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Sample records for mycobacterium tuberculosis identification

  1. Direct identification and typing of Mycobacterium tuberculosis by PCR.

    PubMed Central

    Neimark, H; Ali Baig, M; Carleton, S

    1996-01-01

    We have developed a rapid PCR assay that types strains of Mycobacterium tuberculosis by generating distinct DNA fingerprints directly from primary cultures. This assay allows strain identification analogous to that achieved by the standard restriction fragment length polymorphism method, and fingerprints are obtained in less than 8 h. This assay does not require subculturing, DNA purification, restriction digestion, Southern blotting, or nucleic acid hybridization. Rapid and precise identification of M. tuberculosis strains permits immediate molecular epidemiologic studies. The assay can be converted to a computer-automated system by employing fluorescently labeled PCR primers and the Perkin-Elmer DNA sequencer so that unknown-specimen fingerprints are identified by computer comparison to a database of M. tuberculosis strain fingerprints. PMID:8880499

  2. Identification of proteins from Mycobacterium tuberculosis missing in attenuated Mycobacterium bovis BCG strains.

    PubMed

    Mattow, J; Jungblut, P R; Schaible, U E; Mollenkopf, H J; Lamer, S; Zimny-Arndt, U; Hagens, K; Müller, E C; Kaufmann, S H

    2001-08-01

    A proteome approach, combining high-resolution two-dimensional electrophoresis (2-DE) with mass spectrometry, was used to compare the cellular protein composition of two virulent strains of Mycobacterium tuberculosis with two attenuated strains of Mycobacterium bovis Bacillus Calmette-Guerin (BCG), in order to identify unique proteins of these strains. Emphasis was given to the identification of M. tuberculosis specific proteins, because we consider these proteins to represent putative virulence factors and interesting candidates for vaccination and diagnosis of tuberculosis. The genome of M. tuberculosis strain H37Rv comprises nearly 4000 predicted open reading frames. In contrast, the separation of proteins from whole mycobacterial cells by 2-DE resulted in silver-stained patterns comprising about 1800 distinct protein spots. Amongst these, 96 spots were exclusively detected either in the virulent (56 spots) or in the attenuated (40 spots) mycobacterial strains. Fifty-three of these spots were analyzed by mass spectrometry, of which 41 were identified, including 32 M. tuberculosis specific spots. Twelve M. tuberculosis specific spots were identified as proteins, encoded by genes previously reported to be deleted in M. bovis BCG. The remaining 20 spots unique for M. tuberculosis were identified as proteins encoded by genes that are not known to be missing in M. bovis BCG. PMID:11565788

  3. Evaluation of an Immunochromatographic Assay Kit for Rapid Identification of Mycobacterium tuberculosis Complex in Clinical Isolates▿

    PubMed Central

    Park, Mi Young; Kim, Young Jin; Hwang, Sang Hyun; Kim, Hyoung Hoi; Lee, Eun Yup; Jeong, Seok Hoon; Chang, Chulhun L.

    2009-01-01

    We evaluated a new immunochromatographic assay (ICA) using mouse monoclonal anti-MPT64 antibody for rapid discrimination between Mycobacterium tuberculosis and nontuberculous mycobacteria in clinical isolates. A study with mycobacteria and other organisms showed excellent sensitivity (≅99%) and specificity (100%) and an appropriate detection limit (105 CFU/ml) when tested with M. tuberculosis H37Rv. This ICA can simplify the identification of M. tuberculosis in clinical laboratories. PMID:19052177

  4. Identification of Mycobacterium tuberculosis antigens in Seibert fractions by immunoblotting.

    PubMed Central

    Coates, S R; Hansen, D; Schecter, G; Slutkin, G; Hopewell, P; Affronti, L; Echenberg, D F

    1986-01-01

    Seibert fractions prepared from Mycobacterium tuberculosis culture filtrates were evaluated by immunoblotting with a serum pool from patients with active pulmonary tuberculosis. Antibody activity was observed primarily with antigens in the polysaccharide II and A protein fractions; these fractions were further evaluated by immunoblotting with sera from individual patients with tuberculosis, from individuals without tuberculosis and positive for the purified protein derivative antigen skin test, and from individuals negative for the purified protein derivative antigen skin test. The antigens identified in the protein A fraction, a 32,000-molecular-weight antigen and a heterogeneous high-molecular-weight antigen, reacted with antibody found in sera from all patients with tuberculosis and with antibody from over 25% of the control individuals. A 10,000-molecular-weight antigen, a 30,000- to 44,000-molecular-weight antigen, and a heterogeneous high-molecular-weight antigen were observed in the polysaccharide II fraction; these antigens reacted with serum antibody from 70% or more of the patients with tuberculosis and with antibody from 20 to 70% of the control individuals. One of the antigens, with a molecular weight ranging from 17,000 to 28,000 in the polysaccharide II fraction, reacted with antibody in 64% of the sera from patients with tuberculosis but with only 1 of 15 control normal sera. This antigen may elicit an antibody response specifically associated with tuberculosis. Images PMID:3088029

  5. Identification of new diamine scaffolds with activity against Mycobacterium tuberculosis

    PubMed Central

    Bogatcheva, Elena; Hanrahan, Colleen; Nikonenko, Boris; Samala, Rowena; Chen, Ping; Gearhart, Jacqueline; Barbosa, Francis; Einck, Leo; Nacy, Carol A.; Protopopova, Marina

    2015-01-01

    A diverse 5,000-compound library was synthesized from commercially available diamines and screened for activity against Mycobacterium tuberculosis in vitro, revealing 143 hits with MIC equal to or less than 12.5 µM. New prospective scaffolds with antitubercular activity derived from homopiperazine, phenyl- and benzyl substituted piperazines, 4-aminomethylpiperidine, 4-aminophenylethylamine, 4,4'-methylenebiscyclohexylamine were identified. Compound SQ775 derived from homopiperazine, and compound SQ786 derived from benzylpiperazine had potent antimicrobial activity against M. tuberculosis in experimental animals in vivo. PMID:16722620

  6. Identification of outer membrane proteins of Mycobacterium tuberculosis.

    PubMed

    Song, Houhui; Sandie, Reatha; Wang, Ying; Andrade-Navarro, Miguel A; Niederweis, Michael

    2008-11-01

    The cell wall of mycobacteria includes an unusual outer membrane of extremely low permeability. While Escherichia coli uses more than 60 proteins to functionalize its outer membrane, only two mycobacterial outer membrane proteins (OMPs) are known. The porin MspA of Mycobacterium smegmatis provided the proof of principle that integral mycobacterial OMPs share the beta-barrel structure, the absence of hydrophobic alpha-helices and the presence of a signal peptide with OMPs of gram-negative bacteria. These properties were exploited in a multi-step bioinformatic approach to predict OMPs of M. tuberculosis. A secondary structure analysis was performed for 587 proteins of M. tuberculosis predicted to be exported. Scores were calculated for the beta-strand content and the amphiphilicity of the beta-strands. Reference OMPs of gram-negative bacteria defined threshold values for these parameters that were met by 144 proteins of unknown function of M. tuberculosis. Two of them were verified as OMPs by a novel two-step experimental approach. Rv1698 and Rv1973 were detected only in the total membrane fraction of M. bovis BCG in Western blot experiments, while proteinase K digestion of whole cells showed the surface accessibility of these proteins. These findings established that Rv1698 and Rv1973 are indeed localized in the outer membrane and tripled the number of known OMPs of M. tuberculosis. Significantly, these results provide evidence for the usefulness of the bioinformatic approach to predict mycobacterial OMPs and indicate that M. tuberculosis likely has many OMPs with beta-barrel structure. Our findings pave the way to identify the set of proteins which functionalize the outer membrane of M. tuberculosis. PMID:18439872

  7. Novel Multiplex Real-Time PCR Diagnostic Assay for Identification and Differentiation of Mycobacterium tuberculosis, Mycobacterium canettii, and Mycobacterium tuberculosis Complex Strains▿†

    PubMed Central

    Reddington, Kate; O'Grady, Justin; Dorai-Raj, Siobhan; Maher, Majella; van Soolingen, Dick; Barry, Thomas

    2011-01-01

    Tuberculosis (TB) in humans is caused by members of the Mycobacterium tuberculosis complex (MTC). Rapid detection of the MTC is necessary for the timely initiation of antibiotic treatment, while differentiation between members of the complex may be important to guide the appropriate antibiotic treatment and provide epidemiological information. In this study, a multiplex real-time PCR diagnostics assay using novel molecular targets was designed to identify the MTC while simultaneously differentiating between M. tuberculosis and M. canettii. The lepA gene was targeted for the detection of members of the MTC, the wbbl1 gene was used for the differentiation of M. tuberculosis and M. canettii from the remainder of the complex, and a unique region of the M. canettii genome, a possible novel region of difference (RD), was targeted for the specific identification of M. canettii. The multiplex real-time PCR assay was tested using 125 bacterial strains (64 MTC isolates, 44 nontuberculosis mycobacteria [NTM], and 17 other bacteria). The assay was determined to be 100% specific for the mycobacteria tested. Limits of detection of 2.2, 2.17, and 0.73 cell equivalents were determined for M. tuberculosis/M. canettii, the MTC, and M. canettii, respectively, using probit regression analysis. Further validation of this diagnostics assay, using clinical samples, should demonstrate its potential for the rapid, accurate, and sensitive diagnosis of TB caused by M. tuberculosis, M. canettii, and the other members of the MTC. PMID:21123525

  8. Identification of gene targets against dormant phase Mycobacterium tuberculosis infections

    PubMed Central

    Murphy, Dennis J; Brown, James R

    2007-01-01

    Background Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), infects approximately 2 billion people worldwide and is the leading cause of mortality due to infectious disease. Current TB therapy involves a regimen of four antibiotics taken over a six month period. Patient compliance, cost of drugs and increasing incidence of drug resistant M. tuberculosis strains have added urgency to the development of novel TB therapies. Eradication of TB is affected by the ability of the bacterium to survive up to decades in a dormant state primarily in hypoxic granulomas in the lung and to cause recurrent infections. Methods The availability of M. tuberculosis genome-wide DNA microarrays has lead to the publication of several gene expression studies under simulated dormancy conditions. However, no single model best replicates the conditions of human pathogenicity. In order to identify novel TB drug targets, we performed a meta-analysis of multiple published datasets from gene expression DNA microarray experiments that modeled infection leading to and including the dormant state, along with data from genome-wide insertional mutagenesis that examined gene essentiality. Results Based on the analysis of these data sets following normalization, several genome wide trends were identified and used to guide the selection of targets for therapeutic development. The trends included the significant up-regulation of genes controlled by devR, down-regulation of protein and ATP synthesis, and the adaptation of two-carbon metabolism to the hypoxic and nutrient limited environment of the granuloma. Promising targets for drug discovery were several regulatory elements (devR/devS, relA, mprAB), enzymes involved in redox balance and respiration, sulfur transport and fixation, pantothenate, isoprene, and NAD biosynthesis. The advantages and liabilities of each target are discussed in the context of enzymology, bacterial pathways, target tractability, and drug development

  9. Identification of substrates of the Mycobacterium tuberculosis proteasome

    PubMed Central

    Pearce, Michael J; Arora, Pooja; Festa, Richard A; Butler-Wu, Susan M; Gokhale, Rajesh S; Darwin, K Heran

    2006-01-01

    The putative proteasome-associated proteins Mpa (Mycobaterium proteasomal ATPase) and PafA (proteasome accessory factor A) of the human pathogen Mycobacterium tuberculosis (Mtb) are essential for virulence and resistance to nitric oxide. However, a direct link between the proteasome protease and Mpa or PafA has never been demonstrated. Furthermore, protein degradation by bacterial proteasomes in vitro has not been accomplished, possibly due to the failure to find natural degradation substrates or other necessary proteasome co-factors. In this work, we identify the first bacterial proteasome substrates, malonyl Co-A acyl carrier protein transacylase and ketopantoate hydroxymethyltransferase, enzymes that are required for the biosynthesis of fatty acids and polyketides that are essential for the pathogenesis of Mtb. Maintenance of the physiological levels of these enzymes required Mpa and PafA in addition to proteasome protease activity. Mpa levels were also regulated in a proteasome-dependent manner. Finally, we found that a conserved tyrosine of Mpa was essential for function. Thus, these results suggest that Mpa, PafA, and the Mtb proteasome degrade bacterial proteins that are important for virulence in mice. PMID:17082771

  10. Identification of widespread adenosine nucleotide binding in Mycobacterium tuberculosis

    SciTech Connect

    Ansong, Charles; Ortega, Corrie; Payne, Samuel H.; Haft, Daniel H.; Chauvigne-Hines, Lacie M.; Lewis, Michael P.; Ollodart, Anja R.; Purvine, Samuel O.; Shukla, Anil K.; Fortuin, Suereta; Smith, Richard D.; Adkins, Joshua N.; Grundner, Christoph; Wright, Aaron T.

    2013-01-24

    The annotation of protein function is almost completely performed by in silico approaches. However, computational prediction of protein function is frequently incomplete and error prone. In Mycobacterium tuberculosis (Mtb), ~25% of all genes have no predicted function and are annotated as hypothetical proteins. This lack of functional information severely limits our understanding of Mtb pathogenicity. Current tools for experimental functional annotation are limited and often do not scale to entire protein families. Here, we report a generally applicable chemical biology platform to functionally annotate bacterial proteins by combining activity-based protein profiling (ABPP) and quantitative LC-MS-based proteomics. As an example of this approach for high-throughput protein functional validation and discovery, we experimentally annotate the families of ATP-binding proteins in Mtb. Our data experimentally validate prior in silico predictions of >250 ATPases and adenosine nucleotide-binding proteins, and reveal 73 hypothetical proteins as novel ATP-binding proteins. We identify adenosine cofactor interactions with many hypothetical proteins containing a diversity of unrelated sequences, providing a new and expanded view of adenosine nucleotide binding in Mtb. Furthermore, many of these hypothetical proteins are both unique to Mycobacteria and essential for infection, suggesting specialized functions in mycobacterial physiology and pathogenicity. Thus, we provide a generally applicable approach for high throughput protein function discovery and validation, and highlight several ways in which application of activity-based proteomics data can improve the quality of functional annotations to facilitate novel biological insights.

  11. Validation of a real-time PCR assay for the molecular identification of Mycobacterium tuberculosis

    PubMed Central

    Sales, Mariana L.; Fonseca, Antônio Augusto; Orzil, Lívia; Alencar, Andrea Padilha; Silva, Marcio Roberto; Issa, Marina Azevedo; Filho, Paulo Martins Soares; Lage, Andrey Pereira; Heinemann, Marcos Bryan

    2014-01-01

    Mycobacterium tuberculosis is the major cause of tuberculosis in humans. This bacillus gained prominence with the occurrence of HIV, presenting itself as an important opportunistic infection associated with acquired immunodeficiency syndrome (AIDS). The current study aimed to develop a real-time PCR using Eva Green technology for molecular identification of M. tuberculosis isolates. The primers were designed to Rv1510 gene. Ninety nine samples of M. tuberculosis and sixty samples of M. bovis were tested and no sample of the bovine bacillus was detected by the qPCR. Statistical tests showed no difference between the qPCR and biochemical tests used to identify the Mycobacterium tuberculosis. The correlation between tests was perfect with Kappa index of 1.0 (p < 0.001, CI = 0.84 – 1.0). The diagnostic sensitivity and specificity were 100% (CI = 95.94% – 100%) and 100% (CI = 93.98% – 100%). This qPCR was developed with the goal of diagnosing the bacillus M. tuberculosis in samples of bacterial suspension. TB reference laboratories (health and agriculture sectors), public health programs and epidemiological studies probably may benefit from such method. PMID:25763042

  12. Identification of Functional Tat Signal Sequences in Mycobacterium tuberculosis Proteins▿ †

    PubMed Central

    McDonough, Justin A.; McCann, Jessica R.; Tekippe, Erin McElvania; Silverman, Jason S.; Rigel, Nathan W.; Braunstein, Miriam

    2008-01-01

    The twin-arginine translocation (Tat) pathway is a system used by some bacteria to export proteins out from the cytosol to the cell surface or extracellular environment. A functional Tat pathway exists in the important human pathogen Mycobacterium tuberculosis. Identification of the substrates exported by the Tat pathway can help define the role that this pathway plays in the physiology and pathogenesis of M. tuberculosis. Here we used a reporter of Tat export, a truncated β-lactamase, ′BlaC, to experimentally identify M. tuberculosis proteins with functional Tat signal sequences. Of the 13 proteins identified, one lacks the hallmark of a Tat-exported substrate, the twin-arginine dipeptide, and another is not predicted by in silico analysis of the annotated M. tuberculosis genome. Full-length versions of a subset of these proteins were tested to determine if the native proteins are Tat exported. For three proteins, expression in a Δtat mutant of Mycobacterium smegmatis revealed a defect in precursor processing compared to expression in the wild type, indicating Tat export of the full-length proteins. Conversely, two proteins showed no obvious Tat export in M. smegmatis. One of this latter group of proteins was the M. tuberculosis virulence factor phospholipase C (PlcB). Importantly, when tested in M. tuberculosis a different result was obtained and PlcB was exported in a twin-arginine-dependent manner. This suggests the existence of an M. tuberculosis-specific factor(s) for Tat export of a proven virulence protein. It also emphasizes the importance of domains beyond the Tat signal sequence and bacterium-specific factors in determining if a given protein is Tat exported. PMID:18658266

  13. Mycobacteria mobility shift assay: a method for the rapid identification of Mycobacterium tuberculosis and nontuberculous mycobacteria

    PubMed Central

    Wildner, Letícia Muraro; Bazzo, Maria Luiza; Liedke, Susie Coutinho; Nogueira, Christiane Lourenço; Segat, Gabriela; Senna, Simone Gonçalves; Schlindwein, Aline Daiane; de Oliveira, Jaquelline Germano; Rovaris, Darcita B; Bonjardim, Claudio A; Kroon, Erna G; Ferreira, Paulo CP

    2014-01-01

    The identification of mycobacteria is essential because tuberculosis (TB) and mycobacteriosis are clinically indistinguishable and require different therapeutic regimens. The traditional phenotypic method is time consuming and may last up to 60 days. Indeed, rapid, affordable, specific and easy-to-perform identification methods are needed. We have previously described a polymerase chain reaction-based method called a mycobacteria mobility shift assay (MMSA) that was designed for Mycobacterium tuberculosis complex (MTC) and nontuberculous mycobacteria (NTM) species identification. The aim of this study was to assess the MMSA for the identification of MTC and NTM clinical isolates and to compare its performance with that of the PRA-hsp65 method. A total of 204 clinical isolates (102 NTM and 102 MTC) were identified by the MMSA and PRA-hsp65. For isolates for which these methods gave discordant results, definitive species identification was obtained by sequencing fragments of the 16S rRNA and hsp65 genes. Both methods correctly identified all MTC isolates. Among the NTM isolates, the MMSA alone assigned 94 (92.2%) to a complex or species, whereas the PRA-hsp65 method assigned 100% to a species. A 91.5% agreement was observed for the 94 NTM isolates identified by both methods. The MMSA provided correct identification for 96.8% of the NTM isolates compared with 94.7% for PRA-hsp65. The MMSA is a suitable auxiliary method for routine use for the rapid identification of mycobacteria. PMID:24821059

  14. Identification of Secretory Proteins in Mycobacterium tuberculosis Using Pseudo Amino Acid Composition.

    PubMed

    Yang, Huan; Tang, Hua; Chen, Xin-Xin; Zhang, Chang-Jian; Zhu, Pan-Pan; Ding, Hui; Chen, Wei; Lin, Hao

    2016-01-01

    Tuberculosis is killing millions of lives every year and on the blacklist of the most appalling public health problems. Recent findings suggest that secretory protein of Mycobacterium tuberculosis may serve the purpose of developing specific vaccines and drugs due to their antigenicity. Responding to global infectious disease, we focused on the identification of secretory proteins in Mycobacterium tuberculosis. A novel method called MycoSec was designed by incorporating g-gap dipeptide compositions into pseudo amino acid composition. Analysis of variance-based technique was applied in the process of feature selection and a total of 374 optimal features were obtained and used for constructing the final predicting model. In the jackknife test, MycoSec yielded a good performance with the area under the receiver operating characteristic curve of 0.93, demonstrating that the proposed system is powerful and robust. For user's convenience, the web server MycoSec was established and an obliging manual on how to use it was provided for getting around any trouble unnecessary. PMID:27597968

  15. Identification of Secretory Proteins in Mycobacterium tuberculosis Using Pseudo Amino Acid Composition

    PubMed Central

    Yang, Huan; Tang, Hua; Chen, Xin-Xin; Zhang, Chang-Jian; Zhu, Pan-Pan; Ding, Hui

    2016-01-01

    Tuberculosis is killing millions of lives every year and on the blacklist of the most appalling public health problems. Recent findings suggest that secretory protein of Mycobacterium tuberculosis may serve the purpose of developing specific vaccines and drugs due to their antigenicity. Responding to global infectious disease, we focused on the identification of secretory proteins in Mycobacterium tuberculosis. A novel method called MycoSec was designed by incorporating g-gap dipeptide compositions into pseudo amino acid composition. Analysis of variance-based technique was applied in the process of feature selection and a total of 374 optimal features were obtained and used for constructing the final predicting model. In the jackknife test, MycoSec yielded a good performance with the area under the receiver operating characteristic curve of 0.93, demonstrating that the proposed system is powerful and robust. For user's convenience, the web server MycoSec was established and an obliging manual on how to use it was provided for getting around any trouble unnecessary. PMID:27597968

  16. Comprehensive multicenter evaluation of a new line probe assay kit for identification of Mycobacterium species and detection of drug-resistant Mycobacterium tuberculosis.

    PubMed

    Mitarai, Satoshi; Kato, Seiya; Ogata, Hideo; Aono, Akio; Chikamatsu, Kinuyo; Mizuno, Kazue; Toyota, Emiko; Sejimo, Akiko; Suzuki, Katsuhiro; Yoshida, Shiomi; Saito, Takefumi; Moriya, Ataru; Fujita, Akira; Sato, Shuko; Matsumoto, Tomoshige; Ano, Hiromi; Suetake, Toshinori; Kondo, Yuji; Kirikae, Teruo; Mori, Toru

    2012-03-01

    We evaluated a new line probe assay (LiPA) kit to identify Mycobacterium species and to detect mutations related to drug resistance in Mycobacterium tuberculosis. A total of 554 clinical isolates of Mycobacterium tuberculosis (n = 316), Mycobacterium avium (n = 71), Mycobacterium intracellulare (n = 51), Mycobacterium kansasii (n = 54), and other Mycobacterium species (n = 62) were tested with the LiPA kit in six hospitals. The LiPA kit was also used to directly test 163 sputum specimens. The results of LiPA identification of Mycobacterium species in clinical isolates were almost identical to those of conventional methods. Compared with standard drug susceptibility testing results for the clinical isolates, LiPA showed a sensitivity and specificity of 98.9% and 97.3%, respectively, for detecting rifampin (RIF)-resistant clinical isolates; 90.6% and 100%, respectively, for isoniazid (INH) resistance; 89.7% and 96.0%, respectively, for pyrazinamide (PZA) resistance; and 93.0% and 100%, respectively, for levofloxacin (LVX) resistance. The LiPA kit could detect target species directly in sputum specimens, with a sensitivity of 85.6%. Its sensitivity and specificity for detecting RIF-, PZA-, and LVX-resistant isolates in the sputum specimens were both 100%, and those for detecting INH-resistant isolates were 75.0% and 92.9%, respectively. The kit was able to identify mycobacterial bacilli at the species level, as well as drug-resistant phenotypes, with a high sensitivity and specificity. PMID:22205814

  17. Identification of Host-Targeted Small Molecules That Restrict Intracellular Mycobacterium tuberculosis Growth

    PubMed Central

    Silvis, Melanie R.; Luo, Samantha S.; Sogi, Kimberly; Vokes, Martha; Bray, Mark-Anthony; Carpenter, Anne E.; Moore, Christopher B.; Siddiqi, Noman; Rubin, Eric J.; Hung, Deborah T.

    2014-01-01

    Mycobacterium tuberculosis remains a significant threat to global health. Macrophages are the host cell for M. tuberculosis infection, and although bacteria are able to replicate intracellularly under certain conditions, it is also clear that macrophages are capable of killing M. tuberculosis if appropriately activated. The outcome of infection is determined at least in part by the host-pathogen interaction within the macrophage; however, we lack a complete understanding of which host pathways are critical for bacterial survival and replication. To add to our understanding of the molecular processes involved in intracellular infection, we performed a chemical screen using a high-content microscopic assay to identify small molecules that restrict mycobacterial growth in macrophages by targeting host functions and pathways. The identified host-targeted inhibitors restrict bacterial growth exclusively in the context of macrophage infection and predominantly fall into five categories: G-protein coupled receptor modulators, ion channel inhibitors, membrane transport proteins, anti-inflammatories, and kinase modulators. We found that fluoxetine, a selective serotonin reuptake inhibitor, enhances secretion of pro-inflammatory cytokine TNF-α and induces autophagy in infected macrophages, and gefitinib, an inhibitor of the Epidermal Growth Factor Receptor (EGFR), also activates autophagy and restricts growth. We demonstrate that during infection signaling through EGFR activates a p38 MAPK signaling pathway that prevents macrophages from effectively responding to infection. Inhibition of this pathway using gefitinib during in vivo infection reduces growth of M. tuberculosis in the lungs of infected mice. Our results support the concept that screening for inhibitors using intracellular models results in the identification of tool compounds for probing pathways during in vivo infection and may also result in the identification of new anti-tuberculosis agents that work by

  18. Use of polymerase chain reaction for early identification of Mycobacterium tuberculosis in positive cultures.

    PubMed Central

    Cormican, M. G.; Barry, T.; Gannon, F.; Flynn, J.

    1992-01-01

    AIMS: To develop a readily applicable polymerase chain reaction (PCR) based technique which would permit the identification of Mycobacterium tuberculosis complex isolates from Bactec phials at an earlier stage than currently available methods. METHODS: Mycobacterial cells cultured in Bactec 12B medium were harvested by centrifugation. The cells were lysed by heating in distilled water. Oligonucleotide primers based on the sequence of the gene coding for the immunogenic protein MPB64 were then used to amplify a 240 base pair fragment of DNA directly from the crude cell lysate. The PCR product was visualised under ultraviolet light following electrophoresis of an aliquot in an agarose gel containing ethidium bromide. The sensitivity of the PCR was adjusted so that about 600 cfu of M tuberculosis gave a positive result. The lowest growth index at which this method of identification might be applied to Bactec phials was determined and a number of routine cultures giving a positive growth index examined. RESULTS: M tuberculosis was positively identified at the lowest growth index, as determined by the Bactec system. Of 45 routine cultures examined, with growth indexes ranging from 6 to 999, the 15 confirmed by conventional means to contain M tuberculosis were correctly identified from 1 ml of culture medium. CONCLUSIONS: The method described can be used to identify M tuberculosis isolates cultured in the Bactec system at the earliest detectable rise in growth index. It may therefore allow cultured mycobacteria to be identified at an earlier stage than conventional methods or the commercially available DNA probes adapted for use with the Bactec system. Images PMID:1517460

  19. Identification of mycobacterium tuberculosis in sputum smear slide using automatic scanning microscope

    NASA Astrophysics Data System (ADS)

    Rulaningtyas, Riries; Suksmono, Andriyan B.; Mengko, Tati L. R.; Saptawati, Putri

    2015-04-01

    Sputum smear observation has an important role in tuberculosis (TB) disease diagnosis, because it needs accurate identification to avoid high errors diagnosis. In development countries, sputum smear slide observation is commonly done with conventional light microscope from Ziehl-Neelsen stained tissue and it doesn't need high cost to maintain the microscope. The clinicians do manual screening process for sputum smear slide which is time consuming and needs highly training to detect the presence of TB bacilli (mycobacterium tuberculosis) accurately, especially for negative slide and slide with less number of TB bacilli. For helping the clinicians, we propose automatic scanning microscope with automatic identification of TB bacilli. The designed system modified the field movement of light microscope with stepper motor which was controlled by microcontroller. Every sputum smear field was captured by camera. After that some image processing techniques were done for the sputum smear images. The color threshold was used for background subtraction with hue canal in HSV color space. Sobel edge detection algorithm was used for TB bacilli image segmentation. We used feature extraction based on shape for bacilli analyzing and then neural network classified TB bacilli or not. The results indicated identification of TB bacilli that we have done worked well and detected TB bacilli accurately in sputum smear slide with normal staining, but not worked well in over staining and less staining tissue slide. However, overall the designed system can help the clinicians in sputum smear observation becomes more easily.

  20. Identification of novel Mycobacterium tuberculosis CD4 T-cell antigens via high throughput proteome screening

    PubMed Central

    Nayak, Kaustuv; Jing, Lichen; Russell, Ronnie M.; Davies, D. Huw; Hermanson, Gary; Molina, Douglas M.; Liang, Xiaowu; Sherman, David R.; Kwok, William W.; Yang, Junbao; Kenneth, John; Ahamed, Syed F.; Chandele, Anmol; Kaja, Murali-Krishna; Koelle, David M.

    2015-01-01

    Elicitation of CD4 IFN-gamma T cell responses to Mycobacterium tuberculosis (MTB) is a rational vaccine strategy to prevent clinical tuberculosis. Diagnosis of MTB infection is based on T-cell immune memory to MTB antigens. The MTB proteome contains over four thousand open reading frames (ORFs). We conducted a pilot antigen identification study using 164 MTB proteins and MTB-specific T-cells expanded in vitro from 12 persons with latent MTB infection. Enrichment of MTB-reactive T-cells from PBMC used cell sorting or an alternate system compatible with limited resources. MTB proteins were used as single antigens or combinatorial matrices in proliferation and cytokine secretion readouts. Overall, our study found that 44 MTB proteins were antigenic, including 27 not previously characterized as CD4 T-cell antigens. Antigen truncation, peptide, NTM homology, and HLA class II tetramer studies confirmed malate synthase G (encoded by gene Rv1837) as a CD4 T-cell antigen. This simple, scalable system has potential utility for the identification of candidate MTB vaccine and biomarker antigens. PMID:25857935

  1. Identification of Mycobacterium tuberculosis adherence-mediating components: a review of key methods to confirm adhesin function

    PubMed Central

    Ramsugit, Saiyur; Pillay, Manormoney

    2016-01-01

    Anti-adhesion therapy represents a potentially promising avenue for the treatment and prevention of tuberculosis in a post-antibiotic era. Adhesins are surface-exposed microbial structures or molecules that enable pathogenic organisms to adhere to host surfaces, a fundamental step towards host infection. Although several Mycobacterium tuberculosis adhesins have been identified, it is predicted that numerous additional adherence-mediating components contribute to the virulence and success of this pathogen. Significant further research to discern and characterize novel M. tuberculosis adhesins is, therefore, required to gain a holistic account of M. tuberculosis adhesion to the host. This would enable the identification of potential drug and vaccine targets for attenuating M. tuberculosis adherence and infectivity. Several methods have been successfully applied to the study and identification of M. tuberculosis adhesins. In this manuscript, we review these methods, which include adherence assays that utilize wild-type and gene knockout mutant strains, epitope masking and competitive inhibition analyses, extracellular matrix protein binding assays, microsphere adhesion assays, M. tuberculosis auto-aggregation assays, and in silico analyses. PMID:27482337

  2. Identification of Mycobacterium tuberculosis adherence-mediating components: a review of key methods to confirm adhesin function.

    PubMed

    Ramsugit, Saiyur; Pillay, Manormoney

    2016-06-01

    Anti-adhesion therapy represents a potentially promising avenue for the treatment and prevention of tuberculosis in a post-antibiotic era. Adhesins are surface-exposed microbial structures or molecules that enable pathogenic organisms to adhere to host surfaces, a fundamental step towards host infection. Although several Mycobacterium tuberculosis adhesins have been identified, it is predicted that numerous additional adherence-mediating components contribute to the virulence and success of this pathogen. Significant further research to discern and characterize novel M. tuberculosis adhesins is, therefore, required to gain a holistic account of M. tuberculosis adhesion to the host. This would enable the identification of potential drug and vaccine targets for attenuating M. tuberculosis adherence and infectivity. Several methods have been successfully applied to the study and identification of M. tuberculosis adhesins. In this manuscript, we review these methods, which include adherence assays that utilize wild-type and gene knockout mutant strains, epitope masking and competitive inhibition analyses, extracellular matrix protein binding assays, microsphere adhesion assays, M. tuberculosis auto-aggregation assays, and in silico analyses. PMID:27482337

  3. Identification of HLA-A*11:01-restricted Mycobacterium tuberculosis CD8(+) T cell epitopes.

    PubMed

    Liu, Su-Dong; Su, Jin; Zhang, Shi-Meng; Dong, Hai-Ping; Wang, Hui; Luo, Wei; Wen, Qian; He, Jian-Chun; Yang, Xiao-Fan; Ma, Li

    2016-09-01

    New vaccines are needed to combat Mycobacterium tuberculosis (MTB) infections. The currently employed Bacillus Calmette-Guérin vaccine is becoming ineffective, due in part to the emergence of multidrug-resistant tuberculosis (MDR-TB) strains and the reduced immune capacity in cases of HIV coinfection. CD8(+) T cells play an important role in the protective immunity against MTB infections, and the identification of immunogenic CD8(+) T cell epitopes specific for MTB is essential for the design of peptide-based vaccines. To identify CD8(+) T cell epitopes of MTB proteins, we screened a set of 94 MTB antigens for HLA class I A*11:01-binding motifs. HLA-A*11:01 is one of the most prevalent HLA molecules in Southeast Asians, and definition of T cell epitopes it can restrict would provide significant coverage for the Asian population. Peptides that bound with high affinity to purified HLA molecules were subsequently evaluated in functional assays to detect interferon-γ release and CD8(+) T cell proliferation in active pulmonary TB patients. We identified six novel epitopes, each derived from a unique MTB antigen, which were recognized by CD8(+) T cells from active pulmonary TB patients. In addition, a significant level of epitope-specific T cells could be detected ex vivo in peripheral blood mononuclear cells from active TB patients by an HLA-A*11:01 dextramer carrying the peptide Rv3130c194-204 (from the MTB triacylglycerol synthase Tgs1), which was the most frequently recognized epitope in our peptide library. In conclusion, this study identified six dominant CD8(+) T cell epitopes that may be considered potential targets for subunit vaccines or diagnostic strategies against TB. PMID:27072810

  4. Identification and survival studies of Mycobacterium tuberculosis within Laboratory-Fermented bovine milk

    PubMed Central

    2014-01-01

    Background Mycobacterium tuberculosis and Mycobacterium bovis are the classic agents causing tuberculosis (TB) in humans and animals respectively. Transmission of tuberculous bacteria to humans usually occurs by inhalation of aerosols containing droplets of tubercle bacilli or via consumption of contaminated foods and drinks, primarily milk. The practice of milk pooling, including from cows with TB of the udder, further exacerbates the situation by rendering the whole milk supply infective. The simultaneous presence of indigenous lactic acid bacteria (LAB) in Mycobacterium-contaminated milk is believed to confer protective effect when the milk is adequately fermented. This study assessed the effect of LAB on the viability of mycobacteria in inherently contaminated pool of raw milk during fermentation as a function of time. Findings Growth was obtained in the pooled raw milk culture, and identified to be M. tuberculosis. This M. tuberculosis growth was undetectable in the milk culture by day 7 as assessed by plating serial dilutions of the milk culture for up to 14 days. Conclusions Some LAB species appear to show inhibitory effect on tubercle bacilli. If proven by more rigorous, controlled experimental results regarding such effect, selected LAB (with proven safety and efficacy) may have potential applications as anti-mycobacterial agents. PMID:24666844

  5. Identification of a Transcription Factor That Regulates Host Cell Exit and Virulence of Mycobacterium tuberculosis

    PubMed Central

    Srinivasan, Lalitha; Gurses, Serdar A.; Hurley, Benjamin E.; Miller, Jessica L.; Karakousis, Petros C.; Briken, Volker

    2016-01-01

    The interaction of Mycobacterium tuberculosis (Mtb) with host cell death signaling pathways is characterized by an initial anti-apoptotic phase followed by a pro-necrotic phase to allow for host cell exit of the bacteria. The bacterial modulators regulating necrosis induction are poorly understood. Here we describe the identification of a transcriptional repressor, Rv3167c responsible for regulating the escape of Mtb from the phagosome. Increased cytosolic localization of MtbΔRv3167c was accompanied by elevated levels of mitochondrial reactive oxygen species and reduced activation of the protein kinase Akt, and these events were critical for the induction of host cell necrosis and macroautophagy. The increase in necrosis led to an increase in bacterial virulence as reflected in higher bacterial burden and reduced survival of mice infected with MtbΔRv3167c. The regulon of Rv3167c thus contains the bacterial mediators involved in escape from the phagosome and host cell necrosis induction, both of which are crucial steps in the intracellular lifecycle and virulence of Mtb. PMID:27191591

  6. Genetic Diversity of Mycobacterium tuberculosis from Guadalajara, Mexico and Identification of a Rare Multidrug Resistant Beijing Genotype

    PubMed Central

    Flores-Treviño, Samantha; Morfín-Otero, Rayo; Rodríguez-Noriega, Eduardo; González-Díaz, Esteban; Pérez-Gómez, Héctor R.; Bocanegra-García, Virgilio; Vera-Cabrera, Lucio; Garza-González, Elvira

    2015-01-01

    Determining the genetic diversity of M. tuberculosis strains allows identification of the distinct Mycobacterium tuberculosis genotypes responsible for tuberculosis in different regions. Several studies have reported the genetic diversity of M. tuberculosis strains in Mexico, but little information is available from the state of Jalisco. Therefore, the aim of this study was to determine the genetic diversity of Mycobacterium tuberculosis clinical isolates from Western Mexico. Sixty-eight M. tuberculosis isolates were tested for susceptibility to first-line drugs using manual Mycobacteria Growth Indicator Tube method and genotyped using spoligotyping and IS6110-restriction fragment length polymorphism (RFLP) pattern analyses. Forty-seven (69.1%) isolates were grouped into 10 clusters and 21 isolates displayed single patterns by spoligotyping. Three of the 21 single patterns corresponded to orphan patterns in the SITVITWEB database, and 1 new type that contained 2 isolates was created. The most prevalent lineages were T (38.2%), Haarlem (17.7%), LAM (17.7%), X (7.4%), S (5.9%), EAI (1.5%) and Beijing (1.5%). Six (12.8%) of the clustered isolates were MDR, and type 406 of the Beijing family was among the MDR isolates. Seventeen (26.2%) isolates were grouped into 8 clusters and 48 isolates displayed single patterns by IS6110-RFLP. Combination of IS6110-RFLP and spoligotyping reduced the clustering rate to 20.0%. The results show that T, Haarlem, and LAM are predominant lineages among clinical isolates of M. tuberculosis in Guadalajara, Mexico. Clustering rates indicated low transmission of MDR strains. We detected a rare Beijing genotype, SIT406, which was a highly resistant strain. This is the first report of this Beijing genotype in Latin America. PMID:25695431

  7. Systems Biology-Based Identification of Mycobacterium tuberculosis Persistence Genes in Mouse Lungs

    PubMed Central

    Dutta, Noton K.; Bandyopadhyay, Nirmalya; Veeramani, Balaji; Lamichhane, Gyanu; Karakousis, Petros C.; Bader, Joel S.

    2014-01-01

    ABSTRACT Identifying Mycobacterium tuberculosis persistence genes is important for developing novel drugs to shorten the duration of tuberculosis (TB) treatment. We developed computational algorithms that predict M. tuberculosis genes required for long-term survival in mouse lungs. As the input, we used high-throughput M. tuberculosis mutant library screen data, mycobacterial global transcriptional profiles in mice and macrophages, and functional interaction networks. We selected 57 unique, genetically defined mutants (18 previously tested and 39 untested) to assess the predictive power of this approach in the murine model of TB infection. We observed a 6-fold enrichment in the predicted set of M. tuberculosis genes required for persistence in mouse lungs relative to randomly selected mutant pools. Our results also allowed us to reclassify several genes as required for M. tuberculosis persistence in vivo. Finally, the new results implicated additional high-priority candidate genes for testing. Experimental validation of computational predictions demonstrates the power of this systems biology approach for elucidating M. tuberculosis persistence genes. PMID:24549847

  8. Identification and Genotyping of Mycobacterium tuberculosis Isolated From Water and Soil Samples of a Metropolitan City

    PubMed Central

    Velayati, Ali Akbar; Farnia, Parissa; Mozafari, Mohadese; Malekshahian, Donya; Farahbod, Amir Masoud; Seif, Shima; Rahideh, Snaz

    2015-01-01

    BACKGROUND: The potential role of environmental Mycobacterium tuberculosis in the epidemiology of TB remains unknown. We investigated the transmission of M tuberculosis from humans to the environment and the possible transmission of M tuberculosis from the environment to humans. METHODS: A total of 1,500 samples were collected from three counties of the Tehran, Iran metropolitan area from February 2012 to January 2014. A total of 700 water samples (47%) and 800 soil samples (53%) were collected. Spoligotyping and the mycobacterial interspersed repetitive units-variable number of tandem repeats typing method were performed on DNA extracted from single colonies. Genotypes of M tuberculosis strains isolated from the environment were compared with the genotypes obtained from 55 patients with confirmed pulmonary TB diagnosed during the study period in the same three counties. RESULTS: M tuberculosis was isolated from 11 of 800 soil samples (1%) and 71 of 700 water samples (10%). T family (56 of 82, 68%) followed by Delhi/CAS (11 of 82, 13.4%) were the most frequent M tuberculosis superfamilies in both water and soil samples. Overall, 27.7% of isolates in clusters were related. No related typing patterns were detected between soil, water, and clinical isolates. The most frequent superfamily of M tuberculosis in clinical isolates was Delhi/CAS (142, 30.3%) followed by NEW-1 (127, 27%). The bacilli in contaminated soil (36%) and damp water (8.4%) remained reculturable in some samples up to 9 months. CONCLUSIONS: Although the dominant M tuberculosis superfamilies in soil and water did not correspond to the dominant M tuberculosis family in patients, the presence of circulating genotypes of M tuberculosis in soil and water highlight the risk of transmission. PMID:25340935

  9. Comparative analyses of the proteins from Mycobacterium tuberculosis and human genomes: Identification of potential tuberculosis drug targets.

