate that the binding free energy of rifampicin with three mutants decreases. In addition, the dynamic network analysis and residue interaction network analysis show that when H451 was mutated, the interactions of residue 451 with its adjacent residues such as Q438, F439, M440, D441, and S447 disappeared or weakened, increasing the flexibility of binding pocket. At the same time, the disappearance of hydrogen bonds between R613 and rifampicin caused by the flipping of R613 is another important reason for the reduction of binding ability of rifampicin in H451D/Y mutants. In H451R mutant, the mutation causes the binding pocket change too much so that the position of rifampicin has a large movement in the binding pocket. In this study, the resistance mechanism of rifampicin at the atomic level is proposed. The proposed drug-resistance mechanism will provide the valuable guidance for the design of antituberculosis drugs.