2019年
No.17
Medical Abstracts
Keyword: tuberculosis
1. Nat Rev Microbiol. 2019 Sep;17(9):533-545. doi: 10.1038/s41579-019-0214-5.
Whole genome sequencing of Mycobacterium tuberculosis: current standards and open
issues.
Meehan CJ(1), Goig GA(2), Kohl TA(3)(4), Verboven L(5), Dippenaar A(6), Ezewudo
M(7),....
Author information:
(1)Unit of Mycobacteriology, Department of Biomedical Sciences, Institute of
Tropical Medicine, Antwerp, Belgium.
(2)Institute of Biomedicine of Valencia, CSIC, Valencia, Spain.
(3)Molecular and Experimental Mycobacteriology, Priority Area Infections,
Research Center Borstel, Borstel, Germany.
...
Whole genome sequencing (WGS) of Mycobacterium tuberculosis has rapidly
progressed from a research tool to a clinical application for the diagnosis and
management of tuberculosis and in public health surveillance. This development
has been facilitated by drastic drops in cost, advances in technology and
concerted efforts to translate sequencing data into actionable information. There
is, however, a risk that, in the absence of a consensus and international
standards, the widespread use of WGS technology may result in data and processes
that lack harmonization, comparability and validation. In this Review, we outline
the current landscape of WGS pipelines and applications, and set out best
practices for M. tuberculosis WGS, including standards for bioinformatics
pipelines, curated repositories of resistance-causing variants, phylogenetic
analyses, quality control and standardized reporting.
DOI: 10.1038/s41579-019-0214-5
PMID: 31209399
2. Lancet. 2019 Sep 14;394(10202):967-978. doi: 10.1016/S0140-6736(19)32045-8.
Challenges and controversies in childhood tuberculosis.
Reuter A(1), Hughes J(2), Furin J(3).
Author information:
(1)Médecins Sans Frontières, Khayelitsha, South Africa.
(2)Desmond Tutu Tuberculosis Center, Stellenbosch University, Stellenbosch, South
Africa.
(3)Department of Global Health and Social Medicine, Harvard Medical School,
Boston, MA, USA. Electronic address: jennifer_furin@hms.harvard.edu.
Children bear a substantial burden of suffering when it comes to tuberculosis.
Ironically, they are often left out of the scientific and public health advances
that have led to important improvements in tuberculosis diagnosis, treatment, and
prevention over the past decade. This Series paper describes some of the
challenges and controversies in paediatric tuberculosis, including the
epidemiology and treatment of tuberculosis in children. Two areas in which
substantial challenges and controversies exist (ie, diagnosis and prevention) are
explored in more detail. This Series paper also offers possible solutions for
including children in all efforts to end tuberculosis, with a focus on ensuring
that the proper financial and human resources are in place to best serve children
exposed to, infected with, and sick from all forms of tuberculosis.
Copyright © 2019 Elsevier Ltd. All rights reserved.
DOI: 10.1016/S0140-6736(19)32045-8
PMID: 31526740 [Indexed for MEDLINE]
3. Lancet. 2019 Sep 14;394(10202):953-966. doi: 10.1016/S0140-6736(19)31882-3.
Management of drug-resistant tuberculosis.
Lange C(1), Dheda K(2), Chesov D(3), Mandalakas AM(4), Udwadia Z(5), Horsburgh CR
Jr(6).
Author information:
(1)Clinical Infectious Diseases, Research Center Borstel, Borstel, Germany;
Respiratory Medicine and International Health, University of Lübeck, Lübeck,
Germany; German Center for Infection Research Clinical Tuberculosis Unit,
Borstel, Germany; Department of Medicine, Karolinska Institute, Stockholm,
Sweden. Electronic address: clange@fz-borstel.de.
...
Drug-resistant tuberculosis is a major public health concern in many countries.
Over the past decade, the number of patients infected with Mycobacterium
tuberculosis resistant to the most effective drugs against tuberculosis (ie,
rifampicin and isoniazid), which is called multidrug-resistant tuberculosis, has
continued to increase. Globally, 4·6% of patients with tuberculosis have
multidrug-resistant tuberculosis, but in some areas, like Kazakhstan, Kyrgyzstan,
Moldova, and Ukraine, this proportion exceeds 25%. Treatment for patients with
multidrug-resistant tuberculosis is prolonged (ie, 9-24 months) and patients with
multidrug-resistant tuberculosis have less favourable outcomes than those treated
for drug-susceptible tuberculosis. Individualised multidrug-resistant
tuberculosis treatment with novel (eg, bedaquiline) and repurposed (eg,
linezolid, clofazimine, or meropenem) drugs and guided by genotypic and
phenotypic drug susceptibility testing can improve treatment outcomes. Some
clinical trials are evaluating 6-month regimens to simplify management and
improve outcomes of patients with multidrug-resistant tuberculosis. Here we
review optimal diagnostic and treatment strategies for patients with
drug-resistant tuberculosis and their contacts.
Copyright © 2019 Elsevier Ltd. All rights reserved.
DOI: 10.1016/S0140-6736(19)31882-3
PMID: 31526739 [Indexed for MEDLINE]
4. Cell. 2019 Sep 5;178(6):1344-1361.e11. doi: 10.1016/j.cell.2019.08.004. Epub 2019
Aug 29.
TNF Induces Pathogenic Programmed Macrophage Necrosis in Tuberculosis through a
Mitochondrial-Lysosomal-Endoplasmic Reticulum Circuit.
Roca FJ(1), Whitworth LJ(2), Redmond S(3), Jones AA(2), Ramakrishnan L(4).
