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Rodríguez-Beltrán É, López GD, Anzola JM, Rodríguez-Castillo JG, Carazzone C, Murcia MI. Heterogeneous fitness landscape cues, pknG low expression, and phthiocerol dimycocerosate low production of Mycobacterium tuberculosis ATCC25618 rpoB S450L in enriched broth. Tuberculosis (Edinb) 2021; 132:102156. [PMID: 34891037 DOI: 10.1016/j.tube.2021.102156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 11/23/2021] [Accepted: 11/26/2021] [Indexed: 10/19/2022]
Abstract
Multidrug-resistant tuberculosis (isoniazid/rifampin[RIF]-resistant TB) ravages developing countries. Fitness is critical in clinical outcomes. Previous studies on RIF-resistant TB (RR-TB) showed competitive fitness gains and losses, with rpoB-S450L as the most isolated/fit mutation. This study measured virulence/resistance genes, phthiocerol dimycocerosate (PDIM) levels and their relationship with rpoB S450L ATCC25618 RR-TB strain fitness. After obtaining 10 different RR-TB GenoType MTBDRplus 2.0-genotyped isolates (with nontyped, S441, H445 and S450 positions), only one S450L isolate (R9, rpoB-S450L ATCC 25618, RR 1 μg/mL) was observed, with H445Y being the most common. A competitive fitness in vitro assay with wild-type (wt) ATCC 25618: R9 1:1 in 50 mL Middlebrook 7H9/OADC was performed, and generation time (G) in vitro and relative fitness were obtained. mRNA and PDIM were extracted on log and stationary phases. Fitness decreased in rpoB S450L and H445Y strains, with heterogeneous fitness cues in three biological replicas of rpoB-S450L: one high and two low fitness replicas. S450L strain had significant pknG increase. Compared with S450L, wt-rpoB showed increased polyketide synthase ppsA expression and high PDIM peak measured by HPLC-MS in log phase compared to S450L. This contrasts with previously increased PDIM in other RR-TB isolates.
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Affiliation(s)
- Édgar Rodríguez-Beltrán
- MicobacUN Group, Microbiology Department, The National University of Colombia (NUC) School of Medicine, AV CR 30 45-03, Bogotá, D.C, 111321, Colombia
| | - Gerson-Dirceu López
- Laboratory of Advanced Analytical Techniques in Natural Products (LATNAP), Chemistry Department, Universidad de los Andes, CR 1 18A-12, Bogotá, D.C, 111711, Colombia
| | - Juan Manuel Anzola
- Corpogen, CR 4 20-41, Bogotá, D.C, 110311, Colombia; Universidad Central, CR 5 21-38, Bogotá, D.C, 110311, Colombia
| | - Juan Germán Rodríguez-Castillo
- MicobacUN Group, Microbiology Department, The National University of Colombia (NUC) School of Medicine, AV CR 30 45-03, Bogotá, D.C, 111321, Colombia
| | - Chiara Carazzone
- Laboratory of Advanced Analytical Techniques in Natural Products (LATNAP), Chemistry Department, Universidad de los Andes, CR 1 18A-12, Bogotá, D.C, 111711, Colombia
| | - Martha I Murcia
- MicobacUN Group, Microbiology Department, The National University of Colombia (NUC) School of Medicine, AV CR 30 45-03, Bogotá, D.C, 111321, Colombia.
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Peñuelas-Urquides K, Bermúdez de León M, Silva-Ramírez B, Castorena-Torres F, Molina-Salinas GM, Castro-Garza J, Becerril-Montes P, Del Olmo E, San Feliciano A, González-Escalante LA, Villarreal-Treviño L, Said-Fernández S. Two New Dihydrosphingosine Analogs Against Mycobacterium tuberculosis Affect gltA1, lprQ, and rpsO Expression. Front Microbiol 2021; 12:742867. [PMID: 34803964 PMCID: PMC8595602 DOI: 10.3389/fmicb.2021.742867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 10/12/2021] [Indexed: 11/24/2022] Open
Abstract
The emergence of multidrug-resistant (MDR) Mycobacterium tuberculosis strains threaten the control of tuberculosis. New antitubercular dihydrosphingosine analogs, named UCIs, have been evaluated in preclinical studies but their cellular and molecular mechanisms of action against M. tuberculosis are still unknown. The aim of this study was to evaluate the effect of UCI exposure on gene expression of drug-sensitive H37Rv and MDR CIBIN:UMF:15:99 clones of M. tuberculosis which were isolated, phenotypically, and genetically characterized, cultured to log phase and treated with UCI compounds; followed by total RNA isolation, reverse transcription and hybridization assays on Affymetrix genomic microarrays. Data were validated with RT-qPCR assays. As results, UCI-05 and UCI-14 exposure increased gltA1 expression in drug-sensitive H37Rv clones. Furthermore, UCI-05 increased lprQ expression in MDR CIBIN:UMF:15:99 M. tuberculosis clones while UCI-14 reduced the expression of this gene in drug-sensitive H37Rv clones. In addition, UCI-05 reduced rpsO expression in drug-sensitive H37Rv clones. We found gene expression alterations that suggest these molecules may alter carbon and lipid metabolism as well as interfere in the protein-producing machinery in M. tuberculosis.
