Strains Of Mycobacteria Research Articles

Antimycobacterial Activity of Essential Oils from Bulgarian Rosa Species Against Phylogenomically Different Mycobacterium tuberculosis Strains

In this study, we aimed to assess the activity of the essential oils from four Bulgarian oil-bearing roses Rosa damascena Mill., R. alba L., R. centifolia L., and R. gallica L., on the reference strain Mycobacterium tuberculosis H37Rv and clinical M. tuberculosis strains of the Beijing and Latin-American Mediterraneum genotypes. The chemical composition of the essential oils was determined by gas chromatography (GC-FID/MS). Minimal inhibitory concentrations (MIC) were determined using the resazurin method. R. alba oil showed the highest inhibitory activity when tested on all strains of different phylogenetic origins with MIC in the range of 0.16–0.31 mg/mL, while R. gallica oil was the least active (MIC 0.62–1.25 mg/mL). The obtained results show heterogeneity of rose oil action on different mycobacterial strains and we hypothesize that the combined level of geraniol and nerol is a key factor that underlies the antimycobacterial action of the rose oils. Strain Beijing 396 was relatively more susceptible to the rose oils probably due to multiple and likely deleterious mutations in its efflux pump genes. Two clinical MDR strains have likely developed during their previous adaptation to anti-TB drugs certain drug tolerance mechanisms that also permitted them to demonstrate intrinsic tolerance to the essential oils. Further research should investigate a possible synergistic action of the new-generation anti-TB drugs and the most promising rose oil extracts on the large panel of different strains.

2-Aryl-Benzoimidazoles as Type II NADH Dehydrogenase Inhibitors of Mycobacterium tuberculosis.

The nonproton pumping type II NADH dehydrogenase in Mycobacterium tuberculosis is essential for meeting the energy needs in terms of ATP under normal aerobic and stressful hypoxic environmental states. Type II NADH dehydrogenase conduits electrons into the electron transport chain in Mycobacterium tuberculosis, which results in ATP synthesis. Therefore, the inhibition of NDH-2 ensures the abolishment of the entire ATP synthesis machinery. Also, type II NADH dehydrogenase is absent in the mammalian genome, thus making it a potential target for antituberculosis drug discovery. Herein, we have screened a commercially available library of drug-like molecules and have identified a hit having a benzimidazole core moiety (6, H37Rv mc26230; minimum inhibitory concentration (MIC) = 16 μg/mL and ATP IC50 = 0.23 μg/mL) interfering with the oxidative phosphorylation pathway. Extensive medicinal chemistry optimization resulted in analogue 8, with MIC = 4 μg/mL and ATP IC50 = 0.05 μg/mL against the H37Rv mc26230 strain of Mycobacterium tuberculosis. Compounds 6 and 8 were found to be active against mono- and multidrug-resistant mycobacterium strains and demonstrated a bactericidal response. The Peredox-mCherry experiment and identification of single-nucleotide polymorphisms in mutants of CBR-5992 (a known type II NADH dehydrogenase inhibitor) were used to confirm the molecules as inhibitors of the type II NADH dehydrogenase enzyme. The safety index >10 for the test active molecules revealed the safety of test molecules.

Evaluation of protein extraction protocols for MALDI-TOF Biotyper analysis of mycobacteria

Infections caused by Mycobacterium tuberculosis and nontuberculous mycobacteria represent a significant global threat and medical concern. Therefore, accurate and reliable methods must be employed to identify mycobacteria rapidly. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a technique that compares the cellular protein profiles of unknown isolates with reference mass spectra in a database to identify microorganisms. However, the thick and waxy lipid layer, which is rich in mycolic acids and is present in mycobacterial cells, makes protein extraction challenging. To identify the optimal protocol for correctly identifying bacilli using MALDI-TOF mass spectrometry, this study compared four different cellular protein extraction methods. Four strains of M. bovis BCG were selected as representatives of slow-growing mycobacteria, while three strains of fast-growing mycobacteria were also included: M. peregrinum, M. smegmatis, and M. farcinogenes. The extraction method that proved most effective was the extraction of inactivated cells with chloroform and methanol, which partially delipidates the cells. These cells were then extracted with formic acid, as is standard practice for protein extraction. The advantage of this method is that it allows the parallel analysis of cellular lipids and proteins from a single sample. It is therefore important to optimize mycobacterial protein extraction for MALDI-TOF MS analysis in clinical microbiology laboratories.