Author information:
(1)Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC
Laboratory of Molecular Biology, Cambridge CB2 OQH, UK. Electronic address:
froca@mrc-lmb.cam.ac.uk.
(2)Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC
Laboratory of Molecular Biology, Cambridge CB2 OQH, UK.
(3)Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC
Laboratory of Molecular Biology, Cambridge CB2 OQH, UK; Department of
Microbiology, University of Washington, Seattle, WA 98195, USA.
(4)Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC
Laboratory of Molecular Biology, Cambridge CB2 OQH, UK; Department of
Microbiology, University of Washington, Seattle, WA 98195, USA. Electronic
address: lr404@cam.ac.uk.
Necrosis of infected macrophages constitutes a critical pathogenetic event in
tuberculosis by releasing mycobacteria into the growth-permissive extracellular
environment. In zebrafish infected with Mycobacterium marinum or Mycobacterium
tuberculosis, excess tumor necrosis factor triggers programmed necrosis of
infected macrophages through the production of mitochondrial reactive oxygen
species (ROS) and the participation of cyclophilin D, a component of the
mitochondrial permeability transition pore. Here, we show that this necrosis
pathway is not mitochondrion-intrinsic but results from an inter-organellar
circuit initiating and culminating in the mitochondrion. Mitochondrial ROS induce
production of lysosomal ceramide that ultimately activates the cytosolic protein
BAX. BAX promotes calcium flow from the endoplasmic reticulum into the
mitochondrion through ryanodine receptors, and the resultant mitochondrial
calcium overload triggers cyclophilin-D-mediated necrosis. We identify ryanodine
receptors and plasma membrane L-type calcium channels as druggable targets to
intercept mitochondrial calcium overload and necrosis of mycobacterium-infected
zebrafish and human macrophages.
Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved.
DOI: 10.1016/j.cell.2019.08.004
PMCID: PMC6736209
PMID: 31474371
5. Nat Rev Immunol. 2019 Sep;19(9):550-562. doi: 10.1038/s41577-019-0174-z.
Moving tuberculosis vaccines from theory to practice.
Andersen P(1)(2), Scriba TJ(3).
Author information:
(1)Center for Vaccine Research, Statens Serum Institut, Copenhagen, Denmark.
pa@ssi.dk.
(2)Department of Immunology and Microbiology, University of Copenhagen,
Copenhagen, Denmark. pa@ssi.dk.
(3)South African Tuberculosis Vaccine Initiative, Institute of Infectious Disease
and Molecular Medicine and Division of Immunology, Department of Pathology,
University of Cape Town, Cape Town, South Africa. thomas.scriba@uct.ac.za.
Tuberculosis (TB) vaccine research has reached a unique point in time.
Breakthrough findings in both the basic immunology of Mycobacterium tuberculosis
infection and the clinical development of TB vaccines suggest, for the first time
since the discovery of the Mycobacterium bovis bacillus Calmette-Guérin (BCG)
vaccine more than a century ago, that a novel, efficacious TB vaccine is
imminent. Here, we review recent data in the light of our current understanding
of the immunology of TB infection and discuss the identification of biomarkers
for vaccine efficacy and the next steps in the quest for an efficacious vaccine
that can control the global TB epidemic.
DOI: 10.1038/s41577-019-0174-z
PMID: 31114037
6. Nat Commun. 2019 Sep 18;10(1):4260. doi: 10.1038/s41467-019-12109-5.
Heme and hemoglobin utilization by Mycobacterium tuberculosis.
Mitra A(1), Ko YH(2), Cingolani G(3)(4), Niederweis M(5).
Author information:
(1)Department of Microbiology, University of Alabama at Birmingham, 845 19th
Street South, Birmingham, AL, 35294, USA.
(2)Department of Biochemistry and Molecular Biology, Thomas Jefferson University,
233S. 10th Street, Philadelphia, PA, 19107, USA.
(3)Department of Biochemistry and Molecular Biology, Thomas Jefferson University,
233S. 10th Street, Philadelphia, PA, 19107, USA. Gino.Cingolani@jefferson.edu.
(4)Institute of Biomembranes and Bioenergetics, National Research Council, Via
Amendola 165/A, 70126, Bari, Italy. Gino.Cingolani@jefferson.edu.
(5)Department of Microbiology, University of Alabama at Birmingham, 845 19th
Street South, Birmingham, AL, 35294, USA. mnieder@uab.edu.
Iron is essential for growth of Mycobacterium tuberculosis (Mtb), but most iron
in the human body is stored in heme within hemoglobin. Here, we demonstrate that
the substrate-binding protein DppA of the inner membrane Dpp transporter is
required for heme and hemoglobin utilization by Mtb. The 1.27 Å crystal structure
of DppA shows a tetrapeptide bound in the protein core and a large
solvent-exposed crevice for heme binding. Mutation of arginine 179 in this cleft
eliminates heme binding to DppA and prevents heme utilization by Mtb. The outer
membrane proteins PPE36 and PPE62 are also required for heme and hemoglobin
utilization, indicating that these pathways converge at the cell surface of Mtb.
Albumin, the most abundant blood protein, binds heme specifically and bypasses
the requirements for PPE36, PPE62 and Dpp. Thus, our study reveals
albumin-dependent and -independent heme uptake pathways, highlighting the
importance of iron acquisition from heme for Mtb.
DOI: 10.1038/s41467-019-12109-5
PMCID: PMC6751184
PMID: 31534126
7. Mol Biol Evol. 2019 Sep 18. pii: msz214. doi: 10.1093/molbev/msz214. [Epub ahead
of print]
The Genetic Background modulates the Evolution of Fluoroquinolone-Resistance in
Mycobacterium tuberculosis.
