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Nehls C, Schröder M, Haubenthal T, Haas A, Gutsmann T. The mechanistic basis of the membrane-permeabilizing activities of the virulence-associated protein A (VapA) from Rhodococcus equi. Mol Microbiol 2024; 121:578-592. [PMID: 38308564 DOI: 10.1111/mmi.15233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 01/12/2024] [Accepted: 01/17/2024] [Indexed: 02/05/2024]
Abstract
Pathogenic Rhodococcus equi release the virulence-associated protein A (VapA) within macrophage phagosomes. VapA permeabilizes phagosome and lysosome membranes and reduces acidification of both compartments. Using biophysical techniques, we found that VapA interacts with model membranes in four steps: (i) binding, change of mechanical properties, (ii) formation of specific membrane domains, (iii) permeabilization within the domains, and (iv) pH-specific transformation of domains. Biosensor data revealed that VapA binds to membranes in one step at pH 6.5 and in two steps at pH 4.5 and decreases membrane fluidity. The integration of VapA into lipid monolayers was only significant at lateral pressures <20 mN m-1 indicating preferential incorporation into membrane regions with reduced integrity. Atomic force microscopy of lipid mono- and bilayers showed that VapA increased the surface heterogeneity of liquid disordered domains. Furthermore, VapA led to the formation of a new microstructured domain type and, at pH 4.5, to the formation of 5 nm high domains. VapA binding, its integration and lipid domain formation depended on lipid composition, pH, protein concentration and lateral membrane pressure. VapA-mediated permeabilization is clearly distinct from that caused by classical microbial pore formers and is a key contribution to the multiplication of Rhodococcus equi in phagosomes.
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Affiliation(s)
- Christian Nehls
- Division of Biophysics, Research Center Borstel - Leibniz Lung Center, Borstel, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Kiel Nano, Surface and Interface Science KiNSIS, Kiel University, Kiel, Germany
| | - Marcel Schröder
- Division of Biophysics, Research Center Borstel - Leibniz Lung Center, Borstel, Germany
| | | | - Albert Haas
- Cell Biology Institute, University of Bonn, Bonn, Germany
| | - Thomas Gutsmann
- Division of Biophysics, Research Center Borstel - Leibniz Lung Center, Borstel, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Kiel Nano, Surface and Interface Science KiNSIS, Kiel University, Kiel, Germany
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2
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Alvarez Narvaez S, Sanchez S. Exploring the Accessory Genome of Multidrug-Resistant Rhodococcus equi Clone 2287. Antibiotics (Basel) 2023; 12:1631. [PMID: 37998833 PMCID: PMC10669575 DOI: 10.3390/antibiotics12111631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/15/2023] [Accepted: 11/16/2023] [Indexed: 11/25/2023] Open
Abstract
Decades of antimicrobial overuse to treat respiratory disease in foals have promoted the emergence and spread of zoonotic multidrug-resistant (MDR) Rhodococcus equi worldwide. Three main R. equi MDR clonal populations-2287, G2106, and G2017-have been identified so far. However, only clones 2287 and G2016 have been isolated from sick animals, with clone 2287 being the main MDR R. equi recovered. The genetic mechanisms that make this MDR clone superior to the others at infecting foals are still unknown. Here, we performed a deep genetic characterization of the accessory genomes of 207 R. equi isolates, and we describe IME2287, a novel genetic element in the accessory genome of clone 2287, potentially involved in the maintenance and spread of this MDR population over time. IME2287 is a putative self-replicative integrative mobilizable element (IME) carrying a DNA replication and partitioning operon and genes encoding its excision and integration from the R. equi genome via a serine recombinase. Additionally, IME2287 encodes a protein containing a Toll/interleukin-1 receptor (TIR) domain that may inhibit TLR-mediated NF-kB signaling in the host and a toxin-antitoxin (TA) system, whose orthologs have been associated with antibiotic resistance/tolerance, virulence, pathogenicity islands, bacterial persistence, and pathogen trafficking. This new set of genes may explain the success of clone 2287 over the other MDR R. equi clones.