Silver(I) and gold(III) complexes with miconazole: The influence of the metal ion on the antimicrobial activity of the coordinated azole

To develop a new antimicrobial agent, we used the clinically approved antifungal azole, miconazole (mcz), as a ligand for the synthesis of silver(I) and gold(III) complexes. The new complexes [Ag(NO3-O)(mcz-N)2] (1) and [AuCl3(mcz-N)] (2) were synthesized and characterized by 1H NMR, IR and UV–Vis spectroscopy and mass spectrometry, while the crystal structure of 1 was determined by single-crystal X-ray diffraction analysis. From the results obtained, it can be concluded that in both complexes, mcz is monodentately coordinated to the silver(I) and gold(III) ions through the imidazole nitrogen atom N3. In the solid state, complex 1 contains two mcz ligands and monodentately coordinated nitrate in the third position, while in the case of 2 gold(III) ion is coordinated by one mcz and three chlorido ligands, resulting in the expected square-planar arrangement around the metal center. DFT and TDDFT calculations were employed to elucidate the electronic structures and thermodynamic stability of the synthesized complexes in solution to complement the experimental findings. The coordination of mcz to silver(I) and gold(III) ions leads to an enhancement of its activity against Gram-negative Escherichia coli and Pseudomonas aeruginosa strains, while against the panel of Staphylococcus aureus and Candida species, only 2 shows improved activity compared to mcz. Both complexes 1 and 2 were tested in vitro for their antimycobacterial activity against the strain Mycobacterium tuberculosis H37Rv and showed good growth inhibition with minimum inhibitory concentration (MIC) values of 3.12 and 8.69 μM, respectively, with complex 1 being twice effective as mcz (MIC = 7.50 μM). Complex 2 significantly reduced the production of pyocyanin, a virulence factor in P. aeruginosa controlled by quorum sensing, while this effect was not observed for 1.

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

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

Bioassay-guided isolation and structure elucidation of anti-mycobacterium tuberculosis compounds from Galatella grimmii (Regel & Schmalh.) Sennikov

BackgroundGalatella is a genus in the family Asteraceae, represented by 35-45 species. Considering the high effectiveness of the ethyl acetate (EtOAc) fraction of G. grimmii against Mycobacterium tuberculosis (MIC = 0.5 µg/mL), a bioassay-directed fractionation of this extract was carried out.MethodsThe methanolic extract of the aerial parts of G. grimmii was obtained using maceration, then it was suspended in water and partitioned with petroleum ether, dichloromethane (CH2Cl2), EtOAc, and n-butanol (n-BuOH), successively. The most potent fraction (EtOAc), was selected for further isolation by Sephadex LH–20 and semi-preparative HPLC to obtain active compounds.ResultsFractionation of the EtOAc solvent fraction resulted in the characterization of five compounds, among them, compounds 1 and 2 showed the highest anti-mycobacterial effects with MICs of 0.062 and 1.00 µg/mL against H37Rv M. tuberculosis, respectively, which were higher than those of rifampin (MIC of 1.25 µg/mL) and isoniazid (MIC of 0.31 µg/mL), as positive controls. Also, compound 1 ​​inhibited all tested strains of drug-resistant Mycobacterium (MDR and XDR). Notably, the isolated compounds have been reported for the first time from G. grimmii.ConclusionDue to the potent anti-mycobacterial effect of isolated compounds from G. grimmii, this study could pave the way for developing a novel class of natural anti-tuberculosis compounds.

Therapeutic potential of Zanha africana (Radlk.) Exell: antimycobacterial activity and safety evaluation