    PubMed

    Sridhar, Settu; Dash, Pallabini; Guruprasad, Kunchur

    2016-03-15

    Tuberculosis, one of the major infectious diseases affecting human beings is caused by the bacillus Mycobacterium tuberculosis. Increased resistance to known drugs commonly used for the treatment of tuberculosis has created an urgent need to identify new targets for validation and to develop drugs. In this study, we have used various bioinformatics tools, to compare the protein sequences from twenty-three M. tuberculosis genome strains along with the known human protein sequences, in order to identify the 'conserved' M. tuberculosis proteins absent in human. Further, based on the analysis of protein interaction networks, we selected one-hundred and forty proteins that were predicted as potential M. tuberculosis drug targets and prioritized according to the ranking of 'clusters' of interacting proteins. Comparison of the predicted 140 TB targets with literature indicated that 46 of them were previously reported, thereby increasing the confidence in our predictions of the remaining 94 targets too. The analyses of the structures and functions corresponding to the predicted potential TB drug targets indicated a diverse range of proteins that included ten 'druggable' targets with some of the known drugs. PMID:26762852

  10. Identification of inhibitors against Mycobacterium tuberculosis thiamin phosphate synthase, an important target for the development of anti-TB drugs.

    PubMed

    Khare, Garima; Kar, Ritika; Tyagi, Anil K

    2011-01-01

    Tuberculosis (TB) continues to pose a serious challenge to human health afflicting a large number of people throughout the world. In spite of the availability of drugs for the treatment of TB, the non-compliance to 6-9 months long chemotherapeutic regimens often results in the emergence of multidrug resistant strains of Mycobacterium tuberculosis adding to the precariousness of the situation. This has necessitated the development of more effective drugs. Thiamin biosynthesis, an important metabolic pathway of M. tuberculosis, is shown to be essential for the intracellular growth of this pathogen and hence, it is believed that inhibition of this pathway would severely affect the growth of M. tuberculosis. In this study, a comparative homology model of M. tuberculosis thiamin phosphate synthase (MtTPS) was generated and employed for virtual screening of NCI diversity set II to select potential inhibitors. The best 39 compounds based on the docking results were evaluated for their potential to inhibit the MtTPS activity. Seven compounds inhibited MtTPS activity with IC(50) values ranging from 20-100 µg/ml and two of these exhibited weak inhibition of M. tuberculosis growth with MIC(99) values being 125 µg/ml and 162.5 µg/ml while one compound was identified as a very potent inhibitor of M. tuberculosis growth with an MIC(99) value of 6 µg/ml. This study establishes MtTPS as a novel drug target against M. tuberculosis leading to the identification of new lead molecules for the development of antitubercular drugs. Further optimization of these lead compounds could result in more potent therapeutic molecules against Tuberculosis. PMID:21818324

  11. Bioinformatics Identification of Drug Resistance-Associated Gene Pairs in Mycobacterium tuberculosis.

    PubMed

    Cui, Ze-Jia; Yang, Qing-Yong; Zhang, Hong-Yu; Zhu, Qiang; Zhang, Qing-Ye

    2016-01-01

    Tuberculosis is a chronic infectious disease caused by Mycobacterium tuberculosis (Mtb). Due to the extensive use of anti-tuberculosis drugs and the development of mutations, the emergence and spread of multidrug-resistant tuberculosis is recognized as one of the most dangerous threats to global tuberculosis control. Some single mutations have been identified to be significantly linked with drug resistance. However, the prior research did not take gene-gene interactions into account, and the emergence of transmissible drug resistance is connected with multiple genetic mutations. In this study we use the bioinformatics software GBOOST (The Hong Kong University, Clear Water Bay, Kowloon, Hong Kong, China) to calculate the interactions of Single Nucleotide Polymorphism (SNP) pairs and identify gene pairs associated with drug resistance. A large part of the non-synonymous mutations in the drug target genes that were included in the screened gene pairs were confirmed by previous reports, which lent sound solid credits to the effectiveness of our method. Notably, most of the identified gene pairs containing drug targets also comprise Pro-Pro-Glu (PPE) family proteins, suggesting that PPE family proteins play important roles in the drug resistance of Mtb. Therefore, this study provides deeper insights into the mechanisms underlying anti-tuberculosis drug resistance, and the present method is useful for exploring the drug resistance mechanisms for other microorganisms. PMID:27618895

  12. Bioinformatic identification of Mycobacterium tuberculosis proteins likely to target host cell mitochondria: virulence factors?

    PubMed Central

    2012-01-01

    Background M. tuberculosis infection either induces or inhibits host cell death, depending on the bacterial strain and the cell microenvironment. There is evidence suggesting a role for mitochondria in these processes. On the other hand, it has been shown that several bacterial proteins are able to target mitochondria, playing a critical role in bacterial pathogenesis and modulation of cell death. However, mycobacteria–derived proteins able to target host cell mitochondria are less studied. Results A bioinformaic analysis based on available genomic sequences of the common laboratory virulent reference strain Mycobacterium tuberculosis H37Rv, the avirulent strain H37Ra, the clinical isolate CDC1551, and M. bovis BCG Pasteur strain 1173P2, as well as of suitable bioinformatic tools (MitoProt II, PSORT II, and SignalP) for the in silico search for proteins likely to be secreted by mycobacteria that could target host cell mitochondria, showed that at least 19 M. tuberculosis proteins could possibly target host cell mitochondria. We experimentally tested this bioinformatic prediction on four M. tuberculosis recombinant proteins chosen from this list of 19 proteins (p27, PE_PGRS1, PE_PGRS33, and MT_1866). Confocal microscopy analyses showed that p27, and PE_PGRS33 proteins colocalize with mitochondria. Conclusions Based on the bioinformatic analysis of whole M. tuberculosis genome sequences, we propose that at least 19 out of 4,246 M. tuberculosis predicted proteins would be able to target host cell mitochondria and, in turn, control mitochondrial physiology. Interestingly, such a list of 19 proteins includes five members of a mycobacteria specific family of proteins (PE/PE_PGRS) thought to be virulence factors, and p27, a well known virulence factor. P27, and PE_PGRS33 proteins experimentally showed to target mitochondria in J774 cells. Our results suggest a link between mitochondrial targeting of M. tuberculosis proteins and virulence. PMID:23259719

  13. Identification of Novel Anti-mycobacterial Compounds by Screening a Pharmaceutical Small-Molecule Library against Nonreplicating Mycobacterium tuberculosis.

    PubMed

    Warrier, Thulasi; Martinez-Hoyos, Maria; Marin-Amieva, Manuel; Colmenarejo, Gonzalo; Porras-De Francisco, Esther; Alvarez-Pedraglio, Ana Isabel; Fraile-Gabaldon, Maria Teresa; Torres-Gomez, Pedro Alfonso; Lopez-Quezada, Landys; Gold, Ben; Roberts, Julia; Ling, Yan; Somersan-Karakaya, Selin; Little, David; Cammack, Nicholas; Nathan, Carl; Mendoza-Losana, Alfonso

    2015-12-11

    Identification of compounds that target metabolically diverse subpopulations of Mycobacterium tuberculosis (Mtb) may contribute to shortening the course of treatment for tuberculosis. This study screened 270,000 compounds from GlaxoSmithKline's collection against Mtb in a nonreplicating (NR) state imposed in vitro by a combination of four host-relevant stresses. Evaluation of 166 confirmed hits led to detailed characterization of 19 compounds for potency, specificity, cytotoxicity, and stability. Compounds representing five scaffolds depended on reactive nitrogen species for selective activity against NR Mtb, and two were stable in the assay conditions. Four novel scaffolds with activity against replicating (R) Mtb were also identified. However, none of the 19 compounds was active against Mtb in both NR and R states. There was minimal overlap between compounds found active against NR Mtb and those previously identified as active against R Mtb, supporting the hypothesis that NR Mtb depends on distinct metabolic pathways for survival. PMID:27623055

  14. Identification of specific metabolites in culture supernatant of Mycobacterium tuberculosis using metabolomics: exploration of potential biomarkers

    PubMed Central

    Lau, Susanna KP; Lam, Ching-Wan; Curreem, Shirly OT; Lee, Kim-Chung; Lau, Candy CY; Chow, Wang-Ngai; Ngan, Antonio HY; To, Kelvin KW; Chan, Jasper FW; Hung, Ivan FN; Yam, Wing-Cheong; Yuen, Kwok-Yung; Woo, Patrick CY

    2015-01-01

    Although previous studies have reported the use of metabolomics for Mycobacterium species differentiation, little is known about the potential of extracellular metabolites of Mycobacterium tuberculosis (MTB) as specific biomarkers. Using an optimized ultrahigh performance liquid chromatography–electrospray ionization–quadruple time of flight–mass spectrometry (UHPLC–ESI–Q–TOF–MS) platform, we characterized the extracellular metabolomes of culture supernatant of nine MTB strains and nine non-tuberculous Mycobacterium (NTM) strains (four M. avium complex, one M. bovis Bacillus Calmette–Guérin (BCG), one M. chelonae, one M. fortuitum and two M. kansasii). Principal component analysis readily distinguished the metabolomes between MTB and NTM. Using multivariate and univariate analysis, 24 metabolites with significantly higher levels in MTB were identified. While seven metabolites were identified by tandem mass spectrometry (MS/MS), the other 17 metabolites were unidentified by MS/MS against database matching, suggesting that they may be potentially novel compounds. One metabolite was identified as dexpanthenol, the alcohol analog of pantothenic acid (vitamin B5), which was not known to be produced by bacteria previously. Four metabolites were identified as 1-tuberculosinyladenosine (1-TbAd), a product of the virulence-associated enzyme Rv3378c, and three previously undescribed derivatives of 1-TbAd. Two derivatives differ from 1-TbAd by the ribose group of the nucleoside while the other likely differs by the base. The remaining two metabolites were identified as a tetrapeptide, Val-His-Glu-His, and a monoacylglycerophosphoglycerol, phosphatidylglycerol (PG) (16∶0/0∶0), respectively. Further studies on the chemical structure and biosynthetic pathway of these MTB-specific metabolites would help understand their biological functions. Studies on clinical samples from tuberculosis patients are required to explore for their potential role as diagnostic

  15. Identification of specific metabolites in culture supernatant of Mycobacterium tuberculosis using metabolomics: exploration of potential biomarkers.

    PubMed

    Lau, Susanna K P; Lam, Ching-Wan; Curreem, Shirly O T; Lee, Kim-Chung; Lau, Candy C Y; Chow, Wang-Ngai; Ngan, Antonio H Y; To, Kelvin K W; Chan, Jasper F W; Hung, Ivan F N; Yam, Wing-Cheong; Yuen, Kwok-Yung; Woo, Patrick C Y

    2015-01-01

    Although previous studies have reported the use of metabolomics for Mycobacterium species differentiation, little is known about the potential of extracellular metabolites of Mycobacterium tuberculosis (MTB) as specific biomarkers. Using an optimized ultrahigh performance liquid chromatography-electrospray ionization-quadruple time of flight-mass spectrometry (UHPLC-ESI-Q-TOF-MS) platform, we characterized the extracellular metabolomes of culture supernatant of nine MTB strains and nine non-tuberculous Mycobacterium (NTM) strains (four M. avium complex, one M. bovis Bacillus Calmette-Guérin (BCG), one M. chelonae, one M. fortuitum and two M. kansasii). Principal component analysis readily distinguished the metabolomes between MTB and NTM. Using multivariate and univariate analysis, 24 metabolites with significantly higher levels in MTB were identified. While seven metabolites were identified by tandem mass spectrometry (MS/MS), the other 17 metabolites were unidentified by MS/MS against database matching, suggesting that they may be potentially novel compounds. One metabolite was identified as dexpanthenol, the alcohol analog of pantothenic acid (vitamin B5), which was not known to be produced by bacteria previously. Four metabolites were identified as 1-tuberculosinyladenosine (1-TbAd), a product of the virulence-associated enzyme Rv3378c, and three previously undescribed derivatives of 1-TbAd. Two derivatives differ from 1-TbAd by the ribose group of the nucleoside while the other likely differs by the base. The remaining two metabolites were identified as a tetrapeptide, Val-His-Glu-His, and a monoacylglycerophosphoglycerol, phosphatidylglycerol (PG) (16∶0/0∶0), respectively. Further studies on the chemical structure and biosynthetic pathway of these MTB-specific metabolites would help understand their biological functions. Studies on clinical samples from tuberculosis patients are required to explore for their potential role as diagnostic biomarkers. PMID

  16. Identification of Quantitative Proteomic Differences between Mycobacterium tuberculosis Lineages with Altered Virulence

    PubMed Central

    Peters, Julian S.; Calder, Bridget; Gonnelli, Giulia; Degroeve, Sven; Rajaonarifara, Elinambinina; Mulder, Nicola; Soares, Nelson C.; Martens, Lennart; Blackburn, Jonathan M.

    2016-01-01

    Evidence currently suggests that as a species Mycobacterium tuberculosis exhibits very little genomic sequence diversity. Despite limited genetic variability, members of the M. tuberculosis complex (MTBC) have been shown to exhibit vast discrepancies in phenotypic presentation in terms of virulence, elicited immune response and transmissibility. Here, we used qualitative and quantitative mass spectrometry tools to investigate the proteomes of seven clinically-relevant mycobacterial strains—four M. tuberculosis strains, M. bovis, M. bovis BCG, and M. avium—that show varying degrees of pathogenicity and virulence, in an effort to rationalize the observed phenotypic differences. Following protein preparation, liquid chromatography mass spectrometry (LC MS/MS) and data capture were carried out using an LTQ Orbitrap Velos. Data analysis was carried out using a novel bioinformatics strategy, which yielded high protein coverage and was based on high confidence peptides. Through this approach, we directly identified a total of 3788 unique M. tuberculosis proteins out of a theoretical proteome of 4023 proteins and identified an average of 3290 unique proteins for each of the MTBC organisms (representing 82% of the theoretical proteomes), as well as 4250 unique M. avium proteins (80% of the theoretical proteome). Data analysis showed that all major classes of proteins are represented in every strain, but that there are significant quantitative differences between strains. Targeted selected reaction monitoring (SRM) assays were used to quantify the observed differential expression of a subset of 23 proteins identified by comparison to gene expression data as being of particular relevance to virulence. This analysis revealed differences in relative protein abundance between strains for proteins which may promote bacterial fitness in the more virulent W. Beijing strain. These differences may contribute to this strain's capacity for surviving within the host and resisting

  17. Identification and Characterization of Lipase Activity and Immunogenicity of LipL from Mycobacterium tuberculosis

    PubMed Central

    Cao, Jun; Dang, Guanghui; Li, Huafang; Li, Tiantian; Yue, Zhiguo; Li, Na; Liu, Yajun; Liu, Siguo; Chen, Liping

    2015-01-01

    Lipids and lipid-metabolizing esterases/lipases are highly important for the mycobacterial life cycle and, possibly, for mycobacterial virulence. In this study, we expressed 10 members of the Lip family of Mycobacterium tuberculosis. Among the 10 proteins, LipL displayed a significantly high enzymatic activity for the hydrolysis of long-chain lipids. The optimal temperature for the lipase activity of LipL was demonstrated to be 37°C, and the optimal pH was 8.0. The lipase active center was not the conserved motif G-x-S-x-G, but rather the S-x-x-K and GGG motifs, and the key catalytic amino acid residues were identified as G50, S88, and K91, as demonstrated through site-directed mutagenesis experiments. A three-dimensional modeling structure of LipL was constructed, which showed that the GGG motif was located in the surface of a pocket structure. Furthermore, the subcellular localization of LipL was demonstrated to be on the mycobacterial surface by Western blot analysis. Our results revealed that the LipL protein could induce a strong humoral immune response in humans and activate a CD8+ T cell-mediated response in mice. Overall, our study identified and characterized a novel lipase denoted LipL from M. tuberculosis, and demonstrated that LipL functions as an immunogen that activates both humoral and cell-mediated responses. PMID:26398213

  18. targetTB: A target identification pipeline for Mycobacterium tuberculosis through an interactome, reactome and genome-scale structural analysis

    PubMed Central

    Raman, Karthik; Yeturu, Kalidas; Chandra, Nagasuma

    2008-01-01

    Background Tuberculosis still remains one of the largest killer infectious diseases, warranting the identification of newer targets and drugs. Identification and validation of appropriate targets for designing drugs are critical steps in drug discovery, which are at present major bottle-necks. A majority of drugs in current clinical use for many diseases have been designed without the knowledge of the targets, perhaps because standard methodologies to identify such targets in a high-throughput fashion do not really exist. With different kinds of 'omics' data that are now available, computational approaches can be powerful means of obtaining short-lists of possible targets for further experimental validation. Results We report a comprehensive in silico target identification pipeline, targetTB, for Mycobacterium tuberculosis. The pipeline incorporates a network analysis of the protein-protein interactome, a flux balance analysis of the reactome, experimentally derived phenotype essentiality data, sequence analyses and a structural assessment of targetability, using novel algorithms recently developed by us. Using flux balance analysis and network analysis, proteins critical for survival of M. tuberculosis are first identified, followed by comparative genomics with the host, finally incorporating a novel structural analysis of the binding sites to assess the feasibility of a protein as a target. Further analyses include correlation with expression data and non-similarity to gut flora proteins as well as 'anti-targets' in the host, leading to the identification of 451 high-confidence targets. Through phylogenetic profiling against 228 pathogen genomes, shortlisted targets have been further explored to identify broad-spectrum antibiotic targets, while also identifying those specific to tuberculosis. Targets that address mycobacterial persistence and drug resistance mechanisms are also analysed. Conclusion The pipeline developed provides rational schema for drug target

  19. An automated approach for global identification of sRNA-encoding regions in RNA-Seq data from Mycobacterium tuberculosis.

    PubMed

    Wang, Ming; Fleming, Joy; Li, Zihui; Li, Chuanyou; Zhang, Hongtai; Xue, Yunxin; Chen, Maoshan; Zhang, Zongde; Zhang, Xian-En; Bi, Lijun

    2016-06-01

    Deep-sequencing of bacterial transcriptomes using RNA-Seq technology has made it possible to identify small non-coding RNAs, RNA molecules which regulate gene expression in response to changing environments, on a genome-wide scale in an ever-increasing range of prokaryotes. However, a simple and reliable automated method for identifying sRNA candidates in these large datasets is lacking. Here, after generating a transcriptome from an exponential phase culture of Mycobacterium tuberculosis H37Rv, we developed and validated an automated method for the genome-wide identification of sRNA candidate-containing regions within RNA-Seq datasets based on the analysis of the characteristics of reads coverage maps. We identified 192 novel candidate sRNA-encoding regions in intergenic regions and 664 RNA transcripts transcribed from regions antisense (as) to open reading frames (ORF), which bear the characteristics of asRNAs, and validated 28 of these novel sRNA-encoding regions by northern blotting. Our work has not only provided a simple automated method for genome-wide identification of candidate sRNA-encoding regions in RNA-Seq data, but has also uncovered many novel candidate sRNA-encoding regions in M. tuberculosis, reinforcing the view that the control of gene expression in bacteria is more complex than previously anticipated. PMID:27174874

  20. Target-Based Identification of Whole-Cell Active Inhibitors of Biotin Biosynthesis in Mycobacterium tuberculosis

    PubMed Central

    Park, Sae Woong; Casalena, Dominick; Wilson, Daniel; Dai, Ran; Nag, Partha; Liu, Feng; Boyce, Jim P.; Bittker, Joshua; Schreiber, Stuart; Finzel, Barry C.; Schnappinger, Dirk; Aldrich, Courtney C.

    2014-01-01

    SUMMARY Biotin biosynthesis is essential for survival and persistence of Mycobacterium tuberculosis (Mtb) in vivo. The aminotransferase BioA, which catalyzes the antepenultimate step in the biotin pathway, has been established as a promising target due to its vulnerability to chemical inhibition. We performed high-throughput screening (HTS) employing a fluorescence displacement assay and identified a diverse set of potent inhibitors including many diversity-oriented synthesis (DOS) scaffolds. To efficiently select only hits targeting biotin biosynthesis, we then deployed a whole-cell counter-screen in either biotin-free and biotin-containing medium against wild-type Mtb and in parallel with isogenic bioA Mtb strains that possess differential levels of BioA expression. This counter-screen proved crucial to filter out compounds whose whole-cell activity was off-target as well as identify hits with weak, but measurable whole-cell activity in BioA-depleted strains. Several of the most promising hits were co-crystallized with BioA to provide a framework for future structure-based drug design efforts. PMID:25556942

  1. Crowd Sourcing a New Paradigm for Interactome Driven Drug Target Identification in Mycobacterium tuberculosis

    PubMed Central

    Rohira, Harsha; Bhat, Ashwini G.; Passi, Anurag; Mukherjee, Keya; Choudhary, Kumari Sonal; Kumar, Vikas; Arora, Anshula; Munusamy, Prabhakaran; Subramanian, Ahalyaa; Venkatachalam, Aparna; S, Gayathri; Raj, Sweety; Chitra, Vijaya; Verma, Kaveri; Zaheer, Salman; J, Balaganesh; Gurusamy, Malarvizhi; Razeeth, Mohammed; Raja, Ilamathi; Thandapani, Madhumohan; Mevada, Vishal; Soni, Raviraj; Rana, Shruti; Ramanna, Girish Muthagadhalli; Raghavan, Swetha; Subramanya, Sunil N.; Kholia, Trupti; Patel, Rajesh; Bhavnani, Varsha; Chiranjeevi, Lakavath; Sengupta, Soumi; Singh, Pankaj Kumar; Atray, Naresh; Gandhi, Swati; Avasthi, Tiruvayipati Suma; Nisthar, Shefin; Anurag, Meenakshi; Sharma, Pratibha; Hasija, Yasha; Dash, Debasis; Sharma, Arun; Scaria, Vinod; Thomas, Zakir; Chandra, Nagasuma; Brahmachari, Samir K.; Bhardwaj, Anshu

    2012-01-01

    A decade since the availability of Mycobacterium tuberculosis (Mtb) genome sequence, no promising drug has seen the light of the day. This not only indicates the challenges in discovering new drugs but also suggests a gap in our current understanding of Mtb biology. We attempt to bridge this gap by carrying out extensive re-annotation and constructing a systems level protein interaction map of Mtb with an objective of finding novel drug target candidates. Towards this, we synergized crowd sourcing and social networking methods through an initiative ‘Connect to Decode’ (C2D) to generate the first and largest manually curated interactome of Mtb termed ‘interactome pathway’ (IPW), encompassing a total of 1434 proteins connected through 2575 functional relationships. Interactions leading to gene regulation, signal transduction, metabolism, structural complex formation have been catalogued. In the process, we have functionally annotated 87% of the Mtb genome in context of gene products. We further combine IPW with STRING based network to report central proteins, which may be assessed as potential drug targets for development of drugs with least possible side effects. The fact that five of the 17 predicted drug targets are already experimentally validated either genetically or biochemically lends credence to our unique approach. PMID:22808064

  2. Immune Responses in Cattle Inoculated with Mycobacterium bovis, Mycobacterium tuberculosis, or Mycobacterium kansasii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cattle were inoculated with Mycobacterium bovis, Mycobacterium tuberculosis, or Mycobacterium kansasii to compare antigen-specific immune responses to varied patterns of mycobacterial disease. Disease expression ranged from colonization with associated pathology (M. bovis), colonization without path...

  3. Cluster-based molecular docking study for in silico identification of novel 6-fluoroquinolones as potential inhibitors against Mycobacterium tuberculosis.

    PubMed

    Minovski, Nikola; Perdih, Andrej; Novic, Marjana; Solmajer, Tom

    2013-04-01

    A classical protein sequence alignment and homology modeling strategy were used for building three Mycobacterium tuberculosis-DNA gyrase protein models using the available topoII-DNA-6FQ crystal structure complexes originating from different organisms. The recently determined M. tuberculosis-DNA gyrase apoprotein structures and topoII-DNA-6FQ complexes were used for defining the 6-fluoroquinolones (6-FQs) binding pockets. The quality of the generated models was initially validated by docking of the cocrystallized ligands into their binding site, and subsequently by quantitative evaluation of their discriminatory performances (identification of active/inactive 6-FQs) for a set of 145 6-FQs with known biological activity values. The M. tuberculosis-DNA gyrase model with the highest estimated discriminatory power was selected and used afterwards in an additional molecular docking experiment on a mixed combinatorial set of 427 drug-like 6-FQ analogs for which the biological activity values were predicted using a prebuilt counter-propagation artificial neural network model. A novel three-level Boolean-based [T/F (true/false)] clustering algorithm was used to assess the generated binding poses: Level 1 (geometry properties assessment), Level 2 (score-based clustering and selection of the (T)-signed highly scored Level 1 poses), and Level 3 (activity-based clustering and selection of the most "active" (T)-signed Level 2 hits). The frequency analysis of occurrence of the fragments attached at R(1) and R(7) position of the (T)-signed 6-FQs selected in Level 3 revealed several novel attractive fragments and confirmed some previous findings. We believe that this methodology could be successfully used in establishing novel possible structure-activity relationship recommendations in the 6-FQs optimization, which could be of great importance in the current antimycobacterial hit-to-lead processes. PMID:23280926

  4. Hyphenated and comprehensive liquid chromatography × gas chromatography-mass spectrometry for the identification of Mycobacterium tuberculosis.

    PubMed

    Mourão, Marta P B; Denekamp, Ilse; Kuijper, Sjoukje; Kolk, Arend H J; Janssen, Hans-Gerd

    2016-03-25

    Tuberculosis is one of the world's most emerging public health problems, particularly in developing countries. Chromatography based methods have been used to tackle this epidemic by focusing on biomarker detection. Unfortunately, interferences from lipids in the sputum matrix, particularly cholesterol, adversely affect the identification and detection of the marker compounds. The present contribution describes the serial combination of normal phase liquid chromatography (NPLC) with thermally assisted hydrolysis and methylation followed by gas chromatography-mass spectrometry (THM-GC-MS) to overcome the difficulties of biomarker evaluation. The in-series combination consists of an LC analysis where fractions are collected and then transferred to the THM-GC-MS system. This was either done with comprehensive coupling, transferring all the fractions, or with hyphenated interfacing, i.e. off-line multi heart-cutting, transferring only selected fractions. Owing to the high sensitivity and selectivity of LC as a sample pre-treatment method, and to the high specificity of the MS as a detector, this analytical approach, NPLC × THM-GC-MS, is extremely sensitive. The results obtained indicate that this analytical set-up is able to detect down to 1 × 10(3) mycobacteria/mL of Mycobacterium tuberculosis strain 124, spiked in blank sputum samples. It is a powerful analytical tool and also has great potential for full automation. If further studies demonstrate its usefulness when applied blind in real sputum specimens, this technique could compete with the current smear microscopy in the early diagnosis of tuberculosis. PMID:26585206

  5. Identification and Validation of Aspartic Acid Semialdehyde Dehydrogenase as a New Anti-Mycobacterium Tuberculosis Target

    PubMed Central

    Meng, Jianzhou; Yang, Yanhui; Xiao, Chunling; Guan, Yan; Hao, Xueqin; Deng, Qi; Lu, Zhongyang

    2015-01-01

    Aspartic acid semialdehyde dehydrogenase (ASADH) lies at the first branch point in the essential aspartic acid biosynthetic pathway that is found in bacteria and plants but is absent from animals. Mutations in the asadh gene encoding ASADH produce an inactive enzyme, which is lethal. Therefore, in this study, we investigated the hypothesis that ASADH represents a new anti-Mycobacterium tuberculosis (MTB) target. An asadh promoter-replacement mutant MTB, designated MTB::asadh, in which asadh gene expression is regulated by pristinamycin, was constructed to investigate the physiological functions of ASADH in the host bacteria. Bacterial growth was evaluated by monitoring OD600 and ASADH expression was analyzed by Western blotting. The results showed that the growth and survival of MTB::asadh was completely inhibited in the absence of the inducer pristinamycin. Furthermore, the growth of the mutant was rigorously dependent on the presence of the inducer in the medium. The starved mutant exhibited a marked reduction (approximately 80%) in the cell wall materials compared to the wild-type, in addition to obvious morphological differences that were apparent in scanning electron microscopy studies; however, with the addition of pristinamycin, the cell wall contents and morphology similar to those of the wild-type strain were recovered. The starved mutant also exhibited almost no pathogenicity in an in vitro model of infection using mouse macrophage J774A.1 cells. The mutant showed a concentration-dependent recovery of pathogenicity with the addition of the inducer. These findings implicate ASADH as a promising target for the development of novel anti-MTB drugs. PMID:26437401

  6. Evaluation of methods for detection and identification of Mycobacterium species in patients suspected of having pulmonary tuberculosis

    PubMed Central

    Marchi, A. M.; Juttel, I. D.; Kawacubo, E. M.; Dalmarco, E. M.; Blatt, S. L.; Cordova, C. M. M.

    2008-01-01

    Tuberculosis control is a priority for the Ministry of Health policies in Brazil. In the present work, the detection of Mycobacterium tuberculosis by the Polymerase Chain Reaction (PCR) was standardized, and the laboratory diagnosis of pulmonary tuberculosis was evaluated comparing baciloscopy, culture and PCR tests. The study was carried out with 117 sputum samples from different patients suspected of having pulmonary tuberculosis, for whom physicians had ordered a baciloscopy test. Baciloscopy was performed using the Ziehl-Neelsen method, and culture was performed by incubation of treated samples in Lowenstein-Jensen’s medium at 37°C for eight weeks. For PCR, DNA was amplified with a specific pair of primers to the M. tuberculosis complex, with a resulting product of 123 bp from the insertion element IS6110. Three (2.56%) samples presented a positive baciloscopy result and a positive PCR result (100% agreement), and nine (7.69%) presented Mycobacterium sp. growth in culture (P= 0.1384). Among six samples with positive results in culture, one was identified by PCR-RFLP as belonging to the M. tuberculosis complex and one was identified as a non-tuberculosis mycobacteria. Sensitivity and specificity of PCR compared to culture were 33.3% and 100%, respectively. PMID:24031276

  7. Evaluation of methods for detection and identification of Mycobacterium species in patients suspected of having pulmonary tuberculosis.

    PubMed

    Marchi, A M; Juttel, I D; Kawacubo, E M; Dalmarco, E M; Blatt, S L; Cordova, C M M

    2008-10-01

    Tuberculosis control is a priority for the Ministry of Health policies in Brazil. In the present work, the detection of Mycobacterium tuberculosis by the Polymerase Chain Reaction (PCR) was standardized, and the laboratory diagnosis of pulmonary tuberculosis was evaluated comparing baciloscopy, culture and PCR tests. The study was carried out with 117 sputum samples from different patients suspected of having pulmonary tuberculosis, for whom physicians had ordered a baciloscopy test. Baciloscopy was performed using the Ziehl-Neelsen method, and culture was performed by incubation of treated samples in Lowenstein-Jensen's medium at 37°C for eight weeks. For PCR, DNA was amplified with a specific pair of primers to the M. tuberculosis complex, with a resulting product of 123 bp from the insertion element IS6110. Three (2.56%) samples presented a positive baciloscopy result and a positive PCR result (100% agreement), and nine (7.69%) presented Mycobacterium sp. growth in culture (P= 0.1384). Among six samples with positive results in culture, one was identified by PCR-RFLP as belonging to the M. tuberculosis complex and one was identified as a non-tuberculosis mycobacteria. Sensitivity and specificity of PCR compared to culture were 33.3% and 100%, respectively. PMID:24031276

  8. Rapid and simple identification of Beijing genotype strain of Mycobacterium tuberculosis using a loop-mediated isothermal amplification assay.

    PubMed

    Nagai, Yuhki; Iwade, Yoshito; Nakano, Manabu; Akachi, Shigehiro; Kobayashi, Takashi; Nishinaka, Takamichi

    2016-07-01

    Beijing genotype strains of Mycobacterium tuberculosis are geographically widespread and pose a notorious public health problem, these strains causing outbreaks of multidrug-resistant tuberculosis (TB); some studies have reported an association with drug resistance. Because the prevalence of Beijing strain has a substantial impact on TB control programs, the availability of a rapid and reliable method for detecting these strains is important for epidemiological monitoring of their circulation. The main methods currently used to identify Beijing genotype strains are IS6110 DNA fingerprinting, spoligotyping and PCR to detect specific deletions such as region of difference (RD)207. More recently, multiplex PCR assay using a Beijing-specific single nucleotide polymorphism (SNP) has been developed for detecting Beijing lineage strains. However, these methods are time-consuming and technically demanding. In the present study, a loop-mediated isothermal amplification (LAMP) assay that allows specific identification of Beijing genotype strain was developed. This Beijing genotype strain-identifying LAMP assay was performed 214 clinical isolates and the results compared with those of conventional PCR that targeted RD207 and Rv0679c-targreting multiplex PCR for Beijing lineage identification. LAMP assay showed 100% sensitivity and specificity compared with RD207-PCR. Furthermore, the sensitivity and specificity were 99.3% and 100%, respectively, compared with Rv0679c-multiplex PCR. This LAMP assay could be used routinely in local laboratories to monitor the prevalence of the Beijing genotype strain and thereby used to help control the spread of these potentially highly virulent and drug resistant strains. PMID:27213686

  9. A novel method for the rapid and prospective identification of Beijing Mycobacterium tuberculosis strains by high-resolution melting analysis.

    PubMed

    Alonso, M; Navarro, Y; Barletta, F; Martínez Lirola, M; Gotuzzo, E; Bouza, E; García de Viedma, D

    2011-03-01

    Genotypic analysis of Mycobacterium tuberculosis (MTB) has enabled the definition of several lineages. The Beijing family, which is considered highly virulent and transmissible, has been associated with resistance in certain settings and involved in severe outbreaks, making it one of the most closely-monitored lineages. Therefore, rapid prospective identification of Beijing MTB strains could be relevant. In the present study, we evaluate a real-time PCR followed by high-resolution melting (HRM) based on the identification of a single nucleotide polymorphism (SNP) in the Rv2629 gene which defines Beijing lineage (A191C for Beijing genotype and A191A for non-Beijing genotype). This combined methodology efficiently differentiated Beijing and non-Beijing strains in 100% of the isolates from a collection of reference strains without requiring specific DNA probes. Additionally, HRM was able to assign a Beijing/non-Beijing genotype in 90.9% of the respiratory specimens assayed. Its applicability was tested on a Peruvian sample of circulating MTB strains, in which it identified 10.7% as belonging to the Beijing genotype; this proportion reached 20% in the North Lima area. HRM analysis of the A191C SNP is a rapid, reliable, and sensitive method for the efficient prospective survey of high-risk Beijing MTB strains, even in developing settings where MTB culture is often not available. PMID:20384709

  10. Significance of the Identification in the Horn of Africa of an Exceptionally Deep Branching Mycobacterium tuberculosis Clade

    PubMed Central

    Blouin, Yann; Hauck, Yolande; Soler, Charles; Fabre, Michel; Vong, Rithy; Dehan, Céline; Cazajous, Géraldine; Massoure, Pierre-Laurent; Kraemer, Philippe; Jenkins, Akinbowale; Garnotel, Eric; Pourcel, Christine; Vergnaud, Gilles

    2012-01-01

    Molecular and phylogeographic studies have led to the definition within the Mycobacterium tuberculosis complex (MTBC) of a number of geotypes and ecotypes showing a preferential geographic location or host preference. The MTBC is thought to have emerged in Africa, most likely the Horn of Africa, and to have spread worldwide with human migrations. Under this assumption, there is a possibility that unknown deep branching lineages are present in this region. We genotyped by spoligotyping and multiple locus variable number of tandem repeats (VNTR) analysis (MLVA) 435 MTBC isolates recovered from patients. Four hundred and eleven isolates were collected in the Republic of Djibouti over a 12 year period, with the other 24 isolates originating from neighbouring countries. All major M. tuberculosis lineages were identified, with only two M. africanum and one M. bovis isolates. Upon comparison with typing data of worldwide origin we observed that several isolates showed clustering characteristics compatible with new deep branching. Whole genome sequencing (WGS) of seven isolates and comparison with available WGS data from 38 genomes distributed in the different lineages confirms the identification of ancestral nodes for several clades and most importantly of one new lineage, here referred to as lineage 7. Investigation of specific deletions confirms the novelty of this lineage, and analysis of its precise phylogenetic position indicates that the other three superlineages constituting the MTBC emerged independently but within a relatively short timeframe from the Horn of Africa. The availability of such strains compared to the predominant lineages and sharing very ancient ancestry will open new avenues for identifying some of the genetic factors responsible for the success of the modern lineages. Additional deep branching lineages may be readily and efficiently identified by large-scale MLVA screening of isolates from sub-Saharan African countries followed by WGS analysis of

  11. Identification and Characterization of a Major Cell Wall-Associated Iron-Regulated Envelope Protein (Irep-28) in Mycobacterium tuberculosis

    PubMed Central

    Yeruva, Veena C.; Duggirala, Sridevi; Lakshmi, V.; Kolarich, Daniel; Altmann, Friedrich; Sritharan, Manjula

    2006-01-01

    Iron limitation and the expression of mycobactin and carboxymycobactin by Mycobacterium tuberculosis are known. Here, we report how iron regulated the coordinate expression of these two siderophores and a 28-kDa cell wall-associated iron-regulated protein (Irep-28). Irep-28 is identified as the DNA-binding HU homologue HupB protein (hupB [Rv2986c]). Antibodies to this protein were detected in sera from tuberculosis patients. The location of the protein in the cell wall makes it a potential drug target. PMID:17028216

  12. Computationally Guided Identification of Novel Mycobacterium tuberculosis GlmU Inhibitory Leads, Their Optimization, and in Vitro Validation.

    PubMed

    Mehra, Rukmankesh; Rani, Chitra; Mahajan, Priya; Vishwakarma, Ram Ashrey; Khan, Inshad Ali; Nargotra, Amit

    2016-02-01

    Mycobacterium tuberculosis (Mtb) infections are causing serious health concerns worldwide. Antituberculosis drug resistance threatens the current therapies and causes further need to develop effective antituberculosis therapy. GlmU represents an interesting target for developing novel Mtb drug candidates. It is a bifunctional acetyltransferase/uridyltransferase enzyme that catalyzes the biosynthesis of UDP-N-acetyl-glucosamine (UDP-GlcNAc) from glucosamine-1-phosphate (GlcN-1-P). UDP-GlcNAc is a substrate for the biosynthesis of lipopolysaccharide and peptidoglycan that are constituents of the bacterial cell wall. In the current study, structure and ligand based computational models were developed and rationally applied to screen a drug-like compound repository of 20,000 compounds procured from ChemBridge DIVERSet database for the identification of probable inhibitors of Mtb GlmU. The in vitro evaluation of the in silico identified inhibitor candidates resulted in the identification of 15 inhibitory leads of this target. Literature search of these leads through SciFinder and their similarity analysis with the PubChem training data set (AID 1376) revealed the structural novelty of these hits with respect to Mtb GlmU. IC50 of the most potent identified inhibitory lead (5810599) was found to be 9.018 ± 0.04 μM. Molecular dynamics (MD) simulation of this inhibitory lead (5810599) in complex with protein affirms the stability of the lead within the binding pocket and also emphasizes on the key interactive residues for further designing. Binding site analysis of the acetyltransferase pocket with respect to the identified structural moieties provides a thorough analysis for carrying out the lead optimization studies. PMID:26812086

  13. Rapid Identification and Drug Susceptibility Testing of Mycobacterium tuberculosis: Standard Operating Procedure for Non-Commercial Assays: Part 3: Colorimetric Redox Indicator Assay v1.3.12

    PubMed Central

    Singh, Sarman; Kumar, Parveen; Sharma, Shreya; Mumbowa, Francis; Martin, Anandi; Durier, Nicolas

    2012-01-01

    The previous two standard operating procedures (SOPs) related to the culture and drug susceptibility testing (DST) of Mycobacterium tuberculosis with the microscopic observation drug susceptibility assay (Part 1) and nitrate reductase assay (Part 2). The present SOP is devoted to a third non-commercial culture and DST method known as colorimetric redox indicator assay (CRI). As its name indicates, the CRI detects the ability of the M. tuberculosis to reduce the colored oxidation-reduction indicator when added to a liquid culture of M. tuberculosis, after exposing the growth to different anti-mycobacterial drugs. The change in the color of the indicator denotes the proportionate number of viable Mycobacteria in the medium. The identification and DST results can be obtained in 7-8 days. This SOP document has been developed through the culture and DST subgroup of the STOP tuberculosis (TB) Partnership New Diagnostic Working Group. It is intended for laboratories that would want to use or already use this rapid non-commercial method for culture identification and DST of M. tuberculosis, notably in resource-constraint settings in Asia and Africa. PMID:23440615

  14. Identification of an alpha(1-->6) mannopyranosyltransferase (MptA), involved in Corynebacterium glutamicum lipomanann biosynthesis, and identification of its orthologue in Mycobacterium tuberculosis.

