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Chapartegui-González I, Stockton JL, Bowser S, Badten AJ, Torres AG. Unraveling the role of toxin-antitoxin systems in Burkholderia pseudomallei: exploring bacterial pathogenesis and interactions within the HigBA families. Microbiol Spectr 2024:e0074824. [PMID: 38916327 DOI: 10.1128/spectrum.00748-24] [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: 03/21/2024] [Accepted: 05/28/2024] [Indexed: 06/26/2024] Open
Abstract
Burkholderia pseudomallei (Bpm) is a Gram-negative intracellular pathogen that causes melioidosis in humans, a neglected, underreported, and lethal disease that can reach a fatal outcome in over 50% of the cases. It can produce both acute and chronic infections, the latter being particularly challenging to eliminate because of the intracellular life cycle of the bacteria and its ability to generate a "persister" dormant state. The molecular mechanism that allows the switch between growing and persister phenotypes is not well understood but it is hypothesized to be due at least in part to the participation of toxin-antitoxin (TA) systems. We have previously studied the link between one of those systems (defined as HigBA) with specific expression patterns associated with levofloxacin antibiotic exposure. Through in silico methods, we predicted the presence of another three pairs of genes encoding for additional putative HigBA systems. Therefore, our main goal was to establish which mechanisms are conserved as well as which pathways are specific among different Bpm TA systems from the same family. We hypothesize that the high prevalence, and sometimes even redundancy of these systems in the Bpm chromosomes indicates that they can interact with each other and not function as only individual systems, as it was traditionally thought, and might be playing an undefined role in Bpm lifecycle. Here, we show that both the toxin and the antitoxin of the different systems contribute to bacterial survival and that toxins from the same family can have a cumulative effect under environmental stressful conditions. IMPORTANCE Toxin-antitoxin (TA) systems play a significant role in bacterial persistence, a phenomenon where bacterial cells enter a dormant or slow-growing state to survive adverse conditions such as nutrient deprivation, antibiotic exposure, or host immune responses. By studying TA systems in Burkholderia pseudomallei, we can gain insights into how this pathogen survives and persists in the host environment, contributing to its virulence and ability to cause melioidosis chronic infections.
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Affiliation(s)
| | - Jacob L Stockton
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Sarah Bowser
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Alexander J Badten
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
- Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas, USA
| | - Alfredo G Torres
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA
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2
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Helaine S, Conlon BP, Davis KM, Russell DG. Host stress drives tolerance and persistence: The bane of anti-microbial therapeutics. Cell Host Microbe 2024; 32:852-862. [PMID: 38870901 DOI: 10.1016/j.chom.2024.04.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Revised: 04/03/2024] [Accepted: 04/25/2024] [Indexed: 06/15/2024]
Abstract
Antibiotic resistance, typically associated with genetic changes within a bacterial population, is a frequent contributor to antibiotic treatment failures. Antibiotic persistence and tolerance, which we collectively term recalcitrance, represent transient phenotypic changes in the bacterial population that prolong survival in the presence of typically lethal concentrations of antibiotics. Antibiotic recalcitrance is challenging to detect and investigate-traditionally studied under in vitro conditions, our understanding during infection and its contribution to antibiotic failure is limited. Recently, significant progress has been made in the study of antibiotic-recalcitrant populations in pathogenic species, including Mycobacterium tuberculosis, Staphylococcus aureus, Salmonella enterica, and Yersiniae, in the context of the host environment. Despite the diversity of these pathogens and infection models, shared signals and responses promote recalcitrance, and common features and vulnerabilities of persisters and tolerant bacteria have emerged. These will be discussed here, along with progress toward developing therapeutic interventions to better treat recalcitrant pathogens.
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Affiliation(s)
- Sophie Helaine
- Department of Microbiology, Harvard Medical School, Boston, MA, USA.
| | - Brian P Conlon
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC, USA.