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Affiliation(s)
- Sonsiray Alvarez Narvaez
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - Susan Sanchez
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
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3
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Sanz MG. Rhodococcus equi-What is New This Decade? Vet Clin North Am Equine Pract 2023; 39:1-14. [PMID: 36898784 DOI: 10.1016/j.cveq.2022.11.002] [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: 03/12/2023] Open
Abstract
Foals become infected shortly after birth; most develop subclinical pneumonia and 20% to 30% develop clinical pneumonia that requires treatment. It is now well established that the combination of screening programs based on thoracic ultrasonography and treatment of subclinical foals with antimicrobials has led to the development of resistant Rhodococcus equi strains. Thus, targeted treatment programs are needed. Administration of R equi-specific hyperimmune plasma shortly after birth is beneficial as foals develop less severe pneumonia but does not seem to prevent infection. This article provides a summary of clinically relevant research published during this past decade.
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Haubenthal T, Hansen P, Krämer I, Gindt M, Jünger-Leif A, Utermöhlen O, Haas A. Specific preadaptations of Rhodococcus equi cooperate with its Virulence-associated protein A during macrophage infection. Mol Microbiol 2023; 119:285-301. [PMID: 36627747 DOI: 10.1111/mmi.15026] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/03/2023] [Accepted: 01/04/2023] [Indexed: 01/12/2023]
Abstract
Gram-positive Rhodococcus equi (Prescotella equi) is a lung pathogen of foals and immunocompromised humans. Intra-macrophage multiplication requires production of the bacterial Virulence-associated protein A (VapA) which is released into the phagosome lumen. VapA pH-neutralizes intracellular compartments allowing R. equi to multiply in an atypical macrophage phagolysosome. Here, we show that VapA does not support intra-macrophage growth of several other bacterial species demonstrating that only few bacteria have the specific preadaptations needed to profit from VapA. We show that the closest relative of R. equi, environmental Rhodococcus defluvii (Prescotella defluvii), does not multiply in macrophages at 37°C even when VapA is present because of its thermosensitivity but it does so once the infection temperature is lowered providing rare experimental evidence for 'thermal restriction'. Using growth experiments with isolated macrophage lysosomes and modified infection schemes we provide evidence that R. equi resists the attack by phagolysosome contents at low pH for several hours. During this time, R. equi produces and secretes VapA which enables it to grow at the expense of lysosome constituents. We present arguments that, under natural infection conditions, R. equi is VapA-less during the initial encounter with the host. This has important implications for vaccine development.
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Affiliation(s)
| | - Philipp Hansen
- Institute for Cell Biology, University of Bonn, Bonn, Germany
| | - Ina Krämer
- Institute for Cell Biology, University of Bonn, Bonn, Germany
| | - Mélanie Gindt
- Institute for Cell Biology, University of Bonn, Bonn, Germany
| | | | - Olaf Utermöhlen
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Germany
| | - Albert Haas
- Institute for Cell Biology, University of Bonn, Bonn, Germany
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5
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Bordin AI, Huber L, Sanz M, Cohen N. Rhodococcus equi Foal Pneumonia: Update on Epidemiology, Immunity, Treatment, and Prevention. Equine Vet J 2022; 54:481-494. [PMID: 35188690 DOI: 10.1111/evj.13567] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/03/2022] [Accepted: 02/17/2022] [Indexed: 11/25/2022]
Abstract
Pneumonia in foals caused by the bacterium Rhodococcus equi has a worldwide distribution and is a common cause of disease and death for foals. The purpose of this narrative review is to summarise recent developments pertaining to the epidemiology, immune responses, treatment, and prevention of rhodococcal pneumonia of foals. Screening tests have been used to implement earlier detection and treatment of foals with presumed subclinical R. equi pneumonia to reduce mortality and severity of disease. Unfortunately, this practice has been linked to the emergence of antimicrobial resistant R. equi in North America. Correlates of protective immunity for R. equi infections of foals remain elusive, but recent evidence indicates that innate immune responses are important both for mediating killing and orchestrating adaptive immune responses. A macrolide antimicrobial in combination with rifampin remains the recommended treatment for foals with R. equi pneumonia. Great need exists to identify which antimicrobial combination is most effective for treating foals with R. equi pneumonia and to limit emergence of antimicrobial-resistant strains. In the absence of an effective vaccine against R. equi, passive immunisation remains the only commercially-available method for effectively reducing the incidence of R. equi pneumonia. Because passive immunisation is expensive, labour-intensive, and carries risks for foals, great need exists to develop alternative approaches for passive and active immunisation.