BackgroundZanha africana (Radlk.) Exell extracts are commonly utilized in Tanzania and other countries for treating conditions associated with HIV and AIDS, including tuberculosis (TB). In Tanzania, it is listed among the most frequently traded plant species for medicinal use in different marketplaces. However, limited literature exists regarding its antimycobacterial properties and safety profile. ObjectiveThis study aimed to evaluate Z. africana ethanolic extract for safety and antimycobacterial activity. MethodsThe antimycobacterial activity of the crude extracts was assessed using the broth microdilution method against various non-pathogenic mycobacteria strains including Mycobacterium aurum (MA), Mycobacterium madagascariense (MM), and Mycobacterium indicus pranii (MIP). Bioassay-guided fractionation was employed to isolate the active compounds. The safety profile of the crude extract was investigated through cytotoxicity assay on peripheral blood mononuclear cells (PBMCs) and the brine shrimp lethality test. ResultsThe 80% ethanolic extracts of Z. africana demonstrated activity against all tested non-pathogenic mycobacteria. The antimycobacterial activity of ethanolic extract of the stem bark was 625 µg/mL, 313 µg/mL and 125 µg/mL against MA, MM, and MIP, respectively. The most potent fraction was the ethyl acetate fraction, from which two active compounds were isolated: proanthocyanidin A2; Compound (1) and its monomer epicatechin, Compound (2). Compound (1) exhibited higher antimycobacterial activity compared to compound (2) with minimum inhibitory concentrations (MICs) of 19.50 µg/mL and 12.98 µg/mL against MM and MIP respectively. The ethanolic extract did not demonstrate toxicity on PBMCs and brine shrimps. ConclusionThis study demonstrates that Z. africana extracts and the isolated compounds possess antimycobacterial activity. This provides evidence supporting the traditional use of Z. africana extracts for TB management. Further research is recommended to comprehensively evaluate the efficacy and safety of the plant constituents using different models.

Photoinactivation of Mycobacterium tuberculosis and Mycobacterium smegmatis by Near-Infrared Radiation Using a Trehalose-Conjugated Heptamethine Cyanine.

The spread of multidrug-resistant mycobacterium strains requires the development of new approaches to combat diseases caused by these pathogens. For that, photodynamic inactivation (PDI) is a promising approach. In this study, a tricarbocyanine (TCC) is used for the first time as a near-infrared (740 nm) activatable PDI photosensitizer to kill mycobacteria with deep light penetration. For better targeting, a novel tricarbocyanine dye functionalized with two trehalose units (TCC2Tre) is developed. The photodynamic effect of the conjugates against mycobacteria, including Mycobacterium tuberculosis, is evaluated. Under irradiation, TCC2Tre causes more effective killing of mycobacteria compared to the photosensitizer without trehalose conjugation, with 99.99% dead vegetative cells of M. tuberculosis and M. smegmatis. In addition, effective photoinactivation of dormant forms of M. smegmatis is observed after incubation with TCC2Tre. Mycobacteria treated with TCC2Tre are more sensitive to 740 nm light than the Gram-positive Micrococcus luteus and the Gram-negative Escherichia coli. For the first time, this study demonstrates the proof of principle of in vitro PDI of mycobacteria including the fast-growing M. smegmatis and the slow-growing M. tuberculosis using near-infrared activatable photosensitizers conjugated with trehalose. These findings are useful for the development of new efficient alternatives to antibiotic therapy.

Rapid and Highly Sensitive Detection of Mycobacterium tuberculosis Utilizing the Recombinase Aided Amplification-Based CRISPR-Cas13a System.

Tuberculosis (TB), a disease caused by Mycobacterium tuberculosis (MTB) infection, remains a major threat to global public health. To facilitate early TB diagnosis, an IS6110 gene-based recombinase aided amplification (RAA) assay was coupled to a clustered, regularly interspaced short palindromic repeats (CRISPR)-Cas13a fluorescence assay to create a rapid MTB detection assay (named RAA-CRISPR-MTB). Its diagnostic efficacy was evaluated for sensitivity and specificity through sequential testing of recombinant plasmids, mycobacterium strains, and clinical specimens. RAA-CRISPR detected IS6110 genes at levels approaching 1 copy/μL with pUC57-6110 as the template and 10 copies/μL with H37Rv as the template. There was no observed cross detection of non-tuberculosis mycobacteria (NTM) with either template. Furthermore, RAA-CRISPR testing of 151 clinical specimens yielded a diagnostic specificity rate of 100% and a diagnostic sensitivity rate of 69% that exceeded the corresponding Xpert MTB/RIF assay rate (60%). In conclusion, we established a novel RAA-CRISPR assay that achieved highly sensitive and specific MTB detection for use as a clinical TB diagnostic tool in resource-poor settings.

Development of a whole-cell biosensor for ethylene oxide and ethylene.

