Publications
130 results found
Arnett E, Krishnan N, Robertson BD, et al., 2016, Host Pathogen Biology for Airborne Mycobacterium tuberculosis: Cellular and Molecular Events in the Lung, Drug Delivery Systems for Tuberculosis Prevention and Treatment, Pages: 11-47, ISBN: 9781118943175
This chapter reviews cellular and molecular events in the pathogenesis of Mycobacterium Tuberculosis, with emphasis on those applicable to the lung. As an airborne pathogen, it is essential that we fully understand the nature of transmissible M. tuberculosis and its encounter with constituents of the lung alveoli as well as the impact of these events on subsequent granuloma formation and persistence. The host response to M. tuberculosis.
Khara JS, Priestman M, Uhia I, et al., 2016, Unnatural amino acid analogues of membrane-active helical peptides with anti-mycobacterial activity and improved stability, Journal of Antimicrobial Chemotherapy, Vol: 71, Pages: 2181-2191, ISSN: 1460-2091
Objectives The emergence of MDR-TB, coupled with shrinking antibiotic pipelines, has increased demands for new antimicrobials with novel mechanisms of action. Antimicrobial peptides have increasingly been explored as promising alternatives to antibiotics, but their inherent poor in vivo stability remains an impediment to their clinical utility. We therefore systematically evaluated unnatural amino acid-modified peptides to design analogues with enhanced anti-mycobacterial activities.Methods Anti-mycobacterial activities were evaluated in vitro and intracellularly against drug-susceptible and MDR isolates of Mycobacterium tuberculosis using MIC, killing efficacy and intracellular growth inhibition studies. Toxicity profiles were assessed against mammalian cells to verify cell selectivity. Anti-mycobacterial mechanisms were investigated using microfluidic live-cell imaging with time-lapse fluorescence microscopy and confocal laser-scanning microscopy.Results Unnatural amino acid incorporation was well tolerated without an appreciable effect on toxicity profiles and secondary conformations of the synthetic peptides. The modified peptides also withstood proteolytic digestion by trypsin. The all D-amino acid peptide, i(llkk)2i (II-D), displayed superior activity against all six mycobacterial strains tested, with a 4-fold increase in selectivity index as compared with the unmodified L-amino acid peptide in broth. II-D effectively reduced the intracellular bacterial burden of both drug-susceptible and MDR clinical isolates of M. tuberculosis after 4 days of treatment. Live-cell imaging studies demonstrated that II-D permeabilizes the mycobacterial membrane, while confocal microscopy revealed that II-D not only permeates the cell membrane, but also accumulates within the cytoplasm.Conclusions Unnatural amino acid modifications not only decreased the susceptibility of peptides to proteases, but also enhanced mycobacterial selectivity.
Comas I, Hailu E, Kiros T, et al., 2015, Population Genomics of Mycobacterium tuberculosis in Ethiopia Contradicts the Virgin Soil Hypothesis for Human Tuberculosis in Sub-Saharan Africa, Current Biology, Vol: 25, Pages: 3260-3266, ISSN: 1879-0445
Colonial medical reports claimed that tuberculosis (TB) was largely unknown in Africa prior to European contact, providing a “virgin soil” for spread of TB in highly susceptible populations previously unexposed to the disease [1 and 2]. This is in direct contrast to recent phylogenetic models which support an African origin for TB [3, 4, 5 and 6]. To address this apparent contradiction, we performed a broad genomic sampling of Mycobacterium tuberculosis in Ethiopia. All members of the M. tuberculosis complex (MTBC) arose from clonal expansion of a single common ancestor [ 7] with a proposed origin in East Africa [ 3, 4 and 8]. Consistent with this proposal, MTBC lineage 7 is almost exclusively found in that region [ 9, 10 and 11]. Although a detailed medical history of Ethiopia supports the view that TB was rare until the 20th century [12], over the last century Ethiopia has become a high-burden TB country [13]. Our results provide further support for an African origin for TB, with some genotypes already present on the continent well before European contact. Phylogenetic analyses reveal a pattern of serial introductions of multiple genotypes into Ethiopia in association with human migration and trade. In place of a “virgin soil” fostering the spread of TB in a previously naive population, we propose that increased TB mortality in Africa was driven by the introduction of European strains of M. tuberculosis alongside expansion of selected indigenous strains having biological characteristics that carry a fitness benefit in the urbanized settings of post-colonial Africa.