    PubMed

    Mishra, Arun K; Alderwick, Luke J; Rittmann, Doris; Tatituri, Raju V V; Nigou, Jerome; Gilleron, Martine; Eggeling, Lothar; Besra, Gurdyal S

    2007-09-01

    Corynebacterium glutamicum and Mycobacterium tuberculosis share a similar cell wall architecture, and the availability of their genome sequences has enabled the utilization of C. glutamicum as a model for the identification and study of, otherwise essential, mycobacterial genes involved in lipomannan (LM) and lipoarabinomannan (LAM) biosynthesis. We selected the putative glycosyltransferase-Rv2174 from M. tuberculosis and deleted its orthologue NCgl2093 from C. glutamicum. This resulted in the formation of a novel truncated lipomannan (Cg-t-LM) and a complete ablation of LM/LAM biosynthesis. Purification and characterization of Cg-t-LM revealed an overall decrease in molecular mass, a reduction of alpha(1-->6) and alpha(1-->2) glycosidic linkages illustrating a reduced degree of branching compared with wild-type LM. The deletion mutant's biochemical phenotype was fully complemented by either NCgl2093 or Rv2174. Furthermore, the use of a synthetic neoglycolipid acceptor in an in vitro cell-free assay utilizing the sugar donor beta-D-mannopyranosyl-1-monophosphoryl-decaprenol together with the neoglycolipid acceptor alpha-D-Manp-(1-->6)-alpha-D-Manp-O-C8 as a substrate, confirmed NCgl2093 and Rv2174 as an alpha(1-->6) mannopyranosyltransferase (MptA), involved in the latter stages of the biosynthesis of the alpha(1-->6) mannan core of LM. Altogether, these studies have identified a new mannosyltransferase, MptA, and they shed further light on the biosynthesis of LM/LAM in Corynebacterianeae. PMID:17714444

  15. Rapid Identification and Drug Susceptibility Testing of Mycobacterium tuberculosis: Standard Operating Procedure for Non-Commercial Assays: Part 2: Nitrate Reductase Assay v1.3.12

    PubMed Central

    Singh, Sarman; Kumar, Parveen; Sharma, Shreya; Mumbowa, Francis; Martin, Anandi; Durier, Nicolas

    2012-01-01

    In the previous part, we presented the standard operating procedure (SOP) of the microscopic observation drug susceptibility assay drug susceptibility testing (DST) for Mycobacterium tuberculosis. The present SOP is devoted to another non-commercial culture and DST method known as nitrate reductase assay (NRA). As the name implies, the NRA detects the ability of M. tuberculosis to reduce nitrate to nitrite. In the assay, the presence of nitrite is detected by the addition of p-nitrobenzoate into the growth yield. The reaction is detected by the naked eye. The incorporation of drugs in the medium allows to use the test for DST, which can be interpreted with naked eyes. The identification and drug susceptibility results can be obtained in 2-3 weeks. This SOP document has been developed through the culture and DST subgroup of the STOP tuberculosis (TB) Partnership New Diagnostic Working Group. It is intended for laboratories that would want to use or already using this rapid non-commercial method for culture identification and DST of M. tuberculosis, notably in resource-constraint settings in Asia and Africa. PMID:23440455

  16. Assessment of the BD MGIT TBc Identification Test for the Detection of Mycobacterium tuberculosis Complex in a Network of Mycobacteriology Laboratories

    PubMed Central

    Ramos, Jorge; Couto, Isabel; Narciso, Inácio; Coelho, Elizabeth; Viegas, Sofia

    2014-01-01

    We evaluate the performance of the TBcID assay in a panel of 100 acid-fast bacilli cultures. Sixty-four isolates were TBcID positive for Mycobacterium tuberculosis complex (MTBC), whereas 36 gave negative results. These included 28 nontuberculous mycobacteria, one nonmycobacterial isolate, one M. tuberculosis, and six M. bovis BCG strains. This corresponds to a sensitivity of 90.14%, specificity of 100%, and positive and negative predictive values of 100% and 80.55%, respectively. The test is rapid, easy to perform and interpret, and does not require sample preparation or instrumentation. However, a negative result does not exclude the presence of a strain belonging to MTBC, especially when mutations in mpb64 gene are present or some M. bovis BCG strains are isolated. The TBcID showed potential to assist in the identification of MTBC when the implementation and usage of molecular methods are often not possible, principally in resource-limited countries. PMID:24587985

  17. Simultaneous identification of rifampin-resistant Mycobacterium tuberculosis and nontuberculous mycobacteria by polymerase chain reaction-single strand conformation polymorphism and sequence analysis of the RNA polymerase gene (rpoB).

    PubMed

    Kim, Bum-Joon; Lee, Keun-Hwa; Yun, Yeo-Jun; Park, Eun-Mi; Park, Young-Gil; Bai, Gil-Han; Cha, Chang-Yong; Kook, Yoon-Hoh

    2004-07-01

    Interspecies variations and mutations associated with rifampin resistance in rpoB of Mycobacterium allow for the simultaneous identification of rifampin-resistant Mycobacterium tuberculosis and nontuberculous mycobacteria by PCR-SSCP analysis and PCR- sequencing. One hundred and ten strains of rifampin-susceptible M. tuberculosis, 14 strains of rifampin-resistant M. tuberculosis, and four strains of the M. avium complex were easily identified by PCR-SSCP. Of another seven strains, which showed unique SSCP patterns, three were identified as rifampin-resistant M. tuberculosis and four as M. terrae complex by subsequent sequence analysis of their rpoB DNAs (306 bp). These results were concordant with those obtained by susceptibility testing, biochemical identification, and 16S rDNA sequencing. PMID:15177909

  18. Peritoneal tuberculosis due to Mycobacterium caprae

    PubMed Central

    Nebreda, T.; Álvarez-Prida, E.; Blanco, B.; Remacha, M.A.; Samper, S.; Jiménez, M.S.

    2016-01-01

    The incidence of tuberculosis in humans due to Mycobacterium caprae is very low and is almost confined to Europe. We report a case of a previously healthy 41-year-old Moroccan with a 6 month history of abdominal pain, weight loss, fatigue and diarrhea. A diagnosis of peritoneal tuberculosis due to M. caprae was made. PMID:27134824

  19. Mycobacterium tuberculosis and the host response

    PubMed Central

    Kaufmann, Stefan H.E.; Cole, Stewart T.; Mizrahi, Valerie; Rubin, Eric; Nathan, Carl

    2005-01-01

    Mycobacterium tuberculosis remains a leading cause of morbidity and mortality worldwide. Advances reported at a recent international meeting highlight insights and controversies in the genetics of M. tuberculosis and the infected host, the nature of protective immune responses, adaptation of the bacillus to host-imposed stresses, animal models, and new techniques. PMID:15939785

  20. Drug Resistance Mechanisms in Mycobacterium tuberculosis

    PubMed Central

    Palomino, Juan Carlos; Martin, Anandi

    2014-01-01

    Tuberculosis (TB) is a serious public health problem worldwide. Its situation is worsened by the presence of multidrug resistant (MDR) strains of Mycobacterium tuberculosis, the causative agent of the disease. In recent years, even more serious forms of drug resistance have been reported. A better knowledge of the mechanisms of drug resistance of M. tuberculosis and the relevant molecular mechanisms involved will improve the available techniques for rapid drug resistance detection and will help to explore new targets for drug activity and development. This review article discusses the mechanisms of action of anti-tuberculosis drugs and the molecular basis of drug resistance in M. tuberculosis. PMID:27025748

  1. Pathway Profiling in Mycobacterium tuberculosis

    PubMed Central

    Thomas, Suzanne T.; VanderVen, Brian C.; Sherman, David R.; Russell, David G.; Sampson, Nicole S.

    2011-01-01

    Mycobacterium tuberculosis, the bacterium that causes tuberculosis, imports and metabolizes host cholesterol during infection. This ability is important in the chronic phase of infection. Here we investigate the role of the intracellular growth operon (igr), which has previously been identified as having a cholesterol-sensitive phenotype in vitro and which is important for intracellular growth of the mycobacteria. We have employed isotopically labeled low density lipoproteins containing either [1,7,15,22,26-14C]cholesterol or [1,7,15,22,26-13C]cholesterol and high resolution LC/MS as tools to profile the cholesterol-derived metabolome of an igr operon-disrupted mutant (Δigr) of M. tuberculosis. A partially metabolized cholesterol species accumulated in the Δigr knock-out strain that was absent in the complemented and parental wild-type strains. Structural elucidation by multidimensional 1H and 13C NMR spectroscopy revealed the accumulated metabolite to be methyl 1β-(2′-propanoate)-3aα-H-4α-(3′-propanoic acid)-7aβ-methylhexahydro-5-indanone. Heterologously expressed and purified FadE28-FadE29, an acyl-CoA dehydrogenase encoded by the igr operon, catalyzes the dehydrogenation of 2′-propanoyl-CoA ester side chains in substrates with structures analogous to the characterized metabolite. Based on the structure of the isolated metabolite, enzyme activity, and bioinformatic annotations, we assign the primary function of the igr operon to be degradation of the 2′-propanoate side chain. Therefore, the igr operon is necessary to completely metabolize the side chain of cholesterol metabolites. PMID:22045806

  2. Identification of the missing trans-acting enoyl reductase required for phthiocerol dimycocerosate and phenolglycolipid biosynthesis in Mycobacterium tuberculosis.

    PubMed

    Siméone, Roxane; Constant, Patricia; Guilhot, Christophe; Daffé, Mamadou; Chalut, Christian

    2007-07-01

    Phthiocerol dimycocerosates (DIM) and phenolglycolipids (PGL) are functionally important surface-exposed lipids of Mycobacterium tuberculosis. Their biosynthesis involves the products of several genes clustered in a 70-kb region of the M. tuberculosis chromosome. Among these products is PpsD, one of the modular type I polyketide synthases responsible for the synthesis of the lipid core common to DIM and PGL. Bioinformatic analyses have suggested that this protein lacks a functional enoyl reductase activity domain required for the synthesis of these lipids. We have identified a gene, Rv2953, that putatively encodes an enoyl reductase. Mutation in Rv2953 prevents conventional DIM formation and leads to the accumulation of a novel DIM-like product. This product is unsaturated between C-4 and C-5 of phthiocerol. Consistently, complementation of the mutant with a functional pks15/1 gene from Mycobacterium bovis BCG resulted in the accumulation of an unsaturated PGL-like substance. When an intact Rv2953 gene was reintroduced into the mutant strain, the phenotype reverted to the wild type. These findings indicate that Rv2953 encodes a trans-acting enoyl reductase that acts with PpsD in phthiocerol and phenolphthiocerol biosynthesis. PMID:17468241

  3. Rapid presumptive identification of the Mycobacterium tuberculosis-bovis complex by radiometric determination of heat stable urease

    SciTech Connect

    Gandy, J.H.; Pruden, E.L.; Cox, F.R.

    1983-12-01

    Simple and rapid Bactec methodologies for the determination of neat (unaltered) and heat stable urease activity of mycobacteria are presented. Clinical isolates (63) and stock cultures (32)--consisting of: M. tuberculosis (19), M. bovis (5), M. kansasii (15), M. marinum (4), M. simiae (3), M. scrofulaceum (16), M. gordonae (6), M. szulgai (6), M. flavescens (1), M. gastri (1), M. intracellulare (6), M. fortuitum-chelonei complex (12), and M. smegmatis (1)--were tested for neat urease activity by Bactec radiometry. Mycobacterial isolates (50-100 mg wet weight) were incubated at 35 degrees C for 30 minutes with microCi14C-urea. Urease-positive mycobacteria gave Bactec growth index (GI) values greater than 100 units, whereas urease-negative species gave values less than 10 GI units. Eighty-three isolates possessing neat urease activity were heated at 80 degrees C for 30 minutes followed by incubation at 35 degrees C for 30 minutes with 1 microCi14C-urea. Mycobacterium tuberculosis-bovis complex demonstrated heat-stable urease activity (GI more than 130 units) and could be distinguished from mycobacteria other than tuberculosis (MOTT), which gave GI values equal to or less than 40 units.

  4. Evaluation of three real-time PCR assays for differential identification of Mycobacterium tuberculosis complex and nontuberculous mycobacteria species in liquid culture media.

    PubMed

    Jung, Yu Jung; Kim, Ji-Youn; Song, Dong Joon; Koh, Won-Jung; Huh, Hee Jae; Ki, Chang-Seok; Lee, Nam Yong

    2016-06-01

    We evaluated the analytical performance of M. tuberculosis complex (MTBC)/nontuberculous mycobacteria (NTM) PCR assays for differential identification of MTBC and NTM using culture-positive liquid media. Eighty-five type strains and 100 consecutive mycobacterial liquid media cultures (MGIT 960 system) were analyzed by a conventional PCR assay (MTB-ID(®) V3) and three real-time PCR assays (AdvanSure™ TB/NTM real-time PCR, AdvanSure; GENEDIA(®) MTB/NTM Detection Kit, Genedia; Real-Q MTB & NTM kit, Real-Q). The accuracy rates for reference strains were 89.4%, 100%, 98.8%, and 98.8% for the MTB-ID V3, AdvanSure, Genedia, and Real-Q assays, respectively. Cross-reactivity in the MTB-ID V3 assay was mainly attributable to non-mycobacterium Corynebacterineae species. The diagnostic performance was determined using clinical isolates grown in liquid media, and the overall sensitivities for all PCR assays were higher than 95%. In conclusion, the three real-time PCR assays showed better performance in discriminating mycobacterium species and non-mycobacterium Corynebacterineae species than the conventional PCR assay. PMID:27105774

  5. Dormancy models for Mycobacterium tuberculosis: A minireview.

    PubMed

    Alnimr, Amani M

    2015-01-01

    Dormancy models for Mycobacterium tuberculosis play important roles in understanding various aspects of tuberculosis pathogenesis and in the testing of novel therapeutic regimens. By simulating the latent tuberculosis infection, in which the bacteria exist in a non-replicative state, the models demonstrate reduced susceptibility to antimycobacterial agents. This minireview outlines the models available for simulating latent tuberculosis both in vitro and in several animal species. Additionally, this minireview discusses the advantages and disadvantages of these models for investigating the bacterial subpopulations and susceptibilities to sterilization by various antituberculosis drugs. PMID:26413043

  6. Dormancy models for Mycobacterium tuberculosis: A minireview

    PubMed Central

    Alnimr, Amani M.

    2015-01-01

    Dormancy models for Mycobacterium tuberculosis play important roles in understanding various aspects of tuberculosis pathogenesis and in the testing of novel therapeutic regimens. By simulating the latent tuberculosis infection, in which the bacteria exist in a non-replicative state, the models demonstrate reduced susceptibility to antimycobacterial agents. This minireview outlines the models available for simulating latent tuberculosis both in vitro and in several animal species. Additionally, this minireview discusses the advantages and disadvantages of these models for investigating the bacterial subpopulations and susceptibilities to sterilization by various antituberculosis drugs. PMID:26413043

  7. Identification of a predominant isolate of Mycobacterium tuberculosis using molecular and clinical epidemiology tools and in vitro cytokine responses

    PubMed Central

    Sharma, M Kaushal; Al-Azem, A; Wolfe, J; Hershfield, E; Kabani, A

    2003-01-01

    Background Tuberculosis (TB) surveillance programs in Canada have established that TB in Canada is becoming a disease of geographically and demographically distinct groups. In 1995, treaty status aboriginals from the province of Manitoba accounted for 46% of the disease burden of this sub-group in Canada. The TB incidence rates are dramatically high in certain reserves of Manitoba and are equivalent to rates in African countries. The objective of our study was to identify prevalent isolates of Mycobacterium tuberculosis in the patient population of Manitoba using molecular epidemiology tools, studying the patient demographics associated with the prevalent strain and studying the in vitro cytokine profiles post-infection with the predominant strain. Methods Molecular typing was performed on all isolates available between 1992 to1997. A clinical database was generated using patient information from Manitoba. THP-1 cells were infected using strains of M. tuberculosis and cytokine profiles were determined using immunoassays for cytokines IL-1β, IL-10, IL-12, IFN-γ and TNF-α. Results In Manitoba, 24% of the disease burden is due to a particular M. tuberculosis strain (Type1). The strain is common in patients of aboriginal decent and is responsible for at least 87% of these cases. Cytokine assays indicate that the Type1 strain induces comparatively lower titers of IL-1β, IFN-γ and TNF-α in infected THP-1 cells as compared to H37Ra and H37Rv strains. Conclusion In Manitoba, Type1 strain is predominant in TB patients. The majority of the cases infected with this particular strain are newly active with a high incidence of respiratory disease, positive chest radiographs and pulmonary cavities. In vitro secretion of IL-1β, IFN-γ and TNF-α is suppressed in Type1 infected culture samples when compared to H37Ra and H37Rv infected cells. PMID:12697047

  8. Identification of rifampin-resistant mycobacterium tuberculosis strains by hybridization, PCR, and ligase detaction reaction on oligonucleotide microchips.

    SciTech Connect

    Mikhailovich, V.; Lapa, S.; Gryadunov, D.; Sobolev, A.; Strizhkov, B.; Chernyh, N.; Skotnikova, O.; Irtuganova, O.; Moroz, A.; Litvinov, V.; Vladimirskii, M.; Perelman, M.; Chernousova, L.; Erokhin, V.; Mirzabekov, A.; Biochip Technology Center; Russian Academy of Sciences; Moscow Antituberculosis Center; Moscow Medical Academy; Russian Academy of Medical Sciences

    2001-07-01

    Three new molecular approaches were developed to identify drug-resistant strains of Mycobacterium tuberculosis using biochips with oligonucleotides immobilized in polyacrylamide gel pads. These approaches are significantly faster than traditional bacteriological methods. All three approaches -- hybridization, PCR, and ligase detection reaction -- were designed to analyze an 81-bp fragment of the gene rpoB encoding the {beta}-subunit of RNA polymerase, where most known mutations of rifampin resistance are located. The call set for hybridization analysis consisted of 42 immobilized oligonucleotides and enabled us to identify 30 mutant variants of the rpoB gene within 24 h. These variants are found in 95% of all mutants whose rifampin resistance is caused by mutations in the 81-bp fragment. Using the second approach, allele-specific on-chip PCR, it was possible to directly identify mutations in clinical samples within 1.5 h. The third approach, on-chip ligase detection reaction, was sensitive enough to reveal rifampin-resistant strains in a model mixture containing 1% of resistant and 99% of susceptible bacteria. This level of sensitivity is comparable to that from the determination of M. tuberculosis drug resistance by using standard bacteriological tests.

  9. High-throughput identification and dendritic cell-based functional validation of MHC class I-restricted Mycobacterium tuberculosis epitopes

    PubMed Central

    Nair, Smita K.; Tomaras, Georgia D.; Sales, Ana Paula; Boczkowski, David; Chan, Cliburn; Plonk, Kelly; Cai, Yongting; Dannull, Jens; Kepler, Thomas B.; Pruitt, Scott K.; Weinhold, Kent J.

    2014-01-01

    Emergence of drug-resistant strains of the pathogen Mycobacterium tuberculosis (Mtb) and the ineffectiveness of BCG in curtailing Mtb infection makes vaccine development for tuberculosis an important objective. Identifying immunogenic CD8+ T cell peptide epitopes is necessary for peptide-based vaccine strategies. We present a three-tiered strategy for identifying and validating immunogenic peptides: first, identify peptides that form stable complexes with class I MHC molecules; second, determine whether cytotoxic T lymphocytes (CTLs) raised against the whole protein antigen recognize and lyse target cells pulsed with peptides that passed step 1; third, determine whether peptides that passed step 2, when administered in vivo as a vaccine in HLA-A2 transgenic mice, elicit CTLs that lyse target cells expressing the whole protein antigen. Our innovative approach uses dendritic cells transfected with Mtb antigen-encoding mRNA to drive antigen expression. Using this strategy, we have identified five novel peptide epitopes from the Mtb proteins Apa, Mtb8.4 and Mtb19. PMID:24755960

  10. High-throughput identification and dendritic cell-based functional validation of MHC class I-restricted Mycobacterium tuberculosis epitopes.

    PubMed

    Nair, Smita K; Tomaras, Georgia D; Sales, Ana Paula; Boczkowski, David; Chan, Cliburn; Plonk, Kelly; Cai, Yongting; Dannull, Jens; Kepler, Thomas B; Pruitt, Scott K; Weinhold, Kent J

    2014-01-01

    Emergence of drug-resistant strains of the pathogen Mycobacterium tuberculosis (Mtb) and the ineffectiveness of BCG in curtailing Mtb infection makes vaccine development for tuberculosis an important objective. Identifying immunogenic CD8+ T cell peptide epitopes is necessary for peptide-based vaccine strategies. We present a three-tiered strategy for identifying and validating immunogenic peptides: first, identify peptides that form stable complexes with class I MHC molecules; second, determine whether cytotoxic T lymphocytes (CTLs) raised against the whole protein antigen recognize and lyse target cells pulsed with peptides that passed step 1; third, determine whether peptides that passed step 2, when administered in vivo as a vaccine in HLA-A2 transgenic mice, elicit CTLs that lyse target cells expressing the whole protein antigen. Our innovative approach uses dendritic cells transfected with Mtb antigen-encoding mRNA to drive antigen expression. Using this strategy, we have identified five novel peptide epitopes from the Mtb proteins Apa, Mtb8.4 and Mtb19. PMID:24755960

  11. Macrophage infection models for Mycobacterium tuberculosis.

    PubMed

    Johnson, Benjamin K; Abramovitch, Robert B

    2015-01-01

    Mycobacterium tuberculosis colonizes, survives, and grows inside macrophages. In vitro macrophage infection models, using both primary macrophages and cell lines, enable the characterization of the pathogen response to macrophage immune pressure and intracellular environmental cues. We describe methods to propagate and infect primary murine bone marrow-derived macrophages and J774 and THP-1 macrophage-like cell lines. We also present methods on the characterization of M. tuberculosis intracellular survival and the preparation of infected macrophages for imaging. PMID:25779326

  12. In silico identification and characterization of the ion transport specificity for P-type ATPases in the Mycobacterium tuberculosis complex

    PubMed Central

    2012-01-01

    Background P-type ATPases hydrolyze ATP and release energy that is used in the transport of ions against electrochemical gradients across plasma membranes, making these proteins essential for cell viability. Currently, the distribution and function of these ion transporters in mycobacteria are poorly understood. Results In this study, probabilistic profiles were constructed based on hidden Markov models to identify and classify P-type ATPases in the Mycobacterium tuberculosis complex (MTBC) according to the type of ion transported across the plasma membrane. Topology, hydrophobicity profiles and conserved motifs were analyzed to correlate amino acid sequences of P-type ATPases and ion transport specificity. Twelve candidate P-type ATPases annotated in the M. tuberculosis H37Rv proteome were identified in all members of the MTBC, and probabilistic profiles classified them into one of the following three groups: heavy metal cation transporters, alkaline and alkaline earth metal cation transporters, and the beta subunit of a prokaryotic potassium pump. Interestingly, counterparts of the non-catalytic beta subunits of Hydrogen/Potassium and Sodium/Potassium P-type ATPases were not found. Conclusions The high content of heavy metal transporters found in the MTBC suggests that they could play an important role in the ability of M. tuberculosis to survive inside macrophages, where tubercle bacilli face high levels of toxic metals. Finally, the results obtained in this work provide a starting point for experimental studies that may elucidate the ion specificity of the MTBC P-type ATPases and their role in mycobacterial infections. PMID:23031689

  13. Cholesterol catabolism as a therapeutic target in Mycobacterium tuberculosis

    PubMed Central

    Ouellet, Hugues; Johnston, Jonathan B.; Ortiz de Montellano, Paul R.

    2011-01-01

    Mycobacterium tuberculosis (Mtb) is an intracellular pathogen that infects 10 million worldwide and kills 2 million people every year. The uptake and utilization of nutrients by Mtb within the host cell is still poorly understood, although lipids play an important role in Mtb persistence. The recent identification of a large regulon of cholesterol catabolic genes suggests that Mtb can use host sterol for infection and persistence. In this review, we report on recent progress in elucidation of the Mtb cholesterol catabolic reactions and their potential utility as targets for tuberculosis therapeutic agents. PMID:21924910

  14. Mycobacterium tuberculosis wears what it eats

    PubMed Central

    Russell, David G.; VanderVen, Brian C.; Lee, Wonsik; Abramovitch, Robert B.; Kim, Mijeong; Homolka, Susanne; Niemann, Stefan; Rohde, Kyle H.

    2010-01-01

    Mycobacterium tuberculosis remains one of the most pernicious of human pathogens. Current vaccines are ineffective and drugs, although efficacious, require prolonged treatment with constant medical oversight. Overcoming these problems requires a greater appreciation of M. tuberculosis in the context of its host. Upon infection of either macrophages in culture or animal models, the bacterium re-aligns its metabolism in response to the new environments it encounters. Understanding these environments, and the stresses that they place on M. tuberculosis, should provide insights invaluable for the development of new chemo- and immuno-therapeutic strategies. PMID:20638643

  15. Radioimmunoassay of tuberculoprotein derived from Mycobacterium tuberculosis.

    PubMed Central

    Straus, E; Wu, N

    1980-01-01

    A radioimmunoassay was developed for constituent of the purified-protein derivative obtained from cultures of Mycobacterium tuberculosis. Crossreacting immunoreactive material was detected in cultures of other mycobacterial species, but no immunoreactivity was present in cultures of various fungal and bacterial species. The development of specific radioimmunoassays for tuberculoproteins offers a new research and diagnostic approach. Images PMID:6933481

  16. PCR identification of Mycobacterium bovis BCG.

    PubMed Central

    Talbot, E A; Williams, D L; Frothingham, R

    1997-01-01

    The attenuated bacillus Calmette-Guérin (BCG) vaccine strain is derived from a virulent strain of Mycobacterium bovis. BCG is difficult to differentiate from other strains of M. bovis and other members of the M. tuberculosis complex by conventional methods. Recently, a genomic region designated RD1 was found to be present in all virulent M. bovis and M. tuberculosis strains tested but deleted from all BCG strains tested. With this information, a multiplex PCR method was developed to detect the RD1 deletion. A large collection of BCG and other M. tuberculosis complex strains from diverse host and geographic origins was tested. RD1 was deleted in 23 of 23 BCG strains. RD1 was present in 129 of 129 other M. tuberculosis complex strains. This multiplex PCR method can be used as a tool for the rapid and specific identification of BCG. PMID:9041390

  17. The Mycobacterium tuberculosis Cytochrome P450 System

    PubMed Central

    Ouellet, Hugues; Johnston, Jonathan B.; Ortiz de Montellano, Paul R.

    2009-01-01

    Tuberculosis remains a leading cause of human mortality. The emergence of strains of Mycobacterium tuberculosis, the causative agent, that are resistant to the major frontline antitubercular drugs increases the urgency for the development of new therapeutic agents. Sequencing of the M. tuberculosis genome revealed the existence of twenty cytochrome P450 enzymes, some of which are potential candidates for drug targeting. The recent burst of studies reporting microarray-based gene essentiality and transcriptome analyses under in vitro, ex vivo and in vivo conditions highlight the importance of selected P450 isoforms for M. tuberculosis viability and pathogenicity. Current knowledge of the structural and biochemical properties of the M. tuberculosis P450 enzymes and their putative redox partners is reviewed, with an emphasis on findings related to their physiological function(s) as well as their potential as drug targets. PMID:19635450

  18. Proteome Analysis of the Plasma Membrane of Mycobacterium Tuberculosis

    PubMed Central

    Arora, Shalini; Kosalai, K.; Namane, Abdelkader; Pym, Alex S.; Cole, Stewart T.

    2002-01-01

    The plasma membrane of Mycobacterium tuberculosis is likely to contain proteins that could serve as novel drug targets, diagnostic probes or even components of a vaccine against tuberculosis. With this in mind, we have undertaken proteome analysis of the membrane of M. tuberculosis H37Rv. Isolated membrane vesicles were extracted with either a detergent (Triton X114) or an alkaline buffer (carbonate) following two of the protocols recommended for membrane protein enrichment. Proteins were resolved by 2D-GE using immobilized pH gradient (IPG) strips, and identified by peptide mass mapping utilizing the M. tuberculosis genome database. The two extraction procedures yielded patterns with minimal overlap. Only two proteins, both HSPs, showed a common presence. MALDI–MS analysis of 61 spots led to the identification of 32 proteins, 17 of which were new to the M. tuberculosis proteome database. We classified 19 of the identified proteins as ‘membrane-associated’; 14 of these were further classified as ‘membrane-bound’, three of which were lipoproteins. The remaining proteins included four heat-shock proteins and several enzymes involved in energy or lipid metabolism. Extraction with Triton X114 was found to be more effective than carbonate for detecting ‘putative’ M. tuberculosis membrane proteins. The protocol was also found to be suitable for comparing BCG and M. tuberculosis membranes, identifying ESAT-6 as being expressed selectively in M. tuberculosis. While this study demonstrates for the first time some of the membrane proteins of M. tuberculosis, it also underscores the problems associated with proteomic analysis of a complex membrane such as that of a mycobacterium. PMID:18629250

  19. Structure-based virtual screening as a tool for the identification of novel inhibitors against Mycobacterium tuberculosis 3-dehydroquinate dehydratase.

    PubMed

    Petersen, Guilherme O; Saxena, Shalini; Renuka, Janupally; Soni, Vijay; Yogeeswari, Perumal; Santos, Diogenes S; Bizarro, Cristiano V; Sriram, Dharmarajan

    2015-07-01

    3-Dehydroquinate dehydratase (DHQase), the third enzyme of the shikimate pathway, catalyzes the reversible reaction of 3-dehydroquinate into 3-dehydroshikimate. The aim of the present study was to identify new drug-like molecules as inhibitors for Mycobacterium tuberculosis DHQase employing structure-based pharmacophore modeling technique using an in house database consisting of about 2500 small molecules. Further the pharmacophore models were validated using enrichment calculations, and finally three models were employed for high-throughput virtual screening and docking to identify novel small molecules as DHQase inhibitors. Five compounds were identified, out of which, one molecule (Lead 1) showed 58% inhibition at 50μ M concentration in the Mtb DHQase assay. Chemical derivatives of the Lead 1 when tested evolved top two hits with IC50s of 17.1 and 31.5 μM as well as MIC values of 25 and 6.25 μg/mL respectively and no cytotoxicity up to 100 μM concentration. PMID:26043661

  20. The identification of novel Mycobacterium tuberculosis DHFR inhibitors and the investigation of their binding preferences by using molecular modelling

    PubMed Central

    Hong, Wei; Wang, Yu; Chang, Zhe; Yang, Yanhui; Pu, Jing; Sun, Tao; Kaur, Sargit; Sacchettini, James C.; Jung, Hunmin; Lin Wong, Wee; Fah Yap, Lee; Fong Ngeow, Yun; Paterson, Ian C.; Wang, Hao

    2015-01-01

    It is an urgent need to develop new drugs for Mycobacterium tuberculosis (Mtb), and the enzyme, dihydrofolate reductase (DHFR) is a recognised drug target. The crystal structures of methotrexate binding to mt- and h-DHFR separately indicate that the glycerol (GOL) binding site is likely to be critical for the function of mt-DHFR selective inhibitors. We have used in silico methods to screen NCI small molecule database and a group of related compounds were obtained that inhibit mt-DHFR activity and showed bactericidal effects against a test Mtb strain. The binding poses were then analysed and the influence of GOL binding site was studied by using molecular modelling. By comparing the chemical structures, 4 compounds that might be able to occupy the GOL binding site were identified. However, these compounds contain large hydrophobic side chains. As the GOL binding site is more hydrophilic, molecular modelling indicated that these compounds were failed to occupy the GOL site. The most potent inhibitor (compound 6) demonstrated limited selectivity for mt-DHFR, but did contain a novel central core (7H-pyrrolo[3,2-f]quinazoline-1,3-diamine), which may significantly expand the chemical space of novel mt-DHFR inhibitors. Collectively, these observations will inform future medicinal chemistry efforts to improve the selectivity of compounds against mt-DHFR. PMID:26471125

  1. The identification of novel Mycobacterium tuberculosis DHFR inhibitors and the investigation of their binding preferences by using molecular modelling.

    PubMed

    Hong, Wei; Wang, Yu; Chang, Zhe; Yang, Yanhui; Pu, Jing; Sun, Tao; Kaur, Sargit; Sacchettini, James C; Jung, Hunmin; Lin Wong, Wee; Fah Yap, Lee; Fong Ngeow, Yun; Paterson, Ian C; Wang, Hao

    2015-01-01

    It is an urgent need to develop new drugs for Mycobacterium tuberculosis (Mtb), and the enzyme, dihydrofolate reductase (DHFR) is a recognised drug target. The crystal structures of methotrexate binding to mt- and h-DHFR separately indicate that the glycerol (GOL) binding site is likely to be critical for the function of mt-DHFR selective inhibitors. We have used in silico methods to screen NCI small molecule database and a group of related compounds were obtained that inhibit mt-DHFR activity and showed bactericidal effects against a test Mtb strain. The binding poses were then analysed and the influence of GOL binding site was studied by using molecular modelling. By comparing the chemical structures, 4 compounds that might be able to occupy the GOL binding site were identified. However, these compounds contain large hydrophobic side chains. As the GOL binding site is more hydrophilic, molecular modelling indicated that these compounds were failed to occupy the GOL site. The most potent inhibitor (compound 6) demonstrated limited selectivity for mt-DHFR, but did contain a novel central core (7H-pyrrolo[3,2-f]quinazoline-1,3-diamine), which may significantly expand the chemical space of novel mt-DHFR inhibitors. Collectively, these observations will inform future medicinal chemistry efforts to improve the selectivity of compounds against mt-DHFR. PMID:26471125

  2. [Coinfection of Mycobacterium malmoense and Mycobacterium tuberculosis in a patient with acquired inmune deficiency syndrome].

    PubMed

    Mederos Cuervo, Lilian María; Reyes Pérez, Angélica; Valdes Alonso, Lidunka; Rodríguez Delgado, Francisco; Sardiñas Aragón, Misleydis; Martínez Romero, María Rosarys; Díaz Romero, Raúl

    2014-01-01

    A case is presented of coinfection with Mycobacterium malmoense and Mycobacterium tuberculosis in a Cuban patient with AIDS which produced respiratory and liver disease respectively. Cultures done from sputum samples showed the presence of a non-pigmented, slow growing mycobacterial strain belonging to Runyon group III and identified as Mycobacterium malmoense. From cultures of liver tissue removed laparoscopically, a strain was isolated and subsequently identified as Mycobacterium tuberculosis. Anatomapathologic examination confirmed the diagnosis of tuberculosis, the patient received specific treatment and had a favorable clinical course. This report of a rare case of coinfection of Mycobacterium describes the first report of hepatic tuberculosis in a patient with AIDS in Cuba. PMID:25597735

  3. Porins increase copper susceptibility of Mycobacterium tuberculosis.

    PubMed

    Speer, Alexander; Rowland, Jennifer L; Haeili, Mehri; Niederweis, Michael; Wolschendorf, Frank

    2013-11-01

    Copper resistance mechanisms are crucial for many pathogenic bacteria, including Mycobacterium tuberculosis, during infection because the innate immune system utilizes copper ions to kill bacterial intruders. Despite several studies detailing responses of mycobacteria to copper, the pathways by which copper ions cross the mycobacterial cell envelope are unknown. Deletion of porin genes in Mycobacterium smegmatis leads to a severe growth defect on trace copper medium but simultaneously increases tolerance for copper at elevated concentrations, indicating that porins mediate copper uptake across the outer membrane. Heterologous expression of the mycobacterial porin gene mspA reduced growth of M. tuberculosis in the presence of 2.5 μM copper by 40% and completely suppressed growth at 15 μM copper, while wild-type M. tuberculosis reached its normal cell density at that copper concentration. Moreover, the polyamine spermine, a known inhibitor of porin activity in Gram-negative bacteria, enhanced tolerance of M. tuberculosis for copper, suggesting that copper ions utilize endogenous outer membrane channel proteins of M. tuberculosis to gain access to interior cellular compartments. In summary, these findings highlight the outer membrane as the first barrier against copper ions and the role of porins in mediating copper uptake in M. smegmatis and M. tuberculosis. PMID:24013632

  4. Characterization of Lipoyl Synthase from Mycobacterium tuberculosis.

    PubMed

    Lanz, Nicholas D; Lee, Kyung-Hoon; Horstmann, Abigail K; Pandelia, Maria-Eirini; Cicchillo, Robert M; Krebs, Carsten; Booker, Squire J

    2016-03-01

    The prevalence of multiple and extensively drug-resistant strains of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, is on the rise, necessitating the identification of new targets to combat an organism that has infected one-third of the world's population, according to the World Health Organization. The biosynthesis of the lipoyl cofactor is one possible target, given its critical importance in cellular metabolism and the apparent lack of functional salvage pathways in Mtb that are found in humans and many other organisms. The lipoyl cofactor is synthesized de novo in two committed steps, involving the LipB-catalyzed transfer of an octanoyl chain derived from fatty acid biosynthesis to a lipoyl carrier protein and the LipA-catalyzed insertion of sulfur atoms at C6 and C8 of the octanoyl chain. A number of in vitro studies of lipoyl synthases from Escherichia coli, Sulfolobus solfataricus, and Thermosynechococcus elongatus have been conducted, but the enzyme from Mtb has not been characterized. Herein, we show that LipA from Mtb contains two [4Fe-4S] clusters and converts an octanoyl peptide substrate to the corresponding lipoyl peptide product via the same C6-monothiolated intermediate as that observed in the E. coli LipA reaction. In addition, we show that LipA from Mtb forms a complex with the H protein of the glycine cleavage system and that the strength of association is dependent on the presence of S-adenosyl-l-methionine. We also show that LipA from Mtb can complement a lipA mutant of E. coli, demonstrating the commonalities of the two enzymes. Lastly, we show that the substrate for LipA, which normally acts on a post-translationally modified protein, can be reduced to carboxybenzyl-octanoyllysine. PMID:26841001

  5. Virulence factors of the Mycobacterium tuberculosis complex

    PubMed Central

    Forrellad, Marina A.; Klepp, Laura I.; Gioffré, Andrea; Sabio y García, Julia; Morbidoni, Hector R.; Santangelo, María de la Paz; Cataldi, Angel A.; Bigi, Fabiana

    2013-01-01

    The Mycobacterium tuberculosis complex (MTBC) consists of closely related species that cause tuberculosis in both humans and animals. This illness, still today, remains to be one of the leading causes of morbidity and mortality throughout the world. The mycobacteria enter the host by air, and, once in the lungs, are phagocytated by macrophages. This may lead to the rapid elimination of the bacillus or to the triggering of an active tuberculosis infection. A large number of different virulence factors have evolved in MTBC members as a response to the host immune reaction. The aim of this review is to describe the bacterial genes/proteins that are essential for the virulence of MTBC species, and that have been demonstrated in an in vivo model of infection. Knowledge of MTBC virulence factors is essential for the development of new vaccines and drugs to help manage the disease toward an increasingly more tuberculosis-free world. PMID:23076359

  6. Identification and structural basis of the reaction catalyzed by CYP121, an essential cytochrome P450 in Mycobacterium tuberculosis

    PubMed Central

    Belin, Pascal; Le Du, Marie Hélène; Fielding, Alistair; Lequin, Olivier; Jacquet, Mickaël; Charbonnier, Jean-Baptiste; Lecoq, Alain; Thai, Robert; Courçon, Marie; Masson, Cédric; Dugave, Christophe; Genet, Roger; Pernodet, Jean-Luc; Gondry, Muriel

    2009-01-01

    The gene encoding the cytochrome P450 CYP121 is essential for Mycobacterium tuberculosis. However, the CYP121 catalytic activity remains unknown. Here, we show that the cyclodipeptide cyclo(l-Tyr-l-Tyr) (cYY) binds to CYP121, and is efficiently converted into a single major product in a CYP121 activity assay containing spinach ferredoxin and ferredoxin reductase. NMR spectroscopy analysis of the reaction product shows that CYP121 catalyzes the formation of an intramolecular C-C bond between 2 tyrosyl carbon atoms of cYY resulting in a novel chemical entity. The X-ray structure of cYY-bound CYP121, solved at high resolution (1.4 Å), reveals one cYY molecule with full occupancy in the large active site cavity. One cYY tyrosyl approaches the heme and establishes a specific H-bonding network with Ser-237, Gln-385, Arg-386, and 3 water molecules, including the sixth iron ligand. These observations are consistent with low temperature EPR spectra of cYY-bound CYP121 showing a change in the heme environment with the persistence of the sixth heme iron ligand. As the carbon atoms involved in the final C-C coupling are located 5.4 Å apart according to the CYP121-cYY complex crystal structure, we propose that C-C coupling is concomitant with substrate tyrosyl movements. This study provides insight into the catalytic activity, mechanism, and biological function of CYP121. Also, it provides clues for rational design of putative CYP121 substrate-based antimycobacterial agents. PMID:19416919

  7. Identification of Major Factors Influencing ELISpot-Based Monitoring of Cellular Responses to Antigens from Mycobacterium tuberculosis

    PubMed Central

    Smith, Steven G.; Joosten, Simone A.; Verscheure, Virginie; Pathan, Ansar A.; McShane, Helen; Ottenhoff, Tom H. M.; Dockrell, Hazel M.; Mascart, Françoise

    2009-01-01

    A number of different interferon-γ ELISpot protocols are in use in laboratories studying antigen-specific immune responses. It is therefore unclear how results from different assays compare, and what factors most significantly influence assay outcome. One such difference is that some laboratories use a short in vitro stimulation period of cells before they are transferred to the ELISpot plate; this is commonly done in the case of frozen cells, in order to enhance assay sensitivity. Other differences that may be significant include antibody coating of plates, the use of media with or without serum, the serum source and the number of cells added to the wells. The aim of this paper was to identify which components of the different ELISpot protocols influenced assay sensitivity and inter-laboratory variation. Four laboratories provided protocols for quantifying numbers of interferon-γ spot forming cells in human peripheral blood mononuclear cells stimulated with Mycobacterium tuberculosis derived antigens. The differences in the protocols were compared directly. We found that several sources of variation in assay protocols can be eliminated, for example by avoiding serum supplementation and using AIM-V serum free medium. In addition, the number of cells added to ELISpot wells should also be standardised. Importantly, delays in peripheral blood mononuclear cell processing before stimulation had a marked effect on the number of detectable spot forming cells; processing delay thus should be minimised as well as standardised. Finally, a pre-stimulation culture period improved the sensitivity of the assay, however this effect may be both antigen and donor dependent. In conclusion, small differences in ELISpot protocols in routine use can affect the results obtained and care should be given to conditions selected for use in a given study. A pre-stimulation step may improve the sensitivity of the assay, particularly when cells have been previously frozen. PMID:19956718

  8. Mycobacterium tuberculosis produces pili during human infection

    PubMed Central

    Alteri, Christopher J.; Xicohténcatl-Cortes, Juan; Hess, Sonja; Caballero-Olín, Guillermo; Girón, Jorge A.; Friedman, Richard L.