Ethylene and ethylene oxide are widely used in the chemical industry, and ethylene is also important for its role in fruit ripening. Better sensing systems would assist risk management of these chemicals. Here, we characterise the ethylene regulatory system in Mycobacterium strain NBB4 and use these genetic parts to create a biosensor. The regulatory genes etnR1 and etnR2 and cognate promoter Petn were combined with a fluorescent reporter gene (fuGFP) in a Mycobacterium shuttle vector to create plasmid pUS301-EtnR12P. Cultures of M. smegmatis mc2-155(pUS301-EtnR12P) gave a fluorescent signal in response to ethylene oxide with a detection limit of 0.2 μM (9 ppb). By combining the epoxide biosensor cells with another culture expressing the ethylene monooxygenase, the system was converted into an ethylene biosensor. The co-culture was capable of detecting ethylene emission from banana fruit. These are the first examples of whole-cell biosensors for epoxides or aliphatic alkenes. This work also resolves long-standing questions concerning the regulation of ethylene catabolism in bacteria.

Revisiting Bacille Calmette‐Guérin revaccination strategies: timing of immunization, Mycobacterium tuberculosis and non‐tuberculous mycobacteria infections, strain potency and standardization of randomized controlled trials

AbstractThe persistent threat of tuberculosis (TB) on a global scale hasprompted a reevaluation of preventive strategies, with a particular focus onthe Bacille Calmette‐Guérin (BCG) vaccine's role in revaccination. Theresurgence underscores an urgent need for enhanced measures, prompting acritical examination of BCG revaccination strategies. Drawing from the researchof Paulo Cesar Pereira dos Santos and a synthesis of randomized controlledtrials (RCTs), this review identifies key considerations for refining BCGrevaccination's efficacy against Mycobacterium tuberculosis (MTB) andTB. The main body of this review integrates four principal domains essentialfor optimizing BCG revaccination: the timing of revaccination, the assessmentof various BCG strains, the evaluation of the vaccine's effectiveness on MTBand non‐tuberculous mycobacteria (NTM) strains, and the enhancement of RCTmethodologies. Determining the optimal revaccination timing is paramount forbolstering immunity, especially in regions with high TB prevalence. Theanalysis of different BCG strains provides insights into strain‐specificimmunogenicity, informing vaccine deployment strategies. Additionally,understanding the vaccine's impact on a range of mycobacterial infections iscrucial for its broader application in various microbial contexts. The reviewemphasizes the refinement of RCT designs to ensure robust and consistentoutcomes, facilitating the reproducibility of results in diverse settings. Itproposes a strategy that not only suggests modifications to revaccinationpractices to increase global TB prevention effectiveness but also calls forcontinuous research to improve BCG revaccination methodologies. The paperadvocates for a standardized, evidence‐driven approach to global TB preventionthat takes into account regional epidemiological differences. In conclusion,this review significantly contributes to the discourse on TB prevention,advocating for evidence‐based, standardized approaches that could potentiallytransform the role of BCG revaccination in global TB prevention efforts. Thefindings support current initiatives aimed at developing policies based onsolid evidence, ensuring the scientific integrity and practical relevance ofBCG revaccination strategies.

Synthesis, Electronic, and Antibacterial Properties of 3,7-Di(hetero)aryl-substituted Phenothiazinyl N-Propyl Trimethylammonium Salts.

In this study, a library of 3,7-di(hetero)aryl-substituted 10-(3-trimethylammoniumpropyl)10H-phenothiazine salts is prepared. These title compounds and their precursors are reversible redox systems with tunable potentials. The Hammett correlation gives a very good correlation of the first oxidation potentials with σp parameters. Furthermore, the title compounds and their precursors are blue to green-blue emissive. Screening of the salts reveals for some derivatives a distinct inhibition of several pathogenic bacterial strains (Mycobacterium tuberculosis, Staphylococcus aureus, Escherichia coli, Aconetobacter baumannii, and Klebsiella pneumoniae) in the lower micromolar range.

