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Li Y, Chadwick B, Pham T, Xie X, Lin X. Aspartyl peptidase May1 induces host inflammatory response by altering cell wall composition in the fungal pathogen Cryptococcus neoformans. mBio 2024:e0092024. [PMID: 38742885 DOI: 10.1128/mbio.00920-24] [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: 03/28/2024] [Accepted: 04/09/2024] [Indexed: 05/16/2024] Open
Abstract
Cryptococcus neoformans causes cryptococcal meningoencephalitis, a disease that kills more than 180,000 people annually. Contributing to its success as a fungal pathogen is its cell wall surrounded by a capsule. When the cryptococcal cell wall is compromised, exposed pathogen-associated molecular pattern molecules (PAMPs) could trigger host recognition and initiate attack against this fungus. Thus, cell wall composition and structure are tightly regulated. The cryptococcal cell wall is unusual in that chitosan, the acetylated form of chitin, is predominant over chitin and is essential for virulence. Recently, it was shown that acidic pH weakens the cell wall and increases exposure of PAMPs partly due to decreased chitosan levels. However, the molecular mechanism responsible for the cell wall remodeling in acidic pH is unknown. In this study, by screening for genes involved in cryptococcal tolerance to high levels of CO2, we serendipitously discovered that the aspartyl peptidase May1 contributes to cryptococcal sensitivity to high levels of CO2 due to acidification of unbuffered media. Overexpression of MAY1 increases the cryptococcal cell size and elevates PAMP exposure, causing a hyper-inflammatory response in the host while MAY1 deletion does the opposite. We discovered that May1 weakens the cell wall and reduces the chitosan level, partly due to its involvement in the degradation of Chs3, the sole chitin synthase that supplies chitin to be converted to chitosan. Consistently, overexpression of CHS3 largely rescues the phenotype of MAY1oe in acidic media. Collectively, we demonstrate that May1 remodels the cryptococcal cell wall in acidic pH by reducing chitosan levels through its influence on Chs3. IMPORTANCE The fungal cell wall is a dynamic structure, monitoring and responding to internal and external stimuli. It provides a formidable armor to the fungus. However, in a weakened state, the cell wall also triggers host immune attack when PAMPs, including glucan, chitin, and mannoproteins, are exposed. In this work, we found that the aspartyl peptidase May1 impairs the cell wall of Cryptococcus neoformans and increases the exposure of PAMPs in the acidic environment by reducing the chitosan level. Under acidic conditions, May1 is involved in the degradation of the chitin synthase Chs3, which supplies chitin to be deacetylated to chitosan. Consistently, the severe deficiency of chitosan in acidic pH can be rescued by overexpressing CHS3. These findings improve our understanding of cell wall remodeling and reveal a potential target to compromise the cell wall integrity in this important fungal pathogen.
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Affiliation(s)
- Yeqi Li
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Benjamin Chadwick
- Department of Plant Biology, University of Georgia, Athens, Georgia, USA
| | - Tuyetnhu Pham
- Department of Plant Biology, University of Georgia, Athens, Georgia, USA
| | - Xiaofeng Xie
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Xiaorong Lin
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
- Department of Plant Biology, University of Georgia, Athens, Georgia, USA
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2
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Meya DB, Williamson PR. Cryptococcal Disease in Diverse Hosts. N Engl J Med 2024; 390:1597-1610. [PMID: 38692293 DOI: 10.1056/nejmra2311057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Affiliation(s)
- David B Meya
- From the Infectious Diseases Institute and the Department of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda (D.B.M.); the Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis (D.B.M.); and the Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD (P.R.W.)
| | - Peter R Williamson
- From the Infectious Diseases Institute and the Department of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda (D.B.M.); the Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis (D.B.M.); and the Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD (P.R.W.)
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3
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Ortiz SC, Hull CM. Biogenesis, germination, and pathogenesis of Cryptococcus spores. Microbiol Mol Biol Rev 2024; 88:e0019623. [PMID: 38440970 PMCID: PMC10966950 DOI: 10.1128/mmbr.00196-23] [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] [Indexed: 03/06/2024] Open
Abstract
SUMMARYSpores are primary infectious propagules for the majority of human fungal pathogens; however, relatively little is known about their fundamental biology. One strategy to address this deficiency has been to develop the basidiospores of Cryptococcus into a model for pathogenic spore biology. Here, we provide an update on the state of the field with a comprehensive review of the data generated from the study of Cryptococcus basidiospores from their formation (sporulation) and differentiation (germination) to their roles in pathogenesis. Importantly, we provide support for the presence of basidiospores in nature, define the key characteristics that distinguish basidiospores from yeast cells, and clarify their likely roles as infectious particles. This review is intended to demonstrate the importance of basidiospores in the field of Cryptococcus research and provide a solid foundation from which researchers who wish to study sexual spores in any fungal system can launch their studies.
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Affiliation(s)
- Sébastien C. Ortiz
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Christina M. Hull
- Department of Biomolecular Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
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4
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Barros K, Tepper JW, Ramchandani J, Kelley MK, Kussin ML, Israel EN, Tompkins MG, Alali M. Unusual presentation of disseminated cryptococcal infection complicated by myocarditis in a heart transplant recipient. Pediatr Transplant 2024; 28:e14585. [PMID: 37489596 DOI: 10.1111/petr.14585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 06/21/2023] [Accepted: 07/10/2023] [Indexed: 07/26/2023]
Abstract
BACKGROUND Cryptococcus neoformans is the third most common cause of invasive fungal infection in solid organ transplant (SOT) recipients. While cryptococcal infection can involve any organ, cases of myocarditis are exceedingly rare. METHODS A retrospective chart review was completed for this case report. RESULTS We present the case of a 21-year-old heart transplant recipient who developed disseminated cryptococcal infection with biopsy-proven cryptococcal myocarditis. CONCLUSIONS Cryptococcal disease in SOT recipients poses diagnostic and therapeutic challenges. There are no current guidelines for the duration of cryptococcal myocarditis treatment. Repeat myocardial biopsy may play a role in guiding length of therapy.