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Affiliation(s)
- Angela I Bordin
- Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843-4475, USA
| | - Laura Huber
- Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, 36849, USA
| | - Macarena Sanz
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, 99164-6610, USA
| | - Noah Cohen
- Equine Infectious Disease Laboratory, Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843-4475, USA
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Affiliation(s)
- Lucjan Witkowski
- Laboratory of Veterinary Epidemiology and Economics, Faculty of Veterinary Medicine, Warsaw University of Life Sciences - SGGW, Warsaw, Poland
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Mourenza Á, Collado C, Bravo-Santano N, Gil JA, Mateos LM, Letek M. The extracellular thioredoxin Etrx3 is required for macrophage infection in Rhodococcus equi. Vet Res 2020; 51:38. [PMID: 32156317 PMCID: PMC7063783 DOI: 10.1186/s13567-020-00763-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 02/18/2020] [Indexed: 01/19/2023] Open
Abstract
Rhodococcus equi is an intracellular veterinary pathogen that is becoming resistant to current antibiotherapy. Genes involved in preserving redox homeostasis could be promising targets for the development of novel anti-infectives. Here, we studied the role of an extracellular thioredoxin (Etrx3/REQ_13520) in the resistance to phagocytosis. An etrx3-null mutant strain was unable to survive within macrophages, whereas the complementation with the etrx3 gene restored its intracellular survival rate. In addition, the deletion of etrx3 conferred to R. equi a high susceptibility to sodium hypochlorite. Our results suggest that Etrx3 is essential for the resistance of R. equi to specific oxidative agents.
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Affiliation(s)
- Álvaro Mourenza
- Department of Molecular Biology, Area of Microbiology, University of León, León, Spain
| | - Cristina Collado
- Department of Molecular Biology, Area of Microbiology, University of León, León, Spain
| | | | - José A Gil
- Department of Molecular Biology, Area of Microbiology, University of León, León, Spain
| | - Luís M Mateos
- Department of Molecular Biology, Area of Microbiology, University of León, León, Spain.
| | - Michal Letek
- Department of Molecular Biology, Area of Microbiology, University of León, León, Spain.
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A Novel Screening Strategy Reveals ROS-Generating Antimicrobials That Act Synergistically against the Intracellular Veterinary Pathogen Rhodococcus equi. Antioxidants (Basel) 2020; 9:antiox9020114. [PMID: 32012850 PMCID: PMC7070597 DOI: 10.3390/antiox9020114] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/20/2020] [Accepted: 01/26/2020] [Indexed: 12/13/2022] Open
Abstract
Rhodococcus equi is a facultative intracellular pathogen that causes infections in foals and many other animals such as pigs, cattle, sheep, and goats. Antibiotic resistance is rapidly rising in horse farms, which makes ineffective current antibiotic treatments based on a combination of macrolides and rifampicin. Therefore, new therapeutic strategies are urgently needed to treat R. equi infections caused by antimicrobial resistant strains. Here, we employed a R. equi mycoredoxin-null mutant strain highly susceptible to oxidative stress to screen for novel ROS-generating antibiotics. Then, we used the well-characterized Mrx1-roGFP2 biosensor to confirm the redox stress generated by the most promising antimicrobial agents identified in our screening. Our results suggest that different combinations of antibacterial compounds that elicit oxidative stress are promising anti-infective strategies against R. equi. In particular, the combination of macrolides with ROS-generating antimicrobial compounds such as norfloxacin act synergistically to produce a potent antibacterial effect against R. equi. Therefore, our screening approach could be applied to identify novel ROS-inspired therapeutic strategies against intracellular pathogens.