Al Shammari B, Shiomi T, Tezera L, et al., 2015, The extracellular matrix regulates granuloma necrosis in tuberculosis, Journal of Infectious Diseases, Vol: 212, Pages: 463-473, ISSN: 1537-6613
A central tenet of tuberculosis pathogenesis is that caseous necrosis leads to extracellular matrix destruction and bacterial transmission. We reconsider the underlying mechanism of tuberculosis pathology and demonstrate that collagen destruction may be a critical initial event, causing caseous necrosis as opposed to resulting from it. In human tuberculosis granulomas, regions of extracellular matrix destruction map to areas of caseous necrosis. In mice, transgenic expression of human matrix metalloproteinase 1 causes caseous necrosis, the pathological hallmark of human tuberculosis. Collagen destruction is the principal pathological difference between humanised mice and wild-type mice with tuberculosis, whereas the release of proinflammatory cytokines does not differ, demonstrating that collagen breakdown may lead to cell death and caseation. To investigate this hypothesis, we developed a 3-dimensional cell culture model of tuberculosis granuloma formation, using bioelectrospray technology. Collagen improved survival of Mycobacterium tuberculosis–infected cells analyzed on the basis of a lactate dehydrogenase release assay, propidium iodide staining, and measurement of the total number of viable cells. Taken together, these findings suggest that collagen destruction is an initial event in tuberculosis immunopathology, leading to caseous necrosis and compromising the immune response, revealing a previously unappreciated role for the extracellular matrix in regulating the host-pathogen interaction.
Williams KJ, Jenkins VA, Barton GR, et al., 2015, Deciphering the metabolic response of Mycobacterium tuberculosis to nitrogen stress., Molecular Microbiology, Vol: 97, Pages: 1142-1157, ISSN: 1365-2958
A key component to the success of Mycobacterium tuberculosis as a pathogen is the ability to sense and adapt metabolically to the diverse range of conditions encountered in vivo, such as oxygen tension, environmental pH and nutrient availability. Although nitrogen is an essential nutrient for every organism, little is known about the genes and pathways responsible for nitrogen assimilation in M. tuberculosis. In this study we have used transcriptomics and ChIP-seq to address this. In response to nitrogen starvation a total of 185 genes were significantly differentially expressed (96 up-regulated and 89 down regulated; 5% genome) highlighting several significant areas of metabolic change during nitrogen limitation such as nitrate/nitrite metabolism, aspartate metabolism and changes in cell wall biosynthesis. We identify GlnR as a regulator involved in the nitrogen response, controlling the expression of at least 33 genes in response to nitrogen limitation. We identify a consensus GlnR binding site and relate its location to known transcriptional start sites. We also show that the GlnR response regulator plays a very different role in M. tuberculosis to that in non-pathogenic mycobacteria, controlling genes involved in nitric oxide detoxification and intracellular survival instead of genes involved in nitrogen scavenging.
Uhia I, Williams KJ, Shahrezaei V, et al., 2015, Mycobacterial growth, Cold Spring Harbor Perspectives in Medicine, Vol: 5, ISSN: 2157-1422
In this work, we review progress made in understanding the molecular underpinnings of growth and division in mycobacteria, concentrating on work published since the last comprehensive review ( Hett and Rubin 2008). We have focused on exciting work making use of new time-lapse imaging technologies coupled with reporter-gene fusions and antimicrobial treatment to generate insights into how mycobacteria grow and divide in a heterogeneous manner. We try to reconcile the different observations reported, providing a model of how they might fit together. We also review the topic of mycobacterial spores, which has generated considerable discussion during the last few years. Resuscitation promoting factors, and regulation of growth and division, have also been actively researched, and we summarize progress in these areas.