Identifying Mtb-Specific T Cell Epitopes Across the Spectrum of Tuberculosis Infection: Implications for Diagnostics and Vaccines

Abstract The challenge in advancing tuberculosis (TB) diagnostics and vaccines arises from our limited understanding of diverse Mtb antigens triggering distinct T cell responses in spectrum of TB infection. We addressed this with a comprehensive analysis, screening 20,610 Mtb-derived T cell epitopes using IFNγ Fluorospot in active TB (ATB) and BCG-vaccinated individuals, comparing to LTBI. We identified 137 unique epitopes in ATB, 16% recognized by multiple participants, suggesting a broad response, mainly targeting cell wall and cell processes antigens. BCG-vaccinated individuals also showed a heterogeneous response with 85 unique epitopes. There was little overlap between the epitopes found in ATB and BCG-vaccinated individuals, implying distinct antigen recognition in spectrum of TB. From these findings, we developed an ATB-specific peptide pool (ATB116), distinguishing pulmonary ATB with over 60% sensitivity and 80% specificity across diverse locations. We also aligned the identified epitopes with 157 mycobacteria strains to assess their conservation across different Mtb strains and the broader mycobacterium genus. This revealed 17% of the epitopes are 100% conserved across the mycobacterium genus, suggesting that the sensitivity and specificity of the peptide pools can be improved. In summary, our T cell reactivity analysis identified stage-specific Mtb epitopes, offering diagnostic potential, measuring Mtb-specific immune responses, and advancing vaccine development.

Lanthanide furoate complexes as promising systems with double effects – From suppression of mycobacteria to potential bioimaging

Several ternary complexes of rare earth ions (Gd3+, Eu3+, Sm3+) with 3-furoic (H3fur) / 5-nitro-2-furoic (Hnfur) acids and 1,10-phenanthroline (phen) have been synthesized. According to the X-ray data the resulting complexes can be divided into two groups − heterocarboxylate [Ln2(3fur)4(OAc)2(phen)2]·L and homocarboxylate complexes [Ln2(nfur)6(phen)2]·L (LnIII = Gd (1, 2), Eu (3, 4), Sm (5, 6, 7); L = 4EtOH (1–4), 4MeOH (5), H2O (7)). The stability of the complexes 1–6 in solutions was studied by recording electronic absorption spectra for two days. Optical properties of the complexes 1–6 were studied by recording absorption, excitation and luminescence spectra. The study of antibacterial properties 1–7 showed high activity of complexes in vitro against non-pathogenic Mycolicibacterium smegmatis. For the most active 3, antibacterial activity against the reference strain Mycobacterium tuberculosis H37Rv was determined (minimum inhibitory concentration (MIC) up to 12.5 μg/mL)..

BIOLOGICAL MODEL OF LUNG CANCER COMBINATION AND TUBERCULOSIS: DEVELOPMENT FOR PRECLINICAL STUDY OF RATIONAL COMBINATIONS OF TARGETED ANTITUMOR AND ANTITUBERCULOSIS THERAPY

Introduction. Lung cancer occupies a leading position in the structure of mortality from cancer. Chronic inflammation characteristic of tuberculosis increases the risk of lung cancer. Currently, more and more information is emerging confirming the cause-and-effect relationship between tuberculosis and cancer. The need to develop recommendations for public health regarding screening and treatment of tuberculosis in the tumor process determines the relevance of experimental studies on biological models of the combination of cancer and tuberculosis.. Aim. Creation а biological model of the combination of lung cancer and tuberculosis for preclinical study of rational combinations of antitumor and antituberculosis therapy. Material and methods: The biological model was implemented on C57BL/6 mice at the age of two months. Lewis epidermoid lung carcinoma was used to reproduce the tumor process. Modeling of tuberculosis was carried out using the reference strain Mycobacterium Tuberculosis H37RV. During the study, the following groups were formed: “intact mice” (healthy, uninfected with the Mycobacterium Tuberculosis (MBT) H37Rv strain without tumor cell transplantation); “control of MBT infection” (animals infected with Mycobacterium Tuberculosis strain H37Rv), “tumor control” (animals that were transplanted with epidermoid Lewis lung carcinoma) and “main group” (animals that were transplanted with epidermoid Lewis lung carcinoma simultaneously with MBT infection). Results. During the experiment, several models for creating the combined pathology of lung cancer and tuberculosis were identified. In the first (simultaneous infection and tumor inoculation), carcinoma developed more slowly in infected animals than in the tumor control group, and lung damage occurred with a predominance of the tuberculous process over the tumor process. The second (staged infection) also showed minimal metastatic manifestations with pronounced secondary changes in the primary tumor node. Analysis of the choice of model showed that the model with simultaneous infection and tumor inoculation most adequately ensures the development of the tumor process and tuberculosis infection, which allows maintaining the viability of the animal, fully developing the tumor process with metastasis to the lungs and obtaining the development of morphologically verified pulmonary tuberculosis.

