scholarly journals Characterisation of a putative M23-domain containing protein in Mycobacterium tuberculosis

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259181
Author(s):  
Andrea Olga Papadopoulos ◽  
Christopher Ealand ◽  
Bhavna Gowan Gordhan ◽  
Michael VanNieuwenhze ◽  
Bavesh Davandra Kana
Keyword(s):  
Cell Wall ◽  
Mycobacterium Tuberculosis ◽  
Drug Target ◽  
Hydrolytic Activity ◽  
Zinc Binding ◽  
Health Concern ◽  
Drug Resistant ◽  
Transcript Analysis ◽  
Bacterial Peptidoglycan

Mycobacterium tuberculosis, the causative agent of tuberculosis remains a global health concern, further compounded by the high rates of HIV-TB co-infection and emergence of multi- and extensive drug resistant TB, all of which have hampered efforts to eradicate this disease. As a result, novel anti-tubercular interventions are urgently required, with the peptidoglycan component of the M. tuberculosis cell wall emerging as an attractive drug target. Peptidoglycan M23 endopeptidases can function as active cell wall hydrolases or degenerate activators of hydrolases in a variety of bacteria, contributing to important processes such as bacterial growth, division and virulence. Herein, we investigate the function of the Rv0950-encoded putative M23 endopeptidase in M. tuberculosis. In silico analysis revealed that this protein is conserved in mycobacteria, with a zinc-binding catalytic site predictive of hydrolytic activity. Transcript analysis indicated that expression of Rv0950c was elevated during lag and log phases of growth and reduced in stationary phase. Deletion of Rv0950c yielded no defects in growth, colony morphology, antibiotic susceptibility or intracellular survival but caused a reduction in cell length. Staining with a monopeptide-derived fluorescent D-amino acid, which spatially reports on sites of active PG biosynthesis or repair, revealed an overall reduction in uptake of the probe in ΔRv0950c. When stained with a dipeptide probe in the presence of cell wall damaging agents, the ΔRv0950c mutant displayed reduced sidewall labelling. As bacterial peptidoglycan metabolism is important for survival and pathogenesis, the role of Rv0950c and other putative M23 endopeptidases in M. tuberculosis should be explored further.

scholarly journals Anti-drug Pattern of Drug-resistant Mycobacterium tuberculosis and Analysis of Mutation in Drug-target Genes

2005 ◽  
Vol 79 (6) ◽  
pp. 388-396 ◽  
Author(s):  
Jun MUKAIGAWA ◽  
Miyoko ENDOH ◽  
Yoshitoki YANAGAWA ◽  
Satoshi MOROZUMI
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Drug Target ◽  
Target Genes ◽  
Drug Resistant

scholarly journals Population structure of drug-resistant Mycobacterium tuberculosis in Central Asia

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Anna Engström ◽  
Uladzimir Antonenka ◽  
Abdylat Kadyrov ◽  
Gulmira Kalmambetova ◽  
Katharina Kranzer ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Population Structure ◽  
Central Asia ◽  
Tandem Repeats ◽  
Relative Size ◽  
Multidrug Resistant ◽  
Variable Number ◽  
Health Concern ◽  
Drug Resistant ◽  
Recent Emergence

Abstract Background Drug-resistant tuberculosis (TB) is a major public health concern threathing the success of TB control efforts, and this is particularily problematic in Central Asia. Here, we present the first analysis of the population structure of Mycobacterium tuberculosis complex isolates in the Central Asian republics Uzbekistan, Tajikistan, and Kyrgyzstan. Methods The study set consisted of 607 isolates with 235 from Uzbekistan, 206 from Tajikistan, and 166 from Kyrgyzstan. 24-loci MIRU-VNTR (Mycobacterial Interspersed Repetitive Units - Variable Number of Tandem Repeats) typing and spoligotyping were combined for genotyping. In addition, phenotypic drug suceptibility was performed. Results The population structure mainly comprises strains of the Beijing lineage (411/607). 349 of the 411 Beijing isolates formed clusters, compared to only 33 of the 196 isolates from other clades. Beijing 94–32 (n = 145) and 100–32 (n = 70) formed the largest clusters. Beijing isolates were more frequently multidrug-resistant, pre-extensively resistant (pre-XDR)- or XDR-TB than other genotypes. Conclusions Beijing clusters 94–32 and 100–32 are the dominant MTB genotypes in Central Asia. The relative size of 100–32 compared to previous studies in Kazakhstan and its unequal geographic distribution support the hypothesis of its more recent emergence in Central Asia. The data also demonstrate that clonal spread of resistant TB strains, particularly of the Beijing lineage, is a root of the so far uncontroled MDR-TB epidemic in Central Asia.