Joyce G, Robertson BD, Williams KJ, 2015, A modified agar pad method for mycobacterial live-cell imaging., BMC Research Notes, Vol: 4, ISSN: 1756-0500
BACKGROUND: Two general approaches to prokaryotic live-cell imaging have been employed to date, growing bacteria on thin agar pads or growing bacteria in micro-channels. The methods using agar pads 'sandwich' the cells between the agar pad on the bottom and a glass cover slip on top, before sealing the cover slip. The advantages of this technique are that it is simple and relatively inexpensive to set up. However, once the cover slip is sealed, the environmental conditions cannot be manipulated. Furthermore, desiccation of the agar pad, and the growth of cells in a sealed environment where the oxygen concentration will be in gradual decline, may not permit longer term studies such as those required for the slower growing mycobacteria. FINDINGS: We report here a modified agar pad method where the cells are sandwiched between a cover slip on the bottom and an agar pad on top of the cover slip (rather than the reverse) and the cells viewed from below using an inverted microscope. This critical modification overcomes some of the current limitations with agar pad methods and was used to produce time-lapse images and movies of cell growth for Mycobacterium smegmatis and Mycobacterium bovis BCG. CONCLUSIONS: This method offers improvement on the current agar pad methods in that long term live cell imaging studies can be performed and modification of the media during the experiment is permitted.
Berg S, Schelling E, Hailu E, et al., 2015, Investigation of the high rates of extrapulmonary tuberculosis in Ethiopia reveals no single driving factor and minimal evidence for zoonotic transmission of Mycobacterium bovis infection, BMC Infectious Diseases, Vol: 15, ISSN: 1471-2334
Sampson SL, Saraiva L, Gustafsson K, et al., 2014, Cell Electrospinning: An In Vitro and In Vivo Study, Small, Vol: 10, Pages: 78-82, ISSN: 1613-6810
Cell electrospinning and aerodynamically assisted bio-threading are novel bioplatforms for directly forming large quantities of cell-laden scaffolds for creating living sheets and vessels in three-dimensions. The functional biological architectures generated will be useful in both the laboratory and the clinic.
Al Shammari B, Shiomi T, Tezera L, et al., 2013, Cell-matrix interactions regulate the immune response to Mycobacterium tuberculosis, Annual Congress of the British-Society-for-Immunology, Publisher: WILEY-BLACKWELL, Pages: 104-104, ISSN: 0019-2805
Andreu N, Zelmer A, Sampson SL, et al., 2013, Rapid in vivo assessment of drug efficacy against Mycobacterium tuberculosis using an improved firefly luciferase, Journal of Antimicrobial Chemotherapy, Vol: 68, Pages: 2118-2127, ISSN: 1460-2091
Objectives In vivo experimentation is costly and time-consuming, and presents a major bottleneck in anti-tuberculosis drug development. Conventional methods rely on the enumeration of bacterial colonies, and it can take up to 4 weeks for Mycobacterium tuberculosis to grow on agar plates. Light produced by recombinant bacteria expressing luciferase enzymes can be used as a marker of bacterial load, and disease progression can be easily followed non-invasively in live animals by using the appropriate imaging equipment. The objective of this work was to develop a bioluminescence-based mouse model of tuberculosis to assess antibiotic efficacy against M. tuberculosis in vivo.Methods We used an M. tuberculosis strain carrying a red-shifted derivative of the firefly luciferase gene (FFlucRT) to infect mice, and monitored disease progression in living animals by bioluminescence imaging before and after treatment with the frontline anti-tuberculosis drug isoniazid. The resulting images were analysed and the bioluminescence was correlated with bacterial counts.Results Using bioluminescence imaging we detected as few as 1.7 × 103 and 7.5 × 104 reporter bacteria ex vivo and in vivo, respectively, in the lungs of mice. A good correlation was found between bioluminescence and bacterial load in both cases. Furthermore, a marked reduction in luminescence was observed in living mice given isoniazid treatment.Conclusions We have shown that an improved bioluminescent strain of M. tuberculosis can be visualized by non-invasive imaging in live mice during an acute, progressive infection and that this technique can be used to rapidly visualize and quantify the effect of antibiotic treatment. We believe that the model presented here will be of great benefit in early drug discovery as an easy and rapid way to identify active compounds in vivo.