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Ruocco NA, Luedke LK, Fortier LA, Ducharme NG, Reesink HL. Rhodococcus equi Joint Sepsis and Osteomyelitis Is Associated With a Grave Prognosis in Foals. Front Vet Sci 2020; 6:503. [PMID: 31993449 PMCID: PMC6971166 DOI: 10.3389/fvets.2019.00503] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 12/19/2019] [Indexed: 11/16/2022] Open
Abstract
The most common pathologic manifestation of Rhodococcus equi, a gram-positive, facultative intracellular bacterium, is pyogranulomatous pneumonia in foals and weanlings. Hematogenous spread of bacteria may subsequently occur, resulting in joint sepsis, osteomyelitis, or subcutaneous abscessation. Medical records from horses presenting to the Cornell University Equine Hospital from 1998 to 2018 were reviewed for cases diagnosed with R. equi joint and/or bone infection, and information about case progression and outcome were analyzed. We hypothesized that, despite advances in diagnostic imaging, antimicrobials and antimicrobial delivery methods, the prognosis for R. equi joint sepsis and osteomyelitis remains grave for athletic activity and poor for survival. The 12 cases that met the review criteria had a mortality rate of 84% (10/12), with one case lost to follow up after discharge and one case discharged with a grave prognosis for athleticism.
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Affiliation(s)
- Nicholas A Ruocco
- Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY, United States
| | - Lauren K Luedke
- Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY, United States
| | - Lisa A Fortier
- Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY, United States
| | - Norm G Ducharme
- Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY, United States
| | - Heidi L Reesink
- Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY, United States
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10
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Mourenza Á, Bravo-Santano N, Pradal I, Gil JA, Mateos LM, Letek M. Mycoredoxins Are Required for Redox Homeostasis and Intracellular Survival in the Actinobacterial Pathogen Rhodococcus equi. Antioxidants (Basel) 2019; 8:antiox8110558. [PMID: 31731720 PMCID: PMC6912445 DOI: 10.3390/antiox8110558] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 11/11/2019] [Accepted: 11/13/2019] [Indexed: 12/11/2022] Open
Abstract
Rhodococcus equi is a facultative intracellular pathogen that can survive within macrophages of a wide variety of hosts, including immunosuppressed humans. Current antibiotherapy is often ineffective, and novel therapeutic strategies are urgently needed to tackle infections caused by this pathogen. In this study, we identified three mycoredoxin-encoding genes (mrx) in the genome of R. equi, and we investigated their role in virulence. Importantly, the intracellular survival of a triple mrx-null mutant (Δmrx1Δmrx2Δmrx3) in murine macrophages was fully impaired. However, each mycoredoxin alone could restore the intracellular proliferation rate of R. equi Δmrx1Δmrx2Δmrx3 to wild type levels, suggesting that these proteins could have overlapping functions during host cell infection. Experiments with the reduction-oxidation sensitive green fluorescent protein 2 (roGFP2) biosensor confirmed that R. equi was exposed to redox stress during phagocytosis, and mycoredoxins were involved in preserving the redox homeostasis of the pathogen. Thus, we studied the importance of each mycoredoxin for the resistance of R. equi to different oxidative stressors. Interestingly, all mrx genes did have overlapping roles in the resistance to sodium hypochlorite. In contrast, only mrx1 was essential for the survival against high concentrations of nitric oxide, while mrx3 was not required for the resistance to hydrogen peroxide. Our results suggest that all mycoredoxins have important roles in redox homeostasis, contributing to the pathogenesis of R. equi and, therefore, these proteins may be considered interesting targets for the development of new anti-infectives.
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Affiliation(s)
- Álvaro Mourenza
- Department of Molecular Biology, Area of Microbiology, University of León, 24071 León, Spain; (Á.M.); (I.P.); (J.A.G.)
| | | | - Inés Pradal
- Department of Molecular Biology, Area of Microbiology, University of León, 24071 León, Spain; (Á.M.); (I.P.); (J.A.G.)
| | - Jose A. Gil
- Department of Molecular Biology, Area of Microbiology, University of León, 24071 León, Spain; (Á.M.); (I.P.); (J.A.G.)
| | - Luis M. Mateos
- Department of Molecular Biology, Area of Microbiology, University of León, 24071 León, Spain; (Á.M.); (I.P.); (J.A.G.)
- Correspondence: (L.M.M.); (M.L.)
| | - Michal Letek
- Health Sciences Research Centre, University of Roehampton, London SW15 4JD, UK;
- Correspondence: (L.M.M.); (M.L.)