Castro RAD(1)(2), Ross A(1)(2), Kamwela L(1)(2), Reinhard M(1)(2), Loiseau
C(1)(2), Feldmann J(1)(2), Borrell S(1)(2), Trauner A(1)(2), Gagneux S(1)(2).
Author information:
(1)Swiss Tropical and Public Health Institute, Basel, Switzerland.
(2)University of Basel, Basel, Switzerland.
Fluoroquinolones (FQ) form the backbone in experimental treatment regimens
against drug-susceptible tuberculosis. However, little is known on whether the
genetic variation present in natural populations of Mycobacterium tuberculosis
(Mtb) affects the evolution of FQ-resistance (FQ-R). To investigate this
question, we used nine genetically distinct drug-susceptible clinical isolates of
Mtb and measured their frequency of resistance to the FQ ofloxacin (OFX) in
vitro. We found that the Mtb genetic background led to differences in the
frequency of OFX-resistance (OFX-R) that spanned two orders of magnitude and
substantially modulated the observed mutational profiles for OFX-R. Further in
vitro assays showed that the genetic background also influenced the minimum
inhibitory concentration and the fitness effect conferred by a given OFX-R
mutation. To test the clinical relevance of our in vitro work, we surveyed the
mutational profile for FQ-R in publicly available genomic sequences from clinical
Mtb isolates, and found substantial Mtb lineage-dependent variability. Comparison
of the clinical and the in vitro mutational profiles for FQ-R showed that 51% and
39% of the variability in the clinical frequency of FQ-R gyrA mutation events in
Lineage 2 and Lineage 4 strains, respectively, can be attributed to how Mtb
evolves FQ-R in vitro. As the Mtb genetic background strongly influenced the
evolution of FQ-R in vitro, we conclude that the genetic background of Mtb also
impacts the evolution of FQ-R in the clinic.
© The Author(s) 2019. Published by Oxford University Press on behalf of the
Society for Molecular Biology and Evolution.
DOI: 10.1093/molbev/msz214
PMID: 31532481
8. Nat Commun. 2019 Sep 16;10(1):4215. doi: 10.1038/s41467-019-12224-3.
Derailing the aspartate pathway of Mycobacterium tuberculosis to eradicate
persistent infection.
Hasenoehrl EJ(1), Rae Sajorda D(1), Berney-Meyer L(1), Johnson S(1), Tufariello
JM(1)(2), Fuhrer T(3), Cook GM(4)(5), Jacobs WR Jr(1)(6), Berney M(7).
Author information:
(1)Department of Microbiology and Immunology, Albert Einstein College of
Medicine, Bronx, NY, USA.
...
A major constraint for developing new anti-tuberculosis drugs is the limited
number of validated targets that allow eradication of persistent infections.
Here, we uncover a vulnerable component of Mycobacterium tuberculosis (Mtb)
persistence metabolism, the aspartate pathway. Rapid death of threonine and
homoserine auxotrophs points to a distinct susceptibility of Mtb to inhibition of
this pathway. Combinatorial metabolomic and transcriptomic analysis reveals that
inability to produce threonine leads to deregulation of aspartate kinase, causing
flux imbalance and lysine and DAP accumulation. Mtb's adaptive response to this
metabolic stress involves a relief valve-like mechanism combining lysine export
and catabolism via aminoadipate. We present evidence that inhibition of the
aspartate pathway at different branch-point enzymes leads to clearance of chronic
infections. Together these findings demonstrate that the aspartate pathway in Mtb
relies on a combination of metabolic control mechanisms, is required for
persistence, and represents a target space for anti-tuberculosis drug
development.
DOI: 10.1038/s41467-019-12224-3
PMCID: PMC6746716
PMID: 31527595
9. PLoS Med. 2019 Sep 11;16(9):e1002907. doi: 10.1371/journal.pmed.1002907.
eCollection 2019 Sep.
Vitamin D status and risk of incident tuberculosis disease: A nested case-control
study, systematic review, and individual-participant data meta-analysis.
Aibana O(1), Huang CC(2), Aboud S(3), Arnedo-Pena A(4), Becerra MC(2),
...
Author information:
(1)Department of Internal Medicine, McGovern Medical School at the University of
Texas Health Science Center, Houston, Texas, United States of America.
(2)Department of Global Health and Social Medicine, Harvard Medical School,
Boston, Massachusetts, United States of America.
(3)Department of Microbiology and Immunology, Muhimbili University of Health and
Allied Sciences, Upanga West, Dar es Salaam, Tanzania.
...
BACKGROUND: Few studies have evaluated the association between preexisting
vitamin D deficiency and incident tuberculosis (TB). We assessed the impact of
baseline vitamins D levels on TB disease risk.