Complete genome sequences and multidrug resistance genotypes of nontuberculous mycobacteria isolates from the Central Tuberculosis Reference Laboratory Muhimbili Tanzania

Background: Nontuberculous mycobacteria (NTM) usually comprise a group of environmental bacteria, with emerging but elusive coinfection with tuberculous mycobacteria, causing pulmonary tuberculosis. Whole genome sequencing may give insight into potential antimicrobial resistance genotypes, giving clinicians and policymakers proper directions in clinical applications and management regimens. Methods: WGS was performed on twenty-four gDNA isolates from archival samples at the Central Tuberculosis Reference Laboratory using the MinION Oxford Nanopore Sequencing approach. Out of twenty-four, two were confirmed to belong to the NTM group. Further analysis was done to resolve the complete genomes of two nontuberculous mycobacteria strains isolated from tuberculosis patients. We then combined phylogenomics, reference-based scaffolding and average nucleotide identity (ANI) analysis to delineate each strain's taxonomic position and corresponding features. Results: Our findings reveal that the two strains fit into the genus Mycolicibacterium, and the closest relative is Mycolicibacterium novocastrense. Coupling BacAnt and CARD-based antibiotic resistance analyses revealed multidrug-resistant genotypes of diverse spectra and mechanisms. While the BC02 strain is genetically resistant to beta-lactams, macrolides and rifamycins, the BC05 strain portrays an extended drug resistance genotype encompassing beta-lactams, macrolides, polyamines, and aminoglycosides. Both strains possess a single nucleotide polymorphism (SNP) of the RNA polymerase beta-subunit (rpoB), representing resistance to the first-line rifampicin. Additionally, the BC05 strain genetically portrays resistance to ethambutol, isoniazid and fosfomycin through mechanisms involving target alteration through SNPs, drug inactivation and efflux. Conclusion: Our findings strongly suggest the potential implication of multidrug-resistant NTM clinical isolates in the pathogenesis of pulmonary tuberculosis.

Oral and Maxillofacial Manifestations of Tuberculosis Presented to Primary Health Care Centres in Port Sudan, Sudan

Tuberculosis is a chronic granulomatous disease caused by various strains of mycobacteria, usually Mycobacterium Tuberculosis in humans. Robert Koch, a German physician, discovered the Tuberculosis bacillus in 1882 [1]. It has been a worldwide major health problem for centuries. Although the disease’s prevalence reduced decades ago, it still has extremely high prevalence in Asian and African countries. It may take any form clinically, but with decline in number, these tuberculosis lesions of oral cavity have become so rare that they are frequently overlooked in the differential diagnosis of oral lesions. Although, oral manifestations of tuberculosis has a rare occurrence, but it has been considered to account for 0.1-5% of all TB infections.

Molecular docking, molecular dynamics simulations and binding free energy studies of interactions between Mycobacterium tuberculosis Pks13, PknG and bioactive constituents of extremophilic bacteria