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Barros T, Moran G, Uberti B. Reactive Seizures After Vaccination in a Thoroughbred Broodmare. J Equine Vet Sci 2019. [DOI: 10.1016/j.jevs.2018.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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Current taxonomy of Rhodococcus species and their role in infections. Eur J Clin Microbiol Infect Dis 2018; 37:2045-2062. [PMID: 30159693 DOI: 10.1007/s10096-018-3364-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/20/2018] [Indexed: 10/28/2022]
Abstract
Rhodococcus is a genus of obligate aerobic, Gram-positive, partially acid-fast, catalase-positive, non-motile, and none-endospore bacteria. The genus Rhodococcus was first introduced by Zopf. This bacterium can be isolated from various sources of the environment and can grow well in non-selective medium. A large number of phenotypic characterizations are used to compare different species of the genus Rhodococcus, and these tests are not suitable for accurate identification at the genus and species level. Among nucleic acid-based methods, the most powerful target gene for revealing reliable phylogenetic relationships is 16S ribosomal RNA gene (16S rRNA gene) sequence analysis, but this gene is unable to differentiation some of Rhodococcus species. To date, whole genome sequencing analysis has solved taxonomic complexities in this genus. Rhodococcus equi is the major cause of foal pneumonia, and its implication in human health is related to cases in immunocompromised patients. Macrolide family together with rifampicin is one of the most effective antibiotic agents for treatment rhodococcal infections.
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Cywes-Bentley C, Rocha JN, Bordin AI, Vinacur M, Rehman S, Zaidi TS, Meyer M, Anthony S, Lambert M, Vlock DR, Giguère S, Cohen ND, Pier GB. Antibody to Poly-N-acetyl glucosamine provides protection against intracellular pathogens: Mechanism of action and validation in horse foals challenged with Rhodococcus equi. PLoS Pathog 2018; 14:e1007160. [PMID: 30024986 PMCID: PMC6053243 DOI: 10.1371/journal.ppat.1007160] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 06/15/2018] [Indexed: 12/16/2022] Open
Abstract
Immune correlates of protection against intracellular bacterial pathogens are largely thought to be cell-mediated, although a reasonable amount of data supports a role for antibody-mediated protection. To define a role for antibody-mediated immunity against an intracellular pathogen, Rhodococcus equi, that causes granulomatous pneumonia in horse foals, we devised and tested an experimental system relying solely on antibody-mediated protection against this host-specific etiologic agent. Immunity was induced by vaccinating pregnant mares 6 and 3 weeks prior to predicted parturition with a conjugate vaccine targeting the highly conserved microbial surface polysaccharide, poly-N-acetyl glucosamine (PNAG). We ascertained antibody was transferred to foals via colostrum, the only means for foals to acquire maternal antibody. Horses lack transplacental antibody transfer. Next, a randomized, controlled, blinded challenge was conducted by inoculating at ~4 weeks of age ~106 cfu of R. equi via intrabronchial challenge. Eleven of 12 (91%) foals born to immune mares did not develop clinical R. equi pneumonia, whereas 6 of 7 (86%) foals born to unvaccinated controls developed pneumonia (P = 0.0017). In a confirmatory passive immunization study, infusion of PNAG-hyperimmune plasma protected 100% of 5 foals against R. equi pneumonia whereas all 4 recipients of normal horse plasma developed clinical disease (P = 0.0079). Antibodies to PNAG mediated killing of extracellular and intracellular R. equi and other intracellular pathogens. Killing of intracellular organisms depended on antibody recognition of surface expression of PNAG on infected cells, along with complement deposition and PMN-assisted lysis of infected macrophages. Peripheral blood mononuclear cells from immune and protected foals released higher levels of interferon-γ in response to PNAG compared to controls, indicating vaccination also induced an antibody-dependent cellular release of this critical immune cytokine. Overall, antibody-mediated opsonic killing and interferon-γ release in response to PNAG may protect against diseases caused by intracellular bacterial pathogens. Development of effective vaccines for diseases such as tuberculosis, brucellosis and others caused by intracellular pathogens has proved challenging, as data exist supporting both antibody and cellular immune effectors as mediators of protection. To address this problem against an important, and representative, equine intracellular pathogen, we chose to test a vaccine candidate for the ability to protect horse foals challenged at 4 weeks of age with Rhodococcus equi. To make these foals immune, their pregnant mares were immunized with a vaccine targeting the conserved surface antigen found on many microbes, termed PNAG. Antibody in the pregnant mares was transferred to their foals and, after the foals were challenged, 91% of those born to vaccinated mares were protected against R. equi pneumonia. Meanwhile, 86% of the non-vaccinated controls developed pneumonia. We also showed antibody to PNAG could kill various bacteria that produce this antigen when residing inside of human macrophage cells, a new mechanism for antibody-mediated immunity to intracellular bacteria. These results support the development of PNAG as a vaccine for intracellular bacterial pathogens.