METHODS AND FINDINGS: We assessed the association between baseline vitamin D and
incident TB in a prospective cohort of 6,751 HIV-negative household contacts of
TB patients enrolled between September 1, 2009, and August 29, 2012, in Lima,
Peru. We screened for TB disease at 2, 6, and 12 months after enrollment. We
defined cases as household contacts who developed TB disease at least 15 days
after enrollment of the index patient. For each case, we randomly selected four
controls from among contacts who did not develop TB disease, matching on gender
and year of age. We also conducted a one-stage individual-participant data (IPD)
meta-analysis searching PubMed and Embase to identify prospective studies of
vitamin D and TB disease until June 8, 2019. We included studies that assessed
vitamin D before TB diagnosis. In the primary analysis, we defined vitamin D
deficiency as 25-(OH)D < 50 nmol/L, insufficiency as 50-75 nmol/L, and
sufficiency as >75nmol/L. We estimated the association between baseline vitamin D
status and incident TB using conditional logistic regression in the Lima cohort
and generalized linear mixed models in the meta-analysis. We further defined
severe vitamin D deficiency as 25-(OH)D < 25 nmol/L and performed stratified
analyses by HIV status in the IPD meta-analysis. In the Lima cohort, we analyzed
180 cases and 709 matched controls. The adjusted odds ratio (aOR) for TB risk
among participants with baseline vitamin D deficiency compared to sufficient
vitamin D was 1.63 (95% CI 0.75-3.52; p = 0.22). We included seven published
studies in the meta-analysis and analyzed 3,544 participants. In the pooled
analysis, the aOR was 1.48 (95% CI 1.04-2.10; p = 0.03). The aOR for severe
vitamin D deficiency was 2.05 (95% CI 0.87-4.87; p trend for decreasing 25-(OH)D
levels from sufficient vitamin D to severe deficiency = 0.02). Among 1,576
HIV-positive patients, vitamin D deficiency conferred a 2-fold (aOR 2.18, 95% CI
1.22-3.90; p = 0.01) increased risk of TB, and the aOR for severe vitamin D
deficiency compared to sufficient vitamin D was 4.28 (95% CI 0.85-21.45; p =
0.08). Our Lima cohort study is limited by the short duration of follow-up, and
the IPD meta-analysis is limited by the number of possible confounding covariates
available across all studies.
CONCLUSION: Our findings suggest vitamin D predicts TB disease risk in a
dose-dependent manner and that the risk of TB disease is highest among
HIV-positive individuals with severe vitamin D deficiency. Randomized control
trials are needed to evaluate the possible role of vitamin D supplementation on
reducing TB disease risk.
DOI: 10.1371/journal.pmed.1002907
PMCID: PMC6738590
PMID: 31509529
Conflict of interest statement: The authors of this manuscript have the following
competing interests: MBM is a member of the Editorial Board of PLOS Medicine. All
other authors have declared no competing interests.
10. Nat Commun. 2019 Sep 5;10(1):3994. doi: 10.1038/s41467-019-11948-6.
Genome-wide mutational biases fuel transcriptional diversity in the Mycobacterium
tuberculosis complex.
Chiner-Oms Á(1)(2), Berney M(3), Boinett C(4)(5), González-Candelas F(1)(6),
Young DB(7), Gagneux S(8)(9), Jacobs WR Jr(3), Parkhill J(10), Cortes T(11),
Comas I(12)(13).
Author information:
(1)Unidad Mixta "Infección y Salud Pública" FISABIO-CSISP/Universidad de
Valencia, Instituto de Biología Integrativa de Sistemas-I2SysBio, Valencia,
Spain.
(2)Instituto de Biomedicina de Valencia, IBV-CSIC, Valencia, Spain.
(3)Department of Microbiology and Immunology and Department of Molecular
Genetics, Albert Einstein College of Medicine, New York, USA.
...
The Mycobacterium tuberculosis complex (MTBC) members display different
host-specificities and virulence phenotypes. Here, we have performed a
comprehensive RNAseq and methylome analysis of the main clades of the MTBC and
discovered unique transcriptional profiles. The majority of genes differentially
expressed between the clades encode proteins involved in host interaction and
metabolic functions. A significant fraction of changes in gene expression can be
explained by positive selection on single mutations that either create or disrupt
transcriptional start sites (TSS). Furthermore, we show that clinical strains
have different methyltransferases inactivated and thus different methylation
patterns. Under the tested conditions, differential methylation has a minor
direct role on transcriptomic differences between strains. However, disruption of
a methyltransferase in one clinical strain revealed important expression
differences suggesting indirect mechanisms of expression regulation. Our study
demonstrates that variation in transcriptional profiles are mainly due to TSS
mutations and have likely evolved due to differences in host characteristics.
DOI: 10.1038/s41467-019-11948-6
PMCID: PMC6728331
PMID: 31488832
11. J Clin Invest. 2019 Sep 3;129(9):3482-3491. doi: 10.1172/JCI128877.
Targeting innate immunity for tuberculosis vaccination.
Khader SA(1), Divangahi M(2), Hanekom W(3), Hill PC(4), Maeurer M(5)(6), Makar
KW(3), Mayer-Barber KD(7), Mhlanga MM(8), Nemes E(9), Schlesinger LS(10), van
Crevel R(11), Vankalayapati R(12), Xavier RJ(13)(14)(15)(16), Netea MG(11)(17);
Bill and Melinda Gates Foundation Collaboration for TB Vaccine Discovery Innate
Immunity Working Group18.
Author information:
(1)Department of Molecular Microbiology, Washington University School of Medicine
in St. Louis, St. Louis, Missouri, USA.
...
Vaccine development against tuberculosis (TB) is based on the induction of
adaptive immune responses endowed with long-term memory against mycobacterial
antigens. Memory B and T cells initiate a rapid and robust immune response upon
encounter with Mycobacterium tuberculosis, thus achieving long-lasting protection
against infection. Recent studies have shown, however, that innate immune cell
populations such as myeloid cells and NK cells also undergo functional adaptation
after infection or vaccination, a de facto innate immune memory that is also
termed trained immunity. Experimental and epidemiological data have shown that
induction of trained immunity contributes to the beneficial heterologous effects
of vaccines such as bacille Calmette-Guérin (BCG), the licensed TB vaccine.
Moreover, increasing evidence argues that trained immunity also contributes to
the anti-TB effects of BCG vaccination. An interaction among immunological
signals, metabolic rewiring, and epigenetic reprogramming underlies the molecular
mechanisms mediating trained immunity in myeloid cells and their bone marrow
progenitors. Future studies are warranted to explore the untapped potential of
trained immunity to develop a future generation of TB vaccines that would combine
innate and adaptive immune memory induction.
