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Brown GD, Ballou ER, Bates S, Bignell EM, Borman AM, Brand AC, Brown AJP, Coelho C, Cook PC, Farrer RA, Govender NP, Gow NAR, Hope W, Hoving JC, Dangarembizi R, Harrison TS, Johnson EM, Mukaremera L, Ramsdale M, Thornton CR, Usher J, Warris A, Wilson D. The pathobiology of human fungal infections. Nat Rev Microbiol 2024:10.1038/s41579-024-01062-w. [PMID: 38918447 DOI: 10.1038/s41579-024-01062-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2024] [Indexed: 06/27/2024]
Abstract
Human fungal infections are a historically neglected area of disease research, yet they cause more than 1.5 million deaths every year. Our understanding of the pathophysiology of these infections has increased considerably over the past decade, through major insights into both the host and pathogen factors that contribute to the phenotype and severity of these diseases. Recent studies are revealing multiple mechanisms by which fungi modify and manipulate the host, escape immune surveillance and generate complex comorbidities. Although the emergence of fungal strains that are less susceptible to antifungal drugs or that rapidly evolve drug resistance is posing new threats, greater understanding of immune mechanisms and host susceptibility factors is beginning to offer novel immunotherapeutic options for the future. In this Review, we provide a broad and comprehensive overview of the pathobiology of human fungal infections, focusing specifically on pathogens that can cause invasive life-threatening infections, highlighting recent discoveries from the pathogen, host and clinical perspectives. We conclude by discussing key future challenges including antifungal drug resistance, the emergence of new pathogens and new developments in modern medicine that are promoting susceptibility to infection.
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Affiliation(s)
- Gordon D Brown
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK.
| | - Elizabeth R Ballou
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Steven Bates
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Elaine M Bignell
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Andrew M Borman
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Alexandra C Brand
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Alistair J P Brown
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Carolina Coelho
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Peter C Cook
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Rhys A Farrer
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Nelesh P Govender
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Neil A R Gow
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - William Hope
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - J Claire Hoving
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Rachael Dangarembizi
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Thomas S Harrison
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Elizabeth M Johnson
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Liliane Mukaremera
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Mark Ramsdale
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | | | - Jane Usher
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Adilia Warris
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Duncan Wilson
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
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Kottom TJ, Carmona EM, Lepenies B, Limper AH. Metabolic modulation: Pneumocystis phosphoglucomutase is a target influencing host recognition. Cell Surf 2024; 11:100123. [PMID: 39022598 PMCID: PMC467086 DOI: 10.1016/j.tcsw.2024.100123] [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: 01/29/2024] [Revised: 03/08/2024] [Accepted: 03/15/2024] [Indexed: 07/20/2024] Open
Abstract
Herein, this manuscript explores the significance of the phosphoglucomutase (PGM) enzyme in Pneumocystis spp., focusing on its role in fungal surface mannoprotein formation. Through expression of the Pneumocystis murina Pmpgm2 in a Saccharomyces cerevisiae pgm2Δ strain, we demonstrate restoration of binding to the mannose receptor (MR) and macrophages to wildtype yeast levels in this complemented strain. Gas Chromatography-Mass Spectroscopy (GC-MS) confirmed reduced mannose content in the pgm2Δ yeast strain compared to the wild-type and complemented Pmpgm2 cDNA-expressing strains. This study underscores fungal PGM function in dolichol glucosyl phosphate biosynthesis, crucial for proper cell wall mannoprotein formation. Furthermore, highlighting the conservation of targetable cysteine residues across fungal pathogens, PGM inhibition maybe a potential therapeutic strategy against a broad spectrum of fungal infections.