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Affiliation(s)
- Colette Cywes-Bentley
- Harvard Medical School, Brigham & Women’s Hospital, Boston, MA, United States of America
| | - Joana N. Rocha
- College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, United States of America
| | - Angela I. Bordin
- College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, United States of America
| | - Mariana Vinacur
- Harvard Medical School, Brigham & Women’s Hospital, Boston, MA, United States of America
| | - Safia Rehman
- Harvard Medical School, Brigham & Women’s Hospital, Boston, MA, United States of America
| | - Tanweer S. Zaidi
- Harvard Medical School, Brigham & Women’s Hospital, Boston, MA, United States of America
| | - Mark Meyer
- Mg Biologics, Ames, IA, United States of America
| | | | | | | | - Steeve Giguère
- College of Veterinary Medicine, University of Georgia, Athens, GA, United States of America
| | - Noah D. Cohen
- College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, United States of America
- * E-mail: (NDC); (GBP)
| | - Gerald B. Pier
- Harvard Medical School, Brigham & Women’s Hospital, Boston, MA, United States of America
- * E-mail: (NDC); (GBP)
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15
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Trevisani MM, Hanna ES, Oliveira AF, Cardoso SA, Roque-Barreira MC, Soares SG. Vaccination of Mice with Virulence-Associated Protein G (VapG) Antigen Confers Partial Protection against Rhodococcus equi Infection through Induced Humoral Immunity. Front Microbiol 2017; 8:857. [PMID: 28553279 PMCID: PMC5425581 DOI: 10.3389/fmicb.2017.00857] [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: 02/18/2017] [Accepted: 04/27/2017] [Indexed: 11/13/2022] Open
Abstract
Rhodococcus equi is a facultative intracellular bacterium causing severe pyogranulomatous pneumonia, ulcerative enterocolitis, and mesenteric lymphadenopathy in foals aged less than 6 months. Less frequently, this pathogen affects various other species, such as pigs, cattle, cats, and even humans. Although rhodococcosis is treated with a combination of antimicrobial agents, resistance is developed in some cases, and thus, antimicrobial susceptibility must be monitored and managed. Considering these limitations of the current therapy and unavailability of a vaccine to prevent the disease, research is particularly focused on the development of an effective vaccine against rhodococcosis. Most vaccines undergoing development utilize the virulence-associated protein (Vap) A antigen, which was identified previously as a key virulence factor of R. equi. Nevertheless, other proteins, such as VapG, present in most virulent R. equi strains, are also encoded by vap genes located on the R. equi bacterial virulence plasmid. In the present study, we evaluated the effect of VapG immunization on the survival of R. equi-challenged mice. We used attenuated Salmonella as a carrier for VapG (Salmonella-vapG+), a procedure previously adopted to develop a VapA-based vaccine. We observed that vaccination with Salmonella-vapG+ induced both an increased IFN-γ, IL-12, and TNF-α production, and a decreased bacterial burden in organs of the R. equi-challenged mice. Nevertheless, Salmonella-vapG+ vaccination protected only 50% of the mice challenged with a lethal dose of R. equi. Interestingly, we observed an increased frequency of B cells in the spleen of Salmonella-vapG+-vaccinated mice and showed that Salmonella-vapG+-vaccinated R. equi-challenged B-cell-knockout mice did not reduce the bacterial burden. Given these results, we discussed the potential role of the humoral immune response induced by Salmonella-vapG+ vaccination in conferring protection against R. equi infection, as well as the employment of VapG antigen for obtaining hyperimmune plasma to prevent rhodoccocosis in young foals.