Krishnan N, Robertson BD, Thwaites G, 2013, Pathways of IL-1β secretion by macrophages infected with clinical Mycobacterium tuberculosis strains, Tuberculosis, Vol: 93, Pages: 538-547, ISSN: 1873-281X
The pro-inflammatory cytokine IL-1β is a key mediator of inflammation and plays an important role in the host resistance to Mycobacterium tuberculosis infections. To date, most studies have examined the mechanisms of IL-1β secretion using laboratory strains of M. tuberculosis and the findings may not be widely applicable to contemporary clinical strains. Here, we investigated the primary pathways of IL-1β secretion in macrophages infected with a panel of 17 clinical M. tuberculosis isolates, representing Euro-American, Indo-Oceanic and East-Asian/Beijing lineages. Our aim was to dissect the pathways involved in M. tuberculosis induced IL-1β secretion and to determine whether they are common to all clinical isolates. We found that the isolates were capable of eliciting variable concentrations of IL-1β from infected murine macrophages, but this phenomenon could not be attributed to differential IL-1β mRNA transcription or pro-IL-1β accumulation. We demonstrate that viable bacteria are required to induce IL-1β secretion from macrophages, but IL-1β secretion was only partially abrogated by caspase-1 inhibition. Almost complete IL-1β secretion inhibition was produced with combined caspase-1 and some serine protease inhibitors. Taken together, these findings demonstrate that clinical strains of M. tuberculosis employ a unique caspase-1 independent pathway to stimulate IL-1β secretion from macrophages.
Williams KJ, Bryant WA, Jenkins VA, et al., 2013, Deciphering the response of Mycobacterium smegmatis to nitrogen stress using bipartite active modules, BMC Genomics, Vol: 14, ISSN: 1471-2164
BackgroundThe ability to adapt to environments with fluctuating nutrient availability is vital for bacterial survival. Although essential for growth, few nitrogen metabolism genes have been identified or fully characterised in mycobacteria and nitrogen stress survival mechanisms are unknown.ResultsA global transcriptional analysis of the mycobacterial response to nitrogen stress, showed a significant change in the differential expression of 16% of the Mycobacterium smegmatis genome. Gene expression changes were mapped onto the metabolic network using Active Modules for Bipartite Networks (AMBIENT) to identify metabolic pathways showing coordinated transcriptional responses to the stress. AMBIENT revealed several key features of the metabolic response not identified by KEGG enrichment alone. Down regulated reactions were associated with the general reduction in cellular metabolism as a consequence of reduced growth rate. Up-regulated modules highlighted metabolic changes in nitrogen assimilation and scavenging, as well as reactions involved in hydrogen peroxide metabolism, carbon scavenging and energy generation.ConclusionsApplication of an Active Modules algorithm to transcriptomic data identified key metabolic reactions and pathways altered in response to nitrogen stress, which are central to survival under nitrogen limiting environments.