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Affiliation(s)
- Katia Peñuelas-Urquides
- Departamento de Biología Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, Mexico.,Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León (UANL), San Nicolás de los Garza, Mexico
| | - Mario Bermúdez de León
- Departamento de Biología Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, Mexico
| | - Beatriz Silva-Ramírez
- Departamento de Inmunogenética, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, Mexico
| | | | - Gloria María Molina-Salinas
- Unidad de Investigación Médica Yucatán, Unidad Médica de Alta Especialidad, Hospital de Especialidades Centro Médico Nacional Ignacio García Téllez, Instituto Mexicano del Seguro Social, Mérida, Mexico
| | - Jorge Castro-Garza
- Laboratorio de Patogénesis Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, Mexico
| | - Pola Becerril-Montes
- Departamento de Biología Celular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, Mexico
| | - Esther Del Olmo
- Departamento de Ciencias Farmacéuticas, Área de Química Farmacéutica, Facultad de Farmacia, Centro de Enfermedades Tropicales de la Universidad de Salamanca (CIETUS), Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, Salamanca, Spain
| | - Arturo San Feliciano
- Departamento de Ciencias Farmacéuticas, Área de Química Farmacéutica, Facultad de Farmacia, Centro de Enfermedades Tropicales de la Universidad de Salamanca (CIETUS), Instituto de Investigación Biomédica de Salamanca (IBSAL), Universidad de Salamanca, Salamanca, Spain
| | - Laura Adiene González-Escalante
- Departamento de Biología Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, Mexico
| | - Licet Villarreal-Treviño
- Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León (UANL), San Nicolás de los Garza, Mexico
| | - Salvador Said-Fernández
- Departamento de Bioquímica y Medicina Molecular, Facultad de Medicina, Universidad Autónoma de Nuevo León (UANL), Monterrey, Mexico
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3
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Gausi K, Ignatius EH, Sun X, Kim S, Moran L, Wiesner L, von Groote-Bidlingmaier F, Hafner R, Donahue K, Vanker N, Rosenkranz SL, Swindells S, Diacon AH, Nuermberger EL, Dooley KE, Denti P. A Semi-Mechanistic Model of the Bactericidal Activity of High-Dose Isoniazid Against Multi-Drug-Resistant Tuberculosis: Results from a Randomized Clinical Trial. Am J Respir Crit Care Med 2021; 204:1327-1335. [PMID: 34403326 DOI: 10.1164/rccm.202103-0534oc] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE There is accumulating evidence that higher-than-standard doses of isoniazid are effective against low-to-intermediate-level isoniazid-resistant strains of Mycobacterium tuberculosis, but the optimal dose remains unknown. OBJECTIVE Characterizing the association between isoniazid pharmacokinetics (standard or high-dose) and early bactericidal activity against M. tuberculosis (drug-sensitive and inhA-mutated) and N-acetyltransferase 2 status. METHODS ACTG A5312/INHindsight is 7-day early bactericidal activity study with isoniazid at normal dose (5 mg/kg) for patients with drug-sensitive bacteria and 5, 10, and 15 mg/kg doses for patients with inhA mutants. Participants with pulmonary TB received daily isoniazid monotherapy and collected sputum daily. Colony-forming units (CFU) on solid culture and time-to-positivity (TTP) in liquid culture were jointly analyzed using nonlinear mixed-effects modeling. RESULTS Fifty-nine adults were included in this analysis. Decline in sputum CFU was described by a one-compartment model, while an exponential bacterial growth model was used to interpret TTP data. The model found bacterial kill is modulated by isoniazid concentration using an effect compartment and a sigmoidal Emax relationship. The model predicted lower potency but similar maximum-kill of isoniazid against inhA-mutated isolates compared to drug-sensitive. Based on simulations from the PK/PD model, to achieve a drop in bacterial load comparable to 5mg/kg against drug-sensitive TB, 10- and 15-mg/kg doses are necessary against inhA-mutated isolates in slow and intermediate N-acetyltransferase 2 acetylators, respectively. Fast acetylators underperformed even at 15 mg/kg. CONCLUSIONS Dosing of isoniazid based on N-acetyltransferase 2 acetylator status may help patients attain effective exposures against inhA-mutated isolates while mitigating toxicity risks associated with higher doses. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT01936831.
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Affiliation(s)
- Kamunkhwala Gausi
- University of Cape Town Faculty of Health Sciences, 63726, Observatory, Western Cape, South Africa
| | | | - Xin Sun
- Harvard University T H Chan School of Public Health, 1857, Boston, Massachusetts, United States
| | - Soyeon Kim
- Frontier Science Foundation, 2402, Brookline, Massachusetts, United States
| | - Laura Moran
- Social & Scientific Systems Inc, 43740, Silver Spring, Maryland, United States
| | - Lubbe Wiesner
- University of Cape Town Faculty of Health Sciences, 63726, Observatory, Western Cape, South Africa
| | | | - Richard Hafner
- National Institutes of Health, Division of AIDS, Bethesda, Maryland, United States
| | - Kathleen Donahue
- Frontier Science and Technology Research Foundation, 2402, Boston, Massachusetts, United States
| | - Naadira Vanker
- TASK Applied Science and Stellenbosch University, Cape Town, Western Cape, South Africa
| | - Susan L Rosenkranz
- Harvard University T H Chan School of Public Health, 1857, Boston, Massachusetts, United States.,Frontier Science and Technology Research Foundation, 2402, Boston, Massachusetts, United States
| | - Susan Swindells
- University of Nebraska Medical Center, 12284, Department of Internal Medicine, Omaha, Nebraska, United States
| | - Andreas H Diacon
- TASK Applied Science and Stellenbosch University, Cape Town, Western Cape, South Africa
| | | | - Kelly E Dooley
- Johns Hopkins University, Medicine, Baltimore, Maryland, United States
| | - Paolo Denti
- University of Cape Town Faculty of Health Sciences, 63726, Observatory, Western Cape, South Africa;
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le Roux SP, Upton C, Vanker N, Dooley KE. Resistance-Conferring Mycobacterial Mutations and Quantification of Early Bactericidal Activity. Am J Respir Crit Care Med 2021; 203:635-637. [PMID: 33080154 PMCID: PMC7924570 DOI: 10.1164/rccm.202007-2740le] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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5
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Role of α-glucan-induced oxygen species in dendritic cells and its impact in immune response against tuberculosis. Int J Med Microbiol 2019; 309:151328. [PMID: 31324524 DOI: 10.1016/j.ijmm.2019.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 06/25/2019] [Accepted: 07/07/2019] [Indexed: 11/24/2022] Open
Abstract
With 10 million new cases and three million deaths estimated to occur yearly ̶ more than any time in history ̶ tuberculosis (TB) remains the single most widespread and deadly infectious disease. Until recently, it was thought that both latent and active TB was primarily related to host factors. Nonetheless, the participation of bacterial factors is becoming increasingly evident. Minimal variations in genes related to Mycobacterium tuberculosis (Mtb) virulence and pathogenesis can lead to marked differences in immunogenicity. Dendritic cells (DC) are professional antigen presenting cells whose maturation can vary depending on the cell wall composition of each particular Mtb strain being critical for the onset of the immune response against Mtb. Here we evaluated the role played by α-glucan, in the endogenous production of reactive oxygen species, ROS, and the impact on DC maturation and function. Results showed that α-glucans on Mtb induce ROS production leading to DC maturation and lymphocyte proliferation. Even more, α-glucans induced Syk activation but were not essential in non-opsonized phagocytosis. In summary, α-glucans of Mtb participates in ROS production and the subsequent DC maturation and antigen presentation, suggesting a relevant role of α-glucans for the onset of the protective immune response against TB.