scholarly journals Role of embB Codon 306 Mutations in Mycobacterium tuberculosis Revisited: a Novel Association with Broad Drug Resistance and IS6110 Clustering Rather than Ethambutol Resistance

2005 ◽  
Vol 49 (9) ◽  
pp. 3794-3802 ◽  
Author(s):  
Manzour Hernando Hazbón ◽  
Miriam Bobadilla del Valle ◽  
Marta Inírida Guerrero ◽  
Mandira Varma-Basil ◽  
Ingrid Filliol ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Odds Ratio ◽  
Univariate Analysis ◽  
Drug Susceptibility ◽  
Drug Resistant ◽  
Development Of Resistance ◽  
Resistance Patterns ◽  
Novel Association

ABSTRACT Mutations at position 306 of embB (embB306) have been proposed as a marker for ethambutol resistance in Mycobacterium tuberculosis; however, recent reports of embB306 mutations in ethambutol-susceptible isolates caused us to question the biological role of this mutation. We tested 1,020 clinical M. tuberculosis isolates with different drug susceptibility patterns and of different geographical origins for associations between embB306 mutations, drug resistance patterns, and major genetic group. One hundred isolates (10%) contained a mutation in embB306; however, only 55 of these mutants were ethambutol resistant. Mutations in embB306 could not be uniquely associated with any particular type of drug resistance and were found in all three major genetic groups. A striking association was observed between these mutations and resistance to any drug (P < 0.001), and the association between embB306 mutations and resistance to increasing numbers of drugs was highly significant (P < 0.001 for trend). We examined the association between embB306 mutations and IS6110 clustering (as a proxy for transmission) among all drug-resistant isolates. Mutations in embB306 were significantly associated with clustering by univariate analysis (odds ratio, 2.44; P = 0.004). In a multivariate model that also included mutations in katG315, katG463, gyrA95, and kasA269, only mutations in embB306 (odds ratio, 2.14; P = 0.008) and katG315 (odds ratio, 1.99; P = 0.015) were found to be independently associated with clustering. In conclusion, embB306 mutations do not cause classical ethambutol resistance but may predispose M. tuberculosis isolates to the development of resistance to increasing numbers of antibiotics and may increase the ability of drug-resistant isolates to be transmitted between subjects.

scholarly journals Synthetic Lethality Reveals Mechanisms of Mycobacterium tuberculosis Resistance to β-Lactams

mBio ◽  
2014 ◽  
Vol 5 (5) ◽  
Author(s):  
Shichun Lun ◽  
David Miranda ◽  
Andre Kubler ◽  
Haidan Guo ◽  
Mariama C. Maiga ◽  
...  
Keyword(s):  
Cell Wall ◽  
Mycobacterium Tuberculosis ◽  
Synthetic Lethality ◽  
Multidrug Resistant ◽  
Cell Wall Biosynthesis ◽  
Drug Resistant ◽  
Content Type ◽  
Innate Resistance ◽  
Extensively Drug Resistant