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Affiliation(s)
- Theodore J. Kottom
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Eva M. Carmona
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | - Bernd Lepenies
- Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, Hannover, Germany
- Institute for Immunology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Andrew H. Limper
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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Kottom TJ, Carmona EM, Limper AH. Targeting host tyrosine kinase receptor EphA2 signaling via small-molecule ALW-II-41-27 inhibits macrophage pro-inflammatory signaling responses to Pneumocystis carinii β-glucans. Antimicrob Agents Chemother 2024; 68:e0081123. [PMID: 38206037 PMCID: PMC10848750 DOI: 10.1128/aac.00811-23] [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: 06/19/2023] [Accepted: 12/03/2023] [Indexed: 01/12/2024] Open
Abstract
Pneumocystis jirovecii, the fungus that causes Pneumocystis jirovecii pneumonia (PJP), is a leading cause of morbidity and mortality in immunocompromised individuals. We have previously shown that lung epithelial cells can bind Pneumocystis spp. β-glucans via the EphA2 receptor, resulting in activation and release of proinflammatory cytokines. Herein, we show that in vivo Pneumocystis spp. β-glucans activation of the inflammatory signaling cascade in macrophages can be pharmacodynamically inhibited with the EphA2 receptor small-molecule inhibitor ALW-II-41-27. In vitro, when ALW-II-41-27 is administrated via intraperitoneal to mice prior to the administration of highly proinflammatory Saccharomyces cerevisiae β-glucans in the lung, a significant reduction in TNF-alpha release was noted in the ALW-II-41-27 pre-treated group. Taken together, our data suggest that targeting host lung macrophage activation via EphA2 receptor-fungal β-glucans interactions with ALW-II-41-27 or other EphA2 receptor kinase targeting inhibitors might be an attractive and viable strategy to reduce detrimental lung inflammation associated with PJP.
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Affiliation(s)
- Theodore J. Kottom
- Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
- Thoracic Diseases Research Unit, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Eva M. Carmona
- Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
- Thoracic Diseases Research Unit, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Andrew H. Limper
- Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
- Thoracic Diseases Research Unit, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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Abstract
Pneumocystis jirovecii causes pneumonia in immunocompromised patients. A major challenge in drug susceptibility testing and in understanding host/pathogen interactions is that Pneumocystis spp. are not viable in vitro. Continuous culture of the organism is not currently available, and therefore, developing new drug targets is very limited. Due to this limitation, mouse models of Pneumocystis pneumonia have proven to be an invaluable resource to researchers. In this chapter, we provide an overview of selected methods used in mouse models of infection including, in vivo Pneumocystis murina propagation, routes of transmission, genetic mouse models available, a P. murina life form-specific model, a mouse model of PCP immune reconstitution inflammatory syndrome (IRIS), and the experimental parameters associated with these models.
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Affiliation(s)
- J Claire Hoving
- AFRICA CMM Medical Mycology Research Unit, Institute of Infectious Disease and Molecular Medicine (IDM), Cape Town, South Africa.
- Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
- MRC Centre for Medical Mycology, University of Exeter, Exeter, UK.
| | - Ferris T Munyonho
- Centre for Translational Research in Infection and Inflammation, Tulane School of Medicine, New Orleans, LA, USA
| | - Jay K Kolls
- Centre for Translational Research in Infection and Inflammation, Tulane School of Medicine, New Orleans, LA, USA.
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Chesnay A, Paget C, Heuzé-Vourc’h N, Baranek T, Desoubeaux G. Pneumocystis Pneumonia: Pitfalls and Hindrances to Establishing a Reliable Animal Model. J Fungi (Basel) 2022; 8:jof8020129. [PMID: 35205883 PMCID: PMC8877242 DOI: 10.3390/jof8020129] [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] [Received: 12/21/2021] [Revised: 01/20/2022] [Accepted: 01/26/2022] [Indexed: 02/06/2023] Open
Abstract
Pneumocystis pneumonia is a severe lung infection that occurs primarily in largely immunocompromised patients. Few treatment options exist, and the mortality rate remains substantial. To develop new strategies in the fields of diagnosis and treatment, it appears to be critical to improve the scientific knowledge about the biology of the Pneumocystis agent and the course of the disease. In the absence of in vitro continuous culture system, in vivo animal studies represent a crucial cornerstone for addressing Pneumocystis pneumonia in laboratories. Here, we provide an overview of the animal models of Pneumocystis pneumonia that were reported in the literature over the last 60 years. Overall, this review highlights the great heterogeneity of the variables studied: the choice of the host species and its genetics, the different immunosuppressive regimens to render an animal susceptible, the experimental challenge, and the different validation methods of the model. With this work, the investigator will have the keys to choose pivotal experimental parameters and major technical features that are assumed to likely influence the results according to the question asked. As an example, we propose an animal model to explore the immune response during Pneumocystis pneumonia.