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Affiliation(s)
- Marcel M Trevisani
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São PauloSão Paulo, Brazil
| | - Ebert S Hanna
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São PauloSão Paulo, Brazil
| | - Aline F Oliveira
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São PauloSão Paulo, Brazil
| | - Silvia A Cardoso
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São PauloSão Paulo, Brazil
| | - Maria C Roque-Barreira
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São PauloSão Paulo, Brazil
| | - Sandro G Soares
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São PauloSão Paulo, Brazil
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Giles C, Ndi O, Barton MD, Vanniasinkam T. An Adenoviral Vector Based Vaccine for Rhodococcus equi. PLoS One 2016; 11:e0152149. [PMID: 27008624 PMCID: PMC4805240 DOI: 10.1371/journal.pone.0152149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 03/09/2016] [Indexed: 11/26/2022] Open
Abstract
Rhodococcus equi is a respiratory pathogen which primarily infects foals and is endemic on farms around the world with 50% mortality and 80% morbidity in affected foals. Unless detected early and treated appropriately the disease can be fatal. Currently, there is no vaccine available to prevent this disease. For decades researchers have endeavoured to develop an effective vaccine to no avail. In this study a novel human adenoviral vector vaccine for R. equi was developed and tested in the mouse model. This vaccine generated a strong antibody and cytokine response and clearance of R. equi was demonstrated following challenge. These results show that this vaccine could potentially be developed further for use as a vaccine to prevent R. equi disease in foals.
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Affiliation(s)
- Carla Giles
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Olasumbo Ndi
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Mary D. Barton
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Thiru Vanniasinkam
- School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
- * E-mail:
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Rocha JN, Cohen ND, Bordin AI, Brake CN, Giguère S, Coleman MC, Alaniz RC, Lawhon SD, Mwangi W, Pillai SD. Oral Administration of Electron-Beam Inactivated Rhodococcus equi Failed to Protect Foals against Intrabronchial Infection with Live, Virulent R. equi. PLoS One 2016; 11:e0148111. [PMID: 26828865 PMCID: PMC4735123 DOI: 10.1371/journal.pone.0148111] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 01/13/2016] [Indexed: 02/07/2023] Open
Abstract
There is currently no licensed vaccine that protects foals against Rhodococcus equi–induced pneumonia. Oral administration of live, virulent R. equi to neonatal foals has been demonstrated to protect against subsequent intrabronchial challenge with virulent R. equi. Electron beam (eBeam)-inactivated R. equi are structurally intact and have been demonstrated to be immunogenic when administered orally to neonatal foals. Thus, we investigated whether eBeam inactivated R. equi could protect foals against developing pneumonia after experimental infection with live, virulent R. equi. Foals (n = 8) were vaccinated by gavaging with eBeam-inactivated R. equi at ages 2, 7, and 14 days, or gavaged with equal volume of saline solution (n = 4), and subsequently infected intrabronchially with live, virulent R. equi at age 21 days. The proportion of vaccinated foals that developed pneumonia following challenge was similar among the vaccinated (7/8; 88%) and unvaccinated foals (3/4; 75%). This vaccination regimen did not appear to be strongly immunogenic in foals. Alternative dosing regimens or routes of administration need further investigation and may prove to be immunogenic and protective.
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Affiliation(s)
- Joana N. Rocha
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843–4475, United States of America
| | - Noah D. Cohen
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843–4475, United States of America
- * E-mail: (NDC); (SDP)
| | - Angela I. Bordin
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843–4475, United States of America
| | - Courtney N. Brake
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843–4475, United States of America
| | - Steeve Giguère
- Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, Georgia, 30602–7385, United States of America
| | - Michelle C. Coleman
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, 77843–4475, United States of America
| | - Robert C. Alaniz
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, College Station, Texas, 77843, United States of America
| | - Sara D. Lawhon
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, 77843–4467, United States of America
| | - Waithaka Mwangi
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, 77843–4467, United States of America
| | - Suresh D. Pillai
- National Center for Electron Beam Research–IAEA Collaborative Centre for Electron Beam Technology, Texas A&M University, College Station, Texas, 77843, United States of America
- * E-mail: (NDC); (SDP)
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Reuss SM, Cohen ND. Update on Bacterial Pneumonia in the Foal and Weanling. Vet Clin North Am Equine Pract 2015; 31:121-35. [DOI: 10.1016/j.cveq.2014.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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