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6
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Stagg HR, Lipman MC, McHugh TD, Jenkins HE. Isoniazid-resistant tuberculosis: a cause for concern? Int J Tuberc Lung Dis 2018; 21:129-139. [PMID: 28234075 DOI: 10.5588/ijtld.16.0716] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The drug isoniazid (INH) is a key component of global tuberculosis (TB) control programmes. It is estimated, however, that 16.1% of TB disease cases in the former Soviet Union countries and 7.5% of cases outside of these settings have non-multidrug-resistant (MDR) INH resistance. Resistance has been linked to poorer treatment outcomes, post-treatment relapse and death, at least for specific sites of disease. Multiple genetic loci are associated with phenotypic resistance; however, the relationship between genotype and phenotype is complex, and restricts the use of rapid sequencing techniques as part of the diagnostic process to determine the most appropriate treatment regimens for patients. The burden of resistance also influences the usefulness of INH preventive therapy. Despite seven decades of INH use, our knowledge in key areas such as the epidemiology of resistant strains, their clinical consequences, whether tailored treatment regimens are required and the role of INH resistance in fuelling the MDR-TB epidemic is limited. The importance of non-MDR INH resistance needs to be re-evaluated both globally and by national TB control programmes.
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Affiliation(s)
- H R Stagg
- Institute of Global Health, UCL, London, UK
| | - M C Lipman
- University College London (UCL) Respiratory, Division of Medicine, UCL, London, UK;, Royal Free London National Health Service Foundation Trust, London, UK
| | - T D McHugh
- Centre for Clinical Microbiology, UCL, London, UK
| | - H E Jenkins
- Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts, USA
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7
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Leung KSS, Siu GKH, Tam KKG, To SWC, Rajwani R, Ho PL, Wong SSY, Zhao WW, Ma OCK, Yam WC. Comparative Genomic Analysis of Two Clonally Related Multidrug Resistant Mycobacterium tuberculosis by Single Molecule Real Time Sequencing. Front Cell Infect Microbiol 2017; 7:478. [PMID: 29188195 PMCID: PMC5694780 DOI: 10.3389/fcimb.2017.00478] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 10/31/2017] [Indexed: 12/02/2022] Open
Abstract
Background: Multidrug-resistant tuberculosis (MDR-TB) is posing a major threat to global TB control. In this study, we focused on two consecutive MDR-TB isolated from the same patient before and after the initiation of anti-TB treatment. To better understand the genomic characteristics of MDR-TB, Single Molecule Real-Time (SMRT) Sequencing and comparative genomic analyses was performed to identify mutations that contributed to the stepwise development of drug resistance and growth fitness in MDR-TB under in vivo challenge of anti-TB drugs. Result: Both pre-treatment and post-treatment strain demonstrated concordant phenotypic and genotypic susceptibility profiles toward rifampicin, pyrazinamide, streptomycin, fluoroquinolones, aminoglycosides, cycloserine, ethionamide, and para-aminosalicylic acid. However, although both strains carried identical missense mutations at rpoB S531L, inhA C-15T, and embB M306V, MYCOTB Sensititre assay showed that the post-treatment strain had 16-, 8-, and 4-fold elevation in the minimum inhibitory concentrations (MICs) toward rifabutin, isoniazid, and ethambutol respectively. The results have indicated the presence of additional resistant-related mutations governing the stepwise development of MDR-TB. Further comparative genomic analyses have identified three additional polymorphisms between the clinical isolates. These include a single nucleotide deletion at nucleotide position 360 of rv0888 in pre-treatment strain, and a missense mutation at rv3303c (lpdA) V44I and a 6-bp inframe deletion at codon 67-68 in rv2071c (cobM) in the post-treatment strain. Multiple sequence alignment showed that these mutations were occurring at highly conserved regions among pathogenic mycobacteria. Using structural-based and sequence-based algorithms, we further predicted that the mutations potentially have deleterious effect on protein function. Conclusion: This is the first study that compared the full genomes of two clonally-related MDR-TB clinical isolates during the course of anti-TB treatment. Our work has demonstrated the robustness of SMRT Sequencing in identifying mutations among MDR-TB clinical isolates. Comparative genome analysis also suggested novel mutations at rv0888, lpdA, and cobM that might explain the difference in antibiotic resistance and growth pattern between the two MDR-TB strains.
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Affiliation(s)
- Kenneth Siu-Sing Leung
- Department of Microbiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong
| | - Gilman Kit-Hang Siu
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, Hong Kong
| | - Kingsley King-Gee Tam
- Department of Microbiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong
| | - Sabrina Wai-Chi To
- Department of Microbiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong
| | - Rahim Rajwani
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, Hong Kong
| | - Pak-Leung Ho
- Department of Microbiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong
| | - Samson Sai-Yin Wong
- Department of Microbiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong
| | - Wei W. Zhao
- KingMed Diagnostics, Science Park, Hong Kong, Hong Kong
| | | | - Wing-Cheong Yam
- Department of Microbiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong
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Satta G, Lipman M, Smith GP, Arnold C, Kon OM, McHugh TD. Mycobacterium tuberculosis and whole-genome sequencing: how close are we to unleashing its full potential? Clin Microbiol Infect 2017; 24:604-609. [PMID: 29108952 DOI: 10.1016/j.cmi.2017.10.030] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 10/21/2017] [Accepted: 10/30/2017] [Indexed: 01/16/2023]
Abstract
BACKGROUND Nearly two decades after completion of the genome sequence of Mycobacterium tuberculosis (MTB), and with the advent of next generation sequencing technologies (NGS), whole-genome sequencing (WGS) has been applied to a wide range of clinical scenarios. Starting in 2017, England is the first country in the world to pioneer its use on a national scale for the diagnosis of tuberculosis, detection of drug resistance, and typing of MTB. AIMS This narrative review critically analyses the current applications of WGS for MTB and explains how close we are to realizing its full potential as a diagnostic, epidemiologic, and research tool. SOURCES We searched for reports (both original articles and reviews) published in English up to 31 May 2017, with combinations of the following keywords: whole-genome sequencing, Mycobacterium, and tuberculosis. MEDLINE, Embase, and Scopus were used as search engines. We included articles that covered different aspects of whole-genome sequencing in relation to MTB. CONTENT This review focuses on three main themes: the role of WGS for the prediction of drug susceptibility, MTB outbreak investigation and genetic diversity, and research applications of NGS. IMPLICATIONS Many of the original expectations have been accomplished, and we believe that with its unprecedented sensitivity and power, WGS has the potential to address many unanswered questions in the near future. However, caution is still needed when interpreting WGS data as there are some important limitations to be aware of, from correct interpretation of drug susceptibilities to the bioinformatic support needed.