| | - Kimberly M Davis
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | - David G Russell
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
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3
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Dadole I, Blaha D, Personnic N. The macrophage-bacterium mismatch in persister formation. Trends Microbiol 2024:S0966-842X(24)00049-0. [PMID: 38443279 DOI: 10.1016/j.tim.2024.02.009] [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: 07/21/2023] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 03/07/2024]
Abstract
Many pathogens are hard to eradicate, even in the absence of genetically detectable antimicrobial resistance mechanisms and despite proven antibiotic susceptibility. The fraction of clonal bacteria that temporarily elude effective antibiotic treatments is commonly known as 'antibiotic persisters.' Over the past decade, there has been a growing body of research highlighting the pivotal role played by the cellular host in the development of persisters. In parallel, this research has also sought to elucidate the molecular mechanisms underlying the formation of intracellular antibiotic persisters and has demonstrated a prominent role for the bacterial stress response. However, questions remain regarding the conditions leading to the formation of stress-induced persisters among a clonal population of intracellular bacteria and despite an ostensibly uniform environment. In this opinion, following a brief review of the current state of knowledge regarding intracellular antibiotic persisters, we explore the ways in which macrophage functional heterogeneity and bacterial phenotypic heterogeneity may contribute to the emergence of these persisters. We propose that the degree of mismatch between the macrophage permissiveness and the bacterial preparedness to invade and thrive intracellularly may explain the formation of stress-induced nonreplicating intracellular persisters.
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Affiliation(s)
- Iris Dadole
- CIRI - Centre International de Recherche en Infectiologie, CNRS, INSERM, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France; Group Persistence and single-cell dynamics of respiratory pathogens, CIRI, Lyon, France
| | - Didier Blaha
- CIRI - Centre International de Recherche en Infectiologie, CNRS, INSERM, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France; Group Persistence and single-cell dynamics of respiratory pathogens, CIRI, Lyon, France
| | - Nicolas Personnic
- CIRI - Centre International de Recherche en Infectiologie, CNRS, INSERM, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France; Group Persistence and single-cell dynamics of respiratory pathogens, CIRI, Lyon, France.
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Ronneau S, Michaux C, Helaine S. Decline in nitrosative stress drives antibiotic persister regrowth during infection. Cell Host Microbe 2023; 31:993-1006.e6. [PMID: 37236190 DOI: 10.1016/j.chom.2023.05.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/01/2023] [Accepted: 05/02/2023] [Indexed: 05/28/2023]
Abstract
Internalization of pathogenic bacteria by macrophages results in formation of antibiotic-tolerant persisters. These cells are maintained in a non-growing state for extended periods of time, and it is assumed that their growth resumption causes infection relapse after cessation of antibiotic treatment. Despite this clinical relevance, the signals and conditions that drive persister regrowth during infection are not yet understood. Here, we found that after persister formation in macrophages, host reactive nitrogen species (RNS) produced in response to Salmonella infection lock persisters in growth arrest by intoxicating their TCA cycle, lowering cellular respiration and ATP production. Intracellular persisters resume growth when macrophage RNS production subsides and functionality of their TCA cycle is regained. Persister growth resumption within macrophages is slow and heterogeneous, dramatically extending the time the persister reservoir feeds infection relapse. Using an inhibitor of RNS production, we can force recalcitrant bacteria to regrow during antibiotic treatment, thereby facilitating their eradication.
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Affiliation(s)
- Séverin Ronneau
- Department of Microbiology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Charlotte Michaux
- Department of Microbiology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Sophie Helaine
- Department of Microbiology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
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Personnic N, Doublet P, Jarraud S. Intracellular persister: A stealth agent recalcitrant to antibiotics. Front Cell Infect Microbiol 2023; 13:1141868. [PMID: 37065203 PMCID: PMC10102521 DOI: 10.3389/fcimb.2023.1141868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/06/2023] [Indexed: 04/03/2023] Open
Abstract
The bulk of bacteria transiently evading appropriate antibiotic regimes and recovered from non-resolutive infections are commonly refer to as persisters. In this mini-review, we discuss how antibiotic persisters stem from the interplay between the pathogen and the cellular defenses mechanisms and its underlying heterogeneity.