ABSTRACT Most β-lactam antibiotics are ineffective against Mycobacterium tuberculosis due to the microbe’s innate resistance. The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains has prompted interest to repurpose this class of drugs. To identify the genetic determinants of innate β-lactam resistance, we carried out a synthetic lethality screen on a transposon mutant library for susceptibility to imipenem, a carbapenem β-lactam antibiotic. Mutations in 74 unique genes demonstrated synthetic lethality. The majority of mutations were in genes associated with cell wall biosynthesis. A second quantitative real-time PCR (qPCR)-based synthetic lethality screen of randomly selected mutants confirmed the role of cell wall biosynthesis in β-lactam resistance. The global transcriptional response of the bacterium to β-lactams was investigated, and changes in levels of expression of cell wall biosynthetic genes were identified. Finally, we validated these screens in vivo using the MT1616 transposon mutant, which lacks a functional acyl-transferase gene. Mice infected with the mutant responded to β-lactam treatment with a 100-fold decrease in bacillary lung burden over 4 weeks, while the numbers of organisms in the lungs of mice infected with wild-type bacilli proliferated. These findings reveal a road map of genes required for β-lactam resistance and validate synthetic lethality screening as a promising tool for repurposing existing classes of licensed, safe, well-characterized antimicrobials against tuberculosis. IMPORTANCE The global emergence of multidrug-resistant and extensively drug-resistant M. tuberculosis strains has threatened public health worldwide, yet the pipeline of new tuberculosis drugs under development remains limited. One strategy to cope with the urgent need for new antituberculosis agents is to repurpose existing, approved antibiotics. The carbapenem class of β-lactam antibiotics has been proposed as one such class of drugs. Our study identifies molecular determinants of innate resistance to β-lactam drugs in M. tuberculosis, and we demonstrate that functional loss of one of these genes enables successful treatment of M. tuberculosis with β-lactams in the mouse model.

scholarly journals Efficacy of β-lactam/β-lactamase inhibitor combination is linked to WhiB4-mediated changes in redox physiology of Mycobacterium tuberculosis

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Saurabh Mishra ◽  
Prashant Shukla ◽  
Ashima Bhaskar ◽  
Kushi Anand ◽  
Priyanka Baloni ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Redox Potential ◽  
Dependent Manner ◽  
Drug Resistant ◽  
Redox Sensor ◽  
Functional Linkage ◽  
Computer Based ◽  
Inhibitor Combination ◽  
Lactamase Inhibitor

Mycobacterium tuberculosis (Mtb) expresses a broad-spectrum β-lactamase (BlaC) that mediates resistance to one of the highly effective antibacterials, β-lactams. Nonetheless, β-lactams showed mycobactericidal activity in combination with β-lactamase inhibitor, clavulanate (Clav). However, the mechanistic aspects of how Mtb responds to β-lactams such as Amoxicillin in combination with Clav (referred as Augmentin [AG]) are not clear. Here, we identified cytoplasmic redox potential and intracellular redox sensor, WhiB4, as key determinants of mycobacterial resistance against AG. Using computer-based, biochemical, redox-biosensor, and genetic strategies, we uncovered a functional linkage between specific determinants of β-lactam resistance (e.g. β-lactamase) and redox potential in Mtb. We also describe the role of WhiB4 in coordinating the activity of β-lactamase in a redox-dependent manner to tolerate AG. Disruption of WhiB4 enhances AG tolerance, whereas overexpression potentiates AG activity against drug-resistant Mtb. Our findings suggest that AG can be exploited to diminish drug-resistance in Mtb through redox-based interventions.

scholarly journals Current Perceptionson Advanced Molecular Diagnostics for Drug-Resistant Mycobacterium tuberculosis

2021 ◽  
Vol 14 (3) ◽  
pp. 1249-1257
Author(s):  
Pushparaju Ramasamy ◽  
Vignesh Sounderrajan ◽  
Kevin Kumar Vijayakumar ◽  
Shakila Harshavardhan
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Point Of Care ◽  
Health Concern ◽  
Drug Resistant ◽  
X Rays ◽  
Resistance Mutations ◽  
Resistant Tuberculosis ◽  
Pet Ct ◽  
Significant Public Health ◽  
Essential Resource