    2007-01-01

    Mycobacterium tuberculosis is responsible for nearly 3 million human deaths worldwide every year. Understanding the mechanisms and bacterial factors responsible for the ability of M. tuberculosis to cause disease in humans is critical for the development of improved treatment strategies. Many bacterial pathogens use pili as adherence factors to colonize the host. We discovered that M. tuberculosis produces fine (2- to 3-nm-wide), aggregative, flexible pili that are recognized by IgG antibodies contained in sera obtained from patients with active tuberculosis, indicating that the bacilli produce pili or pili-associated antigen during human infection. Purified M. tuberculosis pili (MTP) are composed of low-molecular-weight protein subunits encoded by the predicted M. tuberculosis H37Rv ORF, designated Rv3312A. MTP bind to the extracellular matrix protein laminin in vitro, suggesting that MTP possess adhesive properties. Isogenic mtp mutants lost the ability to produce Mtp in vitro and demonstrated decreased laminin-binding capabilities. MTP shares morphological, biochemical, and functional properties attributed to bacterial pili, especially with curli amyloid fibers. Thus, we propose that MTP are previously unidentified host-colonization factors of M. tuberculosis. PMID:17360408

  9. Mycobacterium tuberculosis Serine/Threonine Protein Kinases

    PubMed Central

    PRISIC, SLADJANA; HUSSON, ROBERT N.

    2014-01-01

    The Mycobacterium tuberculosis genome encodes 11 serine/threonine protein kinases (STPKs). A similar number of two-component systems are also present, indicating that these two signal transduction mechanisms are both important in the adaptation of this bacterial pathogen to its environment. The M. tuberculosis phosphoproteome includes hundreds of Ser- and Thr-phosphorylated proteins that participate in all aspects of M. tuberculosis biology, supporting a critical role for the STPKs in regulating M. tuberculosis physiology. Nine of the STPKs are receptor type kinases, with an extracytoplasmic sensor domain and an intracellular kinase domain, indicating that these kinases transduce external signals. Two other STPKs are cytoplasmic and have regulatory domains that sense changes within the cell. Structural analysis of some of the STPKs has led to advances in our understanding of the mechanisms by which these STPKs are activated and regulated. Functional analysis has provided insights into the effects of phosphorylation on the activity of several proteins, but for most phosphoproteins the role of phosphorylation in regulating function is unknown. Major future challenges include characterizing the functional effects of phosphorylation for this large number of phosphoproteins, identifying the cognate STPKs for these phosphoproteins, and determining the signals that the STPKs sense. Ultimately, combining these STPK-regulated processes into larger, integrated regulatory networks will provide deeper insight into M. tuberculosis adaptive mechanisms that contribute to tuberculosis pathogenesis. Finally, the STPKs offer attractive targets for inhibitor development that may lead to new therapies for drug-susceptible and drug-resistant tuberculosis. PMID:25429354

  10. Comparative Mycobacterium tuberculosis spoligotype distribution in Mexico.

    PubMed

    Vera-Cabrera, Lucio; Ramos-Alvarez, Jessica; Molina-Torres, Carmen A; Rivera-Morales, Lydia Guadalupe; Rendón, Adrian; Quiñones-Falconi, Francisco; Ocampo-Candiani, Jorge

    2014-08-01

    In the present work, we studied the genetic diversity of Mycobacterium tuberculosis clinical isolates from patients according to their gender, age, and geographic location in Mexico. We did not observe any statistically significant differences in regard to age or gender. We found that spoligo international type 53 (SIT53) is more frequent in the northern states and that SIT119 predominates in central Mexico. PMID:24850349

  11. Comparative Mycobacterium tuberculosis Spoligotype Distribution in Mexico

    PubMed Central

    Ramos-Alvarez, Jessica; Molina-Torres, Carmen A.; Rivera-Morales, Lydia Guadalupe; Rendón, Adrian; Quiñones-Falconi, Francisco; Ocampo-Candiani, Jorge

    2014-01-01

    In the present work, we studied the genetic diversity of Mycobacterium tuberculosis clinical isolates from patients according to their gender, age, and geographic location in Mexico. We did not observe any statistically significant differences in regard to age or gender. We found that spoligo international type 53 (SIT53) is more frequent in the northern states and that SIT119 predominates in central Mexico. PMID:24850349

  12. Mycobacterium tuberculosis: Manipulator of Protective Immunity

    PubMed Central

    Korb, Vanessa C.; Chuturgoon, Anil A.; Moodley, Devapregasan

    2016-01-01

    Mycobacterium tuberculosis (MTB) is one of the most successful pathogens in human history and remains a global health challenge. MTB has evolved a plethora of strategies to evade the immune response sufficiently to survive within the macrophage in a bacterial-immunological equilibrium, yet causes sufficient immunopathology to facilitate its transmission. This review highlights MTB as the driver of disease pathogenesis and presents evidence of the mechanisms by which MTB manipulates the protective immune response into a pathological productive infection. PMID:26927066

  13. Targeting the histidine pathway in Mycobacterium tuberculosis.

    PubMed

    Lunardi, Juleane; Nunes, José Eduardo S; Bizarro, Cristiano V; Basso, Luiz Augusto; Santos, Diógenes Santiago; Machado, Pablo

    2013-01-01

    Worldwide, tuberculosis is the leading cause of morbidity and mortality due to a single bacterial pathogen, Mycobacterium tuberculosis (Mtb). The increasing prevalence of this disease, the emergence of multi-, extensively, and totally drug-resistant strains, complicated by co-infection with the human immunodeficiency virus, and the length of tuberculosis chemotherapy have led to an urgent and continued need for the development of new and more effective antitubercular drugs. Within this context, the L-histidine biosynthetic pathway, which converts 5-phosphoribosyl 1-pyrophosphate to L-histidine in ten enzymatic steps, has been reported as a promising target of antimicrobial agents. This pathway is found in bacteria, archaebacteria, lower eukaryotes, and plants but is absent in mammals, making these enzymes highly attractive targets for the drug design of new antimycobacterial compounds with selective toxicity. Moreover, the biosynthesis of L-histidine has been described as essential for Mtb growth in vitro. Accordingly, a comprehensive overview of Mycobacterium tuberculosis histidine pathway enzymes as attractive targets for the development of new antimycobacterial agents is provided, mainly summarizing the previously reported inhibition data for Mtb or orthologous proteins. PMID:24111909

  14. Efficacies of selected disinfectants against Mycobacterium tuberculosis.

    PubMed

    Best, M; Sattar, S A; Springthorpe, V S; Kennedy, M E

    1990-10-01

    The activities of 10 formulations as mycobactericidal agents in Mycobacterium tuberculosis-contaminated suspensions (suspension test) and stainless steel surfaces (carrier test) were investigated with sputum as the organic load. The quaternary ammonium compound, chlorhexidine gluconate, and an iodophor were ineffective in all tests. Ethanol (70%) was effective against M. tuberculosis only in suspension in the absence of sputum. Povidone-iodine was not as efficacious when the test organism was dried on a surface as it was in suspension, and its activity was further reduced in the presence of sputum. Sodium hypochlorite required a higher concentration of available chlorine to achieve an effective level of disinfection than did sodium dichloroisocyanurate. Phenol (5%) was effective under all test conditions, producing at least a 4-log10 reduction in CFU. The undiluted glutaraldehyde-phenate solution was effective against M. tuberculosis and a second test organism, Mycobacterium smegmatis, even in the presence of dried sputum, whereas the diluted solution (1:16) was only effective against M. smegmatis in the suspension test. A solution of 2% glutaraldehyde was effective against M. tuberculosis. This investigation presents tuberculocidal efficacy data generated by methods simulating actual practices of routine disinfection. PMID:2121783

  15. Mycobacterium tuberculosis infection and vaccine development.

    PubMed

    Tang, Jiansong; Yam, Wing-Cheong; Chen, Zhiwei

    2016-05-01

    Following HIV/AIDS, tuberculosis (TB) continues to be the second most deadly infectious disease in humans. The global TB prevalence has become worse in recent years due to the emergence of multi-drug resistant (MDR) and extensively-drug resistant (XDR) strains, as well as co-infection with HIV. Although Bacillus Calmette-Guérin (BCG) vaccine has nearly been used for a century in many countries, it does not protect adult pulmonary tuberculosis and even causes disseminated BCG disease in HIV-positive population. It is impossible to use BCG to eliminate the Mycobacterium tuberculosis (M. tb) infection or to prevent TB onset and reactivation. Consequently, novel vaccines are urgently needed for TB prevention and immunotherapy. In this review, we discuss the TB prevalence, interaction between M. tb and host immune system, as well as recent progress of TB vaccine research and development. PMID:27156616

  16. High Persister Mutants in Mycobacterium tuberculosis

    PubMed Central

    Torrey, Heather L.; Keren, Iris; Via, Laura E.; Lee, Jong Seok; Lewis, Kim

    2016-01-01

    Mycobacterium tuberculosis forms drug-tolerant persister cells that are the probable cause of its recalcitrance to antibiotic therapy. While genetically identical to the rest of the population, persisters are dormant, which protects them from killing by bactericidal antibiotics. The mechanism of persister formation in M. tuberculosis is not well understood. In this study, we selected for high persister (hip) mutants and characterized them by whole genome sequencing and transcriptome analysis. In parallel, we identified and characterized clinical isolates that naturally produce high levels of persisters. We compared the hip mutants obtained in vitro with clinical isolates to identify candidate persister genes. Genes involved in lipid biosynthesis, carbon metabolism, toxin-antitoxin systems, and transcriptional regulators were among those identified. We also found that clinical hip isolates exhibited greater ex vivo survival than the low persister isolates. Our data suggest that M. tuberculosis persister formation involves multiple pathways, and hip mutants may contribute to the recalcitrance of the infection. PMID:27176494

  17. High Persister Mutants in Mycobacterium tuberculosis.

    PubMed

    Torrey, Heather L; Keren, Iris; Via, Laura E; Lee, Jong Seok; Lewis, Kim

    2016-01-01

    Mycobacterium tuberculosis forms drug-tolerant persister cells that are the probable cause of its recalcitrance to antibiotic therapy. While genetically identical to the rest of the population, persisters are dormant, which protects them from killing by bactericidal antibiotics. The mechanism of persister formation in M. tuberculosis is not well understood. In this study, we selected for high persister (hip) mutants and characterized them by whole genome sequencing and transcriptome analysis. In parallel, we identified and characterized clinical isolates that naturally produce high levels of persisters. We compared the hip mutants obtained in vitro with clinical isolates to identify candidate persister genes. Genes involved in lipid biosynthesis, carbon metabolism, toxin-antitoxin systems, and transcriptional regulators were among those identified. We also found that clinical hip isolates exhibited greater ex vivo survival than the low persister isolates. Our data suggest that M. tuberculosis persister formation involves multiple pathways, and hip mutants may contribute to the recalcitrance of the infection. PMID:27176494

  18. Peptide mimotopes of Mycobacterium tuberculosis carbohydrate immunodeterminants

    PubMed Central

    2004-01-01

    Cell-surface saccharides of Mycobacterium tuberculosis appear to be crucial factors in tuberculosis pathogenicity and could be useful antigens in tuberculosis immunodiagnosis. In the present study, we report the successful antigenic and immunogenic mimicry of mannose-containing cell-wall compounds of M. tuberculosis by dodecamer peptides identified by phage-display technology. Using a rabbit antiserum raised against M. tuberculosis cell-surface saccharides as a target for biopanning, peptides with three different consensus sequences were identified. Phage-displayed and chemically synthesized peptides bound to the anticarbohydrate antiserum. Rabbit antibodies elicited against the peptide QEPLMGTVPIRAGGGS recognize the mannosylated M. tuberculosis cell-wall antigens arabinomannan and lipoarabinomannan, and the glycosylated recombinant protein alanine/proline-rich antigen. Furthermore, antibodies were also able to react with mannan from Saccharomyces cerevisiae, but not with phosphatidylinositol dimannosides or arabinogalactan from mycobacteria. These results suggest that the immunogenic peptide mimics oligomannosidic epitopes. Interestingly, this report provides evidence that, in contrast with previously known carbohydrate mimotopes, no aromatic residues are necessary in a peptide sequence for mimicking unusual glycoconjugates synthesized by mycobacteria. The possible usefulness of the identified peptide mimotopes as surrogate reagents for immunodiagnosis and for the study of functional roles of the native non-peptide epitopes is discussed. PMID:15560754

  19. Benzothiazole Derivative as a Novel Mycobacterium tuberculosis Shikimate Kinase Inhibitor: Identification and Elucidation of Its Allosteric Mode of Inhibition.

    PubMed

    Mehra, Rukmankesh; Rajput, Vikrant Singh; Gupta, Monika; Chib, Reena; Kumar, Amit; Wazir, Priya; Khan, Inshad Ali; Nargotra, Amit

    2016-05-23

    Mycobacterium tuberculosis shikimate kinase (Mtb-SK) is a key enzyme involved in the biosynthesis of aromatic amino acids through the shikimate pathway. Since it is proven to be essential for the survival of the microbe and is absent from mammals, it is a promising target for anti-TB drug discovery. In this study, a combined approach of in silico similarity search and pharmacophore building using already reported inhibitors was used to screen a procured library of 20,000 compounds of the commercially available ChemBridge database. From the in silico screening, 15 hits were identified, and these hits were evaluated in vitro for Mtb-SK enzyme inhibition. Two compounds presented significant enzyme inhibition with IC50 values of 10.69 ± 0.9 and 46.22 ± 1.2 μM. The best hit was then evaluated for the in vitro mode of inhibition where it came out to be an uncompetitive and noncompetitive inhibitor with respect to shikimate (SKM) and ATP, respectively, suggesting its binding at an allosteric site. Potential binding sites of Mtb-SK were identified which confirmed the presence of an allosteric binding pocket apart from the ATP and SKM binding sites. The docking simulations were performed at this pocket in order to find the mode of binding of the best hit in the presence of substrates and the products of the enzymatic reaction. Molecular dynamics (MD) simulations elucidated the probability of inhibitor binding at the allosteric site in the presence of ADP and shikimate-3-phosphate (S-3-P), that is, after the formation of products of the reaction. The inhibitor binding may prevent the release of the product from Mtb-SK, thereby inhibiting its activity. The binding stability and the key residue interactions of the inhibitor to this product complex were also revealed by the MD simulations. Residues ARG43, ILE45, and PHE57 were identified as crucial that were involved in interactions with the best hit. This is the first report of an allosteric binding site of Mtb-SK, which

  20. Proteogenomic analysis of Mycobacterium tuberculosis by high resolution mass spectrometry.

    PubMed

    Kelkar, Dhanashree S; Kumar, Dhirendra; Kumar, Praveen; Balakrishnan, Lavanya; Muthusamy, Babylakshmi; Yadav, Amit Kumar; Shrivastava, Priyanka; Marimuthu, Arivusudar; Anand, Sridhar; Sundaram, Hema; Kingsbury, Reena; Harsha, H C; Nair, Bipin; Prasad, T S Keshava; Chauhan, Devendra Singh; Katoch, Kiran; Katoch, Vishwa Mohan; Kumar, Prahlad; Chaerkady, Raghothama; Ramachandran, Srinivasan; Dash, Debasis; Pandey, Akhilesh

    2011-12-01

    The genome sequencing of H37Rv strain of Mycobacterium tuberculosis was completed in 1998 followed by the whole genome sequencing of a clinical isolate, CDC1551 in 2002. Since then, the genomic sequences of a number of other strains have become available making it one of the better studied pathogenic bacterial species at the genomic level. However, annotation of its genome remains challenging because of high GC content and dissimilarity to other model prokaryotes. To this end, we carried out an in-depth proteogenomic analysis of the M. tuberculosis H37Rv strain using Fourier transform mass spectrometry with high resolution at both MS and tandem MS levels. In all, we identified 3176 proteins from Mycobacterium tuberculosis representing ~80% of its total predicted gene count. In addition to protein database search, we carried out a genome database search, which led to identification of ~250 novel peptides. Based on these novel genome search-specific peptides, we discovered 41 novel protein coding genes in the H37Rv genome. Using peptide evidence and alternative gene prediction tools, we also corrected 79 gene models. Finally, mass spectrometric data from N terminus-derived peptides confirmed 727 existing annotations for translational start sites while correcting those for 33 proteins. We report creation of a high confidence set of protein coding regions in Mycobacterium tuberculosis genome obtained by high resolution tandem mass-spectrometry at both precursor and fragment detection steps for the first time. This proteogenomic approach should be generally applicable to other organisms whose genomes have already been sequenced for obtaining a more accurate catalogue of protein-coding genes. PMID:21969609

  1. The progress made in determining the Mycobacterium tuberculosis structural proteome

    PubMed Central

    Hecker, Michael

    2011-01-01

    Mycobacterium tuberculosis is a highly infectious pathogen that is still responsible for millions of deaths annually. Effectively treating this disease typically requires a course of antibiotics, most of which were developed decades ago. These drugs are, however, not effective against persistent tubercle bacilli and the emergence of drug-resistant stains threatens to make many of them obsolete. The identification of new drug targets, allowing the development of new potential drugs, is therefore imperative. Both proteomics and structural biology have important roles to play in this process, the former as a means of identifying promising drug targets and the latter allowing understanding of protein function and protein–drug interactions at atomic resolution. The determination of M. tuberculosis protein structures has been a goal of the scientific community for the last decade, who have aimed to supply a large amount of structural data that can be used in structure-based approaches for drug discovery and design. Only since the genome sequence of M. tuberculosis has been available has the determination of large numbers of tuberculosis protein structures been possible. Currently, the molecular structures of 8.5% of all the pathogen's protein-encoding ORFs have been determined. In this review, we look at the progress made in determining the M. tuberculosis structural proteome and the impact this has had on the development of potential new drugs, as well as the discovery of the function of crucial mycobaterial proteins. PMID:21674801

  2. Gene Transfer in Mycobacterium tuberculosis: Shuttle Phasmids to Enlightenment

    PubMed Central

    JACOBS, WILLIAM R.

    2016-01-01

    Infectious diseases have plagued humankind throughout history and have posed serious public health problems. Yet vaccines have eradicated smallpox and antibiotics have drastically decreased the mortality rate of many infectious agents. These remarkable successes in the control of infections came from knowing the causative agents of the diseases, followed by serendipitous discoveries of attenuated viruses and antibiotics. The discovery of DNA as genetic material and the understanding of how this information translates into specific phenotypes have changed the paradigm for developing new vaccines, drugs, and diagnostic tests. Knowledge of the mechanisms of immunity and mechanisms of action of drugs has led to new vaccines and new antimicrobial agents. The key to the acquisition of the knowledge of these mechanisms has been identifying the elemental causes (i.e., genes and their products) that mediate immunity and drug resistance. The identification of these genes is made possible by being able to transfer the genes or mutated forms of the genes into causative agents or surrogate hosts. Such an approach was limited in Mycobacterium tuberculosis by the difficulty of transferring genes or alleles into M. tuberculosis or a suitable surrogate mycobacterial host. The construction of shuttle phasmids—chimeric molecules that replicate in Escherichia coli as plasmids and in mycobacteria as mycobacteriophages—was instrumental in developing gene transfer systems for M. tuberculosis. This review will discuss M. tuberculosis genetic systems and their impact on tuberculosis research. “I had to know my enemy in order to prevail against him.”Nelson Mandela PMID:26105819

  3. Gamma Interferon Release Assays for Detection of Mycobacterium tuberculosis Infection

    PubMed Central

    Denkinger, Claudia M.; Kik, Sandra V.; Rangaka, Molebogeng X.; Zwerling, Alice; Oxlade, Olivia; Metcalfe, John Z.; Cattamanchi, Adithya; Dowdy, David W.; Dheda, Keertan; Banaei, Niaz

    2014-01-01

    SUMMARY Identification and treatment of latent tuberculosis infection (LTBI) can substantially reduce the risk of developing active disease. However, there is no diagnostic gold standard for LTBI. Two tests are available for identification of LTBI: the tuberculin skin test (TST) and the gamma interferon (IFN-γ) release assay (IGRA). Evidence suggests that both TST and IGRA are acceptable but imperfect tests. They represent indirect markers of Mycobacterium tuberculosis exposure and indicate a cellular immune response to M. tuberculosis. Neither test can accurately differentiate between LTBI and active TB, distinguish reactivation from reinfection, or resolve the various stages within the spectrum of M. tuberculosis infection. Both TST and IGRA have reduced sensitivity in immunocompromised patients and have low predictive value for progression to active TB. To maximize the positive predictive value of existing tests, LTBI screening should be reserved for those who are at sufficiently high risk of progressing to disease. Such high-risk individuals may be identifiable by using multivariable risk prediction models that incorporate test results with risk factors and using serial testing to resolve underlying phenotypes. In the longer term, basic research is necessary to identify highly predictive biomarkers. PMID:24396134

  4. The transmission of Mycobacterium tuberculosis in high burden settings.

    PubMed

    Yates, Tom A; Khan, Palwasha Y; Knight, Gwenan M; Taylor, Jonathon G; McHugh, Timothy D; Lipman, Marc; White, Richard G; Cohen, Ted; Cobelens, Frank G; Wood, Robin; Moore, David A J; Abubakar, Ibrahim

    2016-02-01

    Unacceptable levels of Mycobacterium tuberculosis transmission are noted in high burden settings and a renewed focus on reducing person-to-person transmission in these communities is needed. We review recent developments in the understanding of airborne transmission. We outline approaches to measure transmission in populations and trials and describe the Wells-Riley equation, which is used to estimate transmission risk in indoor spaces. Present research priorities include the identification of effective strategies for tuberculosis infection control, improved understanding of where transmission occurs and the transmissibility of drug-resistant strains, and estimates of the effect of HIV and antiretroviral therapy on transmission dynamics. When research is planned and interventions are designed to interrupt transmission, resource constraints that are common in high burden settings-including shortages of health-care workers-must be considered. PMID:26867464

  5. Consequences of genomic diversity in Mycobacterium tuberculosis.

    PubMed

    Coscolla, Mireia; Gagneux, Sebastien

    2014-12-01

    The causative agent of human tuberculosis, Mycobacterium tuberculosis complex (MTBC), comprises seven phylogenetically distinct lineages associated with different geographical regions. Here we review the latest findings on the nature and amount of genomic diversity within and between MTBC lineages. We then review recent evidence for the effect of this genomic diversity on mycobacterial phenotypes measured experimentally and in clinical settings. We conclude that overall, the most geographically widespread Lineage 2 (includes Beijing) and Lineage 4 (also known as Euro-American) are more virulent than other lineages that are more geographically restricted. This increased virulence is associated with delayed or reduced pro-inflammatory host immune responses, greater severity of disease, and enhanced transmission. Future work should focus on the interaction between MTBC and human genetic diversity, as well as on the environmental factors that modulate these interactions. PMID:25453224

  6. Genetic Diversity and Dynamic Distribution of Mycobacterium tuberculosis Isolates Causing Pulmonary and Extrapulmonary Tuberculosis in Thailand

    PubMed Central

    Srilohasin, Prapaporn; Tokunaga, Katsushi; Nishida, Nao; Prammananan, Therdsak; Smittipat, Nat; Mahasirimongkol, Surakameth; Chaiyasirinroje, Boonchai; Yanai, Hideki; Palittapongarnpim, Prasit

    2014-01-01

    This study examined the genetic diversity and dynamicity of circulating Mycobacterium tuberculosis strains in Thailand using nearly neutral molecular markers. The single nucleotide polymorphism (SNP)-based genotypes of 1,414 culture-positive M. tuberculosis isolates from 1,282 pulmonary tuberculosis (PTB) and 132 extrapulmonary TB (EPTB) patients collected from 1995 to 2011 were characterized. Among the eight SNP cluster groups (SCG), SCG2 (44.1%), which included the Beijing (BJ) genotype, and SCG1 (39.4%), an East African Indian genotype, were dominant. Comparisons between the genotypes of M. tuberculosis isolates causing PTB and EPTB in HIV-negative cases revealed similar prevalence trends although genetic diversity was higher in the PTB patients. The identification of 10 reported sequence types (STs) and three novel STs was hypothesized to indicate preferential expansion of the SCG2 genotype, especially the modern BJ ST10 (15.6%) and ancestral BJ ST19 (13.1%). An association between SCG2 and SCG1 genotypes and particular patient age groups implies the existence of different genetic advantages among the bacterial populations. The results revealed that increasing numbers of young patients were infected with M. tuberculosis SCGs 2 and 5, which contrasts with the reduction of the SCG1 genotype. Our results indicate the selection and dissemination of potent M. tuberculosis genotypes in this population. The determination of heterogeneity and dynamic population changes of circulating M. tuberculosis strains in countries using the Mycobacterium bovis BCG (bacillus Calmette-Guérin) vaccine are beneficial for vaccine development and control strategies. PMID:25297330

  7. Identification of the Mycobacterium marinum Apa antigen O-mannosylation sites reveals important glycosylation variability with the M. tuberculosis Apa homologue.

    PubMed

    Coddeville, Bernadette; Wu, Sz-Wei; Fabre, Emeline; Brassart, Colette; Rombouts, Yoann; Burguière, Adeline; Kremer, Laurent; Khoo, Kay-Hooi; Elass-Rochard, Elisabeth; Guérardel, Yann

    2012-10-22

    The 45/47 kDa Apa, an immuno-dominant antigen secreted by Mycobacterium tuberculosis is O-mannosylated at multiple sites. Glycosylation of Apa plays a key role in colonization and invasion of the host cells by M. tuberculosis through interactions of Apa with the host immune system C-type lectins. Mycobacterium marinum (M.ma) a fish pathogen, phylogenetically close to M. tuberculosis, induces a granulomatous response with features similar to those described for M. tuberculosis in human. Although M.ma possesses an Apa homologue, its glycosylation status is unknown, and whether this represents a crucial element in the pathophysiology induced by M.ma remains to be addressed. To this aim, we have identified two concanavalin A-reactive 45/47 kDa proteins from M.ma, which have been further purified by a two-step anion exchange chromatography process. Advanced liquid chromatography-nanoESI mass spectrometry-based proteomic analyses of peptides, derived from either tryptic digestion alone or in combination with the Asp-N endoproteinase, established that M.ma Apa possesses up to seven distinct O-mannosylated sites with mainly single mannose substitutions, which can be further extended at the Ser/Thr/Pro rich region near the N-terminus. This opens the way to further studies focussing on the involvement and biological functions of Apa O-mannosylation using the M.ma/zebrafish model. PMID:22828516

  8. Mycobacterium tuberculosis expresses two chaperonin-60 homologs.

    PubMed Central

    Kong, T H; Coates, A R; Butcher, P D; Hickman, C J; Shinnick, T M

    1993-01-01

    A 65-kDa protein and a 10-kDa protein are two of the more strongly immunoreactive components of Mycobacterium tuberculosis, the causative agent of tuberculosis. The 65-kDa antigen has homology with members of the GroEL or chaperonin-60 (Cpn60) family of heat shock proteins. The 10-kDa antigen has homology with the GroES or chaperonin-10 family of heat shock proteins. These two proteins are encoded by separate genes in M. tuberculosis. The studies reported here reveal that M. tuberculosis contains a second Cpn60 homolog located 98 bp downstream of the 10-kDa antigen gene. The second Cpn60 homolog (Cpn60-1) displays 61% amino acid sequence identity with the 65-kDa antigen (Cpn60-2) and 53% and 41% identity with the Escherichia coli GroEL protein and the human P60 protein, respectively. Primer-extension analysis revealed that transcription starts 29 bp upstream of the translation start of the Cpn60-1 homolog and protein purification studies indicate that the cpn60-1 gene is expressed as an approximately 60-kDa polypeptide. Images Fig. 3 Fig. 5 PMID:7681982

  9. Mycobacterium tuberculosis is resistant to streptolydigin.

    PubMed

    Speer, Alexander; Rowland, Jennifer L; Niederweis, Michael

    2013-07-01

    Drug resistant strains of Mycobacterium tuberculosis (Mtb) undermine tuberculosis (TB) control. Streptolydigin is a broadly effective antibiotic which inhibits RNA polymerase, similarly to rifampicin, a key drug in current TB chemotherapeutic regimens. Due to a vastly improved chemical synthesis streptolydigin and derivatives are being promoted as putative TB drugs. The microplate Alamar Blue assay revealed that Streptococcus salivarius and Mycobacterium smegmatis were susceptible to streptolydigin with minimum inhibitory concentrations (MICs) of 1.6 mg/L and 6.25 mg/L, respectively. By contrast, the MICs of streptolydigin and two derivatives, streptolydiginone and dihydrostreptolydigin, against Mtb were ≥ 100 mg/L demonstrating that Mtb is resistant to streptolydigin in contrast to previous reports. Further, a porin mutant of M. smegmatis is resistant to streptolydigin indicating that porins mediate uptake of streptolydigin across the outer membrane. Since the RNA polymerase is a validated drug target in Mtb and porins are required for susceptibility of M. smegmatis, the absence of MspA-like porins probably contributes to the resistance of Mtb to streptolydigin. This study shows that streptolydigin is not a suitable drug in TB treatment regimens. PMID:23591156

  10. Comparative Genomics and Proteomic Analysis of Four Non-tuberculous Mycobacterium Species and Mycobacterium tuberculosis Complex: Occurrence of Shared Immunogenic Proteins

    PubMed Central

    Gcebe, Nomakorinte; Michel, Anita; Gey van Pittius, Nicolaas C.; Rutten, Victor

    2016-01-01

    The Esx and PE/PPE families of proteins are among the most immunodominant mycobacterial antigens and have thus been the focus of research to develop vaccines and immunological tests for diagnosis of bovine and human tuberculosis, mainly caused by Mycobacterium bovis and Mycobacterium tuberculosis, respectively. In non-tuberculous mycobacteria (NTM), multiple copies of genes encoding homologous proteins have mainly been identified in pathogenic Mycobacterium species phylogenically related to Mycobacterium tuberculosis and Mycobacterium bovis. Only ancestral copies of these genes have been identified in nonpathogenic NTM species like Mycobacterium smegmatis, Mycobacterium sp. KMS, Mycobacterium sp. MCS, and Mycobacterium sp. JLS. In this study we elucidated the genomes of four nonpathogenic NTM species, viz Mycobacterium komanii sp. nov., Mycobacterium malmesburii sp. nov., Mycobacterium nonchromogenicum, and Mycobacterium fortuitum ATCC 6841. These genomes were investigated for genes encoding for the Esx and PE/PPE (situated in the esx cluster) family of proteins as well as adjacent genes situated in the ESX-1 to ESX-5 regions. To identify proteins actually expressed, comparative proteomic analyses of purified protein derivatives from three of the NTM as well as Mycobacterium kansasii ATCC 12478 and the commercially available purified protein derivatives from Mycobacterium bovis and Mycobacterium avium was performed. The genomic analysis revealed the occurrence in each of the four NTM, orthologs of the genes encoding for the Esx family, the PE and PPE family proteins in M. bovis and M. tuberculosis. The identification of genes of the ESX-1, ESX-3, and ESX-4 region including esxA, esxB, ppe68, pe5, and pe35 adds to earlier reports of these genes in nonpathogenic NTM like M. smegmatis, Mycobacterium sp. JLS and Mycobacterium KMS. This report is also the first to identify esxN gene situated within the ESX-5 locus in M. nonchromogenicum. Our proteomics analysis

  11. Tenosynovitis caused by a novel nontuberculous Mycobacterium species initially misidentified as a member of the Mycobacterium tuberculosis complex.

    PubMed

    Simner, Patricia J; Hyle, Emily P; Buckwalter, Seanne P; Branda, John A; Brown-Elliott, Barbara A; Franklin, Jameelah; Toney, Nadege C; de Man, Tom J B; Wallace, Richard J; Vasireddy, Ravikiran; Gandhi, Rajesh T; Wengenack, Nancy L

    2014-12-01

    We present a case of tenosynovitis caused by a novel, slowly growing, nonchromogenic, nontuberculous mycobacterium (NTM). Originally misidentified as Mycobacterium tuberculosis complex, the NTM cross-reacts with the M. tuberculosis complex nucleic acid hybridization probe, a M. tuberculosis gamma interferon release assay, and is closely related to M. tuberculosis by 16S rRNA gene sequencing. PMID:25253791

  12. Immunogenicity and cross-reactivity against Mycobacterium tuberculosis of proteoliposomes derived from Mycobacterium bovis BCG.

    PubMed

    Reyes, Fátima; Tirado, Yanely; Puig, Alina; Borrero, Reinier; Reyes, Giselle; Fernández, Sonsire; Pérez, José Luis; Kadir, Ramlah; Zayas, Caridad; Norazmi, Mohd Nor; Sarmiento, María E; Acosta, Armando

    2013-01-01

    The only currently available vaccine against tuberculosis (TB) is Mycobacterium bovis Bacille Calmette-Guerin (BCG), which has inconsistent efficacy to protect against the disease in adults. M. tuberculosis (MTB) cell wall components have been implicated in the pathogenicity of TB and therefore have been a prime target for the identification and characterization of cell wall proteins with potential application in vaccine development. In this regard, proteoliposomes (PLs) derived from mycobacteria containing lipids and cell wall proteins could be potential vaccine candidates against TB. In the present study PLs derived from BCG were prepared. These homogeneous population of spherical microparticles was then immunized into Balb/c mice. Sera of immunized animals showed high IgG response and strong cross-reactivity against different MTB antigens.These results showed that BCG PLs could be potential vaccine candidates against TB. PMID:23458692

  13. Molecular Epidemiology of Mycobacterium tuberculosis Isolates in 100 Patients With Tuberculosis Using Pulsed Field Gel Electrophoresis

    PubMed Central

    Pooideh, Mohammad; Jabbarzadeh, Ismail; Ranjbar, Reza; Saifi, Mahnaz

    2015-01-01

    Background: Tuberculosis (TB) is a widespread infectious disease. Today, TB has created a public health crisis in the world. Genotyping of Mycobacterium tuberculosis isolates is useful for surveying the dynamics of TB infection, identifying new outbreaks, and preventing the disease. Different molecular methods for clustering of M. tuberculosis isolates have been used. Objectives: During a one year study of genotyping, 100 M. tuberculosis isolates from patients referred to Pasteur Institute of Iran were collected and their genotyping was accomplished using pulsed field gel electrophoresis (PFGE) method. Materials and Methods: Identification of all M. tuberculosis isolates was accomplished using standard biochemical and species-specific polymerase chain reaction (PCR) methods. Antibiotic susceptibility tests were performed using proportional method. After preparing PFGE plaques for each isolate of M. tuberculosis, XbaI restriction enzyme was applied for genome digestion. Finally, the digested DNA fragments were separated on 1% agarose gel and analyzed with GelCompar II software. Results: Genotyping of the studied isolates in comparison with the molecular weight marker revealed two common types; pulsotype A with 71 isolates and one multidrug resistant mycobacterium (MDR) case, and pulsotype B including 29 isolates and three MDR cases. No correlation between the antibiotypes and pulsotypes was observed. Conclusions: Molecular epidemiology studies of infectious diseases have been useful when bacterial isolates have been clustered in a period of time and in different geographical regions with variable antibiotic resistance patterns. In spite of high geographical differences and different antibiotic resistant patterns, low genetic diversity among the studied TB isolates may refer to the low rate of mutations in XbaI restriction sites in the mycobacterial genome. We also identified three MDR isolates in low-incidence pulsotype B, which could be disseminated and is highly

  14. The 65-kilodalton antigen of Mycobacterium tuberculosis.

    PubMed Central

    Shinnick, T M

    1987-01-01

    The immune response of the host to the antigens of Mycobacterium tuberculosis plays the key role in determining immunity from infection with as well as the pathogenicity of this organism. A 65-kilodalton (kDa) protein has been identified as one of the medically important antigens of M. tuberculosis. The gene encoding this antigen was isolated from a lambda gt11-M. tuberculosis recombinant DNA library using monoclonal antibodies directed against the 65-kDa antigen as the specific probes. The nucleotide sequence of this gene was determined, and a 540-amino-acid sequence was deduced. This sequence was shown to correspond to that of the 65-kDa antigen by constructing a plasmid in which this open reading frame was fused to the lacZ gene. The resulting fusion protein reacted specifically with the anti-65-kDa protein antibodies. A second long open reading frame was found downstream of the 65-kDa antigen gene which could encode a protein of 517 amino acids. This putative protein contained 29 tandemly arranged partial or complete matches to a pentapeptide sequence. Images PMID:3029018

  15. Essential Metabolites of Mycobacterium tuberculosis and Their Mimics

    PubMed Central

    Lamichhane, Gyanu; Freundlich, Joel S.; Ekins, Sean; Wickramaratne, Niluka; Nolan, Scott T.; Bishai, William R.

    2011-01-01

    An organism requires a range of biomolecules for its growth. By definition, these are essential molecules which constitute the basic metabolic requirements of an organism. A small organic molecule with chemical similarity to that of an essential metabolite may bind to the enzyme that catalyzes its production and inhibit it, likely resulting in the stasis or death of the organism. Here, we report a high-throughput approach for identifying essential metabolites of an organism using genetic and biochemical approaches and then implement computational approaches to identify metabolite mimics. We generated and genotyped 5,126 Mycobacterium tuberculosis mutants and performed a statistical analysis to determine putative essential genes. The essential molecules of M. tuberculosis were classified as products of enzymes that are encoded by genes in this list. Although incomplete, as many enzymes of M. tuberculosis have yet to be identified and characterized, this is the first report of a large number of essential molecules of the organism. We identified essential metabolites of three distinct metabolic pathways in M. tuberculosis and selected molecules with chemical similarity using cheminformatics strategies that illustrate a variety of different pharmacophores. Our approach is aimed at systematic identification of essential molecules and their mimics as a blueprint for development of effective chemical probes of M. tuberculosis metabolism, with the ultimate goal of seeking drugs that can kill this pathogen. As an illustration of this approach, we report that compounds JFD01307SC and l-methionine-S-sulfoximine, which share chemical similarity with an essential molecule of M. tuberculosis, inhibited the growth of this organism at micromolar concentrations. PMID:21285434

  16. Genome Sequencing and Annotation of Mycobacterium tuberculosis PR08 strain.

    PubMed

    Jaafar, Mohammad Maaruf; Halim, Mohd Zakihalani A; Ismail, Mohamad Izwan; Shien, Lee Lian; Kek, Teh Lay; Fong, Ngeow Yun; Nor, Norazmi Mohd; Zainuddin, Zainul Fadziruddin; Hock, Tang Thean; Najimudin, Mohd Nazalan Mohd; Salleh, Mohd Zaki

    2016-03-01

    Mycobacterium tuberculosis is an acid fast bacterial species in the family Mycobacteriaceae and is the causative agent of most cases of tuberculosis. Here, we report the genomic features of Mycobacterium tuberculosis isolated from the cerebrospinal fluid (CSF) of a patient diagnosed with both pulmonary and extrapulmonary tuberculosis (TB). The isolated strain was identified as Mycobacterium tuberculosis PR08 (MTB PR08). Genomic DNA of the MTB PR08 strain was extracted and subjected to whole genome sequencing using MiSeq (Illumina, CA,USA). The draft genome size of MTB PR08 strain is 4,292,364 bp with a G + C content of 65.2%. This strain was annotated to have 4723 genes and 48 RNAs. This whole genome shotgun project has been deposited at DDBJ/EMBL/GenBank under the accession number CP010895. PMID:26981383

  17. Lipid composition and transcriptional response of Mycobacterium tuberculosis grown under iron-limitation in continuous culture: identification of a novel wax ester

    PubMed Central

    Bacon, Joanna; Dover, Lynn G.; Hatch, Kim A.; Zhang, Yi; Gomes, Jessica M.; Kendall, Sharon; Wernisch, Lorenz; Stoker, Neil G.; Butcher, Philip D.; Besra, Gurdyal S.; Marsh, Philip D.