DOI: 10.1172/JCI128877
PMCID: PMC6715374 [Available on 2020-09-03]
PMID: 31478909
12. Autophagy. 2019 Sep 8:1-23. doi: 10.1080/15548627.2019.1658436. [Epub ahead of
print]
Induction of autophagy through CLEC4E in combination with TLR4: an innovative
strategy to restrict the survival of Mycobacterium tuberculosis.
Pahari S(1)(2), Negi S(1), Aqdas M(1), Arnett E(2), Schlesinger LS(2), Agrewala
JN(1)(3).
Author information:
(1)Immunology Division, CSIR-Institute of Microbial Technology , Chandigarh ,
India.
(2)Host-Pathogen Interactions Program, Texas Biomedical Research Institute , San
Antonio , TX , USA.
(3)Biomedical Engineering Department, Indian Institute of Technology Ropar ,
Rupnagar , India.
Host-directed therapies are gaining considerable impetus because of the emergence
of drug-resistant strains of pathogens due to antibiotic therapy. Therefore,
there is an urgent need to exploit alternative and novel strategies directed at
host molecules to successfully restrict infections. The C-type lectin receptor
CLEC4E and Toll-like receptor TLR4 expressed by host cells are among the first
line of defense in encountering pathogens. Therefore, we exploited signaling of
macrophages through CLEC4E in association with TLR4 agonists (C4.T4) to control
the growth of Mycobacterium tuberculosis (Mtb). We observed significant
improvement in host immunity and reduced bacterial load in the lungs of
Mtb-infected mice and guinea pigs treated with C4.T4 agonists. Further,
intracellular killing of Mtb was achieved with a 10-fold lower dose of isoniazid
or rifampicin in conjunction with C4.T4 than the drugs alone. C4.T4 activated
MYD88, PtdIns3K, STAT1 and RELA/NFKB, increased lysosome biogenesis, decreased
Il10 and Il4 gene expression and enhanced macroautophagy/autophagy. Macrophages
from autophagy-deficient (atg5 knockout or Becn1 knockdown) mice showed elevated
survival of Mtb. The present findings also unveiled the novel role of CLEC4E in
inducing autophagy through MYD88, which is required for control of Mtb growth.
This study suggests a unique immunotherapeutic approach involving CLEC4E in
conjunction with TLR4 to restrict the survival of Mtb through autophagy.
Abbreviations: 3MA: 3 methyladenine; AO: acridine orange; Atg5: autophagy related
5; AVOs: acidic vesicular organelles; BECN1: beclin 1, autophagy related; BMDMs:
bone marrow derived macrophages; bw: body weight; C4.T4: agonists of CLEC4E
(C4/TDB) and TLR4 (T4/ultra-pure-LPS); CFU: colony forming unit; CLEC4E/Mincle:
C-type lectin domain family 4, member e; CLR: c-type lectin receptor; INH:
isoniazid; LAMP1: lysosomal-associated membrane protein 1; MφC4.T4: Mtb-infected
C4.T4 stimulated macrophages; MAP1LC3/LC3: microtubule-associated protein 1 light
chain 3; MDC: monodansylcadaverine; MTOR: mechanistic target of rapamycin kinase;
MYD88: myeloid differentiation primary response 88; NFKB: nuclear factor of kappa
light polypeptide gene enhance in B cells; NLR: NOD (nucleotide-binding
oligomerization domain)-like receptors; PFA: paraformaldehyde; PPD: purified
protein derivative; PtdIns3K: class III phosphatidylinositol 3-kinase; RELA:
v-rel reticuloendotheliosis viral oncogene homolog A (avian); RIF: rifampicin;
RLR: retinoic acid-inducible gene-I-like receptors; TDB:
trehalose-6,6´-dibehenate; TLR4: toll-like receptor 4; Ultra-pure-LPS: ultra-pure
lipopolysaccharide-EK; V-ATPase: vacuolar-type H+ ATPase.
DOI: 10.1080/15548627.2019.1658436
PMID: 31462144
13. Nat Chem Biol. 2019 Sep;15(9):889-899. doi: 10.1038/s41589-019-0336-0. Epub 2019
Aug 19.
Mycobacterium tuberculosis releases an antacid that remodels phagosomes.
Buter J(1), Cheng TY(1), Ghanem M(2), Grootemaat AE(3), Raman S(1), Feng X(4),
Plantijn AR(5), Ennis T(1), Wang J(2), Cotton RN(1), Layre E(1), Ramnarine AK(1),
Mayfield JA(1), Young DC(1), Jezek Martinot A(6), Siddiqi N(6), Wakabayashi S(6),
Botella H(7), Calderon R(8), Murray M(9), Ehrt S(7), Snider BB(10), Reed MB(2),
Oldfield E(4), Tan S(11), Rubin EJ(6), Behr MA(2), van der Wel NN(3), Minnaard
AJ(5), Moody DB(12).
Author information:
(1)Division of Rheumatology, Immunology and Allergy, Brigham and Women's
Hospital, Harvard Medical School, Boston, MA, USA.
(2)Infectious Diseases and Immunity in Global Health, McGill University Health
Centre Research Institute, McGill International TB Centre, Montreal, Canada.
(3)Electron Microscopy Center Amsterdam, Department of Medical Biology, Amsterdam
UMC, Amsterdam, the Netherlands.
...