Mycobacterial pathogens present a significant challenge to disease control efforts globally due to their inherent resistance to multiple antibiotics. The rise of drug-resistant strains of Mycobacterium tuberculosis has prompted an urgent need for innovative therapeutic solutions. One promising way to discover new tuberculosis drugs is by utilizing natural products from the vast biochemical space. Multidisciplinary methods can used to harness the bioactivity of these natural products. This study aimed to evaluate the antimycobacterial efficacy of functional crude extracts from bacteria isolated from gold mine tailings in South Africa. Bacterial strains were identified using 16S rRNA sequencing. The crude extracts obtained from the bacteria were tested against Mycobacterium tuberculosis H37Rv, Mycobacterium smegmatis mc2155, and Mycobacterium aurum A+. Untargeted HPLC-qTOF and molecular networking were used to identify the functional constituents present in extracts that exhibited inhibitory activity. A virtual screening workflow (VSW) was used to filter compounds that were strong binders to Mycobacterium tuberculosis Pks13 and PknG. The ligands returned from the VSW were subjected to optimization using density functional theory (DFT) at M06-2X/6-311++ (d,p) level of theory and basis set implemented in Gaussian16 Rev.C01. The optimized ligands were re-docked against Mycobacterium tuberculosis Pks13 and PknG. Molecular dynamics simulation and molecular mechanics generalized born surface area were used to evaluate the stability of the protein–ligand complexes formed by the identified hits. The hit that showed promising binding characteristics was virtually modified through multiple synthetic routes using reaction-driven enumeration. Three bacterial isolates showed significant activity against the two strains of Mycobacterium, while only two, Bacillus subtilis and Bacillus licheniformis, exhibited activity against both Mycobacterium tuberculosis H37Rv, Mycobacterium smegmatis mc2155, and Mycobacterium aurum A+. The tentatively identified compounds from the bacterial crude extracts belonged to various classes of natural compounds associated with antimicrobial activity. Two compounds, cyclo-(L-Pro-4-OH-L-Leu) and vazabitide A, showed strong binding against PknG and Pks13, with pre-MD MM-GBSA values of − 42.8 kcal/mol and − 47.6 kcal/mol, respectively. The DFT-optimized compounds exhibited the same docking scores as the ligands optimized using the OPSL-4 force field. After modifying vazabitide A, its affinity to the Pks13 binding site increased to − 85.8 kcal/mol, as revealed by the post-MD MM-GBSA analysis. This study highlights the potential of bacteria isolates from gold mine tailings as a source of new scaffolds for designing and optimizing anti-Mycobacterium agents. These agents synthesized in-silico can be further tested in-vitro to evaluate their efficacy.

Combined antimicrobial action of streptomycin and terpenes against atypical mycobacteria isolated from fish.

The aim of this study was to investigate the antimycobacterial activity of 39 free terpenes and their activity in combination with streptomycin. Antimicrobial activity was first evaluated by screening 39 free terpenes at concentrations from 1.56 to 400 μg/mL. None of these exhibited positive effects against any of the nontuberculous mycobacteria (NTM) strains tested. However, six of the 39 terpenes (isoeugenol, nerol, (+)-α-terpineol, (1R)-(-)-myrtenol, (+)-terpinen-4-ol, and eugenol) were shown to enhance the activity of streptomycin against the NTM strains isolated from diseased ornamental fish.

ЭПИЗООТИЧЕСКАЯ СИТУАЦИЯ ПО ТУБЕРКУЛЕЗУ КРУПНОГО РОГАТОГО СКОТА В ОМСКОЙ ОБЛАСТИ

The purpose of research is to study and assess the current epizootic situation regarding tuberculosis in the administrative-territorial formations of the Omsk Region based on the results of allergic and bacteriological studies. The paper presents the results of an analysis of data from allergic and bacteriological stu¬dies on bovine tuberculosis conducted in the Omsk Region from 2016 to 2022. It is shown that after an increase by 2018 to 0.28 % of cases of detection of positive reactions in animals to intradermal administration of tuberculin subsequently noted a gradual decrease in their number to 0.10 % by 2022. As the compiled cartogram showed, over the entire observation period, the greatest degree of spread of delayed-type skin hypersensitivity was recorded in cattle in the southern districts of the region (Moskalensky, Isilkulsky and Pavlogradsky) with the absence or isolated cases of its manifestation in the northern districts. Due to the wide distribution of non-tuberculous mycobacteria in the region, which are the main cause of non-specific reactions during allergic testing, all animals that gave a positive reaction to intradermal injection of tuberculin are examined by palpebral test, which prevented the unreasonable slaughter of a significant number of cattle. Of the responders, from 1.73 to 4.32 % of heads with pronounced swelling were identified annually when the allergen was introduced into the thickness of the eyelid, with the most frequent cases of reaction observed in the Kalachinsky, Sargatsky, Lyubinsky, Pavlogradsky, Moskalensky and Isilkulsky Districts. When conducting bacteriological studies of biological material from forcedly killed animals over the entire period of observation, 33 strains of bovine mycobacteria and 7 strains of NTM of groups II and III according to the Runyon classification were isolated. Despite the significant improvement in the epizootic situation, the problem of bovine tuberculosis in the Omsk Region remains relevant today due to cases of registration of isolated foci of infection in the Isilkulsky, Tavrichesky and Muromtsevsky Districts of the Omsk Region.