    2011-01-01

    The low level of available iron in vivo is a major obstacle for microbial pathogens and is a stimulus for the expression of virulence genes. In this study, Mycobacterium tuberculosis H37Rv was grown aerobically in the presence of limited iron availability in chemostat culture to determine the physiological response of the organism to iron-limitation. A previously unidentified wax ester accumulated under iron-limited growth, and changes in the abundance of triacylglycerol and menaquinone were also observed between iron-replete and iron-limited chemostat cultures. DNA microarray analysis revealed differential expression of genes involved in glycerolipid metabolism and isoprenoid quinone biosynthesis, providing some insight into the underlying genetic changes that correlate with cell-wall lipid profiles of M. tuberculosis growing in an iron-limited environment. PMID:17464057

  18. Mycobacterium tuberculosis supports protein tyrosine phosphorylation

    PubMed Central

    Kusebauch, Ulrike; Ortega, Corrie; Ollodart, Anja; Rogers, Richard S.; Sherman, David R.; Moritz, Robert L.; Grundner, Christoph

    2014-01-01

    Reversible protein phosphorylation determines growth and adaptive decisions in Mycobacterium tuberculosis (Mtb). At least 11 two-component systems and 11 Ser/Thr protein kinases (STPKs) mediate phosphorylation on Asp, His, Ser, and Thr. In contrast, protein phosphorylation on Tyr has not been described previously in Mtb. Here, using a combination of phospho-enrichment and highly sensitive mass spectrometry, we show extensive protein Tyr phosphorylation of diverse Mtb proteins, including STPKs. Several STPKs function as dual-specificity kinases that phosphorylate Tyr in cis and in trans, suggesting that dual-specificity kinases have a major role in bacterial phospho-signaling. Mutation of a phosphotyrosine site of the essential STPK PknB reduces its activity in vitro and in live Mtb, indicating that Tyr phosphorylation has a functional role in bacterial growth. These data identify a previously unrecognized phosphorylation system in a human pathogen that claims ∼1.4 million lives every year. PMID:24927537

  19. Characterization of Mycobacterium orygis as M. tuberculosis complex subspecies.

    PubMed

    van Ingen, Jakko; Rahim, Zeaur; Mulder, Arnout; Boeree, Martin J; Simeone, Roxane; Brosch, Roland; van Soolingen, Dick

    2012-04-01

    The oryx bacilli are Mycobacterium tuberculosis complex organisms for which phylogenetic position and host range are unsettled. We characterized 22 isolates by molecular methods and propose elevation to subspecies status as M. orygis. M. orygis is a causative agent of tuberculosis in animals and humans from Africa and South Asia. PMID:22469053

  20. The cell envelope glycoconjugates of Mycobacterium tuberculosis

    PubMed Central

    Angala, Shiva Kumar; Belardinelli, Juan Manuel; Huc-Claustre, Emilie; Wheat, William H.; Jackson, Mary

    2015-01-01

    Tuberculosis (TB) remains the second most common cause of death due to a single infectious agent. The cell envelope of Mycobacterium tuberculosis (Mtb), the causative agent of the disease in humans, is a source of unique glycoconjugates and the most distinctive feature of the biology of this organism. It is the basis of much of Mtb pathogenesis and one of the major causes of its intrinsic resistance to chemotherapeutic agents. At the same time, the unique structures of Mtb cell envelope glycoconjugates, their antigenicity and essentiality for mycobacterial growth provide opportunities for drug, vaccine, diagnostic and biomarker development, as clearly illustrated by recent advances in all of these translational aspects. This review focuses on our current understanding of the structure and biogenesis of Mtb glycoconjugates with particular emphasis on one of most intriguing and least understood aspect of the physiology of mycobacteria: the translocation of these complex macromolecules across the different layers of the cell envelope. It further reviews the rather impressive progress made in the last ten years in the discovery and development of novel inhibitors targeting their biogenesis. PMID:24915502

  1. Pulmonary Tuberculosis Caused by Mycobacterium bovis in China

    PubMed Central

    Jiang, Guanglu; Wang, Guirong; Chen, Suting; Yu, Xia; Wang, Xiaobo; Zhao, Liping; Ma, Yifeng; Dong, Lingling; Huang, Hairong

    2015-01-01

    The epidemiology of Mycobacterium bovis infection in humans in China is unknown. In this study, pulmonary tuberculosis caused by M. bovis in China was studied. A total of 4069 clinical strains isolated from sputa during the 2007–2009 nationwide surveillance of drug-resistant tuberculosis in China were analyzed. M. bovis was identified by para-nitrobenzoic acid and thiophen-2-carboxylic acid hydrazide growth tests, spoligotyping and multiplex PCR amplification. In addition, a total of 1828 clinical specimens were recruited from Beijing Chest Hospital (Beijing, China) for Löwenstein-Jensen (LJ) culture, both on standard LJ medium and LJ medium containing 4.5 mg/ml(W/V) sodium pyruvate, the latter being the preferred medium for M. bovis growth. The isolates which demonstrated more vigorous on pyruvate containing medium than on standard LJ medium were then identified by multiplex PCR amplification. Only 1 isolate from the nationwide surveillance was confirmed as M. bovis-BCG. The isolate belonged to a predominant spoligotype SB0120 (ST482). In addition, no M. bovis isolate was acquired by the continuous screening step in Beijing Chest Hospital. M. bovis has a negligible contribution to pulmonary tuberculosis in China, so neither laboratory identification nor clinical treatment of M. bovis infection need be considered in routine work. PMID:25736338

  2. Direct inhibitors of InhA active against Mycobacterium tuberculosis

    PubMed Central

    Manjunatha, Ujjini H.; Rao, Srinivasa P. S.; Kondreddi, Ravinder Reddy; Noble, Christian G.; Camacho, Luis R.; Tan, Bee H.; Ng, Seow H.; Ng, Pearly Shuyi; Ma, N. L.; Lakshminarayana, Suresh B.; Herve, Maxime; Barnes, S. Whitney; Yu, Weixuan; Kuhen, Kelli; Blasco, Francesca; Beer, David; Walker, John R.; Tonge, Peter J.; Glynne, Richard; Smith, Paul W.; Diagana, Thierry T.

    2015-01-01

    New chemotherapeutic agents are urgently required to combat the global spread of multi-drug resistant tuberculosis (MDR-TB). The mycobacterial enoyl reductase, InhA, is one of the few clinically-validated targets in tuberculosis drug discovery. Here, we report the identification of a new class of direct InhA inhibitors, the 4-hydroxy-2-pyridones, using phenotypic high-throughput whole-cell screening. This class of orally-active compounds showed potent bactericidal activity against common isoniazid-resistant TB clinical isolates. Biophysical studies revealed that 4-hydroxy-2-pyridones bound specifically to InhA in an NADH-dependent manner and blocked the enoyl-substrate binding pocket. The lead compound NITD-916 directly blocked InhA in a dose-dependent manner and showed in vivo efficacy in acute and established mouse models of infection by Mycobacterium tuberculosis. Collectively, our structural and biochemical data open up new avenues for rational structure-guided optimization of the 4-hydroxy-2-pyridone class of compounds for the treatment of MDR-TB. PMID:25568071

  3. Human immune response to Mycobacterium tuberculosis antigens.

    PubMed Central

    Havlir, D V; Wallis, R S; Boom, W H; Daniel, T M; Chervenak, K; Ellner, J J

    1991-01-01

    Little is known about the immunodominant or protective antigens of Mycobacterium tuberculosis in humans. Cell-mediated immunity is necessary for protection, and healthy tuberculin-positive individuals are relatively resistant to exogenous reinfection. We compared the targets of the cell-mediated immune response in healthy tuberculin-positive individuals to those of tuberculosis patients and tuberculin-negative persons. By using T-cell Western blotting (immunoblotting) of nitrocellulose-bound M. tuberculosis culture filtrate, peaks of T-cell blastogenic activity were identified in the healthy tuberculin reactors at 30, 37, 44, 57, 64, 71 and 88 kDa. Three of these fractions (30, 64, and 71 kDa) coincided with previously characterized proteins: antigen 6/alpha antigen, HSP60, and HSP70, respectively. The blastogenic responses to purified M. tuberculosis antigen 6/alpha antigen and BCG HSP60 were assessed. When cultured with purified antigen 6/alpha antigen, lymphocytes of healthy tuberculin reactors demonstrated greater [3H]thymidine incorporation than either healthy tuberculin-negative controls or tuberculous patients (8,113 +/- 1,939 delta cpm versus 645 +/- 425 delta cpm and 1,019 +/- 710 delta cpm, respectively; P less than 0.01). Healthy reactors also responded to HSP60, although to a lesser degree than antigen 6/alpha antigen (4,276 +/- 1,095 delta cpm; P less than 0.05). Partially purified HSP70 bound to nitrocellulose paper elicited a significant lymphocyte blastogenic response in two of six of the tuberculous patients but in none of the eight healthy tuberculin reactors. Lymphocytes of none of five tuberculin-negative controls responded to recombinant antigens at 14 or 19 kDa or to HSP70. Antibody reactivity generally was inversely correlated with blastogenic response: tuberculous sera had high titer antibody to M. tuberculosis culture filtrate in a range from 35 to 180 kDa. This is the first systematic evaluation of the human response to a panel of native

  4. Fate of Mycobacterium tuberculosis inside rat peritoneal macrophages in vitro.

    PubMed

    Vishwanath, V; Meera, R; Puvanakrishnan, R; Narayanan, P R

    1997-10-01

    Rat peritoneal macrophages in vitro were infected with Mycobacterium tuberculosis and the fate of M. tuberculosis inside macrophages was monitored. Alteration in the levels of nitric oxide (NO) measured in terms of nitrite formed, hydrogen peroxide (H2O2) and lysosomal enzymes such as acid phosphatase, cathepsin-D and beta-glucuronidase in macrophages following M. tuberculosis infection was also studied. Elevation in the levels of nitrite were observed from 72 h of M. tuberculosis infection. Irrespective of the time point, M. tuberculosis infected macrophages produced elevated levels of H2O2. Maximum increase in the level of acid phosphatase was observed from 72 h of M. tuberculosis infection, whereas maximum elevation in the level of beta-glucuronidase was observed 48 h after M. tuberculosis infection. However these microbicidal agents did not alter the intracellular viability of M. tuberculosis. PMID:9350049

  5. Insights from the complete genome sequence of Mycobacterium marinum on the evolution of Mycobacterium tuberculosis

    PubMed Central

    Stinear, Timothy P.; Seemann, Torsten; Harrison, Paul F.; Jenkin, Grant A.; Davies, John K.; Johnson, Paul D.R.; Abdellah, Zahra; Arrowsmith, Claire; Chillingworth, Tracey; Churcher, Carol; Clarke, Kay; Cronin, Ann; Davis, Paul; Goodhead, Ian; Holroyd, Nancy; Jagels, Kay; Lord, Angela; Moule, Sharon; Mungall, Karen; Norbertczak, Halina; Quail, Michael A.; Rabbinowitsch, Ester; Walker, Danielle; White, Brian; Whitehead, Sally; Small, Pamela L.C.; Brosch, Roland; Ramakrishnan, Lalita; Fischbach, Michael A.; Parkhill, Julian; Cole, Stewart T.

    2008-01-01

    Mycobacterium marinum, a ubiquitous pathogen of fish and amphibia, is a near relative of Mycobacterium tuberculosis, the etiologic agent of tuberculosis in humans. The genome of the M strain of M. marinum comprises a 6,636,827-bp circular chromosome with 5424 CDS, 10 prophages, and a 23-kb mercury-resistance plasmid. Prominent features are the very large number of genes (57) encoding polyketide synthases (PKSs) and nonribosomal peptide synthases (NRPSs) and the most extensive repertoire yet reported of the mycobacteria-restricted PE and PPE proteins, and related-ESX secretion systems. Some of the NRPS genes comprise a novel family and seem to have been acquired horizontally. M. marinum is used widely as a model organism to study M. tuberculosis pathogenesis, and genome comparisons confirmed the close genetic relationship between these two species, as they share 3000 orthologs with an average amino acid identity of 85%. Comparisons with the more distantly related Mycobacterium avium subspecies paratuberculosis and Mycobacterium smegmatis reveal how an ancestral generalist mycobacterium evolved into M. tuberculosis and M. marinum. M. tuberculosis has undergone genome downsizing and extensive lateral gene transfer to become a specialized pathogen of humans and other primates without retaining an environmental niche. M. marinum has maintained a large genome so as to retain the capacity for environmental survival while becoming a broad host range pathogen that produces disease strikingly similar to M. tuberculosis. The work described herein provides a foundation for using M. marinum to better understand the determinants of pathogenesis of tuberculosis. PMID:18403782

  6. Mycobacterium marinum: a potential immunotherapy for Mycobacterium tuberculosis infection

    PubMed Central

    Tian, Wei-wei; Wang, Qian-qiu; Liu, Wei-da; Shen, Jian-ping; Wang, Hong-sheng

    2013-01-01

    Purpose The aim of the present study was to investigate the immune response induced by Mycobacterium marinum infection in vitro and the potential of M. marinum as an immunotherapy for M. tuberculosis infection. Methods The potential human immune response to certain bacillus infections was investigated in an immune cell-bacillus coculture system in vitro. As a potential novel immunotherapy, M. marinum was studied and compared with two other bacilli, Bacillus Calmette-Guérin (BCG) and live attenuated M. tuberculosis. We examined the changes in both the bacilli and immune cells, especially the time course of the viability of mycobacteria in the coculture system and host immune responses including multinuclear giant cell formation by Wright-Giemsa modified staining, macrophage polarization by cell surface antigen expression, and cytokines/chemokine production by both mRNA expression and protein secretion. Results The M. marinum stimulated coculture group showed more expression of CD209, CD68, CD80, and CD86 than the BCG and M. tuberculosis (an attenuated strain, H37Ra) groups, although the differences were not statistically significant. Moreover, the M. marinum group expressed more interleukin (IL)-1B and IL-12p40 on day 3 (IL-1B: P = 0.003 and 0.004, respectively; IL-12p40: P = 0.001 and 0.011, respectively), a higher level of CXCL10 on day 1 (P = 0.006 and 0.026, respectively), and higher levels of chemokine (C-X-C motif) ligand (CXCL) 8 and chemokine (C motif) ligand (XCL) 1 on day 3 (CXCL8: P = 0.012 and 0.014, respectively; XCL1: P = 0.000 and 0.000, respectively). The M. marinum stimulated coculture group also secreted more tumor necrosis factor (TNF)-α, IL-1β, and IL-10 on day 1 (TNF-α: P = 0.000 and 0.000, respectively; IL-1β: P = 0.000 and 0.000, respectively; IL-10: P = 0.002 and 0.019, respectively) and day 3 (TNF-α: P = 0.000 and 0.000, respectively; IL-1β: P = 0.000 and 0.001, respectively; IL-10: P = 0.000 and 0.000, respectively). In addition, the

  7. Profiling Antibodies to Mycobacterium tuberculosis by Multiplex Microbead Suspension Arrays for Serodiagnosis of Tuberculosis▿

    PubMed Central

    Khan, Imran H.; Ravindran, Resmi; Yee, JoAnn; Ziman, Melanie; Lewinsohn, David M.; Gennaro, Marila L.; Flynn, JoAnne L.; Goulding, Celia W.; DeRiemer, Kathryn; Lerche, Nickolas W.; Luciw, Paul A.

    2008-01-01

    Tuberculosis (TB) is a serious global disease. The fatality rate attributed to TB is among the highest of infectious diseases, with approximately 2 million deaths occurring per year worldwide. Identification of individuals infected with Mycobacterium tuberculosis and screening of their immediate contacts is crucial for controlling the spread of TB. Current methods for detection of M. tuberculosis infection are not efficient, in particular, for testing large numbers of samples. We report a novel and efficient multiplex microbead immunoassay (MMIA), based on Luminex technology, for profiling antibodies to M. tuberculosis. Microbead sets identifiable by unique fluorescence were individually coated with each of several M. tuberculosis antigens and tested in multiplex format for antibody detection in the experimental nonhuman primate model of TB. Certain M. tuberculosis antigens, e.g., ESAT-6, CFP-10, and HspX, were included to enhance the specificity of the MMIA, because these antigens are absent in nontuberculous mycobacteria and the vaccine strain Mycobacterium bovis bacillus Calmette-Guérin. The MMIA enabled simultaneous detection of multiple M. tuberculosis plasma antibodies in several cohorts of macaques representing different stages of infection and/or disease. Antibody profiles were defined in early and latent/chronic infection. These proof-of-concept findings demonstrate the potential clinical use of the MMIA. In addition, the MMIA serodetection system has a potential for mining M. tuberculosis open reading frames (about 4,000) to discover novel target proteins for the development of more-comprehensive TB serodiagnostic tests. PMID:18077619

  8. Differentiation of slowly growing Mycobacterium species, including Mycobacterium tuberculosis, by gene amplification and restriction fragment length polymorphism analysis.

    PubMed Central

    Plikaytis, B B; Plikaytis, B D; Yakrus, M A; Butler, W R; Woodley, C L; Silcox, V A; Shinnick, T M

    1992-01-01

    A two-step assay combining a gene amplification step and a restriction fragment length polymorphism analysis was developed to differentiate the Mycobacterium species that account for greater than 90% of potentially pathogenic isolates and greater than 86% of all isolates in clinical laboratories in the United States. These species are M. tuberculosis, M. bovis, M. avium, M. intracellulare, M. kansasii, and M. gordonae. With lysates of pure cultures as the template, two oligonucleotide primers that amplified an approximately 1,380-bp portion of the hsp65 gene from all 139 strains of 19 Mycobacterium species tested, but not from the 19 non-Mycobacterium species tested, were identified. Digestion of the amplicons from 126 strains of the six most commonly isolated Mycobacterium species with the restriction enzymes BstNI and XhoI in separate reactions generated restriction fragment patterns that were distinctive for each of these species, except for those of M. tuberculosis and M. bovis, which were not distinguishable. By including size standards in each sample, the restriction fragment profiles could be normalized to a fixed distance and the similarities of patterns could be calculated by using a computer-aided comparison program. The availability of this data base should enable the identification of an unknown Mycobacterium strain to the species level by a comparison of the restriction fragment pattern of the unknown with the data base of known patterns. Images PMID:1352786

  9. SInCRe—structural interactome computational resource for Mycobacterium tuberculosis

    PubMed Central

    Metri, Rahul; Hariharaputran, Sridhar; Ramakrishnan, Gayatri; Anand, Praveen; Raghavender, Upadhyayula S.; Ochoa-Montaño, Bernardo; Higueruelo, Alicia P.; Sowdhamini, Ramanathan; Chandra, Nagasuma R.; Blundell, Tom L.; Srinivasan, Narayanaswamy

    2015-01-01

    We have developed an integrated database for Mycobacterium tuberculosis H37Rv (Mtb) that collates information on protein sequences, domain assignments, functional annotation and 3D structural information along with protein–protein and protein–small molecule interactions. SInCRe (Structural Interactome Computational Resource) is developed out of CamBan (Cambridge and Bangalore) collaboration. The motivation for development of this database is to provide an integrated platform to allow easily access and interpretation of data and results obtained by all the groups in CamBan in the field of Mtb informatics. In-house algorithms and databases developed independently by various academic groups in CamBan are used to generate Mtb-specific datasets and are integrated in this database to provide a structural dimension to studies on tuberculosis. The SInCRe database readily provides information on identification of functional domains, genome-scale modelling of structures of Mtb proteins and characterization of the small-molecule binding sites within Mtb. The resource also provides structure-based function annotation, information on small-molecule binders including FDA (Food and Drug Administration)-approved drugs, protein–protein interactions (PPIs) and natural compounds that bind to pathogen proteins potentially and result in weakening or elimination of host–pathogen protein–protein interactions. Together they provide prerequisites for identification of off-target binding. Database URL: http://proline.biochem.iisc.ernet.in/sincre PMID:26130660

  10. SInCRe-structural interactome computational resource for Mycobacterium tuberculosis.

    PubMed

    Metri, Rahul; Hariharaputran, Sridhar; Ramakrishnan, Gayatri; Anand, Praveen; Raghavender, Upadhyayula S; Ochoa-Montaño, Bernardo; Higueruelo, Alicia P; Sowdhamini, Ramanathan; Chandra, Nagasuma R; Blundell, Tom L; Srinivasan, Narayanaswamy

    2015-01-01

    We have developed an integrated database for Mycobacterium tuberculosis H37Rv (Mtb) that collates information on protein sequences, domain assignments, functional annotation and 3D structural information along with protein-protein and protein-small molecule interactions. SInCRe (Structural Interactome Computational Resource) is developed out of CamBan (Cambridge and Bangalore) collaboration. The motivation for development of this database is to provide an integrated platform to allow easily access and interpretation of data and results obtained by all the groups in CamBan in the field of Mtb informatics. In-house algorithms and databases developed independently by various academic groups in CamBan are used to generate Mtb-specific datasets and are integrated in this database to provide a structural dimension to studies on tuberculosis. The SInCRe database readily provides information on identification of functional domains, genome-scale modelling of structures of Mtb proteins and characterization of the small-molecule binding sites within Mtb. The resource also provides structure-based function annotation, information on small-molecule binders including FDA (Food and Drug Administration)-approved drugs, protein-protein interactions (PPIs) and natural compounds that bind to pathogen proteins potentially and result in weakening or elimination of host-pathogen protein-protein interactions. Together they provide prerequisites for identification of off-target binding. PMID:26130660

  11. Evaluation of the results of Mycobacterium tuberculosis direct test (MTD) and Mycobacterial culture in urine samples

    PubMed Central

    Sener, Asli Gamze; Kurultay, Nukhet; Afsar, Ilhan

    2008-01-01

    Tuberculosis remains a public health problem in Turkey. Rapid detection of Mycobacterium tuberculosis plays a key role in control of infection. In this article, the Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test (MTD) was evaluated for detection of M. tuberculosis in urine samples. The performance of the MTD was very good and appropriate for routine laboratory diagnosis. PMID:24031287

  12. Pulmonary disease due to Mycobacterium tuberculosis in a horse: zoonotic concerns and limitations of antemortem testing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A case of pulmonary tuberculosis caused by Mycobacterium tuberculosis was diagnosed in a horse. Clinical evaluation performed prior to euthanasia did not suggest tuberculosis, but postmortem examination provided pathological and bacteriological evidence of disease. In the lungs, multiple tuberculoid...

  13. Shrinking the FadE Proteome of Mycobacterium tuberculosis: Insights into Cholesterol Metabolism through Identification of an α2β2 Heterotetrameric Acyl Coenzyme A Dehydrogenase Family

    PubMed Central

    Wipperman, Matthew F.; Yang, Meng; Thomas, Suzanne T.

    2013-01-01

    The ability of the pathogen Mycobacterium tuberculosis to metabolize steroids like cholesterol and the roles that these compounds play in the virulence and pathogenesis of this organism are increasingly evident. Here, we demonstrate through experiments and bioinformatic analysis the existence of an architecturally distinct subfamily of acyl coenzyme A (acyl-CoA) dehydrogenase (ACAD) enzymes that are α2β2 heterotetramers with two active sites. These enzymes are encoded by two adjacent ACAD (fadE) genes that are regulated by cholesterol. FadE26-FadE27 catalyzes the dehydrogenation of 3β-hydroxy-chol-5-en-24-oyl-CoA, an analog of the 5-carbon side chain cholesterol degradation intermediate. Genes encoding the α2β2 heterotetrameric ACAD structures are present in multiple regions of the M. tuberculosis genome, and subsets of these genes are regulated by four different transcriptional repressors or activators: KstR1 (also known as KstR), KstR2, Mce3R, and SigE. Homologous ACAD gene pairs are found in other Actinobacteria, as well as Proteobacteria. Their structures and genomic locations suggest that the α2β2 heterotetrameric structural motif has evolved to enable catalysis of dehydrogenation of steroid- or polycyclic-CoA substrates and that they function in four subpathways of cholesterol metabolism. PMID:23836861

  14. Cloning, expression and characterization of Mycobacterium tuberculosis sirR.

    PubMed

    Namwat, Wises; Somnate, Baramee; Maleehual, Dutsadee; Chareonsudjai, Sorujsiri; Lulitanond, Viraphong; Faksri, Kiatichai

    2014-05-01

    Identification of new drug targets is important for the improvement of chemotherapy for tuberculosis treatment. Metal-associated gene products are candidates for novel drug development. A Mycobacterium tuberculosis (MTB) sirR-encoded protein has been proposed, but the function of MTB SirR has not yet been elucidated. Bioinformatics analysis revealed that MTB SirR contains iron binding domains with 34%-59% similarity to previously described metal-dependent gene regulators and that the gene lies in Rv2787-sirR operon. RT-PCR revealed that the Rv2787-sirR operon is transcribed a single bicistronic mRNA. Heterologous expression, purification and characterization of recombinant MTB His-tagged SirR demonstrated a 25 kDa protein (by SDS-PAGE and immunoblotting) that exists as a dimer (native PAGE). Based on electrophoretic mobility shift assay, MTB SirR bound a cis element located at -85 bp upstream of its operon. As Rv2787-sirR operon is unique only to MTB (and M. bovis), further studies on its regulation and other functions of the encoded proteins should provide leads towards the discovery of novel anti-TB drugs. PMID:24974654

  15. 2-Phenylindole and Arylsulphonamide: Novel Scaffolds Bactericidal against Mycobacterium tuberculosis

    PubMed Central

    2014-01-01

    A cellular activity-based screen on Mycobacterium tuberculosis (Mtb) H37Rv using a focused library from the AstraZeneca corporate collection led to the identification of 2-phenylindoles and arylsulphonamides, novel antimycobacterial scaffolds. Both the series were bactericidal in vitro and in an intracellular macrophage infection model, active against drug sensitive and drug resistant Mtb clinical isolates, and specific to mycobacteria. The scaffolds showed promising structure–activity relationships; compounds with submicromolar cellular potency were identified during the hit to lead exploration. Furthermore, compounds from both scaffolds were tested for inhibition of known target enzymes or pathways of antimycobacterial drugs including InhA, RNA polymerase, DprE1, topoisomerases, protein synthesis, and oxidative-phosphorylation. Compounds did not inhibit any of the targets suggesting the potential of a possible novel mode of action(s). Hence, both scaffolds provide the opportunity to be developed further as leads and tool compounds to uncover novel mechanisms for tuberculosis drug discovery. PMID:25221657

  16. Genetic markers, genotyping methods & next generation sequencing in Mycobacterium tuberculosis

    PubMed Central

    Desikan, Srinidhi; Narayanan, Sujatha

    2015-01-01

    Molecular epidemiology (ME) is one of the main areas in tuberculosis research which is widely used to study the transmission epidemics and outbreaks of tubercle bacilli. It exploits the presence of various polymorphisms in the genome of the bacteria that can be widely used as genetic markers. Many DNA typing methods apply these genetic markers to differentiate various strains and to study the evolutionary relationships between them. The three widely used genotyping tools to differentiate Mycobacterium tuberculosis strains are IS6110 restriction fragment length polymorphism (RFLP), spacer oligotyping (Spoligotyping), and mycobacterial interspersed repeat units - variable number of tandem repeats (MIRU-VNTR). A new prospect towards ME was introduced with the development of whole genome sequencing (WGS) and the next generation sequencing (NGS) methods, where the entire genome is sequenced that not only helps in pointing out minute differences between the various sequences but also saves time and the cost. NGS is also found to be useful in identifying single nucleotide polymorphisms (SNPs), comparative genomics and also various aspects about transmission dynamics. These techniques enable the identification of mycobacterial strains and also facilitate the study of their phylogenetic and evolutionary traits. PMID:26205019

  17. MTBreg: The Database of Conditionally Regulated Proteins in Mycobacterium Tuberculosis

    DOE Data Explorer

    Kaufman, Markus; Pal, Debnath; Eisenberg, David

    Proteins up- and down- regulated in Mycobacterium tuberculosis grown under conditions mimicking infection are included in this database. It also includes information on proteins that are regulated by selected transcription factors or other regulatory proteins. The literature data provided here is complimentary to the databases provided by Michael Strong that include recent TB computational functional linkages and the Prolinks Database by Peter Bowers. The experimental condition, the experimental dataset and a literature reference will be displayed, including links to the computationally linked proteins in the Prolinks Database and the entry in the Mycobacterium tuberculosis Structural Genomics Database.[Copied from information at http://www.doe-mbi.ucla.edu/Services/MTBreg/

  18. Two Cases of Pulmonary Tuberculosis Caused by Mycobacterium tuberculosis subsp. canetti

    PubMed Central

    Morillon, Marc; Koeck, Jean-Louis; Varnerot, Anne; Briant, Jean-François; Nguyen, Gilbert; Verrot, Denis; Bonnet, Daniel; Vincent, Véronique

    2002-01-01

    We identified an unusual strain of mycobacteria from two patients with pulmonary tuberculosis by its smooth, glossy morphotype and, primarily, its genotypic characteristics. Spoligotyping and restriction fragment length polymorphism typing were carried out with the insertion sequence IS6110 patterns. All known cases of tuberculosis caused by Mycobacterium canetti have been contracted in the Horn of Africa. PMID:12453369

  19. Human Xenobiotic Nuclear Receptor PXR Augments Mycobacterium tuberculosis Survival.

    PubMed

    Bhagyaraj, Ella; Nanduri, Ravikanth; Saini, Ankita; Dkhar, Hedwin Kitdorlang; Ahuja, Nancy; Chandra, Vemika; Mahajan, Sahil; Kalra, Rashi; Tiwari, Drishti; Sharma, Charu; Janmeja, Ashok Kumar; Gupta, Pawan

    2016-07-01

    Mycobacterium tuberculosis can evade host defense processes, thereby ensuring its survival and pathogenesis. In this study, we investigated the role of nuclear receptor, pregnane X receptor (PXR), in M. tuberculosis infection in human monocyte-derived macrophages. In this study, we demonstrate that PXR augments M. tuberculosis survival inside the host macrophages by promoting the foamy macrophage formation and abrogating phagolysosomal fusion, inflammation, and apoptosis. Additionally, M. tuberculosis cell wall lipids, particularly mycolic acids, crosstalk with human PXR (hPXR) by interacting with its promiscuous ligand binding domain. To confirm our in vitro findings and to avoid the reported species barrier in PXR function, we adopted an in vivo mouse model expressing hPXR, wherein expression of hPXR in mice promotes M. tuberculosis survival. Therefore, pharmacological intervention and designing antagonists to hPXR may prove to be a promising adjunct therapy for tuberculosis. PMID:27233963

  20. Rapid Identification and Drug Susceptibility Testing of Mycobacterium tuberculosis: Standard Operating Procedure for Non-Commercial Assays: Part 1: Microscopic Observation Drug Susceptibility Assay v2.4.12

    PubMed Central

    Singh, Sarman; Kumar, Parveen; Sharma, Shreya; Mumbowa, Francis; Martin, Anandi; Durier, Nicolas

    2012-01-01

    Multidrug-resistant tuberculosis is an increasing public health concern in many parts of the world, especially in low-income countries, where most cases occur. Traditional mycobacteria culture and drug susceptibility testing (DST) is either time-consuming or expensive and for that reason uptake of these technologies has remained limited in many resource-constrained settings. However, several non-commercial culture and DST methods that do not require sophisticated infrastructure and techniques have been developed. One such method is the microscopic observation drug susceptibility assay (MODS). In this method microcolonies that form in the liquid culture medium after specimen inoculation to drug-free and drug-containing micro-wells are detected by visual observation with a simple inverted microscope. The identification and drug susceptibility results can be obtained in 7-15 days. This standard operating procedure document has been developed through the culture and DST subgroup of the STOP TB Partnership, New Diagnostic Working Group. It is intended for laboratories that would want to use or already using this rapid non-commercial method for culture identification and DST of Mycobacterium tuberculosis, notably in resource-constraint settings in Asia and Africa. PMID:23440310

  1. Dramatic reduction of culture time of Mycobacterium tuberculosis

    NASA Astrophysics Data System (ADS)

    Ghodbane, Ramzi; Raoult, Didier; Drancourt, Michel

    2014-02-01

    Mycobacterium tuberculosis culture, a critical technique for routine diagnosis of tuberculosis, takes more than two weeks. Here, step-by-step improvements in the protocol including a new medium, microaerophlic atmosphere or ascorbic-acid supplement and autofluorescence detection dramatically shortened this delay. In the best case, primary culture and rifampicin susceptibility testing were achieved in 72 hours when specimens were inoculated directly on the medium supplemented by antibiotic at the beginning of the culture.

  2. Portrait of a Pathogen: The Mycobacterium tuberculosis Proteome In Vivo

    PubMed Central

    Kruh, Nicole A.; Troudt, Jolynn; Izzo, Angelo; Prenni, Jessica; Dobos, Karen M.

    2010-01-01

    Background Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is a facultative intracellular pathogen that can persist within the host. The bacteria are thought to be in a state of reduced replication and metabolism as part of the chronic lung infection. Many in vitro studies have dissected the hypothesized environment within the infected lung, defining the bacterial response to pH, starvation and hypoxia. While these experiments have afforded great insight, the picture remains incomplete. The only way to study the combined effects of these environmental factors and the mycobacterial response is to study the bacterial response in vivo. Methodology/Principal Findings We used the guinea pig model of tuberculosis to examine the bacterial proteome during the early and chronic stages of disease. Lungs were harvested thirty and ninety days after aerosol challenge with Mtb, and analyzed by liquid chromatography-mass spectrometry. To date, in vivo proteomics of the tubercle bacillus has not been described and this work has generated the first large-scale shotgun proteomic data set, comprising over 500 unique protein identifications. Cell wall and cell wall processes, and intermediary metabolism and respiration were the two major functional classes of proteins represented in the infected lung. These classes of proteins displayed the greatest heterogeneity indicating important biological processes for establishment of a productive bacterial infection and its persistence. Proteins necessary for adaptation throughout infection, such as nitrate/nitrite reduction were found at both time points. The PE-PPE protein class, while not well characterized, represented the third most abundant category and showed the most consistent expression during the infection. Conclusions/Significance Cumulatively, the results of this work may provide the basis for rational drug design – identifying numerous Mtb proteins, from essential kinases to products involved in

  3. Detection of Mycobacterium tuberculosis by PCR amplification with pan-Mycobacterium primers and hybridization to an M. tuberculosis-specific probe.

    PubMed Central

    Tevere, V J; Hewitt, P L; Dare, A; Hocknell, P; Keen, A; Spadoro, J P; Young, K K

    1996-01-01

    Nucleic acid amplification techniques such as the PCR are very useful in the rapid diagnosis of infections by Mycobacterium tuberculosis. However, recent studies have shown that the accuracy of results can vary widely when tests are performed with nonstandardized reagents. We have developed a PCR assay for the detection of M. tuberculosis that is both rapid and accurate. The assay reagents are standardized and quality controlled. False-positive results due to carryover contamination are prevented by the incorporation of dUTP coupled with uracil-N-glycosylase restriction. This assay also employs pan-Mycobacterium amplification primers, allowing for flexibility in the mycobacterial species that can be identified from a single amplification reaction. The amplification is very sensitive; amplification products generated from as few as three bacteria can be detected by agarose gel electrophoresis. DNAs isolated from 33 of 34 mycobacterial species tested were amplified efficiently. Only DNA from Mycobacterium simiae did not amplify. The amplification is also very specific. Amplification products were generated only from the DNAs of bacteria in closely related genera such as Corynebacterium. The nonmycobacterial amplicons do not pose a problem, as they do not hybridize to mycobacterium-specific probes. Hybridization of amplicons to an M. tuberculosis-specific probe allows for the unambiguous identification of M. tuberculosis complex organisms. The clinical performance of this PCR assay was evaluated against that of culture in 662 respiratory specimens. Sensitivities of 100 and 73.1% were obtained from smear-positive and -negative respiratory specimens, respectively. The corresponding specificities were 100 and 99.8%. The high sensitivity and specificity, coupled with the potential for detecting a wide range of mycobacteria, make this assay a useful tool in the clinical management of mycobacterial infections. PMID:8815108

  4. Genomic signal analysis of Mycobacterium tuberculosis

    NASA Astrophysics Data System (ADS)

    Cristea, Paul Dan; Banica, Dorina; Tuduce, Rodica

    2007-02-01

    As previously shown the conversion of nucleotide sequences into digital signals offers the possibility to apply signal processing methods for the analysis of genomic data. Genomic Signal Analysis (GSA) has been used to analyze large scale features of DNA sequences, at the scale of whole chromosomes, including both coding and non-coding regions. The striking regularities of genomic signals reveal restrictions in the way nucleotides and pairs of nucleotides are distributed along nucleotide sequences. Structurally, a chromosome appears to be less of a "plain text", corresponding to certain semantic and grammar rules, but more of a "poem", satisfying additional symmetry restrictions that evoke the "rhythm" and "rhyme". Recurrent patterns in nucleotide sequences are reflected in simple mathematical regularities observed in genomic signals. GSA has also been used to track pathogen variability, especially concerning their resistance to drugs. Previous work has been dedicated to the study of HIV-1, Clade F and Avian Flu. The present paper applies GSA methodology to study Mycobacterium tuberculosis (MT) rpoB gene variability, relevant to its resistance to antibiotics. Isolates from 50 Romanian patients have been studied both by rapid LightCycler PCR and by sequencing of a segment of 190-250 nucleotides covering the region of interest. The variability is caused by SNPs occurring at specific sites along the gene strand, as well as by inclusions. Because of the mentioned symmetry restrictions, the GS variations tend to compensate. An important result is that MT can act as a vector for HIV virus, which is able to retrotranscribe its specific genes both into human and MT genomes.

  5. PCR-Based Method To Differentiate the Subspecies of the Mycobacterium tuberculosis Complex on the Basis of Genomic Deletions

    PubMed Central

    Huard, Richard C.; de Oliveira Lazzarini, Luiz Claudio; Butler, W. Ray; van Soolingen, Dick; Ho, John L.

    2003-01-01

    The classical Mycobacterium tuberculosis complex (MtbC) subspecies include Mycobacterium tuberculosis, Mycobacterium africanum (subtypes I and II), Mycobacterium bovis (along with the attenuated M. bovis bacillus Calmette-Guérin [BCG]), and Mycobacterium microti; increasingly recognized MtbC groupings include Mycobacterium bovis subsp. caprae and “Mycobacterium tuberculosis subsp. canettii.” Previous investigations have documented each MtbC subspecies as a source of animal and/or human tuberculosis. However, study of these organisms is hindered by the lack of a single protocol that quickly and easily differentiates all of the MtbC groupings. Towards this end we have developed a rapid, simple, and reliable PCR-based MtbC typing method that makes use of MtbC chromosomal region-of-difference deletion loci. Here, seven primer pairs (which amplify within the loci 16S rRNA, Rv0577, IS1561′, Rv1510, Rv1970, Rv3877/8, and Rv3120) were run in separate but simultaneous reactions. Each primer pair either specifically amplified a DNA fragment of a unique size or failed, depending upon the source mycobacterial DNA. The pattern of amplification products from all of the reactions, visualized by agarose gel electrophoresis, allowed immediate identification either as MtbC composed of M. tuberculosis (or M. africanum subtype II), M. africanum subtype I, M. bovis, M. bovis BCG, M. caprae, M. microti, or “M. canettii” or as a Mycobacterium other than MtbC (MOTT). This MtbC PCR typing panel provides an advanced approach to determine the subspecies of MtbC isolates and to differentiate them from clinically important MOTT species. It has proven beneficial in the management of Mycobacterium collections and may be applied for practical clinical and epidemiological use. PMID:12682155

  6. Immunogenicity and protective efficacy of novel Mycobacterium tuberculosis antigens.

    PubMed

    Derrick, Steven C; Yabe, Idalia M; Yang, Amy; Kolibab, Kristopher; Hollingsworth, Brynn; Kurtz, Sherry L; Morris, Sheldon

    2013-09-23

    With tuberculosis continuing to be a major cause of global morbidity and mortality, a new vaccine is urgently needed. Tuberculosis subunit vaccines have been shown to induce robust immune responses in humans and are a potentially safer alternative to BCG for use in HIV-endemic areas. In this study, we investigated the protective efficacy of 16 different novel Mycobacterium tuberculosis antigens using an aerogenic mouse model of pulmonary tuberculosis. These antigens were tested as subunit vaccines formulated in dimethyl dioctadecyl ammonium bromide (DDA) - D(+) with trehalose 6,6 dibenenate (TDB) (DDA/TDB) adjuvant administered alone as monovalent vaccines or in combination. Six of these antigens (Rv1626, Rv1735, Rv1789, Rv2032, Rv2220, and Rv3478) were shown to consistently and significantly reduce bacterial burdens in the lungs of mice relative to nonvaccinated controls. Three of these six (Rv1789, Rv2220, and Rv3478) induced levels of protective immunity that were essentially equivalent to protection induced by the highly immunogenic antigen 85B (>0.5 log₁₀CFU reduction in the lungs relative to naïve mice). Importantly, when these three antigens were combined, protection essentially equivalent to that mediated by BCG was observed. When either Rv1626 or Rv2032 were combined with the highly protective E6-85 fusion protein (antigen 85B fused to ESAT-6), the protection observed was equivalent to BCG-induced protection at one and three months post-aerosol infection and was significantly greater than the protection observed when E6-85 was administered alone at 3 months post-infection. Using multiparameter flow cytometry, monofunctional IFNγ CD4T cells and different multifunctional CD4T cell subsets capable of secreting multiple cytokines (IFNγ, TNFα and/or IL-2) were shown to be induced by the three most protective antigens with splenocyte CD4T cell frequencies significantly greater than observed in naïve controls. The identification of these highly

  7. Detection of Mycobacterium tuberculosis complex by nested polymerase chain reaction in pulmonary and extrapulmonary specimens* ,**

    PubMed Central

    Furini, Adriana Antônia da Cruz; Pedro, Heloisa da Silveira Paro; Rodrigues, Jean Francisco; Montenegro, Lilian Maria Lapa; Machado, Ricardo Luiz Dantas; Franco, Célia; Schindler, Haiana Charifker; Batista, Ida Maria Foschiani Dias; Rossit, Andrea Regina Baptista

    2013-01-01

    OBJECTIVE: To compare the performance of nested polymerase chain reaction (NPCR) with that of cultures in the detection of the Mycobacterium tuberculosis complex in pulmonary and extrapulmonary specimens. METHODS: We analyzed 20 and 78 pulmonary and extrapulmonary specimens, respectively, of 67 hospitalized patients suspected of having tuberculosis. An automated microbial system was used for the identification of Mycobacterium spp. cultures, and M. tuberculosis IS6110 was used as the target sequence in the NPCR. The kappa statistic was used in order to assess the level of agreement among the results. RESULTS: Among the 67 patients, 6 and 5, respectively, were diagnosed with pulmonary and extrapulmonary tuberculosis, and the NPCR was positive in all of the cases. Among the 98 clinical specimens, smear microscopy, culture, and NPCR were positive in 6.00%, 8.16%, and 13.26%, respectively. Comparing the results of NPCR with those of cultures (the gold standard), we found that NPCR had a sensitivity and specificity of 100% and 83%, respectively, in pulmonary specimens, compared with 83% and 96%, respectively, in extrapulmonary specimens, with good concordance between the tests (kappa, 0.50 and 0.6867, respectively). CONCLUSIONS: Although NPCR proved to be a very useful tool for the detection of M. tuberculosis complex, clinical, epidemiological, and other laboratory data should also be considered in the diagnosis and treatment of pulmonary and extrapulmonary tuberculosis. PMID:24473765

  8. Detection of Mycobacterium tuberculosis in clinical specimens by polymerase chain reaction and Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test.