Mycobacterium tuberculosis (Mtb) is the world's most deadly pathogen. Unlike less
virulent mycobacteria, Mtb produces 1-tuberculosinyladenosine (1-TbAd), an
unusual terpene nucleoside of unknown function. In the present study 1-TbAd has
been shown to be a naturally evolved phagolysosome disruptor. 1-TbAd is highly
prevalent among patient-derived Mtb strains, where it is among the most abundant
lipids produced. Synthesis of TbAd analogs and their testing in cells demonstrate
that their biological action is dependent on lipid linkage to the 1-position of
adenosine, which creates a strong conjugate base. Furthermore, C20 lipid moieties
confer passage through membranes. 1-TbAd selectively accumulates in acidic
compartments, where it neutralizes the pH and swells lysosomes, obliterating
their multilamellar structure. During macrophage infection, a 1-TbAd biosynthesis
gene (Rv3378c) confers marked phagosomal swelling and intraphagosomal inclusions,
demonstrating an essential role in regulating the Mtb cellular microenvironment.
Although macrophages kill intracellular bacteria through phagosome acidification,
Mtb coats itself abundantly with antacid.
DOI: 10.1038/s41589-019-0336-0
PMCID: PMC6896213 [Available on 2020-09-01]
PMID: 31427817 [Indexed for MEDLINE]
14. Lancet Infect Dis. 2019 Sep;19(9):e322-e329. doi: 10.1016/S1473-3099(18)30787-4.
Epub 2019 Jun 17.
The evolving research agenda for paediatric tuberculosis infection.
Seddon JA(1), Whittaker E(2), Kampmann B(3), Lewinsohn DA(4), Osman M(5),
Hesseling AC(5), Rustomjee R(6), Amanullah F(7).
Author information:
(1)Academic Department of Paediatrics, Imperial College London, London, UK;
Desmond Tutu TB Centre, Department of Paediatrics and Child Health, Faculty of
Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa.
Electronic address: james.seddon@imperial.ac.uk.
(2)Academic Department of Paediatrics, Imperial College London, London, UK.
(3)The Vaccine Centre, Faculty of Infectious and Tropical Diseases, London School
of Hygiene & Tropical Medicine, London, UK; MRC Unit The Gambia at the London
School of Hygiene and Tropical Medicine, The Gambia.
...
Following exposure to tuberculosis and subsequent infection, children often
progress to tuberculosis disease more rapidly than adults. And yet the natural
history of tuberculosis in children, as a continuum from exposure to infection
and then to disease, is poorly understood. Children are rarely diagnosed with
tuberculosis infection in routine care in international settings and few receive
tuberculosis infection treatment. In this Personal View, we review the most
up-to-date knowledge in three areas of childhood tuberculosis infection-namely,
pathophysiology, diagnosis, and treatment. We then outline what is missing in
each of these three areas to generate a priority research agenda. Finally, we
suggest potential study designs that might answer these questions. Understanding
of pathophysiology could be improved through animal models, laboratory studies
assessing the immunological responses of blood or respiratory samples to
Mycobacterium spp in vitro, as well as investigating immune responses in children
exposed to tuberculosis. Identification of children with sub-clinical disease and
at high risk of progression to clinically overt disease, would allow treatment to
be targeted at those most likely to benefit. Optimisation and discovery of novel
treatments for tuberculosis infection in children should account for mechanisms
of action of tuberculosis drugs, as well as child-specific factors including
pharmacokinetics and appropriate formulations. To conduct these studies, a change
in mindset is required, with a recognition that the diagnosis and treatment of
tuberculosis infection in children is a necessary component in addressing the
overall tuberculosis epidemic. Collaboration between stakeholders will be
required and funding will need to increase, both for research and implementation.
The consequences of inaction, however, will lead to further decades of children
suffering from what should increasingly be recognised as a preventable disease.
Copyright © 2019 Elsevier Ltd. All rights reserved.
DOI: 10.1016/S1473-3099(18)30787-4
PMID: 31221543
15. FEMS Microbiol Rev. 2019 Sep 1;43(5):548-575. doi: 10.1093/femsre/fuz016.
Cell wall peptidoglycan in Mycobacterium tuberculosis: An Achilles' heel for the
TB-causing pathogen.
Maitra A(1), Munshi T(1), Healy J(2), Martin LT(1), Vollmer W(3), Keep NH(1),
Bhakta S(1).
Author information:
(1)Mycobacteria Research Laboratory, Institute of Structural and Molecular
Biology, Department of Biological Sciences, Birkbeck, University of London, Malet
Street, London WC1E 7HX, UK.
(2)Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy,
29-39 Brunswick Square, London WC1N 1AX, UK.
(3)The Centre for Bacterial Cell Biology, Institute for Cell and Molecular
Biosciences, Newcastle University, Richardson Road, Newcastle upon Tyne, NE2 4AX,
UK.
Tuberculosis (TB), caused by the intracellular pathogen Mycobacterium
tuberculosis, remains one of the leading causes of mortality across the world.
There is an urgent requirement to build a robust arsenal of effective
antimicrobials, targeting novel molecular mechanisms to overcome the challenges
posed by the increase of antibiotic resistance in TB. Mycobacterium tuberculosis
has a unique cell envelope structure and composition, containing a peptidoglycan
layer that is essential for maintaining cellular integrity and for virulence. The
enzymes involved in the biosynthesis, degradation, remodelling and recycling of
peptidoglycan have resurfaced as attractive targets for anti-infective drug
discovery. Here, we review the importance of peptidoglycan, including the
structure, function and regulation of key enzymes involved in its metabolism. We
also discuss known inhibitors of ATP-dependent Mur ligases, and discuss the
potential for the development of pan-enzyme inhibitors targeting multiple Mur
ligases.