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Affiliation(s)
- Nicolas Personnic
- CIRI, Centre International de Recherche en Infectiologie, CNRS UMR 5308, INSERM U1111, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Group Persistence and Single-Cell Dynamics of Respiratory Pathogens, Lyon, France
- *Correspondence: Nicolas Personnic,
| | - Patricia Doublet
- CIRI, Centre International de Recherche en Infectiologie, CNRS UMR 5308, INSERM U1111, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Group Legionella Pathogenesis, Lyon, France
| | - Sophie Jarraud
- CIRI, Centre International de Recherche en Infectiologie, CNRS UMR 5308, INSERM U1111, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
- Group Legionella Pathogenesis, Lyon, France
- National Reference Centre for Legionella, Institute of Infectious Agents, Hospices Civils de Lyon, Lyon, France
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6
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Evaluating the Contribution of the Predicted Toxin-Antitoxin System HigBA to Persistence, Biofilm Formation, and Virulence in Burkholderia pseudomallei. Infect Immun 2022; 90:e0003522. [PMID: 35695502 PMCID: PMC9302164 DOI: 10.1128/iai.00035-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Melioidosis is an underreported human disease caused by the Gram-negative intracellular pathogen Burkholderia pseudomallei (Bpm). Both the treatment and the clearance of the pathogen are challenging, with high relapse rates leading to latent infections. This has been linked to the bacterial persistence phenomenon, a growth arrest strategy that allows bacteria to survive under stressful conditions, as in the case of antibiotic treatment, within a susceptible clonal population. At a molecular level, this phenomenon has been associated with the presence of toxin-antitoxin (TA) systems. We annotated the Bpm K96243 genome and selected 11 pairs of genes encoding for these TA systems, and their expression was evaluated under different conditions (supralethal antibiotic conditions; intracellular survival bacteria). The predicted HigB toxin (BPSL3343) and its predicted antitoxin HigA (BPS_RS18025) were further studied using mutant construction. The phenotypes of two mutants (ΔhigB and ΔhigB ΔhigA) were evaluated under different conditions compared to the wild-type (WT) strain. The ΔhigB toxin mutant showed a defect in intracellular survival on macrophages, a phenotype that was eliminated after levofloxacin treatment. We found that the absence of the toxin provides an advantage over the WT strain, in both in vitro and in vivo models, during persister conditions induced by levofloxacin. The lack of the antitoxin also resulted in differential responses to the conditions evaluated, and under some conditions, it restored the WT phenotype, overall suggesting that both toxin and antitoxin components play a role in the persister-induced phenotype in Bpm.
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de Castro GV, Worm DJ, Grabe GJ, Rowan FC, Haggerty L, de la Lastra AL, Popescu O, Helaine S, Barnard A. Characterization of the Key Determinants of Phd Antitoxin Mediated Doc Toxin Inactivation in Salmonella. ACS Chem Biol 2022; 17:1598-1606. [PMID: 35647667 PMCID: PMC9207808 DOI: 10.1021/acschembio.2c00276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the search for novel antimicrobial therapeutics, toxin-antitoxin (TA) modules are promising yet underexplored targets for overcoming antibiotic failure. The bacterial toxin Doc has been associated with the persistence of Salmonella in macrophages, enabling its survival upon antibiotic exposure. After developing a novel method to produce the recombinant toxin, we have used antitoxin-mimicking peptides to thoroughly investigate the mechanism by which its cognate antitoxin Phd neutralizes the activity of Doc. We reveal insights into the molecular detail of the Phd-Doc relationship and discriminate antitoxin residues that stabilize the TA complex from those essential for inhibiting the activity of the toxin. Coexpression of Doc and antitoxin peptides in Salmonella was able to counteract the activity of the toxin, confirming our in vitro results with equivalent sequences. Our findings provide key principles for the development of chemical tools to study and therapeutically interrogate this important class of protein-protein interactions.
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Affiliation(s)
- Guilherme V. de Castro
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12 0BZ, United Kingdom
| | - Dennis J. Worm
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12 0BZ, United Kingdom
| | - Grzegorz J. Grabe
- Department of Microbiology, Harvard Medical School, 4 Blackfan Circle, Boston, Massachusetts 02115, United States
| | - Fiona C. Rowan
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12 0BZ, United Kingdom
| | - Lucy Haggerty
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12 0BZ, United Kingdom
| | - Ana L. de la Lastra
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12 0BZ, United Kingdom
| | - Oana Popescu
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12 0BZ, United Kingdom
| | - Sophie Helaine
- Department of Microbiology, Harvard Medical School, 4 Blackfan Circle, Boston, Massachusetts 02115, United States
| | - Anna Barnard
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London W12 0BZ, United Kingdom
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Bikmetov D, Hall AMJ, Livenskyi A, Gollan B, Ovchinnikov S, Gilep K, Kim J, Larrouy-Maumus G, Zgoda V, Borukhov S, Severinov K, Helaine S, Dubiley S. GNAT toxins evolve toward narrow tRNA target specificities. Nucleic Acids Res 2022; 50:5807-5817. [PMID: 35609997 PMCID: PMC9177977 DOI: 10.1093/nar/gkac356] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 04/10/2022] [Accepted: 05/05/2022] [Indexed: 12/16/2022] Open
Abstract
Type II toxin–antitoxin (TA) systems are two-gene modules widely distributed among prokaryotes. GNAT toxins associated with the DUF1778 antitoxins represent a large family of type II TAs. GNAT toxins inhibit cell growth by disrupting translation via acetylation of aminoacyl-tRNAs. In this work, we explored the evolutionary trajectory of GNAT toxins. Using LC/MS detection of acetylated aminoacyl-tRNAs combined with ribosome profiling, we systematically investigated the in vivo substrate specificity of an array of diverse GNAT toxins. Our functional data show that the majority of GNAT toxins are specific to Gly-tRNA isoacceptors. However, the phylogenetic analysis shows that the ancestor of GNAT toxins was likely a relaxed specificity enzyme capable of acetylating multiple elongator tRNAs. Together, our data provide a remarkable snapshot of the evolution of substrate specificity.