    PubMed Central

    Abe, C; Hirano, K; Wada, M; Kazumi, Y; Takahashi, M; Fukasawa, Y; Yoshimura, T; Miyagi, C; Goto, S

    1993-01-01

    The polymerase chain reaction (PCR) using oligonucleotides based on the repetitive sequence (IS986) of Mycobacterium tuberculosis as a primer and the Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test (MTD), which combines an M. tuberculosis rRNA amplification method with the hybridization protection assay format, were evaluated for detection of M. tuberculosis in clinical samples. The detection limits of these two assay systems based on nucleic acid amplification for cultured M. tuberculosis were less than 10 cells per reaction. A total of 135 sputum specimens were examined by the two assay systems. The PCR and the MTD systems for detection of M. tuberculosis gave overall positivity rates of 84.2% (32 of 38) and 91.9% (34 of 37), respectively, as compared with 71.9% (23 of 32) by smear and 96.9% (31 of 32) by culture in the liquid medium MB-Check. Procedures for sample preparation used in the two methods were different. Although the sensitivities of the PCR and MTD appeared to be similar to that of culture with the MB-Check system, the two methods based on nucleic acid amplification should be very useful for rapid detection of M. tuberculosis infections without the long time required for culture of M. tuberculosis. Images PMID:8308121

  9. Novel Cephalosporins Selectively Active on Nonreplicating Mycobacterium tuberculosis.

    PubMed

    Gold, Ben; Smith, Robert; Nguyen, Quyen; Roberts, Julia; Ling, Yan; Lopez Quezada, Landys; Somersan, Selin; Warrier, Thulasi; Little, David; Pingle, Maneesh; Zhang, David; Ballinger, Elaine; Zimmerman, Matthew; Dartois, Véronique; Hanson, Paul; Mitscher, Lester A; Porubsky, Patrick; Rogers, Steven; Schoenen, Frank J; Nathan, Carl; Aubé, Jeffrey

    2016-07-14

    We report two series of novel cephalosporins that are bactericidal to Mycobacterium tuberculosis alone of the pathogens tested, which only kill M. tuberculosis when its replication is halted by conditions resembling those believed to pertain in the host, and whose bactericidal activity is not dependent upon or enhanced by clavulanate, a β-lactamase inhibitor. The two classes of cephalosporins bear an ester or alternatively an oxadiazole isostere at C-2 of the cephalosporin ring system, a position that is almost exclusively a carboxylic acid in clinically used agents in the class. Representatives of the series kill M. tuberculosis within macrophages without toxicity to the macrophages or other mammalian cells. PMID:27144688

  10. Novel Cephalosporins Selectively Active on Nonreplicating Mycobacterium tuberculosis

    PubMed Central

    2016-01-01

    We report two series of novel cephalosporins that are bactericidal to Mycobacterium tuberculosis alone of the pathogens tested, which only kill M. tuberculosis when its replication is halted by conditions resembling those believed to pertain in the host, and whose bactericidal activity is not dependent upon or enhanced by clavulanate, a β-lactamase inhibitor. The two classes of cephalosporins bear an ester or alternatively an oxadiazole isostere at C-2 of the cephalosporin ring system, a position that is almost exclusively a carboxylic acid in clinically used agents in the class. Representatives of the series kill M. tuberculosis within macrophages without toxicity to the macrophages or other mammalian cells. PMID:27144688

  11. A multi-stress model for high throughput screening against non-replicating Mycobacterium tuberculosis.

    PubMed

    Gold, Ben; Warrier, Thulasi; Nathan, Carl

    2015-01-01

    Models of non-replication help us understand the biology of persistent Mycobacterium tuberculosis. High throughput screening (HTS) against non-replicating M. tuberculosis may lead to identification of tool compounds that affect pathways on which bacterial survival depends in such states, and to development of drugs that can overcome phenotypic tolerance to conventional antimycobacterial agents, which are mostly active against replicating M. tuberculosis. We describe a multi-stress model of non-replication that mimics some of the microenvironmental conditions that M. tuberculosis faces in the host as adapted for HTS. The model includes acidic pH, mild hypoxia, a flux of nitric oxide and other reactive nitrogen intermediates arising from nitrite at low pH, and low concentrations of a fatty acid (butyrate) as a carbon source. PMID:25779324

  12. Co-evolution of Mycobacterium tuberculosis and Homo sapiens

    PubMed Central

    Brites, Daniela; Gagneux, Sebastien

    2015-01-01

    The causative agent of human tuberculosis (TB), Mycobacterium tuberculosis, is an obligate pathogen that evolved to exclusively persist in human populations. For M. tuberculosis to transmit from person to person, it has to cause pulmonary disease. Therefore, M. tuberculosis virulence has likely been a significant determinant of the association between M. tuberculosis and humans. Indeed, the evolutionary success of some M. tuberculosis genotypes seems at least partially attributable to their increased virulence. The latter possibly evolved as a consequence of human demographic expansions. If co-evolution occurred, humans would have counteracted to minimize the deleterious effects of M. tuberculosis virulence. The fact that human resistance to infection has a strong genetic basis is a likely consequence of such a counter-response. The genetic architecture underlying human resistance to M. tuberculosis remains largely elusive. However, interactions between human genetic polymorphisms and M. tuberculosis genotypes have been reported. Such interactions are consistent with local adaptation and allow for a better understanding of protective immunity in TB. Future ‘genome-to-genome’ studies, in which locally associated human and M. tuberculosis genotypes are interrogated in conjunction, will help identify new protective antigens for the development of better TB vaccines. PMID:25703549

  13. Can Molecular Methods Detect 1% Isoniazid Resistance in Mycobacterium tuberculosis?

    PubMed Central

    Folkvardsen, Dorte Bek; Thomsen, Vibeke Ø.; Rasmussen, Erik Michael; Bang, Didi; Werngren, Jim; Hoffner, Sven; Hillemann, Doris; Rigouts, Leen

    2013-01-01

    Patients may harbor both drug-susceptible and -resistant bacteria, representing heteroresistance. We studied mixtures of isoniazid-resistant and -susceptible Mycobacterium tuberculosis strains. Conventional drug susceptibility testing was the most sensitive method of detection, whereas the line probe assay and sequencing were not able to detect the clinically relevant 1% proportion of resistant bacteria. PMID:23447641

  14. A case of Manila type Mycobacterium tuberculosis infection in Japan

    PubMed Central

    Usami, Osamu; Nakajima, Chie; Endo, Shiro; Inomata, Shinya; Kanamori, Hajime; Hirakata, Yoichi; Uchiyama, Bine; Kaku, Mitsuo; Suzuki, Yasuhiko; Hattori, Toshio

    2015-01-01

    Key Clinical Message A 76-year-old Japanese woman contracted a Mycobacterium tuberculosis (TB, Manila type) infection in Japan, despite never having traveled. However, her son was treated for TB in the Philippines 3 years before he stayed at her house. Spoligotyping allows us to identify the TB genotype and identify the route of infection. PMID:26273455

  15. 21 CFR 866.3370 - Mycobacterium tuberculosis immunofluorescent reagents.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Mycobacterium tuberculosis immunofluorescent reagents. 866.3370 Section 866.3370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological...

  16. 21 CFR 866.3370 - Mycobacterium tuberculosis immunofluorescent reagents.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Mycobacterium tuberculosis immunofluorescent reagents. 866.3370 Section 866.3370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological...

  17. 21 CFR 866.3370 - Mycobacterium tuberculosis immunofluorescent reagents.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Mycobacterium tuberculosis immunofluorescent reagents. 866.3370 Section 866.3370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological...

  18. 21 CFR 866.3370 - Mycobacterium tuberculosis immunofluorescent reagents.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Mycobacterium tuberculosis immunofluorescent reagents. 866.3370 Section 866.3370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological...

  19. 21 CFR 866.3370 - Mycobacterium tuberculosis immunofluorescent reagents.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Mycobacterium tuberculosis immunofluorescent reagents. 866.3370 Section 866.3370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological...

  20. Insights into redox sensing metalloproteins in Mycobacterium tuberculosis.

    PubMed

    Chim, Nicholas; Johnson, Parker M; Goulding, Celia W

    2014-04-01

    Mycobacterium tuberculosis, the pathogen that causes tuberculosis, has evolved sophisticated mechanisms for evading assault by the human host. This review focuses on M. tuberculosis regulatory metalloproteins that are sensitive to exogenous stresses attributed to changes in the levels of gaseous molecules (i.e., molecular oxygen, carbon monoxide and nitric oxide) to elicit an intracellular response. In particular, we highlight recent developments on the subfamily of Whi proteins, redox sensing WhiB-like proteins that contain iron-sulfur clusters, sigma factors and their cognate anti-sigma factors of which some are zinc-regulated, and the dormancy survival regulon DosS/DosT-DosR heme sensory system. Mounting experimental evidence suggests that these systems contribute to a highly complex and interrelated regulatory network that controls M. tuberculosis biology. This review concludes with a discussion of strategies that M. tuberculosis has developed to maintain redox homeostasis, including mechanisms to regulate endogenous nitric oxide and carbon monoxide levels. PMID:24314844

  1. Biosensing Technologies for Mycobacterium tuberculosis Detection: Status and New Developments

    PubMed Central

    Zhou, Lixia; He, Xiaoxiao; He, Dinggeng; Wang, Kemin; Qin, Dilan

    2011-01-01

    Biosensing technologies promise to improve Mycobacterium tuberculosis (M. tuberculosis) detection and management in clinical diagnosis, food analysis, bioprocess, and environmental monitoring. A variety of portable, rapid, and sensitive biosensors with immediate “on-the-spot” interpretation have been developed for M. tuberculosis detection based on different biological elements recognition systems and basic signal transducer principles. Here, we present a synopsis of current developments of biosensing technologies for M. tuberculosis detection, which are classified on the basis of basic signal transducer principles, including piezoelectric quartz crystal biosensors, electrochemical biosensors, and magnetoelastic biosensors. Special attention is paid to the methods for improving the framework and analytical parameters of the biosensors, including sensitivity and analysis time as well as automation of analysis procedures. Challenges and perspectives of biosensing technologies development for M. tuberculosis detection are also discussed in the final part of this paper. PMID:21437177

  2. Reconstruction and topological characterization of the sigma factor regulatory network of Mycobacterium tuberculosis.

    PubMed

    Chauhan, Rinki; Ravi, Janani; Datta, Pratik; Chen, Tianlong; Schnappinger, Dirk; Bassler, Kevin E; Balázsi, Gábor; Gennaro, Maria Laura

    2016-01-01

    Accessory sigma factors, which reprogram RNA polymerase to transcribe specific gene sets, activate bacterial adaptive responses to noxious environments. Here we reconstruct the complete sigma factor regulatory network of the human pathogen Mycobacterium tuberculosis by an integrated approach. The approach combines identification of direct regulatory interactions between M. tuberculosis sigma factors in an E. coli model system, validation of selected links in M. tuberculosis, and extensive literature review. The resulting network comprises 41 direct interactions among all 13 sigma factors. Analysis of network topology reveals (i) a three-tiered hierarchy initiating at master regulators, (ii) high connectivity and (iii) distinct communities containing multiple sigma factors. These topological features are likely associated with multi-layer signal processing and specialized stress responses involving multiple sigma factors. Moreover, the identification of overrepresented network motifs, such as autoregulation and coregulation of sigma and anti-sigma factor pairs, provides structural information that is relevant for studies of network dynamics. PMID:27029515

  3. Reconstruction and topological characterization of the sigma factor regulatory network of Mycobacterium tuberculosis

    PubMed Central

    Chauhan, Rinki; Ravi, Janani; Datta, Pratik; Chen, Tianlong; Schnappinger, Dirk; Bassler, Kevin E.; Balázsi, Gábor; Gennaro, Maria Laura

    2016-01-01

    Accessory sigma factors, which reprogram RNA polymerase to transcribe specific gene sets, activate bacterial adaptive responses to noxious environments. Here we reconstruct the complete sigma factor regulatory network of the human pathogen Mycobacterium tuberculosis by an integrated approach. The approach combines identification of direct regulatory interactions between M. tuberculosis sigma factors in an E. coli model system, validation of selected links in M. tuberculosis, and extensive literature review. The resulting network comprises 41 direct interactions among all 13 sigma factors. Analysis of network topology reveals (i) a three-tiered hierarchy initiating at master regulators, (ii) high connectivity and (iii) distinct communities containing multiple sigma factors. These topological features are likely associated with multi-layer signal processing and specialized stress responses involving multiple sigma factors. Moreover, the identification of overrepresented network motifs, such as autoregulation and coregulation of sigma and anti-sigma factor pairs, provides structural information that is relevant for studies of network dynamics. PMID:27029515

  4. Identification of Novel Inhibitors of Mycobacterium tuberculosis PknG Using Pharmacophore Based Virtual Screening, Docking, Molecular Dynamics Simulation, and Their Biological Evaluation.

    PubMed

    Singh, Nidhi; Tiwari, Sameer; Srivastava, Kishore K; Siddiqi, Mohammad Imran

    2015-06-22

    PknG is a Ser/thr protein kinase that plays a crucial role in regulatory processes within the mycobacterial cell and signaling cascade of the infected host cell. The essentiality of PknG in mycobacterial virulence by blocking phagosome-lysosome fusion as well as its role in intrinsic antibiotic resistance makes it an attractive drug target. However, only very few compounds have been reported as Mycobacterium tuberculosis PknG (MtPknG) inhibitors so far. Therefore, in an effort to find potential inhibitors against MtPknG, we report here a sequential pharmacophore-based virtual screening workflow, 3-fold docking with different search algorithms, and molecular dynamic simulations for better insight into the predicted binding mode of identified hits. After detailed analysis of the results, six ligands were selected for in vitro analysis. Three of these molecules showed significant inhibitory activity against MtPknG. In addition, inhibitory studies of mycobacterial growth in infected THP-1 macrophages demonstrated considerable growth inhibition of M. bovis BCG induced through compound NRB04248 without any cytotoxic effect against host macrophages. Our results suggest that the compound NRB04248 can be explored for further design and optimization of MtPknG inhibitors. PMID:25965448

  5. Identification of distant co-evolving residues in antigen 85C from Mycobacterium tuberculosis using statistical coupling analysis of the esterase family proteins.

    PubMed

    Baths, Veeky; Roy, Utpal

    2011-05-01

    A fundamental goal in cellular signaling is to understand allosteric communication, the process by which signals originating at one site in a protein propagate reliably to affect distant functional sites. The general principles of protein structure that underlie this process remain unknown. Statistical coupling analysis (SCA) is a statistical technique that uses evolutionary data of a protein family to measure correlation between distant functional sites and suggests allosteric communication. In proteins, very distant and small interactions between collections of amino acids provide the communication which can be important for signaling process. In this paper, we present the SCA of protein alignment of the esterase family (pfam ID: PF00756) containing the sequence of antigen 85C secreted by Mycobacterium tuberculosis to identify a subset of interacting residues. Clustering analysis of the pairwise correlation highlighted seven important residue positions in the esterase family alignments. These residues were then mapped on the crystal structure of antigen 85C (PDB ID: 1DQZ). The mapping revealed correlation between 3 distant residues (Asp38, Leu123 and Met125) and suggests allosteric communication between them. This information can be used for a new drug against this fatal disease. PMID:23554685

  6. Expression, purification, and characterization of protective MPT64 antigen protein and identification of its multimers isolated from nontoxic Mycobacterium tuberculosis H37Ra.

    PubMed

    Chu, Teng-Ping J; Yuann, Jeu-Ming P

    2011-05-01

    MPT64, a secreted protein of Mycobacterium tuberculosis (MTB), stimulates the immune reactions within cells and is a protective antigen that is lost by the bacilli Calmette-Guérin (BCG) vaccine during propagation. To minimize the toxicity caused by MTB, we used the MPT64 gene encoded by nontoxic H37Ra MTB to carry out genetic expansion via polymerase chain reaction and gene clone MPT64. The plasmid DNA encoded MPT64 was expressed at 20°C for 22 H, and a large quantity of MPT64 was obtained. In the absence of urea, MPT64 multimers with subunits being covalently connected via disulfide bonds were detected by Western blot showing strong protein-protein interactions, as evidenced by the formation of MPT64 tetramers. Finally, with urea of decreasing concentrations, we refolded MPT64 purified in the presence of urea and determined its secondary structures using circular dichroism. MPT64 was found to contain 2.2% α-helix, 50.9% β-sheet, 19.5% turn, and 27.4% random coil. The molecular weight of MPT64 was determined by a matrix-assisted laser desorption ionization-time of flight mass spectrometer and found to be 23,497 Da, very close to the theoretical molecular weight of MPT64. The results presented here provide a sound basis for future biochemical and biophysical studies of MPT64 or any other proteins encoded by nontoxic H37Ra MTB. PMID:21679242

  7. Rapid diagnosis of Mycobacterium tuberculosis bacteremia by PCR.

    PubMed Central

    Folgueira, L; Delgado, R; Palenque, E; Aguado, J M; Noriega, A R

    1996-01-01

    A method based on DNA amplification and hybridization has been used for the rapid detection of Mycobacterium tuberculosis in blood samples from 38 hospitalized patients (15 human immunodeficiency virus [HIV] positive and 23 HIV negative) in whom localized or disseminated forms of tuberculosis were suspected. In 32 of these patients, the diagnosis of tuberculosis was eventually confirmed by conventional bacteriological or histological procedures. M. tuberculosis DNA was detected with the PCR technique in the peripheral blood mononuclear cells from 9 of 11 (82%) HIV-infected patients and in 7 of 21 (33%) HIV-negative patients (P < 0.01), while M. tuberculosis blood cultures were positive in 1 of 8 (12.5%) and 1 of 18 (5.5%) patients, respectively. PCR was positive in all cases with disseminated disease in both HIV-negative and HIV-positive patients and also in the HIV-positive patients with extrapulmonary tuberculosis. Seven samples from patients with documented illness other than tuberculosis and 12 specimens from healthy volunteers, including seven volunteers with a recent positive purified protein derivative test, were used as controls and had a negative PCR. These results suggest that detection of M. tuberculosis DNA in peripheral blood mononuclear cells may be a useful tool for rapid diagnosis of disseminated and extrapulmonary forms of tuberculosis, especially in an HIV-positive population. PMID:8904404

  8. Mycobacterium tuberculosis resistance to antituberculosis drugs in Mozambique*, **

    PubMed Central

    Pires, Germano Manuel; Folgosa, Elena; Nquobile, Ndlovu; Gitta, Sheba; Cadir, Nureisha

    2014-01-01

    OBJECTIVE: To determine the drug resistance profile of Mycobacterium tuberculosis in Mozambique. METHODS: We analyzed secondary data from the National Tuberculosis Referral Laboratory, in the city of Maputo, Mozambique, and from the Beira Regional Tuberculosis Referral Laboratory, in the city of Beira, Mozambique. The data were based on culture-positive samples submitted to first-line drug susceptibility testing (DST) between January and December of 2011. We attempted to determine whether the frequency of DST positivity was associated with patient type or provenance. RESULTS: During the study period, 641 strains were isolated in culture and submitted to DST. We found that 374 (58.3%) were resistant to at least one antituberculosis drug and 280 (43.7%) were resistant to multiple antituberculosis drugs. Of the 280 multidrug-resistant tuberculosis cases, 184 (65.7%) were in previously treated patients, most of whom were from southern Mozambique. Two (0.71%) of the cases of multidrug-resistant tuberculosis were confirmed to be cases of extensively drug-resistant tuberculosis. Multidrug-resistant tuberculosis was most common in males, particularly those in the 21-40 year age bracket. CONCLUSIONS: M. tuberculosis resistance to antituberculosis drugs is high in Mozambique, especially in previously treated patients. The frequency of M. tuberculosis strains that were resistant to isoniazid, rifampin, and streptomycin in combination was found to be high, particularly in samples from previously treated patients. PMID:24831398

  9. [Increased IL-4 production in response to virulent Mycobacterium tuberculosis in tuberculosis patients with advanced disease].

    PubMed

    Ordway, Diane J; Martins, Marta S; Costa, Leonor M; Freire, Mónica S; Arroz, Maria J; Dockrell, Hazel M; Ventura, Fernando A

    2005-01-01

    The study was designed to compare immune responses to Mycobacterium tuberculosis bacilli and antigens in healthy Portuguese subjects and pulmonary tuberculosis patients (TB), and to correlate immune status with clinical severity of tuberculosis disease. PBMC were cultured and stimulated with live and killed M. tuberculosis H37Rv and purified protein derivative (PPD) and lymphoproliferation and production of IFN-gamma and IL-5/IL-4 by these cultures were evaluated by the use of ELISA and multi-parameter flow cytometry. PBMC from 30 tuberculosis patients demonstrated significantly reduced amounts of proliferation and IFN-gamma when stimulated with live M. tuberculosis compared the control group. Of 15 tuberculosis patients tested for intracellular IL-4 following stimulation with M. tuberculosis, 7 showed greatly increased IL-4 production in CD8+ and gammadelta+ T cells. Tuberculosis patients demonstrated an increase of intracellular IL-4 after PBMC were stimulated with live M. tuberculosis in the CD4+ phenotype, but more notably in CD8+ and gammadelta TCR+ subsets. Increased production of IL-4 in tuberculosis patients was primarily in individuals with advanced involvement of lung parenchymal with high bacterial loads in sputum. These results suggest that an alteration in type 1 and type 2 cytokine balance can occur in patients with tuberculosis at an advanced clinical stage of disease. PMID:16202332

  10. Determination of Urinary Neopterin/Creatinine Ratio to Distinguish Active Tuberculosis from Latent Mycobacterium tuberculosis Infection

    PubMed Central

    Eisenhut, Michael; Hargreaves, Dougal S.; Scott, Anne; Housley, David; Walters, Andrew; Mulla, Rohinton

    2016-01-01

    Background. Biomarkers to distinguish latent from active Mycobacterium (M.) tuberculosis infection in clinical practice are lacking. The urinary neopterin/creatinine ratio can quantify the systemic interferon-gamma effect in patients with M. tuberculosis infection. Methods. In a prospective observational study, urinary neopterin levels were measured by enzyme linked immunosorbent assay in patients with active tuberculosis, in people with latent M. tuberculosis infection, and in healthy controls and the urinary neopterin/creatinine ratio was calculated. Results. We included a total of 44 patients with M. tuberculosis infection and nine controls. 12 patients had active tuberculosis (8 of them culture-confirmed). The median age was 15 years (range 4.5 to 49). Median urinary neopterin/creatinine ratio in patients with active tuberculosis was 374.1 micromol/mol (129.0 to 1072.3), in patients with latent M. tuberculosis infection it was 142.1 (28.0 to 384.1), and in controls it was 146.0 (40.3 to 200.0), with significantly higher levels in patients with active tuberculosis (p < 0.01). The receiver operating characteristics curve had an area under the curve of 0.84 (95% CI 0.70 to 0.97) (p < 0.01). Conclusions. Urinary neopterin/creatinine ratios are significantly higher in patients with active tuberculosis compared to patients with latent infection and may be a significant predictor of active tuberculosis in patients with M. tuberculosis infection. PMID:27433370

  11. Transmission of Mycobacterium orygis (M. tuberculosis complex species) from a tuberculosis patient to a dairy cow in New Zealand.

    PubMed

    Dawson, Kara L; Bell, Anita; Kawakami, R Pamela; Coley, Kathryn; Yates, Gary; Collins, Desmond M

    2012-09-01

    Mycobacterium orygis, previously called the oryx bacillus, is a member of the Mycobacterium tuberculosis complex and has been reported only recently as a cause of human tuberculosis in patients of South Asian origin. We present the first case documenting the transmission of this organism from a human to a cow. PMID:22785186

  12. TuberQ: a Mycobacterium tuberculosis protein druggability database

    PubMed Central

    Radusky, Leandro; Lanzarotti, Esteban; Luque, Javier; Barril, Xavier; Marti, Marcelo A.; Turjanski, Adrián G.

    2014-01-01

    In 2012 an estimated 8.6 million people developed tuberculosis (TB) and 1.3 million died from the disease [including 320 000 deaths among human immunodeficiency virus (HIV)-positive people]. There is an urgent need for new anti-TB drugs owing to the following: the fact that current treatments have severe side effects, the increasing emergence of multidrug-resistant strains of Mycobacterium tuberculosis (Mtb), the negative drug–drug interactions with certain HIV (or other disease) treatments and the ineffectiveness against dormant Mtb. In this context we present here the TuberQ database, a novel resource for all researchers working in the field of drug development in TB. The main feature of TuberQ is to provide a druggability analysis of Mtb proteins in a consistent and effective manner, contributing to a better selection of potential drug targets for screening campaigns and the analysis of targets for structure-based drug design projects. The structural druggability analysis is combined with features related to the characteristics of putative inhibitor binding pockets and with functional and biological data of proteins. The structural analysis is performed on all available unique Mtb structures and high-quality structural homology-based models. This information is shown in an interactive manner, depicting the protein structure, the pockets and the associated characteristics for each protein. TuberQ also provides information about gene essentiality information, as determined from whole cell–based knockout experiments, and expression information obtained from microarray experiments done in different stress-related conditions. We hope that TuberQ will be a powerful tool for researchers working in TB and eventually will lead to the identification of novel putative targets and progresses in therapeutic activities. Database URL: http://tuberq.proteinq.com.ar/ PMID:24816183

  13. Molecular Typing of Mycobacterium Tuberculosis Strains: A Fundamental Tool for Tuberculosis Control and Elimination

    PubMed Central

    Cannas, Angela; Mazzarelli, Antonio; Di Caro, Antonino; Delogu, Giovanni; Girardi, Enrico

    2016-01-01

    Tuberculosis (TB) is still an important cause of morbidity and mortality worldwide. An improvement of the strategies for disease control is necessary in both low- and high-incidence TB countries. Clinicians, epidemiologists, laboratory specialists, and public health players should work together in order to achieve a significant reduction in TB transmission and spread of drug-resistant strains. Effective TB surveillance relies on early diagnosis of new cases, appropriate therapy, and accurate detection of outbreaks in the community, in order to implement proper TB control strategies. To achieve this goal, information from classical and molecular epidemiology, together with patient clinical data need to be combined. In this review, we summarize the methodologies currently used in molecular epidemiology, namely molecular typing. We will discuss their efficiency to phylogenetically characterize Mycobacterium tuberculosis isolates, and their ability to provide information that can be useful for disease control. We will also introduce next generation sequencing as the methodology that potentially could provide in a short time both, detection of new outbreaks and identification of resistance patterns. This could envision a potential of next generation sequencing as an important tool for accurate patient management and disease control. PMID:27403266

  14. Phospholipase C in Beijing strains of Mycobacterium tuberculosis

    PubMed Central

    Mirsamadi, ES; Farnia, P; Jahani Sherafat, S; Esfahani, M; Faramarzi, N

    2010-01-01

    Background and Objectives Phospholipase of Mycobacterium tuberculosis plays an important role in pathogenesis through breaking up phospholipids and production of diacylglycerol. In this study, we examined the Beijing strains of Mycobacterium tuberculosis isolated from Iranian patients for the genes encoding this enzyme. Materials and Methods DNA extraction was performed using CTAB (cetyltrimethylammonium bromide) from positive culture specimens in tuberculosis patients. PCR was then used to amplify the plcA, plcB, plcC genes of Beijing strain, and non-Beijing strains were identified by spoligotyping. Results Of 200 specimens, 19 (9.5%) were Beijing strain and 181 (90.5%) were non-Beijing strains. The results of PCR for Beijing strains were as follows: 16 strains (84.2%) were positive for plcA, 17 (89.4%) were positive for plcB and 17 (89.4%) were positive for plcC genes. The standard strain (H37RV) was used as control. Conclusion The majority of Beijing strains have phospholipase C genes which can contribute to their pathogenesis but we need complementary studies to confirm the role of phospholipase C in pathogenecity of Mycobacterium tuberculosis. PMID:22347572

  15. Mycobacterium tuberculosis Pyrazinamide Resistance Determinants: a Multicenter Study

    PubMed Central

    Cabibbe, Andrea M.; Feuerriegel, Silke; Casali, Nicola; Drobniewski, Francis; Rodionova, Yulia; Bakonyte, Daiva; Stakenas, Petras; Pimkina, Edita; Augustynowicz-Kopeć, Ewa; Degano, Massimo; Ambrosi, Alessandro; Hoffner, Sven; Mansjö, Mikael; Werngren, Jim; Rüsch-Gerdes, Sabine; Niemann, Stefan; Cirillo, Daniela M.

    2014-01-01

    ABSTRACT Pyrazinamide (PZA) is a prodrug that is converted to pyrazinoic acid by the enzyme pyrazinamidase, encoded by the pncA gene in Mycobacterium tuberculosis. Molecular identification of mutations in pncA offers the potential for rapid detection of pyrazinamide resistance (PZAr). However, the genetic variants are highly variable and scattered over the full length of pncA, complicating the development of a molecular test. We performed a large multicenter study assessing pncA sequence variations in 1,950 clinical isolates, including 1,142 multidrug-resistant (MDR) strains and 483 fully susceptible strains. The results of pncA sequencing were correlated with phenotype, enzymatic activity, and structural and phylogenetic data. We identified 280 genetic variants which were divided into four classes: (i) very high confidence resistance mutations that were found only in PZAr strains (85%), (ii) high-confidence resistance mutations found in more than 70% of PZAr strains, (iii) mutations with an unclear role found in less than 70% of PZAr strains, and (iv) mutations not associated with phenotypic resistance (10%). Any future molecular diagnostic assay should be able to target and identify at least the very high and high-confidence genetic variant markers of PZAr; the diagnostic accuracy of such an assay would be in the range of 89.5 to 98.8%. PMID:25336456

  16. Tuberculosis patients co-infected with Mycobacterium bovis and Mycobacterium tuberculosis in an urban area of Brazil

    PubMed Central

    Silva, Marcio Roberto; Rocha, Adalgiza da Silva; da Costa, Ronaldo Rodrigues; de Alencar, Andrea Padilha; de Oliveira, Vania Maria; Fonseca, Antônio Augusto; Sales, Mariana Lázaro; Issa, Marina de Azevedo; Soares, Paulo Martins; Pereira, Omara Tereza Vianello; dos Santos, Eduardo Calazans; Mendes, Rejane Silva; Ferreira, Ângela Maria de Jesus; Mota, Pedro Moacyr Pinto Coelho; Suffys, Philip Noel; Guimarães, Mark Drew Crosland

    2013-01-01

    In this cross-sectional study, mycobacteria specimens from 189 tuberculosis (TB) patients living in an urban area in Brazil were characterised from 2008-2010 using phenotypic and molecular speciation methods (pncA gene and oxyR pseudogene analysis). Of these samples, 174 isolates simultaneously grew on Löwenstein-Jensen (LJ) and Stonebrink (SB)-containing media and presented phenotypic and molecular profiles of Mycobacterium tuberculosis, whereas 12 had molecular profiles of M. tuberculosis based on the DNA analysis of formalin-fixed paraffin wax-embedded tissue samples (paraffin blocks). One patient produced two sputum isolates, the first of which simultaneously grew on LJ and SB media and presented phenotypic and molecular profiles of M. tuberculosis, and the second of which only grew on SB media and presented phenotypic profiles of Mycobacterium bovis. One patient provided a bronchial lavage isolate, which simultaneously grew on LJ and SB media and presented phenotypic and molecular profiles of M. tuberculosis, but had molecular profiles of M. bovis from paraffin block DNA analysis, and one sample had molecular profiles of M. tuberculosis and M. bovis identified from two distinct paraffin blocks. Moreover, we found a low prevalence (1.6%) of M. bovis among these isolates, which suggests that local health service procedures likely underestimate its real frequency and that it deserves more attention from public health officials. PMID:23778657

  17. Evasion and subversion of antigen presentation by Mycobacterium tuberculosis

    PubMed Central

    Baena, Andres; Porcelli, Steven A.

    2009-01-01

    Mycobacterium tuberculosis is one of the most successful of human pathogens, and has acquired the ability to establish latent or progressive infection and persist even in the presence of a fully functioning immune system. The ability of M. tuberculosis to avoid immune-mediated clearance is likely to reflect a highly evolved and coordinated program of immune evasion strategies, including some that interfere with antigen presentation to prevent or alter the quality of T cell responses. Here we review an extensive array of published studies supporting the view that antigen presentation pathways are targeted at many points by pathogenic mycobacteria. These studies reveal the multiple potential mechanisms by which M. tuberculosis may actively inhibit, subvert or otherwise modulate antigen presentation by MHC class I, class II and CD1 molecules. Unraveling the mechanisms by which M. tuberculosis evades or modulates antigen presentation is of critical importance for the development of more effective new vaccines based on live attenuated mycobacterial strains. PMID:19563525

  18. Predominance of modern Mycobacterium tuberculosis strains and active transmission of Beijing sublineage in Jayapura, Indonesia Papua.

    PubMed

    Chaidir, Lidya; Sengstake, Sarah; de Beer, Jessica; Oktavian, Antonius; Krismawati, Hana; Muhapril, Erfin; Kusumadewi, Inri; Annisa, Jessi; Anthony, Richard; van Soolingen, Dick; Achmad, Tri Hanggono; Marzuki, Sangkot; Alisjahbana, Bachti; van Crevel, Reinout

    2016-04-01

    Mycobacterium tuberculosis genotype distribution is different between West and Central Indonesia, but there are no data on the most Eastern part, Papua. We aimed to identify the predominant genotypes of M. tuberculosis responsible for tuberculosis in coastal Papua, their transmission, and the association with patient characteristics. A total of 199 M. tuberculosis isolates were collected. Spoligotyping was applied to describe the population structure of M. tuberculosis, lineage identification was performed using a combination of lineage-specific markers, and genotypic clusters were identified using a combination of 24-locus-MIRU-VNTR and spoligotyping. A high degree of genetic diversity was observed among isolates based on their spoligopatterns. Strains from modern lineage 4 made up almost half of strains (46.9%), being more abundant than the ancient lineage 1 (33.7%), and modern lineage 2 (19.4%). Thirty-five percent of strains belonged to genotypic clusters, especially strains in the Beijing genotype. Previous TB treatment and mutations associated with drug resistance were more common in patients infected with strains of the Beijing genotype. Papua shows a different distribution of M. tuberculosis genotypes compared to other parts of Indonesia. Clustering and drug resistance of modern strains recently introduced to Papua may contribute to the high tuberculosis burden in this region. PMID:26825253

  19. cor, a Novel Carbon Monoxide Resistance Gene, Is Essential for Mycobacterium tuberculosis Pathogenesis

    PubMed Central

    Zacharia, Vineetha M.; Manzanillo, Paolo S.; Nair, Vidhya R.; Marciano, Denise K.; Kinch, Lisa N.; Grishin, Nick V.; Cox, Jeffery S.; Shiloh, Michael U.

    2013-01-01

    ABSTRACT Tuberculosis, caused by Mycobacterium tuberculosis, remains a devastating human infectious disease, causing two million deaths annually. We previously demonstrated that M. tuberculosis induces an enzyme, heme oxygenase (HO1), that produces carbon monoxide (CO) gas and that M. tuberculosis adapts its transcriptome during CO exposure. We now demonstrate that M. tuberculosis carries a novel resistance gene to combat CO toxicity. We screened an M. tuberculosis transposon library for CO-susceptible mutants and found that disruption of Rv1829 (carbon monoxide resistance, Cor) leads to marked CO sensitivity. Heterologous expression of Cor in Escherichia coli rescued it from CO toxicity. Importantly, the virulence of the cor mutant is attenuated in a mouse model of tuberculosis. Thus, Cor is necessary and sufficient to protect bacteria from host-derived CO. Taken together, this represents the first report of a role for HO1-derived CO in controlling infection of an intracellular pathogen and the first identification of a CO resistance gene in a pathogenic organism. PMID:24255121

  20. Draft Genome Sequence of Mycobacterium tuberculosis KT-0184, Isolated in South Korea.

    PubMed

    Kwon, Taesoo; Han, Seung Jung; Yoo, Won Gi; Yun, Mi-Ran; Lee, Sanghyun; Lee, Jong Seok; Kim, Dae-Won

    2016-01-01

    Here, we describe the draft genome sequence of Mycobacterium tuberculosis KT-0184, from the Beijing family. This genome will provide insight into the evolution and adaptation of M. tuberculosis KT-0184 in human hosts. PMID:26893431

  1. Draft Genome Sequence of Mycobacterium tuberculosis KT-0204, Isolated in South Korea.

    PubMed

    Yun, Mi-Ran; Han, Seung Jung; Yoo, Won Gi; Kwon, Taesoo; Lee, Sanghyun; Lee, Jong Seok; Kim, Dae-Won

    2016-01-01

    Here, we describe the draft genome sequence of Mycobacterium tuberculosis KT-0204, non-Beijing family. This sequence will reveal genes related to the evolution and adaptation of M. tuberculosis KT-0204 in human hosts. PMID:26847902

  2. Draft Genome Sequence of a New Zealand Rangipo Strain of Mycobacterium tuberculosis

    PubMed Central

    Gautam, Sanjay S.; Bower, James E.; Basu, Indira

    2016-01-01

    The Rangipo genotype of the Mycobacterium tuberculosis complex has been associated with a number of tuberculosis (TB) outbreaks in New Zealand. We report here the draft whole-genome sequence of a representative isolate of this strain. PMID:27389273

  3. Dispersal of Mycobacterium tuberculosis via the Canadian fur trade.

    PubMed

    Pepperell, Caitlin S; Granka, Julie M; Alexander, David C; Behr, Marcel A; Chui, Linda; Gordon, Janet; Guthrie, Jennifer L; Jamieson, Frances B; Langlois-Klassen, Deanne; Long, Richard; Nguyen, Dao; Wobeser, Wendy; Feldman, Marcus W

    2011-04-19

    Patterns of gene flow can have marked effects on the evolution of populations. To better understand the migration dynamics of Mycobacterium tuberculosis, we studied genetic data from European M. tuberculosis lineages currently circulating in Aboriginal and French Canadian communities. A single M. tuberculosis lineage, characterized by the DS6(Quebec) genomic deletion, is at highest frequency among Aboriginal populations in Ontario, Saskatchewan, and Alberta; this bacterial lineage is also dominant among tuberculosis (TB) cases in French Canadians resident in Quebec. Substantial contact between these human populations is limited to a specific historical era (1710-1870), during which individuals from these populations met to barter furs. Statistical analyses of extant M. tuberculosis minisatellite data are consistent with Quebec as a source population for M. tuberculosis gene flow into Aboriginal populations during the fur trade era. Historical and genetic analyses suggest that tiny M. tuberculosis populations persisted for ∼100 y among indigenous populations and subsequently expanded in the late 19th century after environmental changes favoring the pathogen. Our study suggests that spread of TB can occur by two asynchronous processes: (i) dispersal of M. tuberculosis by minimal numbers of human migrants, during which small pathogen populations are sustained by ongoing migration and slow disease dynamics, and (ii) expansion of the M. tuberculosis population facilitated by shifts in host ecology. If generalizable, these migration dynamics can help explain the low DNA sequence diversity observed among isolates of M. tuberculosis and the difficulties in global elimination of tuberculosis, as small, widely dispersed pathogen populations are difficult both to detect and to eradicate. PMID:21464295

  4. Dispersal of Mycobacterium tuberculosis via the Canadian fur trade

    PubMed Central

    Pepperell, Caitlin S.; Granka, Julie M.; Alexander, David C.; Behr, Marcel A.; Chui, Linda; Gordon, Janet; Guthrie, Jennifer L.; Jamieson, Frances B.; Langlois-Klassen, Deanne; Long, Richard; Nguyen, Dao; Wobeser, Wendy; Feldman, Marcus W.

    2011-01-01

    Patterns of gene flow can have marked effects on the evolution of populations. To better understand the migration dynamics of Mycobacterium tuberculosis, we studied genetic data from European M. tuberculosis lineages currently circulating in Aboriginal and French Canadian communities. A single M. tuberculosis lineage, characterized by the DS6Quebec genomic deletion, is at highest frequency among Aboriginal populations in Ontario, Saskatchewan, and Alberta; this bacterial lineage is also dominant among tuberculosis (TB) cases in French Canadians resident in Quebec. Substantial contact between these human populations is limited to a specific historical era (1710–1870), during which individuals from these populations met to barter furs. Statistical analyses of extant M. tuberculosis minisatellite data are consistent with Quebec as a source population for M. tuberculosis gene flow into Aboriginal populations during the fur trade era. Historical and genetic analyses suggest that tiny M. tuberculosis populations persisted for ∼100 y among indigenous populations and subsequently expanded in the late 19th century after environmental changes favoring the pathogen. Our study suggests that spread of TB can occur by two asynchronous processes: (i) dispersal of M. tuberculosis by minimal numbers of human migrants, during which small pathogen populations are sustained by ongoing migration and slow disease dynamics, and (ii) expansion of the M. tuberculosis population facilitated by shifts in host ecology. If generalizable, these migration dynamics can help explain the low DNA sequence diversity observed among isolates of M. tuberculosis and the difficulties in global elimination of tuberculosis, as small, widely dispersed pathogen populations are difficult both to detect and to eradicate. PMID:21464295

  5. Zirconia based nucleic acid sensor for Mycobacterium tuberculosis detection

    NASA Astrophysics Data System (ADS)

    Das, Maumita; Sumana, Gajjala; Nagarajan, R.; Malhotra, B. D.

    2010-03-01

    Nanostructured zirconium oxide (ZrO2) film (particle size˜35 nm), electrochemically deposited onto gold(Au) surface, has been used to immobilize 21-mer oligonucleotide probe (ssDNA) specific to Mycobacterium tuberculosis by utilizing affinity between oxygen atom of phosphoric group and zirconium to fabricate DNA biosensor. This DNA-ZrO2/Au bioelectrode, characterized using x-ray diffraction, Fourier transform infrared spectroscopy, cyclic voltammetry, and scanning electron microscopy techniques, can be used for early and rapid diagnosis of M. tuberculosis with detection limit of 0.065 ng/μL within 60s.

  6. Efficacy of Nitazoxanide against Clinical Isolates of Mycobacterium tuberculosis

    PubMed Central

    Shigyo, Kristina; Ocheretina, Oksana; Merveille, Yves Mary; Johnson, Warren D.; Pape, Jean William; Nathan, Carl F.