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Affiliation(s)
- Adélaïde Chesnay
- Service de Parasitologie-Mycologie-Médecine Tropicale, Pôle Biologie Médicale, Hôpital Bretonneau, CHRU de Tours, 2 Boulevard Tonnellé, 37044 Tours, France;
- Centre d’Etude des Pathologies Respiratoires (CEPR), Institut National de la Santé et de la Recherche Médicale U1100, Université de Tours, 10 Bouelvard Tonnellé, 37032 Tours, France; (C.P.); (N.H.-V.); (T.B.)
- Correspondence:
| | - Christophe Paget
- Centre d’Etude des Pathologies Respiratoires (CEPR), Institut National de la Santé et de la Recherche Médicale U1100, Université de Tours, 10 Bouelvard Tonnellé, 37032 Tours, France; (C.P.); (N.H.-V.); (T.B.)
| | - Nathalie Heuzé-Vourc’h
- Centre d’Etude des Pathologies Respiratoires (CEPR), Institut National de la Santé et de la Recherche Médicale U1100, Université de Tours, 10 Bouelvard Tonnellé, 37032 Tours, France; (C.P.); (N.H.-V.); (T.B.)
| | - Thomas Baranek
- Centre d’Etude des Pathologies Respiratoires (CEPR), Institut National de la Santé et de la Recherche Médicale U1100, Université de Tours, 10 Bouelvard Tonnellé, 37032 Tours, France; (C.P.); (N.H.-V.); (T.B.)
| | - Guillaume Desoubeaux
- Service de Parasitologie-Mycologie-Médecine Tropicale, Pôle Biologie Médicale, Hôpital Bretonneau, CHRU de Tours, 2 Boulevard Tonnellé, 37044 Tours, France;
- Centre d’Etude des Pathologies Respiratoires (CEPR), Institut National de la Santé et de la Recherche Médicale U1100, Université de Tours, 10 Bouelvard Tonnellé, 37032 Tours, France; (C.P.); (N.H.-V.); (T.B.)
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Targeting CARD9 with Small-Molecule Therapeutics Inhibits Innate Immune Signaling and Inflammatory Response to Pneumocystis carinii β-Glucans. Antimicrob Agents Chemother 2020; 64:AAC.01210-20. [PMID: 32839216 DOI: 10.1128/aac.01210-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 08/15/2020] [Indexed: 11/20/2022] Open
Abstract
Pneumocystis jirovecii, the opportunistic fungus that causes Pneumocystis pneumonia (PCP) in humans, is a significant contributor to morbidity and mortality in immunocompromised patients. Given the profound deleterious inflammatory effects of the major β-glucan cell wall carbohydrate constituents of Pneumocystis through Dectin-1 engagement and downstream caspase recruitment domain-containing protein 9 (CARD9) immune activation, we sought to determine whether the pharmacodynamic activity of the known CARD9 inhibitor BRD5529 might have a therapeutic effect on macrophage innate immune signaling and subsequent downstream anti-inflammatory activity. The small-molecule inhibitor BRD5529 was able to significantly reduce both phospho-p38 and phospho-pERK1 signaling and tumor necrosis factor alpha (TNF-α) release during stimulation of macrophages with Pneumocystis cell wall β-glucans.
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Kottom TJ, Hebrink DM, Carmona EM, Limper AH. Pneumocystis carinii Major Surface Glycoprotein Dampens Macrophage Inflammatory Responses to Fungal β-Glucan. J Infect Dis 2020; 222:1213-1221. [PMID: 32363390 DOI: 10.1093/infdis/jiaa218] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 04/24/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Pneumocystis major surface glycoprotein (Msg) is a 120-kD surface protein complex on the organism with importance in adhesion and immune recognition. In this study, we show that Msg significantly impairs tumor necrosis factor (TNF)-α secretion by macrophages induced by Saccharomyces cerevisiae and Pneumocystis carinii (Pc) β-glucans. METHODS Major surface glycoprotein was shown to greatly reduce β-glucan-induced Dectin-1 immunoreceptor tyrosine-based activating motif (ITAM) phosphorylation. Major surface glycoprotein also down regulated Dectin-1 receptor messenger ribonucleic acid (mRNA) expression in the macrophages. It is interesting that Msg incubation with macrophages resulted in significant mRNA upregulation of both C-type lectin receptors (CLR) Mincle and MCL in Msg protein presence alone but to even greater amounts in the presence of Pc β-glucan. RESULTS The silencing of MCL and Mincle resulted in TNF-α secretions similar to that of macrophages treated with Pneumocystis β-glucan alone, which is suggestive of an inhibitory role for these 2 CLRs in Msg-suppressive effects on host cell immune response. CONCLUSIONS Taken together, these data indicate that the Pneumocystis Msg surface protein complex can act to suppress host macrophage inflammatory responses to the proinflammatory β -glucan components of the organisms.