Globally, rising drug-resistant tuberculosis is a significant public health concern. Prompt diagnosis of tuberculosis and detection of drug-resistant TB within a clinically appropriate timeframe is important for the effective management of the disease. Imaging approaches Chest X-rays, CT, MRI, nuclear medicine technique as PET/CT are non-specific, plays an important role in the diagnosis and assessment of TB, but PET/CT sometimes results in false-positive or negative due to benign lesions.Currently using the point of care molecular modalities, Gene Xpert MTB/RIF and line probe assays focused only on resistance-conferring mutations in specific target hotspot regions, but did not identify novel mutations, outside mutations and they may miss some locally prevalent rifampicin-conferring mutations, and not provided a large number of antibiotics/antibiotic groups that are used for DRTB treatment.Recently revolutionized high throughput next generation sequencing (NGS) technologies are offering new prospects for molecular diagnosis, for example, infectious disease pathogens like tuberculosis, influenza, and most recently SARS-CoV-2. NGS is an essential resource for the tuberculosis communityeither target, WGS, or NGS; a rapid method that offers a complete spectrum of Mycobacterium tuberculosis resistance mutations, strain typing for transmission surveillance, unlike traditional molecular or phenotypic DST. It shall be helpful for early regimen design and TB management before mutations emerge and therefore, we believe that the worldwide TB infection will be eliminated by the use of NGS.

scholarly journals Investigating colistin drug resistance: The role of high-throughput sequencing and bioinformatics

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 150 ◽  
Author(s):  
Dickson Aruhomukama ◽  
Ivan Sserwadda ◽  
Gerald Mboowa
Keyword(s):  
Antibiotic Resistance ◽  
High Throughput ◽  
Bacterial Infections ◽  
High Throughput Sequencing ◽  
Health Concern ◽  
Gram Negative Bacteria ◽  
Drug Resistant ◽  
Colistin Resistance ◽  
Gram Negative

Bacterial infections involving antibiotic resistant gram-negative bacteria continue to increase and represent a major global public health concern. Resistance to antibiotics in these bacteria is mediated by chromosomal and/or acquired resistance mechanisms, these give rise to multi-drug resistant (MDR) or extensive drug resistant (XDR) bacterial strains. Most recently, a novel acquired plasmid mediated resistance mechanism to colistin, an antibiotic that had been set apart as the last resort antibiotic in the treatment of infections involving MDR and XDR gram-negative bacteria, has been reported. Plasmid mediated colistin resistant gram-negative bacteria have been described to be pan-drug resistant, implying a state devoid of alternative antibiotic therapeutic options. This review describes the evolution of antibiotic resistance to plasmid mediated colistin resistance, and discusses the potential role of high-throughput sequencing technologies, genomics and bioinformatics towards improving antibiotic resistance surveillance, the search for novel drug targets and precision antibiotic therapy focused at combating colistin resistance, and antimicrobial resistance as a whole.

PanB over-representation as part of pyrazinamide action: a proteomic insight

2021 ◽  
Author(s):  
Isabella Letícia Esteves Barros ◽  
Jean Eduardo Meneguello ◽  
Luciana Dias Ghiraldi-Lopes ◽  
Gláucia Sayuri Arita ◽  
João Vitor de Oliveira Silva ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Drug Target ◽  
Culture Medium ◽  
Acidic Ph ◽  
Antituberculosis Drug ◽  
First Line ◽  
Proteomic Approach

Background: Pyrazinamide (PZA) represents a milestone as a first-line antituberculosis drug due to its sterilizing activity against Mycobacterium tuberculosis. Materials & Methods: The protein changes induced by subinhibitory PZA exposure of M. tuberculosis in acidic pH were evaluated by a proteomic approach. Results: Among the 1059 M. tuberculosis proteins identified, the specific acidification in the culture medium induced the over-representation of MurF (Rv2157c), and its underrepresentation was induced by 12 h of PZA exposure. PanB (Rv2225) was over-represented at 24 h of PZA exposure. Conclusion: The authors highlight the over-representation of PanB in M. tuberculosis correlates of PZA action in acidic pH, reinforcing the role of the pantothenate pathway as a bacillus drug target to be explored.

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