    2013-01-01

    Nitazoxanide (NTZ) has bactericidal activity against the H37Rv laboratory strain of Mycobacterium tuberculosis with a MIC of 16 μg/ml. However, its efficacy against clinical isolates of M. tuberculosis has not been determined. We found that NTZ's MIC against 50 clinical isolates ranged from 12 to 28 μg/ml with a median of 16 μg/ml and was unaffected by resistance to first- or second-line antituberculosis drugs or a diversity of spoligotypes. PMID:23507275

  7. Inactivation of Mycobacterium tuberculosis for DNA Typing Analysis

    PubMed Central

    Bemer-Melchior, P.; Drugeon, H. B.

    1999-01-01

    DNA fingerprinting analysis of Mycobacterium tuberculosis is used for epidemiological studies and the control of laboratory cross-contamination. Because standardized procedures are not entirely safe for mycobacteriology laboratory staff, the paper proposes a new technique for the processing of specimens. The technique ensures the inactivation of M. tuberculosis before DNA extraction without the loss of DNA integrity. The control of inactivated cultures should be rigorous and should involve the use of two different culture media incubated for at least 4 months. PMID:10364613

  8. Dehalogenation of haloalkanes by Mycobacterium tuberculosis H37Rv and other mycobacteria

    SciTech Connect

    Jesenska, A.; Sedlacek, I.; Damborsky, J.

    2000-01-01

    Haloalkane dehalogenases convert haloalkanes to their corresponding alcohols by a hydrolytic mechanism. To date, various haloalkane dehalogenases have been isolated from bacteria colonizing environments that are contaminated with halogenated compounds. A search of current databases with the sequences of these known haloalkane dehalogenases revealed the presence of three different genes encoding putative haloalkane dehalogenases in the genome of the human parasite Mycobacterium tuberculosis H37Rv. The ability of M. tuberculosis and several other mycobacterial strains to dehalogenate haloaliphatic compounds was therefore studied. Intact cells of M. tuberculosis H37Rv were found to dehalogenate 1-chlorobutane, 1-chlorodecane, 1-bromobutane, and 1,2-dibromoethane. Nine isolates of mycobacteria from clinical material and four strains from a collection of microorganisms were found to be capable of dehalogenating 1,2-dibromoethane. Crude extracts prepared from two of these strains, Mycobacterium avium MU1 and Mycobacterium smegmatis CCM 4622, showed broad substrate specificity toward a number of halogenated substrates. Dehalogenase activity in the absence of oxygen and the identification of primary alcohols as the products of the reaction suggest a hydrolytic dehalogenation mechanism. The presence of dehalogenases in bacterial isolates from clinical material, including the species colonizing both animal tissues and free environment, indicates a possible role of parasitic microorganisms in the distribution of degradation genes in the environment.

  9. Current prospects of synthetic curcumin analogs and chalcone derivatives against mycobacterium tuberculosis.

    PubMed

    Bukhari, Syed Nasir Abbas; Franzblau, Scott G; Jantan, Ibrahim; Jasamai, Malina

    2013-11-01

    Tuberculosis, caused by Mycobacterium tuberculosis, is amongst the foremost infectious diseases. Treatment of tuberculosis is a complex process due to various factors including a patient's inability to persevere with a combined treatment regimen, the difficulty in eradicating the infection in immune-suppressed patients, and multidrug resistance (MDR). Extensive research circumscribing molecules to counteract this disease has led to the identification of many inhibitory small molecules. Among these are chalcone derivatives along with curcumin analogs. In this review article, we summarize the reported literature regarding anti tubercular activity of chalcone derivatives and synthetic curcumin analogs. Our goal is to provide an analysis of research to date in order to facilitate the synthesis of superior antitubercular chalcone derivatives and curcumin analogs. PMID:23305394

  10. Mycobacterium tuberculosis virulence: insights and impact on vaccine development.

    PubMed

    Delogu, Giovanni; Provvedi, Roberta; Sali, Michela; Manganelli, Riccardo

    2015-01-01

    The existing TB vaccine, the attenuated Mycobacterium bovis strain BCG, is effective in protecting infants from severe forms of the disease, while its efficacy in protecting adults from pulmonary TB is poor. In the last two decades, a renewed interest in TB resulted in the development of several candidate vaccines that are now entering clinical trials. However, most of these vaccines are based on a common rationale and aim to induce a strong T-cell response against Mycobacterium tuberculosis. Recent advancements in the understanding of M. tuberculosis virulence determinants and associated pathogenic strategies are opening a new and broader view of the complex interaction between this remarkable pathogen and the human host, providing insights at molecular level that could lead to a new rationale for the design of novel antitubercular vaccines. A vaccination strategy that simultaneously targets different steps in TB pathogenesis may result in improved protection and reduced TB transmission. PMID:26119086

  11. Complete Genome Sequence of Mycobacterium tuberculosis Clinical Isolate Spoligotype SIT745/EAI1-MYS.

    PubMed

    Suraiya, S; Semail, N; Ismail, M F; Abdullah, J M

    2016-01-01

    Mycobacterium tuberculosis is known to cause pulmonary and extrapulmonary tuberculosis. This organism showed special phylogeographical specificity. Here, we report the complete genome sequence of M. tuberculosis clinical isolate spoligotype SIT745/EAI1-MYS, which was isolated from a Malaysian tuberculosis patient. PMID:27198011

  12. Lymphatic endothelial cells are a replicative niche for Mycobacterium tuberculosis.

    PubMed

    Lerner, Thomas R; de Souza Carvalho-Wodarz, Cristiane; Repnik, Urska; Russell, Matthew R G; Borel, Sophie; Diedrich, Collin R; Rohde, Manfred; Wainwright, Helen; Collinson, Lucy M; Wilkinson, Robert J; Griffiths, Gareth; Gutierrez, Maximiliano G

    2016-03-01

    In extrapulmonary tuberculosis, the most common site of infection is within the lymphatic system, and there is growing recognition that lymphatic endothelial cells (LECs) are involved in immune function. Here, we identified LECs, which line the lymphatic vessels, as a niche for Mycobacterium tuberculosis in the lymph nodes of patients with tuberculosis. In cultured primary human LECs (hLECs), we determined that M. tuberculosis replicates both in the cytosol and within autophagosomes, but the bacteria failed to replicate when the virulence locus RD1 was deleted. Activation by IFN-γ induced a cell-autonomous response in hLECs via autophagy and NO production that restricted M. tuberculosis growth. Thus, depending on the activation status of LECs, autophagy can both promote and restrict replication. Together, these findings reveal a previously unrecognized role for hLECs and autophagy in tuberculosis pathogenesis and suggest that hLECs are a potential niche for M. tuberculosis that allows establishment of persistent infection in lymph nodes. PMID:26901813

  13. Lymphatic endothelial cells are a replicative niche for Mycobacterium tuberculosis

    PubMed Central

    Lerner, Thomas R.; de Souza Carvalho-Wodarz, Cristiane; Repnik, Urska; Russell, Matthew R.G.; Borel, Sophie; Diedrich, Collin R.; Rohde, Manfred; Wainwright, Helen; Collinson, Lucy M.; Wilkinson, Robert J.; Griffiths, Gareth; Gutierrez, Maximiliano G.

    2016-01-01

    In extrapulmonary tuberculosis, the most common site of infection is within the lymphatic system, and there is growing recognition that lymphatic endothelial cells (LECs) are involved in immune function. Here, we identified LECs, which line the lymphatic vessels, as a niche for Mycobacterium tuberculosis in the lymph nodes of patients with tuberculosis. In cultured primary human LECs (hLECs), we determined that M. tuberculosis replicates both in the cytosol and within autophagosomes, but the bacteria failed to replicate when the virulence locus RD1 was deleted. Activation by IFN-γ induced a cell-autonomous response in hLECs via autophagy and NO production that restricted M. tuberculosis growth. Thus, depending on the activation status of LECs, autophagy can both promote and restrict replication. Together, these findings reveal a previously unrecognized role for hLECs and autophagy in tuberculosis pathogenesis and suggest that hLECs are a potential niche for M. tuberculosis that allows establishment of persistent infection in lymph nodes. PMID:26901813

  14. Mycobacterium tuberculosis Infection of Domesticated Asian Elephants, Thailand

    PubMed Central

    Angkawanish, Taweepoke; Sirimalaisuwan, Anucha; Kaewsakhorn, Thattawan; Boonsri, Kittikorn; Rutten, Victor P.M.G.

    2010-01-01

    Four Asian elephants were confirmed to be infected with Mycobacterium tuberculosis by bacterial culture, other diagnostic procedures, and sequencing of 16S–23S rDNA internal transcribed spacer region, 16S rRNA, and gyrase B gene sequences. Genotyping showed that the infectious agents originated from 4 sources in Thailand. To identify infections, a combination of diagnostic assays is essential. PMID:21122228

  15. Mycobacterium tuberculosis Mutations Associated with Reduced Susceptibility to Linezolid.

    PubMed

    Zhang, Shuo; Chen, Jiazhen; Cui, Peng; Shi, Wanliang; Shi, Xiaohong; Niu, Hongxia; Chan, Denise; Yew, Wing Wai; Zhang, Wenhong; Zhang, Ying

    2016-04-01

    Linezolid (LZD) has become increasingly important for the treatment of multidrug-resistant tuberculosis (MDR-TB), but its mechanisms of resistance are not well characterized. We isolated 32 mutants ofMycobacterium tuberculosiswith reduced susceptibility to LZD, which was accounted for byrrlandrplCmutations in almost equal proportions, causing lower and higher MICs, respectively. Our findings provide useful information for the rapid detection of LZD resistance for improved treatment of MDR-TB. PMID:26810645

  16. Carbapenems and Rifampin Exhibit Synergy against Mycobacterium tuberculosis and Mycobacterium abscessus

    PubMed Central

    Kaushik, Amit; Makkar, Nayani; Pandey, Pooja; Parrish, Nicole; Singh, Urvashi

    2015-01-01

    An effective regimen for treatment of tuberculosis (TB) is comprised of multiple drugs that inhibit a range of essential cellular activities in Mycobacterium tuberculosis. The effectiveness of a regimen is further enhanced if constituent drugs act with synergy. Here, we report that faropenem (a penem) or biapenem, doripenem, or meropenem (carbapenems), which belong to the β-lactam class of antibiotics, and rifampin, one of the drugs that forms the backbone of TB treatment, act with synergy when combined. One of the reasons (carba)penems are seldom used for treatment of TB is the high dosage levels required, often at the therapeutic limits. The synergistic combination of rifampin and these (carba)penems indicates that (carba)penems can be administered at dosages that are therapeutically relevant. The combination of faropenem and rifampin also limits the frequency of resistant mutants, as we were unable to obtain spontaneous mutants in the presence of these two drugs. The combinations of rifampin and (carba)penems were effective not only against drug-sensitive Mycobacterium tuberculosis but also against drug-resistant clinical isolates that are otherwise resistant to rifampin. A combination of doripenem or biapenem and rifampin also exhibited synergistic activity against Mycobacterium abscessus. Although the MICs of these three drugs alone against M. abscessus are too high to be of clinical relevance, their concentrations in combinations are therapeutically relevant; therefore, they warrant further evaluation for clinical utility to treat Mycobacterium abscessus infection, especially in cystic fibrosis patients. PMID:26259792

  17. Carbapenems and Rifampin Exhibit Synergy against Mycobacterium tuberculosis and Mycobacterium abscessus.

    PubMed

    Kaushik, Amit; Makkar, Nayani; Pandey, Pooja; Parrish, Nicole; Singh, Urvashi; Lamichhane, Gyanu

    2015-10-01

    An effective regimen for treatment of tuberculosis (TB) is comprised of multiple drugs that inhibit a range of essential cellular activities in Mycobacterium tuberculosis. The effectiveness of a regimen is further enhanced if constituent drugs act with synergy. Here, we report that faropenem (a penem) or biapenem, doripenem, or meropenem (carbapenems), which belong to the β-lactam class of antibiotics, and rifampin, one of the drugs that forms the backbone of TB treatment, act with synergy when combined. One of the reasons (carba)penems are seldom used for treatment of TB is the high dosage levels required, often at the therapeutic limits. The synergistic combination of rifampin and these (carba)penems indicates that (carba)penems can be administered at dosages that are therapeutically relevant. The combination of faropenem and rifampin also limits the frequency of resistant mutants, as we were unable to obtain spontaneous mutants in the presence of these two drugs. The combinations of rifampin and (carba)penems were effective not only against drug-sensitive Mycobacterium tuberculosis but also against drug-resistant clinical isolates that are otherwise resistant to rifampin. A combination of doripenem or biapenem and rifampin also exhibited synergistic activity against Mycobacterium abscessus. Although the MICs of these three drugs alone against M. abscessus are too high to be of clinical relevance, their concentrations in combinations are therapeutically relevant; therefore, they warrant further evaluation for clinical utility to treat Mycobacterium abscessus infection, especially in cystic fibrosis patients. PMID:26259792

  18. Detection of Mycobacteria, Mycobacterium avium Subspecies, and Mycobacterium tuberculosis Complex by a Novel Tetraplex Real-Time PCR Assay

    PubMed Central

    Molina, Elena; Elguezabal, Natalia; Pérez, Valentín; Garrido, Joseba M.

    2015-01-01

    Mycobacterium tuberculosis complex, Mycobacterium avium, and many other nontuberculous mycobacteria are worldwide distributed microorganisms of major medical and veterinary importance. Considering the growing epidemiologic significance of wildlife-livestock-human interrelation, developing rapid detection tools of high specificity and sensitivity is vital to assess their presence and accelerate the process of diagnosing mycobacteriosis. Here we describe the development and evaluation of a novel tetraplex real-time PCR for simultaneous detection of Mycobacterium genus, M. avium subspecies, and M. tuberculosis complex in an internally monitored single assay. The method was evaluated using DNA from mycobacterial (n = 38) and nonmycobacterial (n = 28) strains, tissues spiked with different CFU amounts of three mycobacterial species (n = 57), archival clinical samples (n = 233), and strains isolated from various hosts (n = 147). The minimum detectable DNA amount per reaction was 50 fg for M. bovis BCG and M. kansasii and 5 fg for M. avium subsp. hominissuis. When spiked samples were analyzed, the method consistently detected as few as 100 to 1,000 mycobacterial CFU per gram. The sensitivity and specificity values for the panel of clinical samples were 97.5 and 100% using a verified culture-based method as the reference method. The assays performed on clinical isolates confirmed these results. This PCR was able to identify M. avium and M. tuberculosis complex in the same sample in one reaction. In conclusion, the tetraplex real-time PCR we designed represents a highly specific and sensitive tool for the detection and identification of mycobacteria in routine laboratory diagnosis with potential additional uses. PMID:25588660

  19. Mycobacterium thermoresistibile as a source of thermostable orthologs of Mycobacterium tuberculosis proteins.

    PubMed

    Edwards, Thomas E; Liao, Reiling; Phan, Isabelle; Myler, Peter J; Grundner, Christoph

    2012-07-01

    The genus Mycobacterium comprises major human pathogens such as the causative agent of tuberculosis, Mycobacterium tuberculosis (Mtb), and many environmental species. Tuberculosis claims ~1.5 million lives every year, and drug resistant strains of Mtb are rapidly emerging. To aid the development of new tuberculosis drugs, major efforts are currently under way to determine crystal structures of Mtb drug targets and proteins involved in pathogenicity. However, a major obstacle to obtaining crystal structures is the generation of well-diffracting crystals. Proteins from thermophiles can have better crystallization and diffraction properties than proteins from mesophiles, but their sequences and structures are often divergent. Here, we establish a thermophilic mycobacterial model organism, Mycobacterium thermoresistibile (Mth), for the study of Mtb proteins. Mth tolerates higher temperatures than Mtb or other environmental mycobacteria such as M. smegmatis. Mth proteins are on average more soluble than Mtb proteins, and comparison of the crystal structures of two pairs of orthologous proteins reveals nearly identical folds, indicating that Mth structures provide good surrogates for Mtb structures. This study introduces a thermophile as a source of protein for the study of a closely related human pathogen and marks a new approach to solving challenging mycobacterial protein structures. PMID:22544630

  20. Novel genetic polymorphisms that further delineate the phylogeny of the Mycobacterium tuberculosis complex.

    PubMed

    Huard, Richard C; Fabre, Michel; de Haas, Petra; Lazzarini, Luiz Claudio Oliveira; van Soolingen, Dick; Cousins, Debby; Ho, John L

    2006-06-01

    In a previous report, we described a PCR protocol for the differentiation of the various species of the Mycobacterium tuberculosis complex (MTC) on the basis of genomic deletions (R. C. Huard, L. C. de Oliveira Lazzarini, W. R. Butler, D. van Soolingen, and J. L. Ho, J. Clin. Microbiol. 41:1637-1650, 2003). That report also provided a broad cross-comparison of several previously identified, phylogenetically relevant, long-sequence and single-nucleotide polymorphisms (LSPs and SNPs, respectively). In the present companion report, we expand upon the previous work (i) by continuing the evaluation of known MTC phylogenetic markers in a larger collection of tubercle bacilli (n = 125), (ii) by evaluating additional recently reported MTC species-specific and interspecific polymorphisms, and (iii) by describing the identification and distribution of a number of novel LSPs and SNPs. Notably, new genomic deletions were found in various Mycobacterium tuberculosis strains, new species-specific SNPs were identified for "Mycobacterium canettii," Mycobacterium microti, and Mycobacterium pinnipedii, and, for the first time, intraspecific single-nucleotide DNA differences were discovered for the dassie bacillus, the oryx bacillus, and the two Mycobacterium africanum subtype I variants. Surprisingly, coincident polymorphisms linked one M. africanum subtype I genotype with the dassie bacillus and M. microti with M. pinnipedii, thereby suggesting closer evolutionary ties within each pair of species than had been previously thought. Overall, the presented data add to the genetic definitions of several MTC organisms as well as fine-tune current models for the evolutionary history of the MTC. PMID:16740934

  1. Mycobacterium tuberculosis Cluster with Developing Drug Resistance, New York, New York, USA, 2003–2009

    PubMed Central

    Proops, Douglas; Moonan, Patrick K.; Munsiff, Sonal S.; Kreiswirth, Barry N.; Kurepina, Natalia; Goranson, Christopher; Ahuja, Shama D.

    2011-01-01

    In 2004, identification of patients infected with the same Mycobacterium tuberculosis strain in New York, New York, USA, resulted in an outbreak investigation. The investigation involved data collection and analysis, establishing links between patients, and forming transmission hypotheses. Fifty-four geographically clustered cases were identified during 2003–2009. Initially, the M. tuberculosis strain was drug susceptible. However, in 2006, isoniazid resistance emerged, resulting in isoniazid-resistant M. tuberculosis among 17 (31%) patients. Compared with patients with drug-susceptible M. tuberculosis, a greater proportion of patients with isoniazid-resistant M. tuberculosis were US born and had a history of illegal drug use. No patients named one another as contacts. We used patient photographs to identify links between patients. Three links were associated with drug use among patients infected with isoniazid-resistant M. tuberculosis. The photographic method would have been more successful if used earlier in the investigation. Name-based contact investigation might not identify all contacts, particularly when illegal drug use is involved. PMID:21392426

  2. Phosphoproteomics analysis of a clinical Mycobacterium tuberculosis Beijing isolate: expanding the mycobacterial phosphoproteome catalog

    PubMed Central

    Fortuin, Suereta; Tomazella, Gisele G.; Nagaraj, Nagarjuna; Sampson, Samantha L.; Gey van Pittius, Nicolaas C.; Soares, Nelson C.; Wiker, Harald G.; de Souza, Gustavo A.; Warren, Robin M.

    2015-01-01

    Reversible protein phosphorylation, regulated by protein kinases and phosphatases, mediates a switch between protein activity and cellular pathways that contribute to a large number of cellular processes. The Mycobacterium tuberculosis genome encodes 11 Serine/Threonine kinases (STPKs) which show close homology to eukaryotic kinases. This study aimed to elucidate the phosphoproteomic landscape of a clinical isolate of M. tuberculosis. We performed a high throughput mass spectrometric analysis of proteins extracted from an early-logarithmic phase culture. Whole cell lysate proteins were processed using the filter-aided sample preparation method, followed by phosphopeptide enrichment of tryptic peptides by strong cation exchange (SCX) and Titanium dioxide (TiO2) chromatography. The MaxQuant quantitative proteomics software package was used for protein identification. Our analysis identified 414 serine/threonine/tyrosine phosphorylated sites, with a distribution of S/T/Y sites; 38% on serine, 59% on threonine and 3% on tyrosine; present on 303 unique peptides mapping to 214 M. tuberculosis proteins. Only 45 of the S/T/Y phosphorylated proteins identified in our study had been previously described in the laboratory strain H37Rv, confirming previous reports. The remaining 169 phosphorylated proteins were newly identified in this clinical M. tuberculosis Beijing strain. We identified 5 novel tyrosine phosphorylated proteins. These findings not only expand upon our current understanding of the protein phosphorylation network in clinical M. tuberculosis but the data set also further extends and complements previous knowledge regarding phosphorylated peptides and phosphorylation sites in M. tuberculosis. PMID:25713560

  3. Rapid drug susceptibility test of mycobacterium tuberculosis by bioluminescence sensor

    NASA Astrophysics Data System (ADS)

    Lu, Bin; Xu, Shunqing; Chen, Zifei; Zhou, Yikai

    2001-09-01

    With the persisting increase of drug-resistant stains of M. Tuberculosis around the world, rapid and sensitive detection of antibiotic of M. Tuberculosis is becoming more and more important. In the present study, drug susceptibility of M. tuberculosis were detected by recombination mycobacteriophage combined with bioluminescence sensor. It is based on the use of recombination mycobacteriophage which can express firefly luciferase when it infects viable mycobacteria, and can effectively produce quantifiable photon. Meanwhile, in mycobacterium cells treated with active antibiotic, no light is observed. The emitted light is recorded by a bioluminscence sensor, so the result of drug-resistant test can be determined by the naked eye. 159 stains of M. tuberculosis were applied to this test on their resistant to rifampin, streptomycin and isoniazid. It is found that the agreement of this assay with Liewenstein- Jensen slat is: rifampin 95.60 percent, isoniazid 91.82 percent, streptomycin 88.68 percent, which showed that it is a fast and practical method to scene and detect drug resistant of mycobacterium stains.

  4. Uracil excision repair in Mycobacterium tuberculosis cell-free extracts.

    PubMed

    Kumar, Pradeep; Bharti, Sanjay Kumar; Varshney, Umesh

    2011-05-01

    Uracil excision repair is ubiquitous in all domains of life and initiated by uracil DNA glycosylases (UDGs) which excise the promutagenic base, uracil, from DNA to leave behind an abasic site (AP-site). Repair of the resulting AP-sites requires an AP-endonuclease, a DNA polymerase, and a DNA ligase whose combined activities result in either short-patch or long-patch repair. Mycobacterium tuberculosis, the causative agent of tuberculosis, has an increased risk of accumulating uracils because of its G + C-rich genome, and its niche inside host macrophages where it is exposed to reactive nitrogen and oxygen species, two major causes of cytosine deamination (to uracil) in DNA. In vitro assays to study DNA repair in this important human pathogen are limited. To study uracil excision repair in mycobacteria, we have established assay conditions using cell-free extracts of M. tuberculosis and M. smegmatis (a fast-growing mycobacterium) and oligomer or plasmid DNA substrates. We show that in mycobacteria, uracil excision repair is completed primarily via long-patch repair. In addition, we show that M. tuberculosis UdgB, a newly characterized family 5 UDG, substitutes for the highly conserved family 1 UDG, Ung, thereby suggesting that UdgB might function as backup enzyme for uracil excision repair in mycobacteria. PMID:21371942

  5. Characterization of mycobacterium isolates from pulmomary tuberculosis suspected cases visiting Tuberculosis Reference Laboratory at Ethiopian Health and Nutrition Research Institute, Addis Ababa Ethiopia: a cross sectional study

    PubMed Central

    Mathewos, Biniam; Kebede, Nigatu; Kassa, Tesfu; Mihret, Adane; Getahun, Muluwork

    2015-01-01

    Objective To characterize mycobacterium isolates from pulmomary tuberculosis suspected cases visiting National Tuberculosis Reference Laboratory at Ethiopian Health and Nutrition Research Institute, for diagnosis of pulmonary tuberculosis from January 4 to February 22, 2010 with total samples of 263. Methods Sputum specimens were collected and processed; the deposits were cultured. For culturing Lowenstein Jensen medium (LJ) and Mycobacteria Growth Indicator Tube (BACTEC MGIT 960) were used. Capilia Neo was used for detecting NTM isolates from isolates of BACTEC MGIT 960. In Armauer Hansen Research Institute, Addis Ababa Ethiopia, Deletion typing PCR method for species identification (from confirmed Mycobacterium tuberculosis complex (MTBC) isolates by Capilia Neo) was done. Results Out of 263 enrolled in the study, 124 and 117 of them were positive for mycobacterium growth by BACTEC MGIT 960 and LJ culture method, respectively. From BACTEC MGIT 960 positive media of 124 isolates, 117 were randomly taken to perform Capilia TB Neo test. From these 7 (6%) of them were found to be NTM and 110 (94%) were MTBC. From these 110 MTBC isolates, 81 of them were randomly taken and run by the deletion typing RD9 PCR method of molecular technique. Out of these 78 (96.3%) were found to be species of Mycobacterium tuberculosis and 3 (3.7%) were found to be not in the MTBC. Regarding the types of methods of culture media, Mycobacteria Growth Indicator Tube (BACTEC MGIT 960) method was found to have excellent agreement (with kappa value of 0.78) with the routine method of LJ. Conclusions Pulmonary tuberculosis suspected cases visiting the National Tuberculosis Reference Laboratory at EHNRI that were confirmed to be pulmonary tuberculosis are caused by the species of Mycobacterium tuberculosis, hence treatment regimen including pyrazinamide can be applied to the patients as the first choice in the study area in Addis Ababa, Ethiopia. There is indication of the presence of NTM in

  6. Laboratory Diagnosis of Mycobacterium tuberculosis Infection and Disease in Children.

    PubMed

    Dunn, James J; Starke, Jeffrey R; Revell, Paula A

    2016-06-01

    Diagnosis of tuberculosis in children is challenging; even with advanced technologies, the diagnosis is often difficult to confirm microbiologically in part due to the paucibacillary nature of the disease. Clinical diagnosis lacks standardization, and traditional and molecular microbiologic methods lack sensitivity, particularly in children. Immunodiagnostic tests may improve sensitivity, but these tests cannot distinguish tuberculosis disease from latent infection and some lack specificity. While molecular tools like Xpert MTB/RIF have advanced our ability to detect Mycobacterium tuberculosis and to determine antimicrobial resistance, decades old technologies remain the standard in most locales. Today, the battle against this ancient disease still poses one of the primary diagnostic challenges in pediatric laboratory medicine. PMID:26984977

  7. The efficacy of the heat killing of Mycobacterium tuberculosis.

    PubMed

    Doig, C; Seagar, A L; Watt, B; Forbes, K J

    2002-10-01

    There is concern that current procedures for the heat inactivation of Mycobacterium tuberculosis may not be adequate. This raises serious safety issues for laboratory staff performing molecular investigations such as IS6110 restriction fragment length polymorphism typing. This paper confirms that the protocol of van Embden et al, as performed routinely in this laboratory, is safe and effective for the heat inactivation of M tuberculosis. This procedure involves complete immersion of a tube containing a suspension of one loopfull of growth in a water bath at 80 degrees C for 20 minutes. Seventy four isolates were included in this investigation. Despite prolonged incubation for 20 weeks, none of the heat killed M tuberculosis suspensions produced visible colonies or gave a positive growth signal from liquid culture. This method did not affect the integrity of the DNA for subsequent molecular investigations. PMID:12354807

  8. The efficacy of the heat killing of Mycobacterium tuberculosis

    PubMed Central

    Doig, C; Seagar, A L; Watt, B; Forbes, K J

    2002-01-01

    There is concern that current procedures for the heat inactivation of Mycobacterium tuberculosis may not be adequate. This raises serious safety issues for laboratory staff performing molecular investigations such as IS6110 restriction fragment length polymorphism typing. This paper confirms that the protocol of van Embden et al, as performed routinely in this laboratory, is safe and effective for the heat inactivation of M tuberculosis. This procedure involves complete immersion of a tube containing a suspension of one loopfull of growth in a water bath at 80°C for 20 minutes. Seventy four isolates were included in this investigation. Despite prolonged incubation for 20 weeks, none of the heat killed M tuberculosis suspensions produced visible colonies or gave a positive growth signal from liquid culture. This method did not affect the integrity of the DNA for subsequent molecular investigations. PMID:12354807

  9. Advances in Mycobacterium tuberculosis therapeutics discovery utlizing structural biology

    PubMed Central

    Chim, Nicholas; Owens, Cedric P.; Contreras, Heidi; Goulding, Celia W.

    2013-01-01

    In 2012, tuberculosis (TB) remains a global health threat and is exacerbated both by the emergence of drug resistant Mycobacterium tuberculosis strains and its synergy with HIV infection. The waning effectiveness of current treatment regimens necessitates the development of new or repurposed anti-TB therapeutics for improved combination therapies against the disease. Exploiting atomic resolution structural information of proteins in complex with their substrates and/or inhibitors can facilitate structure-based rational drug design. Since our last review in 2009, there has been a wealth of new M. tuberculosis protein structural information. Once again, we have compiled the most promising structures with regards to potential anti-TB drug development and present them in this updated review. PMID:23167715

  10. Development of a new DNA extraction protocol for PFGE typing of Mycobacterium tuberculosis complex.

    PubMed

    Ghodousi, Arash; Arash, Ghodousi A; Vatani, S; Darban-Sarokhalil, Davood; Omrani, Maryam; Fooladi, A; Fooladi, Aa; Khosaravi, A; Khosaravi, Ad; Feizabadi, Mohammad Mehdi

    2012-03-01

    A modified pulsed-field gel electrophoresis (PFGE) protocol was developed and applied to clinical isolates of Mycobacterium tuberculosis complex to reduce the cost of using lyticase. This protocol reduces the expense of PFGE typing of Mycobacterium tuberculosis complex as it removes the use of lyticase during the spheroplast formation from these bacteria. PMID:22783461

  11. Development of a new DNA extraction protocol for PFGE typing of Mycobacterium tuberculosis complex

    PubMed Central

    Arash, Ghodousi A; Vatani, S; Darban-Sarokhalil, Davood; Omrani, Maryam; Fooladi, AA; Khosaravi, AD; Feizabadi, Mohammad Mehdi

    2012-01-01

    A modified pulsed-field gel electrophoresis (PFGE) protocol was developed and applied to clinical isolates of Mycobacterium tuberculosis complex to reduce the cost of using lyticase. This protocol reduces the expense of PFGE typing of Mycobacterium tuberculosis complex as it removes the use of lyticase during the spheroplast formation from these bacteria. PMID:22783461

  12. Granuloma Correlates of Protection Against Tuberculosis and Mechanisms of Immune Modulation by Mycobacterium tuberculosis

    PubMed Central

    Mehra, Smriti; Alvarez, Xavier; Didier, Peter J.; Doyle, Lara A.; Blanchard, James L.; Lackner, Andrew A.; Kaushal, Deepak

    2013-01-01

    Background. The BCG vaccine is ineffective against adult tuberculosis. Hence, new antituberculosis vaccines are needed. Correlates of protection against tuberculosis are not known. We studied the effects of BCG vaccination on gene expression in tuberculosis granulomas using macaques. Methods. Macaques were BCG-vaccinated or sham-vaccinated and then challenged with virulent Mycobacterium tuberculosis. Lung lesions were used for comparative transcriptomics. Results. Vaccinated macaques were protected with lower bacterial burden and immunopathology. Lesions from BCG-vaccinated nonhuman primates (NHPs) showed a better balance of α- and β-chemokine gene expression with higher levels of β-chemokine expression relative to nonvaccinated animals. Consistent with this, sham-vaccinated macaques recruited fewer macrophages relative to neutrophils in their lungs. The expression of indoleamine 2,3-dioxygenase (IDO), a known immunosuppressor, was significantly higher in both week 5 and 10 lesions from sham-vaccinated, relative to BCG-vaccinated, NHPs. IDO expression was primarily limited to the nonlymphocytic region of the lesions, within the inner ring structure surrounding the central necrosis. Conclusions. Our study defines lung gene expression correlates of protective response against tuberculosis, relative to disease, which can potentially be employed to assess the efficacy of candidate antituberculosis vaccines. Mycobacterium tuberculosis may modulate protective immune responses using diverse mechanisms, including increased recruitment of inflammatory neutrophils and the concomitant use of IDO to modulate inflammation. PMID:23255564

  13. Synthetic Long Peptide Derived from Mycobacterium tuberculosis Latency Antigen Rv1733c Protects against Tuberculosis

    PubMed Central

    Coppola, Mariateresa; van den Eeden, Susan J. F.; Wilson, Louis; Franken, Kees L. M. C.; Ottenhoff, Tom H. M.

    2015-01-01

    Responsible for 9 million new cases of active disease and nearly 2 million deaths each year, tuberculosis (TB) remains a global health threat of overwhelming dimensions. Mycobacterium bovis BCG, the only licensed vaccine available, fails to confer lifelong protection and to prevent reactivation of latent infection. Although 15 new vaccine candidates are now in clinical trials, an effective vaccine against TB remains elusive, and new strategies for vaccination are vital. BCG vaccination fails to induce immunity against Mycobacterium tuberculosis latency antigens. Synthetic long peptides (SLPs) combined with adjuvants have been studied mostly for therapeutic cancer vaccines, yet not for TB, and proved to induce efficient antitumor immunity. This study investigated an SLP derived from Rv1733c, a major M. tuberculosis latency antigen which is highly expressed by “dormant” M. tuberculosis and well recognized by T cells from latently M. tuberculosis-infected individuals. In order to assess its in vivo immunogenicity and protective capacity, Rv1733c SLP in CpG was administered to HLA-DR3 transgenic mice. Immunization with Rv1733c SLP elicited gamma interferon-positive/tumor necrosis factor-positive (IFN-γ+/TNF+) and IFN-γ+ CD4+ T cells and Rv1733c-specific antibodies and led to a significant reduction in the bacterial load in the lungs of M. tuberculosis-challenged mice. This was observed both in a pre- and in a post-M. tuberculosis challenge setting. Moreover, Rv1733c SLP immunization significantly boosted the protective efficacy of BCG, demonstrating the potential of M. tuberculosis latency antigens to improve BCG efficacy. These data suggest a promising role for M. tuberculosis latency antigen Rv1733c-derived SLPs as a novel TB vaccine approach, both in a prophylactic and in a postinfection setting. PMID:26202436

  14. Fragment Discovery for the Design of Nitrogen Heterocycles as Mycobacterium tuberculosis Dihydrofolate Reductase Inhibitors.

    PubMed

    Shelke, Rupesh U; Degani, Mariam S; Raju, Archana; Ray, Mukti Kanta; Rajan, Mysore G R

    2016-08-01

    Fragment-based drug design was used to identify Mycobacterium tuberculosis (Mtb) dihydrofolate reductase (DHFR) inhibitors. Screening of ligands against the Mtb DHFR enzyme resulted in the identification of multiple fragment hits with IC50 values in the range of 38-90 μM versus Mtb DHFR and minimum inhibitory concentration (MIC) values in the range of 31.5-125 μg/mL. These fragment scaffolds would be useful for anti-tubercular drug design. PMID:27320965

  15. Rapid Whole-Genome Sequencing of Mycobacterium tuberculosis Isolates Directly from Clinical Samples

    PubMed Central

    Brown, Amanda C.; Einer-Jensen, Katja; Holdstock, Jolyon; Houniet, Darren T.; Chan, Jacqueline Z. M.; Depledge, Daniel P.; Nikolayevskyy, Vladyslav; Broda, Agnieszka; Stone, Madeline J.; Christiansen, Mette T.; Williams, Rachel; McAndrew, Michael B.; Tutill, Helena; Brown, Julianne; Melzer, Mark; Rosmarin, Caryn; McHugh, Timothy D.; Shorten, Robert J.; Drobniewski, Francis; Speight, Graham; Breuer, Judith

    2015-01-01

    The rapid identification of antimicrobial resistance is essential for effective treatment of highly resistant Mycobacterium tuberculosis. Whole-genome sequencing provides comprehensive data on resistance mutations and strain typing for monitoring transmission, but unlike for conventional molecular tests, this has previously been achievable only from cultures of M. tuberculosis. Here we describe a method utilizing biotinylated RNA baits designed specifically for M. tuberculosis DNA to capture full M. tuberculosis genomes directly from infected sputum samples, allowing whole-genome sequencing without the requirement of culture. This was carried out on 24 smear-positive sputum samples, collected from the United Kingdom and Lithuania where a matched culture sample was available, and 2 samples that had failed to grow in culture. M. tuberculosis sequencing data were obtained directly from all 24 smear-positive culture-positive sputa, of which 20 were of high quality (>20× depth and >90% of the genome covered). Results were compared with those of conventional molecular and culture-based methods, and high levels of concordance between phenotypical resistance and predicted resistance based on genotype were observed. High-quality sequence data were obtained from one smear-positive culture-negative case. This study demonstrated for the first time the successful and accurate sequencing of M. tuberculosis genomes directly from uncultured sputa. Identification of known resistance mutations within a week of sample receipt offers the prospect for personalized rather than empirical treatment of drug-resistant tuberculosis, including the use of antimicrobial-sparing regimens, leading to improved outcomes. PMID:25972414

  16. Structural and functional characterization of Mycobacterium tuberculosis triosephosphate isomerase

    SciTech Connect

    Connor, Sean E.; Capodagli, Glenn C.; Deaton, Michelle K.; Pegan, Scott D.

    2012-04-18

    Tuberculosis (TB) is a major infectious disease that accounts for over 1.7 million deaths every year. Mycobacterium tuberculosis, the causative agent of tuberculosis, enters the human host by the inhalation of infectious aerosols. Additionally, one third of the world's population is likely to be infected with latent TB. The incidence of TB is on the rise owing in part to the emergence of multidrug-resistant strains. As a result, there is a growing need to focus on novel M. tuberculosis enzyme targets. M. tuberculosis triosephosphate isomerase (MtTPI) is an essential enzyme for gluconeogenetic pathways, making it a potential target for future therapeutics. In order to determine its structure, the X-ray crystal structure of MtTPI has been determined, as well as that of MtTPI bound with a reaction-intermediate analog. As a result, two forms of the active site were revealed. In conjunction with the kinetic parameters obtained for the MtTPI-facilitated conversion of dihydroxyacetone phosphate (DHAP) to D-glyceraldehyde-3-phosphate (D-GAP), this provides a greater structural and biochemical understanding of this enzyme. Additionally, isothermal titration calorimetry was used to determine the binding constant for a reaction-intermediate analog bound to the active site of MtTPI.

  17. TIM3 Mediates T Cell Exhaustion during Mycobacterium tuberculosis Infection

    PubMed Central

    Jayaraman, Pushpa; Jacques, Miye K.; Zhu, Chen; Steblenko, Katherine M.; Stowell, Britni L.; Madi, Asaf; Anderson, Ana C.; Kuchroo, Vijay K.; Behar, Samuel M.

    2016-01-01

    While T cell immunity initially limits Mycobacterium tuberculosis infection, why T cell immunity fails to sterilize the infection and allows recrudescence is not clear. One hypothesis is that T cell exhaustion impairs immunity and is detrimental to the outcome of M. tuberculosis infection. Here we provide functional evidence for the development T cell exhaustion during chronic TB. Second, we evaluate the role of the inhibitory receptor T cell immunoglobulin and mucin domain–containing-3 (TIM3) during chronic M. tuberculosis infection. We find that TIM3 expressing T cells accumulate during chronic infection, co-express other inhibitory receptors including PD1, produce less IL-2 and TNF but more IL-10, and are functionally exhausted. Finally, we show that TIM3 blockade restores T cell function and improves bacterial control, particularly in chronically infected susceptible mice. These data show that T cell immunity is suboptimal during chronic M. tuberculosis infection due to T cell exhaustion. Moreover, in chronically infected mice, treatment with anti-TIM3 mAb is an effective therapeutic strategy against tuberculosis. PMID:26967901

  18. Genetic diversity of Mycobacterium tuberculosis isolates from central India

    PubMed Central

    Desikan, Prabha; Chauhan, D.S.; Sharma, Pragya; Panwalkar, Nikita; Chourey, Manju; Patidar, Mohan Lal; Yadav, Priyanka; Chandrasekaran, V.; Ohri, B.S.