© FEMS 2019.
DOI: 10.1093/femsre/fuz016
PMCID: PMC6736417
PMID: 31183501
16. Clin Infect Dis. 2019 Sep 27. pii: ciz932. doi: 10.1093/cid/ciz932. [Epub ahead
of print]
Multicenter Study of the Accuracy of the BD MAX™ MDR-TB Assay for Detection of
Mycobacterium tuberculosis Complex and Mutations Associated with Resistance to
Rifampin and Isoniazid.
Shah M(1), Paradis S(2), Betz J(1)(3), Beylis N(4)(5), Bharadwaj R(6), Caceres
T(7), Gotuzzo E(7), Joloba M(8), Mave V(1)(6), Nakiyingi L(8), Nicol MP(4)(9),
Pradhan N(6), King B(1), Armstrong D(1), Knecht D(2), Maus CE(2), Cooper CK(2),
Dorman SE(10), Manabe YC(1)(8).
Author information:
(1)Johns Hopkins University School of Medicine, Baltimore, MD.
(2)Becton, Dickinson and Company, Sparks, MD.
(3)Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health,
Baltimore, MD.
...
BACKGROUND: Tuberculosis (TB) control is hindered by absence of rapid tests to
identify Mycobacterium tuberculosis (MTB), and detect isoniazid (INH) and
rifampin (RIF) resistance. We evaluated the accuracy of the BD MAX MDR-TB assay
(BD MAX) in South Africa, Uganda, India, and Peru.
METHODS: Outpatient adults with signs and/or symptoms of pulmonary TB were
prospectively enrolled. Sputum smear-microscopy and BD MAX were performed on a
single raw sputum, which was then processed for mycobacterial culture and
phenotypic drug susceptibility testing (DST), BD MAX and Xpert MTB/RIF (Xpert).
RESULTS: 1053 participants with presumptive TB were enrolled with median age of
35 (47% female; 32% HIV-infected, and 32% unknown HIV status). In
microbiologically-confirmed TB patients, BD MAX sensitivity was 93% (262/282 [95%
CI 89, 95]); specificity was 97% (593/610 [96, 98]) among participants with
negative cultures on raw sputa. BD MAX sensitivity was 100% (175/175, [98,100])
for smear-positive samples (florescence smear-microscopy), and 81% (87/107,
[73,88]) in smear-negative samples. Among participants with both BD MAX and
Xpert, sensitivity was 91% (249/274, [87,94]) for BD MAX and 90% (246/274
[86,93]) for Xpert on processed sputa. Sensitivity and specificity for RIF
resistance compared to phenotypic DST was 90% (9/10 [60,98]) and 95% (211/222
[91,97]), respectively. Sensitivity and specificity for detection of INH
resistance was 82% (22/27 [63,92]) and 100% (205/205 [98,100]), respectively.
CONCLUSIONS: The BD MAX MDR-TB assay had high sensitivity and specificity for
detection of MTB, and RIF and INH drug resistance and may be an important tool
for rapid detection of TB and MDR-TB globally.
© The Author(s) 2019. Published by Oxford University Press for the Infectious
Diseases Society of America. All rights reserved. For permissions, e-mail:
journals.permissions@oup.com.
DOI: 10.1093/cid/ciz932
PMID: 31560049
17. PLoS Pathog. 2019 Sep 12;15(9):e1008067. doi: 10.1371/journal.ppat.1008067.
eCollection 2019 Sep.
The molecular clock of Mycobacterium tuberculosis.
Menardo F(1)(2), Duchêne S(3), Brites D(1)(2), Gagneux S(1)(2).
Author information:
(1)Department of Medical Parasitology and Infection Biology, Swiss Tropical and
Public Health Institute, Basel, Switzerland.
(2)University of Basel, Basel, Switzerland.
(3)Department of Microbiology and Immunology, Peter Doherty Institute for
Infection and Immunity, University of Melbourne, Melbourne, Australia.
The molecular clock and its phylogenetic applications to genomic data have
changed how we study and understand one of the major human pathogens,
Mycobacterium tuberculosis (MTB), the etiologic agent of tuberculosis. Genome
sequences of MTB strains sampled at different times are increasingly used to
infer when a particular outbreak begun, when a drug-resistant clone appeared and
expanded, or when a strain was introduced into a specific region. Despite the
growing importance of the molecular clock in tuberculosis research, there is a
lack of consensus as to whether MTB displays a clocklike behavior and about its
rate of evolution. Here we performed a systematic study of the molecular clock of
MTB on a large genomic data set (6,285 strains), covering different
epidemiological settings and most of the known global diversity. We found that
sampling times below 15-20 years were often insufficient to calibrate the clock
of MTB. For data sets where such calibration was possible, we obtained a clock
rate between 1x10-8 and 5x10-7 nucleotide changes per-site-per-year (0.04-2.2
SNPs per-genome-per-year), with substantial differences between clades. These
estimates were not strongly dependent on the time of the calibration points as
they changed only marginally when we used epidemiological isolates (sampled in
the last 40 years) or three ancient DNA samples (about 1,000 years old) to
calibrate the tree. Additionally, the uncertainty and the discrepancies in the
results of different methods were sometimes large, highlighting the importance of
using different methods, and of considering carefully their assumptions and
limitations.
DOI: 10.1371/journal.ppat.1008067
PMCID: PMC6759198
PMID: 31513651
18. Proc Natl Acad Sci U S A. 2019 Sep 24;116(39):19646-19651. doi:
10.1073/pnas.1907946116. Epub 2019 Sep 9.
Mode-of-action profiling reveals glutamine synthetase as a collateral metabolic
vulnerability of M. tuberculosis to bedaquiline.