Tsolaki AG, Nagy J, Leiva S, et al., 2013, <i>Mycobacterium tuberculosis</i> antigen 85B and ESAT-6 expressed as a recombinant fusion protein in <i>Mycobacterium smegmatis</i> elicits cell-mediated immune response in a murine vaccination model, MOLECULAR IMMUNOLOGY, Vol: 54, Pages: 278-283, ISSN: 0161-5890
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- Citations: 8
Jenkins VA, Barton GR, Robertson BD, et al., 2013, Genome wide analysis of the complete GlnR nitrogen-response regulon in Mycobacterium smegmatis, BMC Genomics, Vol: 14, ISSN: 1471-2164
BackgroundNitrogen is an essential element for bacterial growth and an important component of biological macromolecules. Consequently, responding to nitrogen limitation is critical for bacterial survival and involves the interplay of signalling pathways and transcriptional regulation of nitrogen assimilation and scavenging genes. In the soil dwelling saprophyte Mycobacterium smegmatis the OmpR-type response regulator GlnR is thought to mediate the transcriptomic response to nitrogen limitation. However, to date only ten genes have been shown to be in the GlnR regulon, a vastly reduced number compared to other organisms.ResultsWe investigated the role of GlnR in the nitrogen limitation response and determined the entire GlnR regulon, by combining expression profiling of M. smegmatis wild type and glnR deletion mutant, with GlnR-specific chromatin immunoprecipitation and high throughput sequencing. We identify 53 GlnR binding sites during nitrogen limitation that control the expression of over 100 genes, demonstrating that GlnR is the regulator controlling the assimilation and utilisation of nitrogen. We also determine a consensus GlnR binding motif and identify key residues within the motif that are required for specific GlnR binding.ConclusionsWe have demonstrated that GlnR is the global nitrogen response regulator in M. smegmatis, directly regulating the expression of more than 100 genes. GlnR controls key nitrogen stress survival processes including primary nitrogen metabolism pathways, the ability to utilise nitrate and urea as alternative nitrogen sources, and the potential to use cellular components to provide a source of ammonium. These studies further our understanding of how mycobacteria survive nutrient limiting conditions.
Firdessa R, Berg S, Hailu E, et al., 2013, Mycobacterial Lineages Causing Pulmonary and Extrapulmonary Tuberculosis, Ethiopia, Emerging Infectious Diseases, Vol: 19, Pages: 460-463, ISSN: 1080-6059
Molecular typing of 964 specimens from patients in Ethiopia with lymph node or pulmonary tuberculosis showed a similar distribution of Mycobacterium tuberculosis strains between the 2 disease manifestations and a minimal role for M. bovis. We report a novel phylogenetic lineage of M. tuberculosis strongly associated with the Horn of Africa.
Williams KJ, Bennett MH, Barton GR, et al., 2013, Adenylylation of mycobacterial Glnk (PII) protein is induced by nitrogen limitation, TUBERCULOSIS, Vol: 93, Pages: 198-206, ISSN: 1472-9792
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- Citations: 10
Arafah S, Kicka S, Trofimov V, et al., 2013, Setting up and monitoring an infection of Dictyostelium discoideum with mycobacteria, Methods in Molecular Biology, Vol: 983, Pages: 403-417, ISSN: 1064-3745
Mycobacterium marinum is the causative agent of fish and amphibian tuberculosis in the wild. It is a genetically close cousin of Mycobacterium tuberculosis, and thereby the infection process remarkably shares many of the hallmarks of M. tuberculosis infection in human, at both the cellular and organism levels. Therefore, M. marinum is used as a model for the study of mycobacterial infection in various host organisms. Recently, the Dictyostelium-M. marinum system has been shown to be a valuable model that recapitulates the main features of the intracellular fate of M. marinum including phagosome maturation arrest, as well as its particular cell-to-cell dissemination mode. We present here a "starter kit" of detailed methods that allows to establish an infection of Dictyostelium with M. marinum and to monitor quantitatively the intracellular bacterial growth. © Springer Science+Business Media, LLC 2013.
Lew JM, Mao C, Shukla M, et al., 2013, Database resources for the tuberculosis community, TUBERCULOSIS, Vol: 93, Pages: 12-17, ISSN: 1472-9792
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- Citations: 22
Arafah S, Kicka S, Trofimov V, et al., 2013, Setting up and monitoring an infection of Dictyostelium discoideum with mycobacteria., Methods Mol Biol, Vol: 983, Pages: 403-417
Mycobacterium marinum is the causative agent of fish and amphibian tuberculosis in the wild. It is a genetically close cousin of Mycobacterium tuberculosis, and thereby the infection process remarkably shares many of the hallmarks of M. tuberculosis infection in human, at both the cellular and organism levels. Therefore, M. marinum is used as a model for the study of mycobacterial infection in various host organisms. Recently, the Dictyostelium-M. marinum system has been shown to be a valuable model that recapitulates the main features of the intracellular fate of M. marinum including phagosome maturation arrest, as well as its particular cell-to-cell dissemination mode. We present here a "starter kit" of detailed methods that allows to establish an infection of Dictyostelium with M. marinum and to monitor quantitatively the intracellular bacterial growth.