    2016-01-01

    Background & objectives: There is a paucity of data available on genetic biodiversity of Mycobacterium tuberculosis isolates from central India. The present study was carried out on isolates of M. tuberculosis cultured from diagnostic clinical samples of patients from Bhopal, central India, using spoligotyping as a method of molecular typing. Methods: DNA was extracted from 340 isolates of M. tuberculosis from culture, confirmed as M. tuberculosis by molecular and biochemical methods and subjected to spoligotyping. The results were compared with the international SITVIT2 database. Results: Sixty five different spoligo international type (SIT) patterns were observed. A total of 239 (70.3%) isolates could be clustered into 25 SITs. The Central Asian (CAS) and East African Indian (EAI) families were found to be the two major circulating families in this region. SIT26/CAS1_DEL was identified as the most predominant type, followed by SIT11/EAI3_IND and SIT288/CAS2. Forty (11.8%) unique (non-clustered) and 61 (17.9%) orphan isolates were identified in the study. There was no significant association of clustering with clinical and demographic characteristics of patients. Interpretation & conclusions: Well established SITs were found to be predominant in our study. SIT26/CAS1_DEL was the most predominant type. However, the occurrence of a substantial number of orphan isolates may indicate the presence of active spatial and temporal evolutionary dynamics within the isolates of M. tuberculosis. PMID:27377505

  19. Bystander Macrophage Apoptosis after Mycobacterium tuberculosis H37Ra Infection▿

    PubMed Central

    Kelly, Deirdre M.; ten Bokum, Annemieke M. C.; O'Leary, Seonadh M.; O'Sullivan, Mary P.; Keane, Joseph

    2008-01-01

    Human macrophages infected with Mycobacterium tuberculosis may undergo apoptosis. Macrophage apoptosis contributes to the innate immune response against M. tuberculosis by containing and limiting the growth of mycobacteria and also by depriving the bacillus of its niche cell. Apoptosis of infected macrophages is well documented; however, bystander apoptosis of uninfected macrophages has not been described in the setting of M. tuberculosis. We observed that uninfected human macrophages underwent significant bystander apoptosis 48 and 96 h after they came into contact with macrophages infected with avirulent M. tuberculosis. The bystander apoptosis was significantly greater than the background apoptosis observed in uninfected control cells cultured for the same length of time. There was no evidence of the involvement of tumor necrosis factor alpha, Fas, tumor necrosis factor-related apoptosis-inducing ligand, transforming growth factor β, Toll-like receptor 2, or MyD88 in contact-mediated bystander apoptosis. This newly described phenomenon may further limit the spread of M. tuberculosis by eliminating the niche cells on which the bacillus relies. PMID:17954721

  20. Resistance to cellular autophagy by Mycobacterium tuberculosis Beijing strains.

    PubMed

    Haque, Md Fazlul; Boonhok, Rachasak; Prammananan, Therdsak; Chaiprasert, Angkana; Utaisincharoen, Pongsak; Sattabongkot, Jetsumon; Palittapongarnpim, Prasit; Ponpuak, Marisa

    2015-10-01

    Autophagy represents a key pathway in innate immune defense to restrict Mycobacterium tuberculosis growth inside host macrophages. Induction of autophagy has been shown to promote mycobacterial phagosome acidification and acquisition of lysosomal hydrolases, resulting in the elimination of intracellular M. tuberculosis reference strains such as H37Rv. The notorious Beijing genotype has been previously shown to be hyper-virulent and associated with increased survival in host cells and a high mortality rate in animal models, but the underlying mechanism that renders this family to have such advantages remains unclear. We hypothesize that autophagic control against M. tuberculosis Beijing strains may be altered. Here, we discovered that the Beijing strains can resist autophagic killing by host cells compared with that of the reference strain H37Rv and a strain belonging to the East African Indian genotype. Moreover, we have determined a possible underlying mechanism and found that the greater ability to evade autophagic elimination possessed by the Beijing strains stems from their higher capacity to inhibit autophagolysosome biogenesis upon autophagy induction. In summary, a previously unrecognized ability of the M. tuberculosis Beijing strains to evade host autophagy was identified, which may have important implications for tuberculosis treatment, especially in regions prevalent by the Beijing genotype. PMID:26160686

  1. Mycobacterium tuberculosis Pathogenesis and Molecular Determinants of Virulence

    PubMed Central

    Smith, Issar

    2003-01-01

    Tuberculosis (TB), one of the oldest known human diseases. is still is one of the major causes of mortality, since two million people die each year from this malady. TB has many manifestations, affecting bone, the central nervous system, and many other organ systems, but it is primarily a pulmonary disease that is initiated by the deposition of Mycobacterium tuberculosis, contained in aerosol droplets, onto lung alveolar surfaces. From this point, the progression of the disease can have several outcomes, determined largely by the response of the host immune system. The efficacy of this response is affected by intrinsic factors such as the genetics of the immune system as well as extrinsic factors, e.g., insults to the immune system and the nutritional and physiological state of the host. In addition, the pathogen may play a role in disease progression since some M. tuberculosis strains are reportedly more virulent than others, as defined by increased transmissibility as well as being associated with higher morbidity and mortality in infected individuals. Despite the widespread use of an attenuated live vaccine and several antibiotics, there is more TB than ever before, requiring new vaccines and drugs and more specific and rapid diagnostics. Researchers are utilizing information obtained from the complete sequence of the M. tuberculosis genome and from new genetic and physiological methods to identify targets in M. tuberculosis that will aid in the development of these sorely needed antitubercular agents. PMID:12857778

  2. Genetic Diversity of Mycobacterium tuberculosis Complex Isolated from Tuberculosis Patients in Bahir Dar City and Its Surroundings, Northwest Ethiopia.

    PubMed

    Nuru, Anwar; Mamo, Gezahegne; Worku, Adane; Admasu, Aschalew; Medhin, Girmay; Pieper, Rembert; Ameni, Gobena

    2015-01-01

    The knowledge of the diversity of strains of Mycobacterium tuberculosis complex (MTBC) species in a specific geographical region can contribute to the control of tuberculosis (TB). This study was conducted to identify the MTBC isolates to the species and spoligotype international type (SIT) level by spoligotyping. A total of 168 MTBC isolates were recovered from TB patients, spoligotyped, and their patterns were compared with those of the strains registered in the SITVIT2 database. Of 168 isolates spoligotyped, 89 patterns were identified. Ninety-eight isolates were clustered into 19 strain groups with clustering percentage of 58.3%. Forty-four strains matched the preexisting SITs in the SITVIT2 database. The dominant strains were SIT289, SIT134, and SIT3411, comprising 16.7% (28/168), 7.14% (12/168), and 4.76% (8/168) of the isolates, respectively. Euro-American (51.2%), East-African-Indian (34.5%), and M. africanum (9.52%) were the major lineages identified. Two strains of M. bovis were isolated from TB lymphadenitis cases. The high percentage of clustered strains of M. tuberculosis could suggest that a small number of lineages of M. tuberculosis are causing the disease in the area while isolation of M. bovis could suggest its zoonotic potential. Additionally, identification of M. africanum requires further confirmation by tools with a better discriminatory power. PMID:26491657

  3. Genetic Diversity of Mycobacterium tuberculosis Complex Isolated from Tuberculosis Patients in Bahir Dar City and Its Surroundings, Northwest Ethiopia

    PubMed Central

    Nuru, Anwar; Mamo, Gezahegne; Worku, Adane; Admasu, Aschalew; Medhin, Girmay; Pieper, Rembert; Ameni, Gobena

    2015-01-01

    The knowledge of the diversity of strains of Mycobacterium tuberculosis complex (MTBC) species in a specific geographical region can contribute to the control of tuberculosis (TB). This study was conducted to identify the MTBC isolates to the species and spoligotype international type (SIT) level by spoligotyping. A total of 168 MTBC isolates were recovered from TB patients, spoligotyped, and their patterns were compared with those of the strains registered in the SITVIT2 database. Of 168 isolates spoligotyped, 89 patterns were identified. Ninety-eight isolates were clustered into 19 strain groups with clustering percentage of 58.3%. Forty-four strains matched the preexisting SITs in the SITVIT2 database. The dominant strains were SIT289, SIT134, and SIT3411, comprising 16.7% (28/168), 7.14% (12/168), and 4.76% (8/168) of the isolates, respectively. Euro-American (51.2%), East-African-Indian (34.5%), and M. africanum (9.52%) were the major lineages identified. Two strains of M. bovis were isolated from TB lymphadenitis cases. The high percentage of clustered strains of M. tuberculosis could suggest that a small number of lineages of M. tuberculosis are causing the disease in the area while isolation of M. bovis could suggest its zoonotic potential. Additionally, identification of M. africanum requires further confirmation by tools with a better discriminatory power. PMID:26491657

  4. Evaluation of the effect of Humulus lupulus alcoholic extract on rifampin-sensitive and resistant isolates of Mycobacterium tuberculosis

    PubMed Central

    Serkani, J. Esmi; Isfahani, B. Nasr; Safaei, H.Gh.; Kermanshahi, R. Kasra; Asghari, Gh.

    2012-01-01

    The increasing incidence of Multi Drug Resistance Tuberculosis (MDR-TB) and Extensively Drug Resistance TB (XDR-TB) worldwide highlight the urgent need to search for newer anti-tuberculosis compounds. It has been determined that pharmaceutical plant, hops (Humulus lupulus), possesses some antibacterial effect. In this study, the antimycobacterial effect of this plant on rifampin sensitive and resistant strains of Mycobacterium tuberculosis were examined. Sensitivity and resistance of 37 Iranian isolates of M. tuberculosis to rifampin was determined by proportion method. Ethanolic extract of hops was prepared using maceration method. PCR-SSCP and direct sequencing were used for confirming existence of mutations in 193-bp rpoB amplicons related to the rifampin resistance in Mycobacterium tuberculosis isolates. Two different concentrations of hops alcoholic extract (4 and 8 mg/ml) were prepared and its effects against 21 resistant and 15 sensitive isolates was determinate using proportion method. Six different mutations in the 193-bp amplified rpoB gene fragments and seven distinguishable PCR-SSCP patterns in 21 Iranian rifampin resistant isolates were recognized. This study showed that the percentage of resistance and the type of mutations were correlated with the PCR-SSCP patterns and the type of mutations in rpoB gene (P<0.05). The results of hops antimycobacterial effect showed that different concentrations of hops ethanolic extract (4 and 8 mg/ml) had a remarkable inhibitory effect on rifampin sensitive and resistant isolates of Mycobacterium tuberculosis. Identification of the effective fraction of hops against Mycobacterium tuberculosis is a further step to be studied. PMID:23248674

  5. Mycobacterium tuberculosis infection in women with unexplained infertility

    PubMed Central

    Eftekhar, Maryam; Pourmasumi, Soheila; Sabeti, Parvin; Aflatoonian, Abbas; Sheikhha, Mohammad Hasan

    2015-01-01

    Background: Genital tuberculosis (GTB) is an important cause of female infertility, especially in developing countries. The positive results of polymerase chain reaction (PCR) in endometrial GTB in the absence of tubal damage raise the possibility of the detection of sub-clinical or latent disease, with doubtful benefits of treatment. Objective: To evaluate the mycobacterium tuberculosis infection in endometrial biopsy samples collected from unexplained infertile women attending Yazd Research and Clinical Center for Infertility by using PCR techniques. Materials and Methods: In this cross sectional study, 144 infertile women with unexplained infertility aged 20-35 years old and normal Histro-saplango graphy findings were enrolled. Endometrial biopsy samples from each participant were tested for mycobacterium tuberculosis detecting by PCR. In 93 patients, peritoneal fluid was also taken for culture and PCR. Results: The PCR results of endometrial specimens were negative in all cases, demonstrating that there was no GTB infection among our patients. Conclusion: Our results showed that GTB could not be considered as a major problem in women with unexplained infertility. Although, studies have indicated that PCR is a useful method in diagnosing early GTB disease in infertile women with no demonstrable evidence of tubal or endometrial involvement. PMID:27141534

  6. Dielectrophoretic characterization of antibiotic-treated Mycobacterium tuberculosis complex cells.

    PubMed

    Inoue, Shinnosuke; Lee, Hyun-Boo; Becker, Annie L; Weigel, Kris M; Kim, Jong-Hoon; Lee, Kyong-Hoon; Cangelosi, Gerard A; Chung, Jae-Hyun

    2015-10-01

    Multi-drug resistant tuberculosis (MDR-TB) has become a serious concern for proper treatment of patients. As a phenotypic method, dielectrophoresis can be useful but is yet to be attempted to evaluate Mycobacterium tuberculosis complex cells. This paper investigates the dielectrophoretic behavior of Mycobacterium bovis (Bacillus Calmette-Guérin, BCG) cells that are treated with heat or antibiotics rifampin (RIF) or isoniazid (INH). The experimental parameters are designed on the basis of our sensitivity analysis. The medium conductivity (σ(m)) and the frequency (f) for a crossover frequency (f(xo1)) test are decided to detect the change of σ(m)-f(xo1) in conjunction with the drug mechanism. Statistical modeling is conducted to estimate the distributions of viable and nonviable cells from the discrete measurement of f (xo1). Finally, the parameters of the electrophysiology of BCG cells, C(envelope) and σ(cyto), are extracted through a sampling algorithm. This is the first evaluation of the dielectrophoresis (DEP) approach as a means to assess the effects of antimicrobial drugs on M. tuberculosis complex cells. PMID:26231690

  7. Structural and Biochemical Characterization of Mycobacterium tuberculosis CYP142

    PubMed Central

    Driscoll, Max D.; McLean, Kirsty J.; Levy, Colin; Mast, Natalia; Pikuleva, Irina A.; Lafite, Pierre; Rigby, Stephen E. J.; Leys, David; Munro, Andrew W.

    2010-01-01

    The Mycobacterium tuberculosis cytochrome P450 enzyme CYP142 is encoded in a large gene cluster involved in metabolism of host cholesterol. CYP142 was expressed and purified as a soluble, low spin P450 hemoprotein. CYP142 binds tightly to cholesterol and its oxidized derivative cholest-4-en-3-one, with extensive shift of the heme iron to the high spin state. High affinity for azole antibiotics was demonstrated, highlighting their therapeutic potential. CYP142 catalyzes either 27-hydroxylation of cholesterol/cholest-4-en-3-one or generates 5-cholestenoic acid/cholest-4-en-3-one-27-oic acid from these substrates by successive sterol oxidations, with the catalytic outcome dependent on the redox partner system used. The CYP142 crystal structure was solved to 1.6 Å, revealing a similar active site organization to the cholesterol-metabolizing M. tuberculosis CYP125, but having a near-identical organization of distal pocket residues to the branched fatty acid oxidizing M. tuberculosis CYP124. The cholesterol oxidizing activity of CYP142 provides an explanation for previous findings that ΔCYP125 strains of Mycobacterium bovis and M. bovis BCG cannot grow on cholesterol, because these strains have a defective CYP142 gene. CYP142 is revealed as a cholesterol 27-oxidase with likely roles in host response modulation and cholesterol metabolism. PMID:20889498

  8. Overview and phylogeny of Mycobacterium tuberculosis complex organisms: implications for diagnostics and legislation of bovine tuberculosis.

    PubMed

    Rodriguez-Campos, Sabrina; Smith, Noel H; Boniotti, Maria B; Aranaz, Alicia

    2014-10-01

    Members of the Mycobacterium tuberculosis complex (MTBC) cause a serious disease with similar pathology, tuberculosis; in this review, bovine tuberculosis will be considered as disease caused by any member of the MTBC in bovids. Bovine tuberculosis is responsible for significant economic loss due to costly eradication programs and trade limitations and poses a threat to both endangered and protected species as well as to public health. We here give an overview on all members of the MTBC, focusing on their isolation from different animal hosts. We also review the recent advances made in elucidating the evolutionary and phylogenetic relationships of members of the MTBC. Because the nomenclature of the MTBC is controversial, its members have been considered species, subspecies or ecotypes, this review discusses the possible implications for diagnostics and the legal consequences of naming of new species. PMID:24630673

  9. Simultaneous detection of Mycobacterium tuberculosis complex and nontuberculous mycobacteria in respiratory specimens.

    PubMed

    Hwang, Sang Mee; Lim, Mi Suk; Hong, Yun Ji; Kim, Taek Soo; Park, Kyoung Un; Song, Junghan; Lee, Jae Ho; Kim, Eui Chong

    2013-11-01

    Many nontuberculous mycobacteria (NTM) species have clinical significance, and the rapid and reliable identification of Mycobacterium tuberculosis complex (MTBC) and NTM species is important. We evaluated the simultaneous detection of MTBC and NTM in respiratory specimens. MTBC and NTM were simultaneously detected and identified by laboratory-developed (LDT) real-time PCR, multiplex real-time PCR/melting curve analysis, rpoB PCR restriction fragment length polymorphisms and the AdvanSure Mycobacteria GenoBlot assay (LG Life Sciences). Eighty-five respiratory specimens from 69 patients showed simultaneous detection of MTBC and NTM. A line probe assay showed 70.6% concordance with LDT. Ten patients (14.5%) had a history of tuberculosis, and eight patients (11.6%) had been previously diagnosed with bronchiectasis. Mixed cultures were present one time in 57 patients (82.6%) and repeatedly in 12 patients (17.4%). MTBC was more frequent in 44 patients (63.8%), and NTM was isolated in seven patients (10.1%). The commonly detected NTM species in the mixed cultures were Mycobacterium intracellulare (29.0%) and Mycobacterium abscessus (29.0%). Co-isolation caused a failure of antitubercular drug susceptibility testing in 2 patients (2.9%). Molecular methods allow MTBC and NTM species to be simultaneously identified in respiratory specimens. NTM isolated with MTBC has clinical significance in some patients and should not be ignored. PMID:23988279

  10. Identification of Mycobacterium tuberculosis and M. avium complex directly from smear-positive sputum specimens and BACTEC 12B cultures by high-performance liquid chromatography with fluorescence detection and computer-driven pattern recognition models.

    PubMed

    Jost, K C; Dunbar, D F; Barth, S S; Headley, V L; Elliott, L B

    1995-05-01

    A high-performance liquid chromatography method that utilized fluorescence detection (HPLC-FL) of mycolic acid 6,7-dimethoxycoumarin esters was developed to identify Mycobacterium tuberculosis (MTB) and M. avium complex (MAC) directly from fluorochrome stain smear-positive sputum specimens and young BACTEC 12B cultures. HPLC-FL chromatograms from a training set that included 202 smear-positive clinical sputum specimens and 343 mycobacterial cultures were used to construct a calibrated peak-naming table and computer-based pattern recognition models for MTB and MAC. Pattern recognition model performance was measured with an evaluation set of samples that included 251 smear-positive clinical sputum specimens and 167 BACTEC 12B cultures. Evaluation sputum specimens were culture positive for MTB (n = 132) and MAC (n = 48). With evaluation sputa, the MTB and MAC models were 56.8 and 33.3% sensitive, respectively. Evaluation set BACTEC 12B cultures were culture positive for MTB (n = 97) and MAC (n = 53). The sensitivities of the MTB and MAC models for identification of BACTEC 12B cultures were 99.0 and 94.3%, respectively. The specificity of both models was 100% for both types of evaluation samples. The average times from BACTEC 12B inoculation to cell harvest were 10.2 and 7.4 days for MTB and MAC, respectively. HPLC-FL can identify MTB and MAC in 1 day from many smear-positive sputa. Rapid and sensitive identification of MTB and MAC from young BACTEC 12B cultures was achieved. PMID:7615740

  11. Tuberculosis in Elephants: Antibody Responses to Defined Antigens of Mycobacterium tuberculosis, Potential for Early Diagnosis, and Monitoring of Treatment

    PubMed Central

    Lyashchenko, Konstantin P.; Greenwald, Rena; Esfandiari, Javan; Olsen, John H.; Ball, Ray; Dumonceaux, Genevieve; Dunker, Freeland; Buckley, Carol; Richard, Michael; Murray, Suzan; Payeur, Janet B.; Andersen, Peter; Pollock, John M.; Mikota, Susan; Miller, Michele; Sofranko, Denise; Waters, W. Ray

    2006-01-01

    Tuberculosis (TB) in elephants is a re-emerging zoonotic disease caused primarily by Mycobacterium tuberculosis. Current diagnosis relies on trunk wash culture, the only officially recognized test, which has serious limitations. Innovative and efficient diagnostic methods are urgently needed. Rapid identification of infected animals is a crucial prerequisite for more effective control of TB, as early diagnosis allows timely initiation of chemotherapy. Serology has diagnostic potential, although key antigens have not been identified and optimal immunoassay formats are not established. To characterize the humoral responses in elephant TB, we tested 143 serum samples collected from 15 elephants over time. These included 48 samples from five culture-confirmed TB cases, of which four were in Asian elephants infected with M. tuberculosis and one was in an African elephant with Mycobacterium bovis. Multiantigen print immunoassay (MAPIA) employing a panel of 12 defined antigens was used to identify serologic correlates of active disease. ESAT-6 was the immunodominant antigen recognized in elephant TB. Serum immunoglobulin G antibodies to ESAT-6 and other proteins were detected up to 3.5 years prior to culture of M. tuberculosis from trunk washes. Antibody levels to certain antigens gradually decreased in response to antitubercular therapy, suggesting the possibility of treatment monitoring. In addition to MAPIA, serum samples were evaluated with a recently developed rapid test (RT) based on lateral flow technology (ElephantTB STAT-PAK). Similarly to MAPIA, infected elephants were identified using the RT up to 4 years prior to positive culture. These findings demonstrate the potential for TB surveillance and treatment monitoring using the RT and MAPIA, respectively. PMID:16829608

  12. Detection of Rifampicin Resistance in Mycobacterium tuberculosis by Padlock Probes and Magnetic Nanobead-Based Readout

    PubMed Central

    Engström, Anna; Zardán Gómez de la Torre, Teresa; Strømme, Maria

    2013-01-01

    Control of the global epidemic tuberculosis is severely hampered by the emergence of drug-resistant Mycobacterium tuberculosis strains. Molecular methods offer a more rapid means of characterizing resistant strains than phenotypic drug susceptibility testing. We have developed a molecular method for detection of rifampicin-resistant M. tuberculosis based on padlock probes and magnetic nanobeads. Padlock probes were designed to target the most common mutations associated with rifampicin resistance in M. tuberculosis, i.e. at codons 516, 526 and 531 in the gene rpoB. For detection of the wild type sequence at all three codons simultaneously, a padlock probe and two gap-fill oligonucleotides were used in a novel assay configuration, requiring three ligation events for circularization. The assay also includes a probe for identification of the M. tuberculosis complex. Circularized probes were amplified by rolling circle amplification. Amplification products were coupled to oligonucleotide-conjugated magnetic nanobeads and detected by measuring the frequency-dependent magnetic response of the beads using a portable AC susceptometer. PMID:23630621

  13. Evaluation of mtp40 genomic fragment amplification for specific detection of Mycobacterium tuberculosis in clinical specimens.

    PubMed Central

    Herrera, E A; Segovia, M

    1996-01-01

    A PCR assay based on the species-specific mtp40 genomic fragment was developed for the specific detection and identification of Mycobacterium tuberculosis in different uncultured clinical specimens. The aim of the study was to evaluate the clinical applicability of this target DNA in comparison with those of conventional microbiological methods and to compare the results obtained with those obtained after amplification with the IS6110 repetitive element. Discrepant results were interpreted in conjunction with the patients' clinical data, medical histories, and response to therapy. A total of 172 specimens from 162 patients with respiratory symptoms were tested, 101 specimens were obtained from 92 patients clinically suspected of having tuberculosis, and 71 specimens were obtained from 70 patients without known mycobacterial infection. The results of our study suggest that PCR amplification with the mtp40 genomic fragment provides a highly sensitive and specific technique for the detection of M. tuberculosis strains in clinical samples. It allows for the differentiation between M. tuberculosis and other related mycobacteria, including M. bovis, and is more specific than the IS6110 target. For these and other reasons, we propose that the mtp40 assay is a possible alternative for the specific direct detection of M. tuberculosis in clinical laboratories. PMID:8727885

  14. Inhibitors of the Cysteine Synthase CysM with Antibacterial Potency against Dormant Mycobacterium tuberculosis.

    PubMed

    Brunner, Katharina; Maric, Selma; Reshma, Rudraraju Srilakshmi; Almqvist, Helena; Seashore-Ludlow, Brinton; Gustavsson, Anna-Lena; Poyraz, Ömer; Yogeeswari, Perumal; Lundbäck, Thomas; Vallin, Michaela; Sriram, Dharmarajan; Schnell, Robert; Schneider, Gunter

    2016-07-28

    Cysteine is an important amino acid in the redox defense of Mycobacterium tuberculosis, primarily as a building block of mycothiol. Genetic studies have implicated de novo cysteine biosynthesis in pathogen survival in infected macrophages, in particular for persistent M. tuberculosis. Here, we report on the identification and characterization of potent inhibitors of CysM, a critical enzyme in cysteine biosynthesis during dormancy. A screening campaign of 17 312 compounds identified ligands that bind to the active site with micromolar affinity. These were characterized in terms of their inhibitory potencies and structure-activity relationships through hit expansion guided by three-dimensional structures of enzyme-inhibitor complexes. The top compound binds to CysM with 300 nM affinity and displays selectivity over the mycobacterial homologues CysK1 and CysK2. Notably, two inhibitors show significant potency in a nutrient-starvation model of dormancy of Mycobacterium tuberculosis, with little or no cytotoxicity toward mammalian cells. PMID:27379713

  15. Au-nanoprobes for detection of SNPs associated with antibiotic resistance in Mycobacterium tuberculosis

    NASA Astrophysics Data System (ADS)

    Veigas, Bruno; Machado, Diana; Perdigão, João; Portugal, Isabel; Couto, Isabel; Viveiros, Miguel; Baptista, Pedro V.

    2010-10-01

    Tuberculosis (TB) is one of the leading causes of infection in humans, causing high morbility and mortality all over the world. The rate of new cases of multidrug resistant tuberculosis (MDRTB) continues to increase, and since these infections are very difficult to manage, they constitute a serious health problem. In most cases, drug resistance in Mycobacterium tuberculosis has been related to mutations in several loci within the pathogen's genome. The development of fast, cheap and simple screening methodologies would be of paramount relevance for the early detection of these mutations, essential for the timely and effective diagnosis and management of MDRTB patients. The use of gold nanoparticles derivatized with thiol-modified oligonucleotides (Au-nanoprobes) has led to new approaches in molecular diagnostics. Based on the differential non-cross-linking aggregation of Au-nanoprobes, we were able to develop a colorimetric method for the detection of specific sequences and to apply this approach to pathogen identification and single base mutations/single nucleotide polymorphisms (SNP) discrimination. Here we report on the development of Au-nanoprobes for the specific identification of SNPs within the beta subunit of the RNA polymerase (rpoB locus), responsible for resistance to rifampicin in over 95% of rifampicin resistant M. tuberculosis strains.

  16. Zoonotic tuberculosis due to Mycobacterium bovis in developing countries.

    PubMed Central

    Cosivi, O.; Grange, J. M.; Daborn, C. J.; Raviglione, M. C.; Fujikura, T.; Cousins, D.; Robinson, R. A.; Huchzermeyer, H. F.; de Kantor, I.; Meslin, F. X.

    1998-01-01

    The World Health Organization (WHO) estimates that human tuberculosis (TB) incidence and deaths for 1990 to 1999 will be 88 million and 30 million, respectively, with most cases in developing countries. Zoonotic TB (caused by Mycobacterium bovis) is present in animals in most developing countries where surveillance and control activities are often inadequate or unavailable; therefore, many epidemiologic and public health aspects of infection remain largely unknown. We review available information on zoonotic TB in developing countries, analyze risk factors that may play a role in the disease, review recent WHO activities, and recommend actions to assess the magnitude of the problem and control the disease in humans and animals. PMID:9452399

  17. Antimicrobial Resistance in Mycobacterium tuberculosis: The Odd One Out.

    PubMed

    Eldholm, Vegard; Balloux, François

    2016-08-01

    Antimicrobial resistance (AMR) threats are typically represented by bacteria capable of extensive horizontal gene transfer (HGT). One clear exception is Mycobacterium tuberculosis (Mtb). It is an obligate human pathogen with limited genetic diversity and a low mutation rate which lacks any evidence for HGT. Such features should, in principle, reduce its ability to rapidly evolve AMR. We identify key features in its biology and epidemiology that allow it to overcome its low adaptive potential. We focus in particular on its innate resistance to drugs, its unusual life cycle, including an often extensive latent phase, and its ability to shelter from exposure to antimicrobial drugs within cavities it induces in the lungs. PMID:27068531

  18. Anti-Mycobacterium tuberculosis activity of fungus Phomopsis stipata

    PubMed Central

    de Prince, Karina Andrade; Sordi, Renata; Pavan, Fernando Rogério; Barreto Santos, Adolfo Carlos; Araujo, Angela R.; Leite, Sergio R.A.; Leite, Clarice Q. F.

    2012-01-01

    Our purpose was to determine the anti-Mycobacterium tuberculosis activity of the metabolites produced by the endophitic fungus Phomopsis stipata (Lib.) B. Sutton, (Diaporthaceae), cultivated in different media. The antimycobacterial activity was assessed through the Resazurin Microtiter Assay (REMA) and the cytotoxicity test performed on macrophage cell line. The extracts derived from fungi grown on Corn Medium and Potato Dextrose Broth presented the smallest values of Minimum Inhibitory Concentration (MIC) and low cytotoxicity, which implies a high selectivity index. This is the first report on the chemical composition and antitubercular activity of metabolites of P. stipata, as well as the influence of culture medium on these properties. PMID:24031821

  19. Autolysis and Secondary Growth of Mycobacterium tuberculosis in Submerged Culture

    PubMed Central

    Wayne, Lawrence G.; Diaz, Gilbert A.

    1967-01-01

    Mycobacterium tuberculosis has been found to exhibit autolysis and spontaneous secondary growth in modified Sauton medium. The phenomenon is a function of high glycerol concentration of the medium and limitation of air in test tubes. It is not a function of depletion of nutrients and is probably not a manifestation of lysogeny or spheroplast formation. The cycle of growth, autolysis, and secondary growth is related to development of lethal conditions during a period of severe oxygen limitation followed by a metabolic change associated with slower depletion of glycerol. PMID:4962059

  20. Genetic regulation of vesiculogenesis and immunomodulation in Mycobacterium tuberculosis

    PubMed Central

    Rath, Poonam; Huang, Chengdong; Wang, Tao; Wang, Tianzhi; Li, Huilin; Prados-Rosales, Rafael; Elemento, Olivier; Casadevall, Arturo; Nathan, Carl F.

    2013-01-01

    Mycobacterium tuberculosis (Mtb) restrains immune responses well enough to escape eradication but elicits enough immunopathology to ensure its transmission. Here we provide evidence that this host–pathogen relationship is regulated in part by a cytosolic, membrane-associated protein with a unique structural fold, encoded by the Mtb gene rv0431. The protein acts by regulating the quantity of Mtb-derived membrane vesicles bearing Toll-like receptor 2 ligands, including the lipoproteins LpqH and SodC. We propose that rv0431 be named “vesiculogenesis and immune response regulator.” PMID:24248369

  1. Interaction of Mycobacterium tuberculosis with Host Cell Death Pathways

    PubMed Central

    Srinivasan, Lalitha; Ahlbrand, Sarah; Briken, Volker

    2014-01-01

    Mycobacterium tuberculosis (Mtb) has coevolved with humans for tens of thousands of years. It is thus highly adapted to its human host and has evolved multiple mechanisms to manipulate host immune responses to its advantage. One central host pathogen interaction modality is host cell death pathways. Host cell apoptosis is associated with a protective response to Mtb infection, whereas a necrotic response favors the pathogen. Consistently, Mtb inhibits host cell apoptosis signaling but promotes induction of programmed necrosis. The molecular mechanisms involved in Mtb-mediated host cell death manipulation, the consequences for host immunity, and the potential for therapeutic and preventive approaches will be discussed. PMID:24968864

  2. Whole Cell Screen for Inhibitors of pH Homeostasis in Mycobacterium tuberculosis

    PubMed Central

    Darby, Crystal M.; Ingólfsson, Helgi I.; Jiang, Xiuju; Shen, Chun; Sun, Mingna; Zhao, Nan; Burns, Kristin; Liu, Gang; Ehrt, Sabine; Warren, J. David; Anderson, Olaf S.; Brickner, Steven J.; Nathan, Carl

    2013-01-01

    Bacterial pathogens like Mycobacterium tuberculosis (Mtb) encounter acidic microenvironments in the host and must maintain their acid-base homeostasis to survive. A genetic screen identified two Mtb strains that cannot control intrabacterial pH (pHIB) in an acidic environment; infection with either strain led to severe attenuation in mice. To search for additional proteins that Mtb requires to survive at low pH, we introduced a whole-cell screen for compounds that disrupt pHIB, along with counter-screens that identify ionophores and membrane perturbors. Application of these methods to a natural product library identified four compounds of interest, one of which may inhibit novel pathway(s). This approach yields compounds that may lead to the identification of pathways that allow Mtb to survive in acidic environments, a setting in which Mtb is resistant to most of the drugs currently used to treat tuberculosis. PMID:23935911

  3. Mycobacterium tuberculosis P-Type ATPases: Possible Targets for Drug or Vaccine Development

    PubMed Central

    2014-01-01

    Tuberculosis (TB) has been the biggest killer in the human history; currently, Mycobacterium tuberculosis (Mtb) kills nearly 2 million people each year worldwide. The high prevalence of TB obligates the identification of new therapeutic targets and the development of anti-TB vaccines that can control multidrug resistance and latent TB infections. Membrane proteins have recently been suggested as key targets for bacterial viability. Current studies have shown that mycobacteria P-type ATPases may play critical roles in ion homeostasis and in the response of mycobacteria to toxic substances in the intraphagosomal environment. In this review, we bring together the genomic, transcriptomic, and structural aspects of the P-type ATPases that are relevant during active and latent Mtb infections, which can be useful in determining the potential of these ATPases as drug targets and in uncovering their possible roles in the development of new anti-TB attenuated vaccines. PMID:25110669

  4. Design and structural analysis of aromatic inhibitors of type II dehydroquinase from Mycobacterium tuberculosis.

    PubMed

    Howard, Nigel I; Dias, Marcio V B; Peyrot, Fabienne; Chen, Liuhong; Schmidt, Marco F; Blundell, Tom L; Abell, Chris

    2015-01-01

    3-Dehydroquinase, the third enzyme in the shikimate pathway, is a potential target for drugs against tuberculosis. Whilst a number of potent inhibitors of the Mycobacterium tuberculosis enzyme based on a 3-dehydroquinate core have been identified, they generally show little or no in vivo activity, and were synthetically complex to prepare. This report describes studies to develop tractable and drug-like aromatic analogues of the most potent inhibitors. A range of carbon-carbon linked biaryl analogues were prepared to investigate the effect of hydrogen bond acceptor and donor patterns on inhibition. These exhibited inhibitory activity in the high-micromolar range. The addition of flexible linkers in the compounds led to the identification of more potent 3-nitrobenzylgallate- and 5-aminoisophthalate-based analogues. PMID:25234229

  5. Mycobacterium terrae: a potential surrogate for Mycobacterium tuberculosis in a standard disinfectant test.

    PubMed

    Griffiths, P A; Babb, J R; Fraise, A P

    1998-03-01

    The susceptibility of Mycobacterium tuberculosis and Mycobacterium avium-intracellulare to the disinfections used for spillage and heat sensitive instruments has received much attention in recent years. The use of clinical isolates of M. tuberculosis and M. avium-intracellulare as test organisms is considered unsuitable for standard tests due to their hazardous nature (category 3 pathogens and slow growth rates). This has led to much debate in standards committees on the selection and use of a possible surrogate which would be safer and more practical to use and yet mimic the susceptibility of clinical isolates. This study compared the susceptibility of one possible surrogate Mycobacterium terrae NCTC 10856, with that of clinical isolates of M. tuberculosis H37 Rv and M. avium-intracellulare using a quantitative suspension test. The instrument and environmental disinfectants tested were a chlorine-releasing agent, sodium dichloroisocyanyurate (NaDCC) at 1000 ppm and 10,000 ppm av. Cl, chlorine dioxide at 1100 ppm av. ClO2 (Tristel, HayMan MediChem), 0.35% peracetic acid (NuCidex, Johnson & Johnson), 70% industrial methylated spirit (IMS), 2% alkaline glutaraldehyde (Asep, Galen), 10% succine dialdehyde and formaldehyde mixture (Gigasept, Schulke and Mayr). Results showed that the clinical isolate of M. avium-intracellulare was the most resistant of the three test organisms. M. terrae, which is not a category 3 pathogen, was slightly more resistant than M. tuberculosis and this would appear to be a suitable surrogate for establishing tuberculocidal activity. However, with an increase in the clinical significance of M. avium-intracellulare, particularly in human immunodeficiency virus (HIV) and immunocompromised patients, a more resistant surrogate is required. In the absence of such a surrogate, testing with M. avium-intracellulare in a clinical laboratory equipped for handling category 3 pathogens is still advised to establish mycobactericidal activity. PMID

  6. Immunogenic membrane-associated proteins of Mycobacterium tuberculosis revealed by proteomics.

    PubMed

    Sinha, Sudhir; Kosalai, K; Arora, Shalini; Namane, Abdelkader; Sharma, Pawan; Gaikwad, Anil N; Brodin, Priscille; Cole, Stewart T

    2005-07-01

    Membrane-associated proteins of Mycobacterium tuberculosis offer a challenge, as well as an opportunity, in the quest for better therapeutic and prophylactic interventions against tuberculosis. The authors have previously reported that extraction with the detergent Triton X-114 (TX-114) is a useful step in proteomic analysis of mycobacterial cell membranes, and detergent-soluble membrane proteins of mycobacteria are potent stimulators of human T cells. In this study 1-D and 2-D gel electrophoresis-based protocols were used for the analysis of proteins in the TX-114 extract of M. tuberculosis membranes. Peptide mass mapping (using MALDI-TOF-MS, matrix assisted laser desorption/ionization time of flight mass spectrometry) of 116 samples led to the identification of 105 proteins, 9 of which were new to the M. tuberculosis proteome. Functional orthologues of 73 of these proteins were also present in Mycobacterium leprae, suggesting their relative importance. Bioinformatics predicted that as many as 73% of the proteins had a hydrophobic disposition. 1-D gel electrophoresis revealed more hydrophobic/transmembrane and basic proteins than 2-D gel electrophoresis. Identified proteins fell into the following major categories: protein synthesis, cell wall biogenesis/architecture and conserved hypotheticals/unknowns. To identify immunodominant proteins of the detergent phase (DP), 14 low-molecular-mass fractions prepared by continuous-elution gel electrophoresis were subjected to T cell activation assays using blood samples from BCG-vaccinated healthy donors from a tuberculosis endemic area. Analysis of the responses (cell proliferation and IFN-gamma production) showed that the immunodominance of certain DP fractions was most probably due to ribosomal proteins, which is consistent with both their specificity for mycobacteria and their abundance. Other membrane-associated proteins, including transmembrane proteins/lipoproteins and ESAT-6, did not appear to contribute

  7. Mycobacterium tuberculosis Infection following Kidney Transplantation

    PubMed Central

    Boubaker, Karima; Gargah, Tahar; Abderrahim, Ezzedine; Ben Abdallah, Taieb; Kheder, Adel

    2013-01-01

    Introduction and Aims. Post-transplant tuberculosis (TB) is a problem in successful long-term outcome of renal transplantation recipients. Our objective was to describe the pattern and risk factors of TB infection and the prognosis in our transplant recipients. Patients and Methods. This study was a retrospective review of the records of 491 renal transplant recipients in our hospital during the period from January 1986 to December 2009. The demographic data, transplant characteristics, clinical manifestations, diagnostic criteria, treatment protocol, and long-term outcome of this cohort of patients were analyzed. Results. 16 patients (3,2%) developed post-transplant TB with a mean age of 32,5 ± 12,7 (range: 13–60) years and a mean post-transplant period of 36,6months (range: 12,3 months–15,9 years). The forms of the diseases were pulmonary in 10/16 (62,6%), disseminated in 3/16 (18,7%), and extrapulmonary in 3/16 (18,7%). Graft dysfunction was observed in 7 cases (43,7%) with tissue-proof acute rejection in 3 cases and loss of the graft in 4 cases. Hepatotoxicity developed in 3 patients (18,7%) during treatment. Recurrences were observed in 4 cases after early stop of treatment. Two patients (12.5%) died. Conclusion. Extra pulmonary and disseminated tuberculosis were observed in third of our patients. More than 9months of treatment may be necessary to prevent recurrence. PMID:24222903

  8. Mycobacterium tuberculosis infection of the 'non-classical immune cell'.

    PubMed

    Randall, Philippa J; Hsu, Nai-Jen; Quesniaux, Valerie; Ryffel, Bernhard; Jacobs, Muazzam

    2015-10-01

    Mycobacterium tuberculosis can infect 'non-classical immune cells', which comprise a significant constituency of cells that reside outside of those defined as 'classical immune cells' from myeloid or lymphoid origin. Here we address the influence of specific 'non-classical immune cells' in host responses and their effects in controlling mycobacterial growth or enabling an environment conducive for bacilli persistence. The interaction of M. tuberculosis with epithelial cells, endothelial cells, fibroblasts, adipocytes, glia and neurons and downstream cellular responses that often dictate immune regulation and disease outcome are discussed. Functional integration and synergy between 'classical' and 'non-classical immune cells' are highlighted as critical for determining optimal immune outcomes that favour the host. PMID:25801479

  9. Selective Mycobacterium tuberculosis Shikimate Kinase Inhibitors as Potential Antibacterials.

    PubMed

    Gordon, Sara; Simithy, Johayra; Goodwin, Douglas C; Calderón, Angela I

    2015-01-01

    Owing to the persistence of tuberculosis (TB) as well as the emergence of multidrug-resistant and extensively drug-resistant (XDR) forms of the disease, the development of new antitubercular drugs is crucial. Developing inhibitors of shikimate kinase (SK) in the shikimate pathway will provide a selective target for antitubercular agents. Many studies have used in silico technology to identify compounds that are anticipated to interact with and inhibit SK. To a much more limited extent, SK inhibition has been evaluated by in vitro methods with purified enzyme. Currently, there are no data on in vivo activity of Mycobacterium tuberculosis shikimate kinase (MtSK) inhibitors available in the literature. In this review, we present a summary of the progress of SK inhibitor discovery and evaluation with particular attention toward development of new antitubercular agents. PMID:25861218

  10. Selective Mycobacterium tuberculosis Shikimate Kinase Inhibitors as Potential Antibacterials

    PubMed Central

    Gordon, Sara; Simithy, Johayra; Goodwin, Douglas C; Calderón, Angela I

    2015-01-01

    Owing to the persistence of tuberculosis (TB) as well as the emergence of multidrug-resistant and extensively drug-resistant (XDR) forms of the disease, the development of new antitubercular drugs is crucial. Developing inhibitors of shikimate kinase (SK) in the shikimate pathway will provide a selective target for antitubercular agents. Many studies have used in silico technology to identify compounds that are anticipated to interact with and inhibit SK. To a much more limited extent, SK inhibition has been evaluated by in vitro methods with purified enzyme. Currently, there are no data on in vivo activity of Mycobacterium tuberculosis shikimate kinase (MtSK) inhibitors available in the literature. In this review, we present a summary of the progress of SK inhibitor discovery and evaluation with particular attention toward development of new antitubercular agents. PMID:25861218