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Affiliation(s)
- G Satta
- UCL-TB and UCL Centre for Clinical Microbiology, Department of Infection, University College London, UK; Imperial College Healthcare NHS Trust, London, UK.
| | - M Lipman
- UCL-TB and UCL Respiratory, University College London, UK; Royal Free London NHS Foundation Trust, London, UK
| | - G P Smith
- National Mycobacterium Reference Laboratory, Public Health England, UK; Heart of England NHS Foundation Trust, Birmingham, UK
| | - C Arnold
- UCL-TB and UCL Centre for Clinical Microbiology, Department of Infection, University College London, UK; Genomic Services and Development Unit, Public Health England, UK
| | - O M Kon
- Imperial College Healthcare NHS Trust, London, UK; National Heart and Lung Institute, Imperial College London, UK
| | - T D McHugh
- UCL-TB and UCL Centre for Clinical Microbiology, Department of Infection, University College London, UK
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9
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Nieto R LM, Mehaffy C, Creissen E, Troudt J, Troy A, Bielefeldt-Ohmann H, Burgos M, Izzo A, Dobos KM. Virulence of Mycobacterium tuberculosis after Acquisition of Isoniazid Resistance: Individual Nature of katG Mutants and the Possible Role of AhpC. PLoS One 2016; 11:e0166807. [PMID: 27893795 PMCID: PMC5125630 DOI: 10.1371/journal.pone.0166807] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 11/03/2016] [Indexed: 11/28/2022] Open
Abstract
In the last decade, there were 10 million new tuberculosis cases per year globally. Around 9.5% of these cases were caused by isoniazid resistant (INHr) Mycobacterium tuberculosis (Mtb) strains. Although isoniazid resistance in Mtb is multigenic, mutations in the catalase-peroxidase (katG) gene predominate among the INHr strains. The effect of these drug-resistance-conferring mutations on Mtb fitness and virulence is variable. Here, we assessed differences in bacterial growth, immune response and pathology induced by Mtb strains harboring mutations at the N-terminus of the katG gene. We studied one laboratory and one clinically isolated Mtb clonal pair from different genetic lineages. The INHr strain in each pair had one and two katG mutations with significantly reduced levels of the enzyme and peroxidase activity. Both strains share the V1A mutation, while the double mutant clinical INHr had also the novel E3V katG mutation. Four groups of C57BL/6 mice were infected with one of the Mtb strains previously described. We observed a strong reduction in virulence (reduced bacterial growth), lower induction of proinflammatory cytokines and significantly reduced pathology scores in mice infected with the clinical INHr strain compared to the infection caused by its INHs progenitor strain. On the other hand, there was a subtle reduction of bacteria growth without differences in the pathology scores in mice infected with the laboratory INHr strain. Our results also showed distinct alkyl-hydroperoxidase C (AhpC) levels in the katG mutant strains, which could explain the difference in the virulence profile observed. The difference in the AhpC levels between clonal strains was not related to a genetic defect in the gene or its promoter. Cumulatively, our results indicate that the virulence, pathology and fitness of INHr strains could be negatively affected by multiple mutations in katG, lack of the peroxidase activity and reduced AhpC levels.
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Affiliation(s)
- Luisa Maria Nieto R
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Carolina Mehaffy
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Elizabeth Creissen
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - JoLynn Troudt
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Amber Troy
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Helle Bielefeldt-Ohmann
- School of Veterinary Science, University of Queensland, Gatton, Queensland, Australia; Australian Infectious Diseases Research Centre, University of Queensland, St Lucia, Queensland, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Queensland, Australia
| | - Marcos Burgos
- Division of Infectious Diseases, Department of Medicine, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Angelo Izzo
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Karen M. Dobos
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
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10
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Satta G, Witney AA, Shorten RJ, Karlikowska M, Lipman M, McHugh TD. Genetic variation in Mycobacterium tuberculosis isolates from a London outbreak associated with isoniazid resistance. BMC Med 2016; 14:117. [PMID: 27530812 PMCID: PMC4988016 DOI: 10.1186/s12916-016-0659-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/26/2016] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND The largest outbreak of isoniazid-resistant (INH-R) Mycobacterium tuberculosis in Western Europe is centred in North London, with over 400 cases diagnosed since 1995. In the current study, we evaluated the genetic variation in a subset of clinical samples from the outbreak with the hypothesis that these isolates have unique biological characteristics that have served to prolong the outbreak. METHODS Fitness assays, mutation rate estimation, and whole-genome sequencing were performed to test for selective advantage and compensatory mutations. RESULTS This detailed analysis of the genetic variation of these INH-R samples suggests that this outbreak consists of successful, closely related, circulating strains with heterogeneous resistance profiles and little or no associated fitness cost or impact on their mutation rate. CONCLUSIONS Specific deletions and SNPs could be a peculiar feature of these INH-R M. tuberculosis isolates, and could potentially explain their persistence over the years.
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Affiliation(s)
- Giovanni Satta
- Department of Infection, Centre for Clinical Microbiology, University College London, London, UK. .,Imperial College Healthcare NHS Trust, London, UK.