Gideon HP, Wilkinson KA, Rustad TR, et al., 2012, Bioinformatic and Empirical Analysis of Novel Hypoxia-Inducible Targets of the Human Antituberculosis T Cell Response, JOURNAL OF IMMUNOLOGY, Vol: 189, Pages: 5867-5876, ISSN: 0022-1767
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- Citations: 22
Butler RE, Brodin P, Jang J, et al., 2012, The Balance of Apoptotic and Necrotic Cell Death in Mycobacterium tuberculosis Infected Macrophages Is Not Dependent on Bacterial Virulence, PLOS One, Vol: 7, ISSN: 1932-6203
BackgroundAn important mechanism of Mycobacterium tuberculosis pathogenesis is the ability to control cell death pathways in infected macrophages: apoptotic cell death is bactericidal, whereas necrotic cell death may facilitate bacterial dissemination and transmission.MethodsWe examine M.tuberculosis control of spontaneous and chemically induced macrophage cell death using automated confocal fluorescence microscopy, image analysis, flow cytometry, plate-reader based vitality assays, and M.tuberculosis strains including H37Rv, and isogenic virulent and avirulent strains of the Beijing lineage isolate GC1237.ResultsWe show that bacterial virulence influences the dynamics of caspase activation and the total level of cytotoxicity. We show that the powerful ability of M.tuberculosis to inhibit exogenously stimulated apoptosis is abrogated by loss of virulence. However, loss of virulence did not influence the balance of macrophage apoptosis and necrosis – both virulent and avirulent isogenic strains of GC1237 induced predominantly necrotic cell death compared to H37Rv which induced a higher relative level of apoptosis.ConclusionsThis reveals that macrophage necrosis and apoptosis are independently regulated during M. tuberculosis infection of macrophages. Virulence affects the level of host cell death and ability to inhibit apoptosis but other strain-specific characteristics influence the ultimate mode of host cell death and alter the balance of apoptosis and necrosis.
Joyce G, Williams KJ, Robb M, et al., 2012, Cell Division Site Placement and Asymmetric Growth in Mycobacteria, PLOS One, Vol: 7, ISSN: 1932-6203
Mycobacteria are members of the actinomycetes that grow by tip extension and lack apparent homologues of the known cell division regulators found in other rod-shaped bacteria. Previous work using static microscopy on dividing mycobacteria led to the hypothesis that these cells can grow and divide asymmetrically, and at a wide range of sizes, in contrast to the cell growth and division patterns observed in the model rod-shaped organisms. In this study, we test this hypothesis using live-cell time-lapse imaging of dividing Mycobacterium smegmatis labelled with fluorescent PBP1a, to probe peptidoglycan synthesis and label the cell septum. We demonstrate that the new septum is placed accurately at mid-cell, and that the asymmetric division observed is a result of differential growth from the cell tips, with a more than 2-fold difference in growth rate between fast and slow growing poles. We also show that the division site is not selected at a characteristic cell length, suggesting this is not an important cue during the mycobacterial cell cycle.