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Affiliation(s)
- Theodore J Kottom
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Deanne M Hebrink
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Eva M Carmona
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Andrew H Limper
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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Kottom TJ, Hebrink DM, Monteiro JT, Lepenies B, Carmona EM, Wuethrich M, Santo Dias LD, Limper AH. Myeloid C-type lectin receptors that recognize fungal mannans interact with Pneumocystis organisms and major surface glycoprotein. J Med Microbiol 2019; 68:1649-1654. [PMID: 31609198 DOI: 10.1099/jmm.0.001062] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Myeloid C-type lectin receptors (CLRs) are innate immune recognition molecules that bind to microorganisms via their carbohydrate recognition domains. In this study, we utilized a library of CLRs that recognize fungal mannans. We used this library to screen against Pneumocystis carinii (Pc) homogenates or purified Pc major surface glycoprotein (Msg) present on Pneumocystis. The results demonstrated that all of the mammalian CLR hFc-fusions tested displayed significant interaction/binding with Pc organisms, and furthermore to isolated Msg. Highest Pc organism and Msg binding activities were with CLR members Mincle, Dectin-2, DC-SIGN and MCL. An immunofluorescence assay with the respective CLR hFc-fusions against whole Pc life forms corroborated these findings. Although some of these CLRs have been implicated previously as important for Pneumocystis pathogenesis (Dectin-1/Dectin-2/Mincle), this is the first analysis of head-to-head comparison of known fungal mannan binding CLR-hFc fusions with Pc. Lastly, heat treatment resulted in reducted CLR binding.
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Affiliation(s)
- Theodore J Kottom
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA
| | - Deanne M Hebrink
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA
| | - Joao T Monteiro
- Immunology Unit and Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine, Germany, Hannover
| | - Bernd Lepenies
- Immunology Unit and Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine, Germany, Hannover
| | - Eva M Carmona
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA
| | - Marcel Wuethrich
- Departments of Pediatrics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Lucas Dos Santo Dias
- Departments of Pediatrics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Andrew H Limper
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA
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Otieno-Odhiambo P, Wasserman S, Hoving JC. The Contribution of Host Cells to Pneumocystis Immunity: An Update. Pathogens 2019; 8:pathogens8020052. [PMID: 31010170 PMCID: PMC6631015 DOI: 10.3390/pathogens8020052] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/15/2019] [Accepted: 04/16/2019] [Indexed: 01/04/2023] Open
Abstract
Pneumocystis is a ubiquitous atypical fungus that is distributed globally. The genus comprises morphologically similar but genetically heterogeneous species that have co-evolved with specific mammalian hosts as obligate intra-pulmonary pathogens. In humans, Pneumocystis jirovecii is the causative organism of Pneumocystis pneumonia (PCP) in immunocompromised individuals, a serious illness frequently leading to life-threatening respiratory failure. Initially observed in acquired immunodeficiency syndrome (AIDS) patients, PCP is increasingly observed in immunocompromised non-AIDS patients. The evolving epidemiology and persistently poor outcomes of this common infection will require new strategies for diagnosis and treatment. A deeper understanding of host immune responses and of the cells that mediate them will improve the chance of developing new treatment strategies. This brief review provides an update on recent studies on the role of host immunity against Pneumocystis.
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Affiliation(s)
- Patricia Otieno-Odhiambo
- AFGrica Medical Mycology Research Unit, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town 7925, South Africa.
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK.
- Division of Immunology, Department of Pathology, University of Cape Town, Cape Town 7925, South Africa.
| | - Sean Wasserman
- Wellcome Centre for Infectious Diseases Research in Africa, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town 7925, South Africa.
- Division of Infectious Diseases and HIV Medicine, Department of Medicine, University of Cape Town, Cape Town 7925, South Africa.
| | - J Claire Hoving
- AFGrica Medical Mycology Research Unit, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town 7925, South Africa.
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK.
- Division of Immunology, Department of Pathology, University of Cape Town, Cape Town 7925, South Africa.
- Wellcome Centre for Infectious Diseases Research in Africa, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town 7925, South Africa.
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