| | - Adam A Witney
- Institute of Infection and Immunity, St George's, University of London, London, UK
| | - Robert J Shorten
- Department of Infection, Centre for Clinical Microbiology, University College London, London, UK.,Public Health Laboratory Manchester, Manchester Royal Infirmary, Manchester, UK
| | - Magdalena Karlikowska
- Department of Infection, Centre for Clinical Microbiology, University College London, London, UK
| | - Marc Lipman
- Royal Free London NHS Foundation Trust, London, UK.,UCL Respiratory, Division of Medicine, University College London, London, UK
| | - Timothy D McHugh
- Department of Infection, Centre for Clinical Microbiology, University College London, London, UK
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11
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Tientcheu LD, Haks MC, Agbla SC, Sutherland JS, Adetifa IM, Donkor S, Quinten E, Daramy M, Antonio M, Kampmann B, Ottenhoff THM, Dockrell HM, Ota MO. Host Immune Responses Differ between M. africanum- and M. tuberculosis-Infected Patients following Standard Anti-tuberculosis Treatment. PLoS Negl Trop Dis 2016; 10:e0004701. [PMID: 27192147 PMCID: PMC4871581 DOI: 10.1371/journal.pntd.0004701] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 04/19/2016] [Indexed: 11/19/2022] Open
Abstract
Epidemiological differences exist between Mycobacterium africanum (Maf)- and Mycobacterium tuberculosis (Mtb)-infected patients, but to date, contributing host factors have not been characterised. We analysed clinical outcomes, as well as soluble markers and gene expression profiles in unstimulated, and ESAT6/CFP-10-, whole-Maf- and Mtb-stimulated blood samples of 26 Maf- and 49 Mtb-HIV-negative tuberculosis patients before, and after 2 and 6 months of anti-tuberculosis therapy. Before treatment, both groups had similar clinical parameters, but differed in few cytokines concentration and gene expression profiles. Following treatment the body mass index, skinfold thickness and chest X-ray scores showed greater improvement in the Mtb- compared to Maf-infected patients, after adjusting for age, sex and ethnicity (p = 0.02; 0.04 and 0.007, respectively). In addition, in unstimulated blood, IL-12p70, IL12A and TLR9 were significantly higher in Maf-infected patients, while IL-15, IL-8 and MIP-1α were higher in Mtb-infected patients. Overnight stimulation with ESAT-6/CFP-10 induced significantly higher levels of IFN-γ and TNF-α production, as well as gene expression of CCL4, IL1B and TLR4 in Mtb- compared to Maf-infected patients. Our study confirms differences in clinical features and immune genes expression and concentration of proteins associated with inflammatory processes between Mtb- and Maf-infected patients following anti-tuberculosis treatment These findings have public health implications for treatment regimens, and biomarkers for tuberculosis diagnosis and susceptibility.
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Affiliation(s)
- Leopold D. Tientcheu
- Vaccines and Immunity Theme, Medical Research Council Unit, The Gambia, Banjul, The Gambia
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Biochemistry, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
- * E-mail: ;
| | - Mariëlle C. Haks
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Schadrac C. Agbla
- Vaccines and Immunity Theme, Medical Research Council Unit, The Gambia, Banjul, The Gambia
- Department of Medical Statistics, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jayne S. Sutherland
- Vaccines and Immunity Theme, Medical Research Council Unit, The Gambia, Banjul, The Gambia
| | - Ifedayo M. Adetifa
- Disease Control and Elimination Theme, Medical Research Council Unit, The Gambia, Fajara, The Gambia
- Department of Infectious Diseases Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Simon Donkor
- Vaccines and Immunity Theme, Medical Research Council Unit, The Gambia, Banjul, The Gambia
| | - Edwin Quinten
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Mohammed Daramy
- Vaccines and Immunity Theme, Medical Research Council Unit, The Gambia, Banjul, The Gambia
| | - Martin Antonio
- Vaccines and Immunity Theme, Medical Research Council Unit, The Gambia, Banjul, The Gambia
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Microbiology and Infection Unit, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Beate Kampmann
- Vaccines and Immunity Theme, Medical Research Council Unit, The Gambia, Banjul, The Gambia
| | - Tom H. M. Ottenhoff
- Department of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Hazel M. Dockrell
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Martin O. Ota
- Vaccines and Immunity Theme, Medical Research Council Unit, The Gambia, Banjul, The Gambia
- World Health Organization Regional Office for Africa, Brazzaville, Congo
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Yao J, Rock CO. Resistance Mechanisms and the Future of Bacterial Enoyl-Acyl Carrier Protein Reductase (FabI) Antibiotics. Cold Spring Harb Perspect Med 2016; 6:a027045. [PMID: 26931811 DOI: 10.1101/cshperspect.a027045] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Missense mutations leading to clinical antibiotic resistance are a liability of single-target inhibitors. The enoyl-acyl carrier protein reductase (FabI) inhibitors have one intracellular protein target and drug resistance is increased by the acquisition of single-base-pair mutations that alter drug binding. The spectrum of resistance mechanisms to FabI inhibitors suggests criteria that should be considered during the development of single-target antibiotics that would minimize the impact of missense mutations on their clinical usefulness. These criteria include high-affinity, fast on/off kinetics, few drug contacts with residue side chains, and no toxicity. These stringent criteria are achievable by structure-guided design, but this approach will only yield pathogen-specific drugs. Single-step acquisition of resistance may limit the clinical application of broad-spectrum, single-target antibiotics, but appropriately designed pathogen-specific antibiotics have the potential to overcome this liability.
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Affiliation(s)
- Jiangwei Yao
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Charles O Rock
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
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Abstract
By using a systems-based approach, mathematical and computational techniques can be used to develop models that describe the important mechanisms involved in infectious diseases. An iterative approach to model development allows new discoveries to continually improve the model and ultimately increase the accuracy of predictions.SIR models are used to describe epidemics, predicting the extent and spread of disease. Genome-wide genotyping and sequencing technologies can be used to identify the biological mechanisms behind diseases. These tools help to build strategies for disease prevention and treatment, an example being the recent outbreak of Ebola in West Africa where these techniques were deployed.HIV is a complex disease where much is still to be learned about the virus and the best effective treatment. With basic mathematical modeling techniques, significant discoveries have been made over the last 20 years. With recent technological advances, the computational resources now available, and interdisciplinary cooperation, further breakthroughs are inevitable.In TB, modeling has traditionally been empirical in nature, with clinical data providing the fuel for this top-down approach. Recently, projects have begun to use data derived from laboratory experiments and clinical trials to create mathematical models that describe the mechanisms responsible for the disease.A systems medicine approach to infection modeling helps identify important biological questions that then direct future experiments, the results of which improve the model in an iterative cycle. This means that data from several model systems can be integrated and synthesized to explore complex biological systems.