Wang Z(1), Soni V(1), Marriner G(2), Kaneko T(3), Boshoff HIM(2), Barry CE
3rd(2), Rhee KY(4).
Author information:
(1)Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell
Medical College, New York, NY 10065.
(2)Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases,
National Institute of Allergy and Infectious Diseases, National Institutes of
Health, Bethesda, MD 20892.
(3)Global Alliance for TB Drug Development, New York, NY 10005.
(4)Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell
Medical College, New York, NY 10065; kyr9001@med.cornell.edu.
Combination chemotherapy can increase treatment efficacy and suppress drug
resistance. Knowledge of how to engineer rational, mechanism-based drug
combinations, however, remains lacking. Although studies of drug activity have
historically focused on the primary drug-target interaction, growing evidence has
emphasized the importance of the subsequent consequences of this interaction.
Bedaquiline (BDQ) is the first new drug for tuberculosis (TB) approved in more
than 40 y, and a species-selective inhibitor of the Mycobacterium tuberculosis
(Mtb) ATP synthase. Curiously, BDQ-mediated killing of Mtb lags significantly
behind its inhibition of ATP synthase, indicating a mode of action more complex
than the isolated reduction of ATP pools. Here, we report that BDQ-mediated
inhibition of Mtb's ATP synthase triggers a complex metabolic response indicative
of a specific hierarchy of ATP-dependent reactions. We identify glutamine
synthetase (GS) as an enzyme whose activity is most responsive to changes in ATP
levels. Chemical supplementation with exogenous glutamine failed to affect BDQ's
antimycobacterial activity. However, further inhibition of Mtb's GS synergized
with and accelerated the onset of BDQ-mediated killing, identifying Mtb's
glutamine synthetase as a collateral, rather than directly antimycobacterial,
metabolic vulnerability of BDQ. These findings reveal a previously unappreciated
physiologic specificity of ATP and a facet of mode-of-action biology we term
collateral vulnerability, knowledge of which has the potential to inform the
development of rational, mechanism-based drug combinations.
DOI: 10.1073/pnas.1907946116
PMCID: PMC6765305 [Available on 2020-03-09]
PMID: 31501323
Conflict of interest statement: The authors declare no conflict of interest.
19. Clin Pharmacokinet. 2019 Sep;58(9):1103-1129. doi: 10.1007/s40262-019-00764-2.
Clinical Pharmacokinetics and Pharmacodynamics of Rifampicin in Human
Tuberculosis.
Abulfathi AA(1), Decloedt EH(2), Svensson EM(3)(4), Diacon AH(5)(6), Donald P(7),
Reuter H(2).
Author information:
(1)Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine
and Health Sciences, Stellenbosch University, PO Box 241, Cape Town, 8000, South
Africa. aaabulfathi@sun.ac.za.
(2)Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine
and Health Sciences, Stellenbosch University, PO Box 241, Cape Town, 8000, South
Africa.
(3)Department of Pharmacy, Radboud Institute for Health Sciences, Radboud
University Medical Center, Nijmegen, The Netherlands.
...
The introduction of rifampicin (rifampin) into tuberculosis (TB) treatment five
decades ago was critical for shortening the treatment duration for patients with
pulmonary TB to 6 months when combined with pyrazinamide in the first 2 months.
Resistance or hypersensitivity to rifampicin effectively condemns a patient to
prolonged, less effective, more toxic, and expensive regimens. Because of cost
and fears of toxicity, rifampicin was introduced at an oral daily dose of 600 mg
(8-12 mg/kg body weight). At this dose, clinical trials in 1970s found cure rates
of ≥ 95% and relapse rates of < 5%. However, recent papers report lower cure
rates that might be the consequence of increased emergence of resistance. Several
lines of evidence suggest that higher rifampicin doses, if tolerated and safe,
could shorten treatment duration even further. We conducted a narrative review of
rifampicin pharmacokinetics and pharmacodynamics in adults across a range of
doses and highlight variables that influence its
pharmacokinetics/pharmacodynamics. Rifampicin exposure has considerable inter-
and intra-individual variability that could be reduced by administration during
fasting. Several factors including malnutrition, HIV infection, diabetes
mellitus, dose size, pharmacogenetic polymorphisms, hepatic cirrhosis, and
substandard medicinal products alter rifampicin exposure and/or efficacy. Renal
impairment has no influence on rifampicin pharmacokinetics when dosed at 600 mg.
Rifampicin maximum (peak) concentration (Cmax) > 8.2 μg/mL is an independent
predictor of sterilizing activity and therapeutic drug monitoring at 2, 4, and
6 h post-dose may aid in optimizing dosing to achieve the recommended rifampicin
concentration of ≥ 8 µg/mL. A higher rifampicin Cmax is required for severe forms
TB such as TB meningitis, with Cmax ≥ 22 μg/mL and area under the
concentration-time curve (AUC) from time zero to 6 h (AUC6) ≥ 70 μg·h/mL
associated with reduced mortality. More studies are needed to confirm whether
doses achieving exposures higher than the current standard dosage could translate
into faster sputum conversion, higher cure rates, lower relapse rates, and less
mortality. It is encouraging that daily rifampicin doses up to 35 mg/kg were
found to be safe and well-tolerated over a period of 12 weeks. High-dose
rifampicin should thus be considered in future studies when constructing
potentially shorter regimens. The studies should be adequately powered to
determine treatment outcomes and should include surrogate markers of efficacy
such as Cmax/MIC (minimum inhibitory concentration) and AUC/MIC.
DOI: 10.1007/s40262-019-00764-2
PMID: 31049868