Andreu N, Thomas D, Saraiva L, et al., 2012, In Vitro and In Vivo Interrogation of Bio-sprayed Cells, SMALL, Vol: 8, Pages: 2495-2500, ISSN: 1613-6810
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- Citations: 18
Robertson BD, Altmann D, Barry C, et al., 2012, Detection and treatment of subclinical tuberculosis, Tuberculosis, Vol: 92, Pages: 447-452, ISSN: 1873-281X
Reduction of active disease by preventive therapy has the potential to make an important contribution towards the goal of tuberculosis (TB) elimination. This report summarises discussions amongst a Working Group convened to consider areas of research that will be important in optimising the design and delivery of preventative therapies. The Working Group met in Cape Town on 26th February 2012, following presentation of results from the GC11 Grand Challenges in Global Health project to discover drugs for latent TB.
Robertson BD, Wren B, 2012, Systems Microbiology, Publisher: Caister Academic Pr, ISBN: 9781908230027
Topics covered include mathematical models for systems biology, systems biology of Escherichia coli metabolism, bacterial chemotaxis, systems biology of infection, host-microbe interactions, phagocytosis, system-level study of metabolism in ...
Behrends V, Williams KJ, Jenkins VA, et al., 2012, Free glucosylglycerate is a marker of nitrogen stress in Mycobacterium smegmatis., Journal of Proteome Research
Zelmer A, Carroll P, Andreu N, et al., 2012, A new in vivo model to test anti-tuberculosis drugs using fluorescence imaging, Journal of Antimicrobial Chemotherapy, Vol: 67, Pages: 1948-1960, ISSN: 1460-2091
Objectives The current method for testing new drugs against tuberculosis in vivo is the enumeration of bacteria in organs by cfu assay. Owing to the slow growth rate of Mycobacterium tuberculosis (Mtb), these assays can take months to complete. Our aim was to develop a more efficient, fluorescence-based imaging assay to test new antibiotics in a mouse model using Mtb reporter strains.Methods A commercial IVIS Kinetic® system and a custom-built laser scanning system with fluorescence molecular tomography (FMT) capability were used to detect fluorescent Mtb in living mice and lungs ex vivo. The resulting images were analysed and the fluorescence was correlated with data from cfu assays.Results We have shown that fluorescent Mtb can be visualized in the lungs of living mice at a detection limit of ∼8 × 107 cfu/lung, whilst in lungs ex vivo a detection limit of ∼2 × 105 cfu/lung was found. These numbers were comparable between the two imaging systems. Ex vivo lung fluorescence correlated to numbers of bacteria in tissue, and the effect of treatment of mice with the antibiotic moxifloxacin could be visualized and quantified after only 9 days through fluorescence measurements, and was confirmed by cfu assays.Conclusions We have developed a new and efficient method for anti-tuberculosis drug testing in vivo, based on fluorescent Mtb reporter strains. Using this method instead of, or together with, cfu assays will reduce the time required to assess the preclinical efficacy of new drugs in animal models and enhance the progress of these candidates into clinical trials against human tuberculosis.
Vordermeier M, Ameni G, Berg S, et al., 2012, The influence of cattle breed on susceptibility to bovine tuberculosis in Ethiopia, Comparative Immunology, Microbiology and Infectious Diseases: the international journal for medical and veterinary researchers and practitioners, Vol: 35, Pages: 227-232, ISSN: 0147-9571
Bovine tuberculosis in domestic livestock such as cattle is an economically important disease with zoonotic potential, particularly in countries with emerging economies. We discuss the findings of recent epidemiological and immunological studies conducted in Ethiopia on host susceptibility differences between native zebu and the exotic Holstein–Friesian cattle that are increasingly part of the Ethiopian National herd, due to the drive to increase milk yields. These findings support the hypothesis that native Zebu cattle are more resistant to bovine tuberculosis. We also summarise the results of experimental infections that support the epidemiological data, and of laboratory experiments that suggest a role for the innate immune response, and in particular interleukin-6, in the outcome of bovine tuberculosis infection.
Jenkins VA, Robertson BD, Williams KJ, 2012, Aspartate D48 is essential for the GlnR-mediated transcriptional response to nitrogen limitation in Mycobacterium smegmatis, FEMS MICROBIOLOGY LETTERS, Vol: 330, Pages: 38-45, ISSN: 0378-1097
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- Citations: 16
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