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14
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Meftahi N, Namouchi A, Mhenni B, Brandis G, Hughes D, Mardassi H. Evidence for the critical role of a secondary site rpoB mutation in the compensatory evolution and successful transmission of an MDR tuberculosis outbreak strain. J Antimicrob Chemother 2015; 71:324-32. [PMID: 26538504 DOI: 10.1093/jac/dkv345] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/24/2015] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND MDR Mycobacterium tuberculosis clinical strains that cause large outbreaks, particularly among HIV-negative patients, are likely to have undergone the most successful compensatory evolution. Hence, mutations secondary to the acquisition of drug resistance are worthy of consideration in these highly transmissible strains. Here, we assessed the role of a mutation within rpoB, rpoB V615M, secondary to the rifampicin resistance-conferring mutation rpoB S531L, which is associated with a major MDR tuberculosis outbreak strain that evolved in an HIV-negative context in northern Tunisia. METHODS Using BCG as a model organism, we engineered strains harbouring either the rpoB S531L mutation alone or the double mutation rpoB S531L, V615M. Individual and competitive in vitro growth assays were performed in order to assess the relative fitness of each BCG mutant. RESULTS The rpoB V615M mutation was found to be invariably associated with rpoB S531L. Structural analysis mapped rpoB V615M to the same bridge helix region as rpoB compensatory mutations previously described in Salmonella. Compared with the rpoB single-mutant BCG, the double mutant displayed improved growth characteristics and fitness rates equivalent to WT BCG. Strikingly, the rpoB double mutation conferred high-level resistance to rifampicin. CONCLUSIONS Here, we demonstrated the fitness compensatory role of a mutation within rpoB, secondary to the rifampicin resistance mutation rpoB S531L, which is characteristic of an MDR M. tuberculosis major outbreak strain. The finding that this secondary mutation concomitantly increased the resistance level to rifampicin argues for its significant contribution to the successful transmission of the MDR-TB strain.
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Affiliation(s)
- Nedra Meftahi
- Unit of Typing & Genetics of Mycobacteria, Laboratory of Molecular Microbiology, Vaccinology, and Biotechnology Development, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Amine Namouchi
- Unit of Typing & Genetics of Mycobacteria, Laboratory of Molecular Microbiology, Vaccinology, and Biotechnology Development, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Besma Mhenni
- Unit of Typing & Genetics of Mycobacteria, Laboratory of Molecular Microbiology, Vaccinology, and Biotechnology Development, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Gerrit Brandis
- Department of Medical Biochemistry and Microbiology, Box 582 Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Diarmaid Hughes
- Department of Medical Biochemistry and Microbiology, Box 582 Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Helmi Mardassi
- Unit of Typing & Genetics of Mycobacteria, Laboratory of Molecular Microbiology, Vaccinology, and Biotechnology Development, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
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15
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Neutrophil apoptosis in the context of tuberculosis infection. Tuberculosis (Edinb) 2015; 95:359-63. [DOI: 10.1016/j.tube.2015.03.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 03/24/2015] [Indexed: 12/21/2022]
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16
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MacLean RC, Vogwill T. Limits to compensatory adaptation and the persistence of antibiotic resistance in pathogenic bacteria. EVOLUTION MEDICINE AND PUBLIC HEALTH 2014; 2015:4-12. [PMID: 25535278 PMCID: PMC4323496 DOI: 10.1093/emph/eou032] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Antibiotic resistance carries a fitness cost that could potentially limit the spread of resistance in bacterial pathogens. In spite of this cost, a large number of experimental evolution studies have found that resistance is stably maintained in the absence of antibiotics as a result of compensatory evolution. Clinical studies, on the other hand, have found that resistance in pathogen populations usually declines after antibiotic use is stopped, suggesting that compensatory adaptation is not effective in vivo. In this article, we argue that this disagreement arises because there are limits to compensatory adaptation in nature that are not captured by the design of current laboratory selection experiments. First, clinical treatment fails to eradicate antibiotic-sensitive strains, and competition between sensitive and resistant strains leads to the rapid loss of resistance following treatment. Second, laboratory studies overestimate the efficacy of compensatory adaptation in nature by failing to capture costs associated with compensatory mutations. Taken together, these ideas can potentially reconcile evolutionary theory with the clinical dynamics of antibiotic resistance and guide the development of strategies for containing resistance in clinical pathogens.
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Affiliation(s)
- R Craig MacLean
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| | - Tom Vogwill
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
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17
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Romero MM, Basile JI, López B, Ritacco V, Barrera L, Sasiain MDC, Alemán M. Outbreaks of Mycobacterium tuberculosis MDR strains differentially induce neutrophil respiratory burst involving lipid rafts, p38 MAPK and Syk. BMC Infect Dis 2014; 14:262. [PMID: 24886274 PMCID: PMC4049492 DOI: 10.1186/1471-2334-14-262] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 05/07/2014] [Indexed: 11/16/2022] Open
Abstract
Background Neutrophils (PMN) are the first cells to infiltrate the lung after infection, and they play a significant protective role in the elimination of pathogen, by releasing preformed oxidants and proteolytic enzymes from granules and generating ROS, thus limiting inflammation by succumbing to apoptosis. In a previous study, we found marked differences in ROS-induced apoptosis between two Mycobacterium tuberculosis (Mtb) strains, M and Ra, representative of widespread Mtb families in South America, i.e. Haarlem and Latin-American Mediterranean (LAM), being strain M able to generate further drug resistance and to disseminate aggressively. Methods In this study we evaluate the nature of bacteria-PMN interaction by assessing ROS production, apoptosis, lipid raft coalescence, and phagocytosis induced by Mtb strains. Results Dectin-1 and TLR2 participate in Mtb-induced ROS generation and apoptosis in PMN involving p38 MAPK and Syk activation with the participation of a TLR2-dependent coalescence of lipid rafts. Further, ROS production occurs during the phagocytosis of non-opsonized bacteria and involves α-glucans on the capsule. In contrast, strain M lacks the ability to induce ROS because of: 1) a reduced phagocytosis and 2) a failure in coalescence of lipid raft. Conclusions The differences in wall composition could explain the success of some strains which stay unnoticed by the host through inhibition of apoptosis and ROS but making possible its replication inside PMN as a potential evasion mechanism. Innate immune responses elicited by Mtb strain-to-strain variations need to be considered in TB vaccine development.
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Affiliation(s)
| | | | | | | | | | | | - Mercedes Alemán
- Inmunologia de enfermedades respiratorias, IMEX-CONTICET-ANM, Buenos Aires, Argentina.
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18
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Dowdy DW, Dye C, Cohen T. Data needs for evidence-based decisions: a tuberculosis modeler's 'wish list'. Int J Tuberc Lung Dis 2014; 17:866-77. [PMID: 23743307 DOI: 10.5588/ijtld.12.0573] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Infectious disease models are important tools for understanding epidemiology and supporting policy decisions for disease control. In the case of tuberculosis (TB), such models have informed our understanding and control strategies for over 40 years, but the primary assumptions of these models--and their most urgent data needs--remain obscure to many TB researchers and control officers. The structure and parameter values of TB models are informed by observational studies and experiments, but the evidence base in support of these models remains incomplete. Speaking from the perspective of infectious disease modelers addressing the broader TB research and control communities, we describe the basic structure common to most TB models and present a 'wish list' that would improve the evidence foundation upon which these models are built. As a comprehensive TB research agenda is formulated, we argue that the data needs of infectious disease models--our primary long-term decision-making tools--should figure prominently.