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Affiliation(s)
| | | | - Alexei Livenskyi
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119992, Russia
| | - Bridget Gollan
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Stepan Ovchinnikov
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Skolkovo 143025, Russia
| | - Konstantin Gilep
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Jenny Y Kim
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Gerald Larrouy-Maumus
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Viktor Zgoda
- Institute of Biomedical Chemistry, Moscow 119435, Russia
| | - Sergei Borukhov
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084-1489, USA
| | | | | | - Svetlana Dubiley
- To whom correspondence should be addressed. Tel: +7 499 135 6089;
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9
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Grabe GJ, Giorgio RT, Hall AMJ, Morgan RML, Dubois L, Sisley TA, Rycroft JA, Hare SA, Helaine S. Auxiliary interfaces support the evolution of specific toxin-antitoxin pairing. Nat Chem Biol 2021; 17:1296-1304. [PMID: 34556858 DOI: 10.1038/s41589-021-00862-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 07/20/2021] [Indexed: 02/08/2023]
Abstract
Toxin-antitoxin (TA) systems are a large family of genes implicated in the regulation of bacterial growth and its arrest in response to attacks. These systems encode nonsecreted toxins and antitoxins that specifically pair, even when present in several paralogous copies per genome. Salmonella enterica serovar Typhimurium contains three paralogous TacAT systems that block bacterial translation. We determined the crystal structures of the three TacAT complexes to understand the structural basis of specific TA neutralization and the evolution of such specific pairing. In the present study, we show that alteration of a discrete structural add-on element on the toxin drives specific recognition by their cognate antitoxin underpinning insulation of the three pairs. Similar to other TA families, the region supporting TA-specific pairing is key to neutralization. Our work reveals that additional TA interfaces beside the main neutralization interface increase the safe space for evolution of pairing specificity.
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Affiliation(s)
- Grzegorz J Grabe
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Rachel T Giorgio
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | | | | | - Laurent Dubois
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Tyler A Sisley
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Julian A Rycroft
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Stephen A Hare
- School of Life Sciences, University of Sussex, Brighton, UK
| | - Sophie Helaine
- Department of Microbiology, Harvard Medical School, Boston, MA, USA. .,MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK.
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10
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Antibiotic persistence and tolerance: not just one and the same. Curr Opin Microbiol 2021; 64:76-81. [PMID: 34634678 DOI: 10.1016/j.mib.2021.09.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 09/23/2021] [Accepted: 09/28/2021] [Indexed: 12/11/2022]
Abstract
Distinguished by their penetrance within a population, antibiotic tolerance and persistence are superficially similar phenomena by which growth-restricted bacteria survive treatment with bactericidal antibiotics. Owing to their apparent similarity, it is often assumed that the same physiological states and molecular mechanisms underlie the ability of individual antibiotic tolerant and persistent bacteria to survive treatment. Experimentally, antibiotic persistence is an extremely challenging phenomenon to study due to both its transience and the co-existence of persisters with non-persisters in the population of interest. In contrast, antibiotic tolerance operates at the whole population level as a result of bacteria acquiring genetic mutations or encountering environmental conditions that result in growth restriction. Therefore, studying antibiotic tolerance is often used as a convenient way to understand the molecular mechanisms governing antibiotic persistence. In this opinion, we discuss our current understanding of these two phenomena, outlining how tolerance and persistence can be distinguished experimentally. We argue that this approach will help avoid controversies in the field, especially in instances where the two phenomena co-exist. Finally, we evaluate the clinical evidence implicating tolerance and persistence in recalcitrance and relapse of bacterial infections.