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Affiliation(s)
- D W Dowdy
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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19
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Alonso M, Martínez-Lirola M, Palacios JJ, Menéndez Á, Herranz M, Martínez S, Bouza E, García-de-Viedma D. Evaluation of the potential role of a new mutation in mabA in modifying the response of Mycobacterium tuberculosis to isoniazid. Tuberculosis (Edinb) 2013; 93:664-7. [PMID: 23973657 DOI: 10.1016/j.tube.2013.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 07/02/2013] [Accepted: 07/29/2013] [Indexed: 10/26/2022]
Abstract
A new mutation in mabA, Thr4Ile, was identified in a Mycobacterium tuberculosis isolate from a patient whose culture remained positive after treatment. The same mutation was found in another 5 patients infected by different strains. A putative role for this mutation in the process of diminishing susceptibility to isoniazid is evaluated.
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Affiliation(s)
- María Alonso
- Servicio de Microbiología Clínica y Enfermedades Infecciosas. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; CIBER Enfermedades Respiratorias (CIBERES06/06/0058), Spain
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20
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Kumar K, Shorten RJ, Capocci S, Solamalai A, Goodburn A, Cropley I, McHugh TD, Lipman M. The value of “inform and advise” guidance in a case of extensive tuberculosis transmission. J Infect 2013; 67:158-60. [DOI: 10.1016/j.jinf.2013.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 04/04/2013] [Accepted: 04/05/2013] [Indexed: 10/27/2022]
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21
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Ritacco V, López B, Ambroggi M, Palmero D, Salvadores B, Gravina E, Mazzeo E, Imaz S, Barrera L. HIV infection and geographically bound transmission of drug-resistant tuberculosis, Argentina. Emerg Infect Dis 2013; 18:1802-10. [PMID: 23092584 PMCID: PMC3559153 DOI: 10.3201/eid1811.120126] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Disease trends are driven by HIV co-infection and transmission of a few strains within narrow geographic niches. During 2003–2009, the National Tuberculosis (TB) Laboratory Network in Argentina gave 830 patients a new diagnosis of multidrug-resistant (MDR) TB and 53 a diagnosis of extensively drug- resistant (XDR) TB. HIV co-infection was involved in nearly one third of these cases. Strain genotyping showed that 7 major clusters gathered 56% of patients within restricted geographic areas. The 3 largest clusters corresponded to epidemic MDR TB strains that have been undergoing transmission for >10 years. The indigenous M strain accounted for 29% and 40% of MDR and XDR TB cases, respectively. Drug-resistant TB trends in Argentina are driven by spread of a few strains in hotspots where the rate of HIV infection is high. To curb transmission, the national TB program is focusing stringent interventions in these areas by strengthening infection control in large hospitals and prisons, expediting drug resistance detection, and streamlining information-sharing systems between HIV and TB programs.
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Affiliation(s)
- Viviana Ritacco
- Instituto Nacional de Enfermedades Infecciosas ANLIS Dr. Carlos G. Malbrán Buenos Aires, Argentina.
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22
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A time-to-event pharmacodynamic model describing treatment response in patients with pulmonary tuberculosis using days to positivity in automated liquid mycobacterial culture. Antimicrob Agents Chemother 2012. [PMID: 23183433 DOI: 10.1128/aac.01876-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Days to positivity in automated liquid mycobacterial culture have been shown to correlate with mycobacterial load and have been proposed as a useful biomarker for treatment responses in tuberculosis. However, there is currently no quantitative method or model to analyze the change in days to positivity with time on treatment. The objectives of this study were to describe the decline in numbers of mycobacteria in sputum collected once weekly for 8 weeks from patients on treatment for tuberculosis using days to positivity in liquid culture. One hundred forty-four patients with smear-positive pulmonary tuberculosis were recruited from a tuberculosis clinic in Cape Town, South Africa. A nonlinear mixed-effects repeated-time-to-event modeling approach was used to analyze the time-to-positivity data. A biexponential model described the decline in the estimated number of bacteria in patients' sputum samples, while a logistic model with a lag time described the growth of the bacteria in liquid culture. At baseline, the estimated number of rapidly killed bacteria is typically 41 times higher than that of those that are killed slowly. The time to kill half of the rapidly killed bacteria was about 1.8 days, while it was 39 days for slowly killed bacteria. Patients with lung cavitation had higher bacterial loads than patients without lung cavitation. The model successfully described the increase in days to positivity as treatment progressed, differentiating between bacteria that are killed rapidly and those that are killed slowly. Our model can be used to analyze similar data from studies testing new drug regimens.
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Shorten RJ, McGregor AC, Platt S, Jenkins C, Lipman MCI, Gillespie SH, Charalambous BM, McHugh TD. When is an outbreak not an outbreak? Fit, divergent strains of Mycobacterium tuberculosis display independent evolution of drug resistance in a large London outbreak. J Antimicrob Chemother 2012; 68:543-9. [DOI: 10.1093/jac/dks430] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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24
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Tamaru A, Nakajima C, Wada T, Wang Y, Inoue M, Kawahara R, Maekura R, Ozeki Y, Ogura H, Kobayashi K, Suzuki Y, Matsumoto S. Dominant incidence of multidrug and extensively drug-resistant specific Mycobacterium tuberculosis clones in Osaka Prefecture, Japan. PLoS One 2012; 7:e42505. [PMID: 22952596 PMCID: PMC3432034 DOI: 10.1371/journal.pone.0042505] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 07/09/2012] [Indexed: 11/19/2022] Open
Abstract
Infection and transmission of multidrug-resistant Mycobacterium tuberculosis (MDR-Mtb) and extensively drug-resistant M. tuberculosis (XDR-Mtb) is a serious health problem. We analyzed a total of 1,110 Mtb isolates in Osaka Prefecture and neighboring areas from April 2000 to March 2009. A total of 89 MDR-Mtb were identified, 36 (48.5%) of which were determined to be XDR-Mtb. Among the 89 MDR-Mtb isolates, 24 (27.0%) phylogenetically distributed into six clusters based on mycobacterial interspersed repetitive units-various number of tandem repeats (MIRU-VNTR) typing. Among these six clusters, the MIRU-VNTR patterns of four (OM-V02, OM-V03, OM-V04, and OM-V06) were only found for MDR-Mtb. Further analysis revealed that all isolates belonging to OM-V02 and OM-V03, and two isolates from OM-V04 were clonal. Importantly such genotypes were not observed for drug-sensitive isolates. These suggest that few but transmissible clones can transmit after acquiring multidrug resistance and colonize even in a country with a developed, well-organized healthcare system.