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Abstract
Many bacterial pathogens can permanently colonize their host and establish either chronic or recurrent infections that the immune system and antimicrobial therapies fail to eradicate. Antibiotic persisters (persister cells) are believed to be among the factors that make these infections challenging. Persisters are subpopulations of bacteria which survive treatment with bactericidal antibiotics in otherwise antibiotic-sensitive cultures and were extensively studied in a hope to discover the mechanisms that cause treatment failures in chronically infected patients; however, most of these studies were conducted in the test tube. Research into antibiotic persistence has uncovered large intrapopulation heterogeneity of bacterial growth and regrowth but has not identified essential, dedicated molecular mechanisms of antibiotic persistence. Diverse factors and stresses that inhibit bacterial growth reduce killing of the bulk population and may also increase the persister subpopulation, implying that an array of mechanisms are present. Hopefully, further studies under conditions that simulate the key aspects of persistent infections will lead to identifying target mechanisms for effective therapeutic solutions.
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Multinucleated Giant Cell Formation as a Portal to Chronic Bacterial Infections. Microorganisms 2020; 8:microorganisms8111637. [PMID: 33113944 PMCID: PMC7690659 DOI: 10.3390/microorganisms8111637] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/16/2020] [Accepted: 10/21/2020] [Indexed: 12/20/2022] Open
Abstract
This review provides a snapshot of chronic bacterial infections through the lens of Burkholderia pseudomallei and detailing its ability to establish multi-nucleated giant cells (MNGC) within the host, potentially leading to the formation of pyogranulomatous lesions. We explore the role of MNGC in melioidosis disease progression and pathology by comparing the similarities and differences of melioidosis to tuberculosis, outline the concerted events in pathogenesis that lead to MNGC formation, discuss the factors that influence MNGC formation, and consider how they fit into clinical findings reported in chronic cases. Finally, we speculate about future models and techniques that can be used to delineate the mechanisms of MNGC formation and function.
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Ross BN, Thiriot JD, Wilson SM, Torres AG. Predicting toxins found in toxin-antitoxin systems with a role in host-induced Burkholderia pseudomallei persistence. Sci Rep 2020; 10:16923. [PMID: 33037311 PMCID: PMC7547725 DOI: 10.1038/s41598-020-73887-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 09/23/2020] [Indexed: 12/19/2022] Open
Abstract
Burkholderia pseudomallei (Bpm) is a bacterial pathogen that causes Melioidosis, a disease with up to 40% mortality and an infection relapse of 15-23% despite antibiotic treatment. Ineffective clearance of Bpm by antibiotics is believed to be due to persistence, a hibernation-like survival mechanism modulated, in part, by toxin-antitoxin systems (TAS). Several organisms possess a repertoire of TASs but defining environmental cues eliciting their activity is hindered by laborious in vitro experiments, especially when there are many toxins with redundant function. Here, we identified which of 103 proteins in Bpm that share features found in toxins of the TAS and repurposed transcriptional data to identify which ones play a role in surviving intracellular host defenses. Putative toxins with the strongest transcriptional response were found to have low conservation between Bpm strains, while toxins that were constitutively expressed were highly conserved. Further examination of highly conserved toxins BPSS0899, BPSS1321, and BPSL1494 showed that they were functional, and their mutation led to reduce survival within macrophages and reduced in vivo persistence-associated pathology (abscesses) during treatment, but did not affect macrophages persistence. These findings highlight the utility of a data-driven approach to select putative toxins and suggests a selective role for some TAS in host survival.
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Affiliation(s)
- Brittany N Ross
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Joseph D Thiriot
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Shane M Wilson
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Alfredo G Torres
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA.
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA.
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Moldoveanu AL, Rycroft JA, Helaine S. Impact of bacterial persisters on their host. Curr Opin Microbiol 2020; 59:65-71. [PMID: 32866708 DOI: 10.1016/j.mib.2020.07.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 07/18/2020] [Indexed: 02/06/2023]
Abstract
The rise of antibiotic failure poses a severe threat to global health. There is growing concern that this failure is not solely driven by stable antibiotic resistance but also by a subpopulation of transiently non-growing, antibiotic tolerant bacteria. These 'persisters' have been proposed to seed relapsing infections, an important clinical outcome of treatment failure - although definitive evidence for this direct link remains elusive. Recent advances in the field have revealed the complex nature of intra-host persisters which drive their high adaptability through biosynthetic activity. These features of persisters contribute to evolution of antimicrobial resistance and modulation of host immune responses, despite clinically efficacious treatment.
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Affiliation(s)
- Ana L Moldoveanu
- Centre for Molecular Bacteriology and Infection, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Julian A Rycroft
- Department of Microbiology, Harvard Medical School, 77 Ave Pasteur, Boston, MA 02115, USA
| | - Sophie Helaine
- Department of Microbiology, Harvard Medical School, 77 Ave Pasteur, Boston, MA 02115, USA.
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