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Affiliation(s)
- Aki Tamaru
- Department of Infectious Diseases, Osaka Prefectural Institute of Public Health, Osaka, Osaka, Japan.
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Walter ND, Strong M, Belknap R, Ordway DJ, Daley CL, Chan ED. Translating basic science insight into public health action for multidrug- and extensively drug-resistant tuberculosis. Respirology 2012; 17:772-91. [PMID: 22458269 PMCID: PMC4540333 DOI: 10.1111/j.1440-1843.2012.02176.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Multidrug (MDR)- and extensively drug-resistant (XDR) tuberculosis (TB) impose a heavy toll of human suffering and social costs. Controlling drug-resistant TB is a complex global public health challenge. Basic science advances including elucidation of the genetic basis of resistance have enabled development of new assays that are transforming the diagnosis of MDR-TB. Molecular epidemiological approaches have provided new insights into the natural history of TB with important implications for drug resistance. In the future, progress in understanding Mycobacterium tuberculosis strain-specific human immune responses, integration of systems biology approaches with traditional epidemiology and insight into the biology of mycobacterial persistence have potential to be translated into new tools for diagnosis and treatment of MDR- and XDR-TB. We review recent basic sciences developments that have contributed or may contribute to improved public health response.
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Affiliation(s)
- Nicholas D Walter
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Denver, Aurora, Colorado, USA.
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26
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Tretter EM, Berger JM. Mechanisms for defining supercoiling set point of DNA gyrase orthologs: II. The shape of the GyrA subunit C-terminal domain (CTD) is not a sole determinant for controlling supercoiling efficiency. J Biol Chem 2012; 287:18645-54. [PMID: 22457352 DOI: 10.1074/jbc.m112.345736] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
DNA topoisomerases are essential enzymes that can overwind, underwind, and disentangle double-helical DNA segments to maintain the topological state of chromosomes. Nearly all bacteria utilize a unique type II topoisomerase, gyrase, which actively adds negative supercoils to chromosomes using an ATP-dependent DNA strand passage mechanism; however, the specific activities of these enzymes can vary markedly from species to species. Escherichia coli gyrase is known to favor supercoiling over decatenation (Zechiedrich, E. L., Khodursky, A. B., and Cozzarelli, N. R. (1997) Genes Dev. 11, 2580-2592), whereas the opposite has been reported for Mycobacterium tuberculosis gyrase (Aubry, A., Fisher, L. M., Jarlier, V., and Cambau, E. (2006) Biochem. Biophys. Res. Commun. 348, 158-165). Here, we set out to understand the molecular basis for these differences using structural and biochemical approaches. Contrary to expectations based on phylogenetic inferences, we find that the dedicated DNA wrapping domains (the C-terminal domains) of both gyrases are highly similar, both architecturally and in their ability to introduce writhe into DNA. However, the M. tuberculosis enzyme lacks a C-terminal control element recently uncovered in E. coli gyrase (see accompanying article (Tretter, E. M., and Berger, J. M. (2012) J. Biol. Chem. 287, 18636-18644)) and turns over ATP at a much slower rate. Together, these findings demonstrate that C-terminal domain shape is not the sole regulatory determinant of gyrase activity and instead indicate that an inability to tightly couple DNA wrapping to ATP turnover is why M. tuberculosis gyrase cannot supercoil DNA to the same extent as its γ-proteobacterial counterpart. Our observations demonstrate that gyrase has been modified in multiple ways throughout evolution to fine-tune its specific catalytic properties.
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Affiliation(s)
- Elsa M Tretter
- Division of Biochemistry, Biophysics, and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
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Bergval I, Kwok B, Schuitema A, Kremer K, van Soolingen D, Klatser P, Anthony R. Pre-existing isoniazid resistance, but not the genotype of Mycobacterium tuberculosis drives rifampicin resistance codon preference in vitro. PLoS One 2012; 7:e29108. [PMID: 22235262 PMCID: PMC3250395 DOI: 10.1371/journal.pone.0029108] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 11/21/2011] [Indexed: 11/19/2022] Open
Abstract
Both the probability of a mutation occurring and the ability of the mutant to persist will influence the distribution of mutants that arise in a population. We studied the interaction of these factors for the in vitro selection of rifampicin (RIF)-resistant mutants of Mycobacterium tuberculosis. We characterised two series of spontaneous RIF-resistant in vitro mutants from isoniazid (INH)-sensitive and -resistant laboratory strains and clinical isolates, representing various M. tuberculosis genotypes. The first series were selected from multiple parallel 1 ml cultures and the second from single 10 ml cultures. RIF-resistant mutants were screened by Multiplex Ligation-dependent Probe Amplification (MLPA) or by sequencing the rpoB gene. For all strains the mutation rate for RIF resistance was determined with a fluctuation assay. The most striking observation was a shift towards rpoB-S531L (TCG→TTG) mutations in a panel of laboratory-generated INH-resistant mutants selected from the 10-ml cultures (p<0.001). All tested strains showed similar mutation rates (1.33×10−8 to 2.49×10−7) except one of the laboratory-generated INH mutants with a mutation rate measured at 5.71×10−7, more than 10 times higher than that of the INH susceptible parental strain (5.46–7.44×10−8). No significant, systematic difference in the spectrum of rpoB-mutations between strains of different genotypes was observed. The dramatic shift towards rpoB-S531L in our INH-resistant laboratory mutants suggests that the relative fitness of resistant mutants can dramatically impact the distribution of (subsequent) mutations that accumulate in a M. tuberculosis population, at least in vitro. We conclude that, against specific genetic backgrounds, certain resistance mutations are particularly likely to spread. Molecular screening for these (combinations of) mutations in clinical isolates could rapidly identify these particular pathogenic strains. We therefore recommend that isolates are screened for the distribution of resistance mutations, especially in regions that are highly endemic for (multi)drug resistant tuberculosis.
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Affiliation(s)
- Indra Bergval
- KIT Biomedical Research, Royal Tropical Institute, Amsterdam, The Netherlands.
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