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Affiliation(s)
- Kathryn Barros
- Ryan White Center for Pediatric Infectious Diseases & Global Health, Indiana University, Indianapolis, Indiana, USA
| | - John William Tepper
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Juhi Ramchandani
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Meagan Kristine Kelley
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Michelle L Kussin
- Pediatric Infectious Diseases, Department of Pharmacy, Riley Hospital for Children at Indiana University Health and Ryan White Center for Pediatric Infectious Diseases & Global Health, Indiana University, Indianapolis, Indiana, USA
| | - Emily N Israel
- Purdue College of Pharmacy, West Lafayette, Indiana, USA
- Department of Pharmacy, Riley Hospital for Children at Indiana University Health, Indianapolis, Indiana, USA
| | - Madeline G Tompkins
- Pediatric Cardiology, Department of Pharmacy, Riley Hospital for Children at Indiana University Health, Indianapolis, Indiana, USA
| | - Muayad Alali
- Ryan White Center for Pediatric Infectious Diseases & Global Health, Indiana University, Indianapolis, Indiana, USA
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5
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Meena P, Bhargava V, Singh K, sethi J, Prabhakar A, panda S. Cryptococcosis in kidney transplant recipients: Current understanding and practices. World J Nephrol 2023; 12:120-131. [PMID: 38230297 PMCID: PMC10789088 DOI: 10.5527/wjn.v12.i5.120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/15/2023] [Accepted: 11/02/2023] [Indexed: 12/22/2023] Open
Abstract
Cryptococcosis is the third most commonly occurring invasive fungal disease in solid organ transplant recipients (SOT). It is caused by encapsulated yeast, Cryptococcus species, predominantly Cryptococcus neoformans and Cryptococcus gattii. Though kidney transplant recipients are at the lowest risk of cryptococcosis when compared to other solid organ transplant recipients such as lung, liver or heart, still this opportunistic infection causes significant morbidity and mortality in this subset of patients. Mortality rates with cryptococcosis range from 10%-25%, while it can be as high as 50% in SOT recipients with central nervous system involvement. The main aim of diagnosis is to find out if there is any involvement of the central nervous system in disseminated disease or whether there is only localized pulmonary involvement as it has implications for both prognostication and treatment. Detection of cryptococcal antigen (CrAg) in cerebrospinal fluid or plasma is a highly recommended test as it is more sensitive and specific than India ink and fungal cultures. The CrAg lateral flow assay is the single point of care test that can rapidly detect cryptococcal polysaccharide capsule. Treatment of cryptococcosis is challenging in kidney transplant recipients. Apart from the reduction or optimization of immunosuppression, lipid formulations of amphotericin B are preferred as induction antifungal agents. Consolidation and maintenance are done with fluconazole; carefully monitoring its interactions with calcineurin inhibitors. This review further discusses in depth the evolving developments in the epidemiology, pathogenesis, diagnostic assays, and management approach of cryptococcosis in kidney transplant recipients.
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Affiliation(s)
- Priti Meena
- Department of Nephrology, All India Institute of Medical Sciences, Bhubaneswar 751019, Odhisha, India
| | - Vinant Bhargava
- Department of Nephrology, Sir Ganga Ram Hospital New Delhi, New Delhi 110001, New Delhi, India
| | - Kulwant Singh
- Department of Nephrology, Ivy Hospital, Mohali Punjab, Mohali 160071, Punjab, India
| | - Jasmine sethi
- Department of Nephrology, Post Graduate Institute of Medical Education & Research, Chandigarh 160012, Punjab, India
| | - Aniketh Prabhakar
- Department of Nephrology, Consultant Nephrologist, Sigma Hospital, Mysore 570009, Karnataka, India
| | - Sandip panda
- Department of Nephrology, All India Institute of Medical Sciences, Bhubaneswar 751019, Odhisha, India
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de Castro RJA, Marina CL, Sturny-Leclère A, Hoffmann C, Bürgel PH, Wong SSW, Aimanianda V, Varet H, Agrawal R, Bocca AL, Alanio A. Kicking sleepers out of bed: Macrophages promote reactivation of dormant Cryptococcus neoformans by extracellular vesicle release and non-lytic exocytosis. PLoS Pathog 2023; 19:e1011841. [PMID: 38033163 PMCID: PMC10715671 DOI: 10.1371/journal.ppat.1011841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 12/12/2023] [Accepted: 11/18/2023] [Indexed: 12/02/2023] Open
Abstract
Macrophages play a key role in disseminated cryptococcosis, a deadly fungal disease caused by Cryptococcus neoformans. This opportunistic infection can arise following the reactivation of a poorly characterized latent infection attributed to dormant C. neoformans. Here, we investigated the mechanisms underlying reactivation of dormant C. neoformans using an in vitro co-culture model of viable but non-culturable (VBNC; equivalent of dormant) yeast cells with bone marrow-derived murine macrophages (BMDMs). Comparative transcriptome analysis of BMDMs incubated with log, stationary phase or VBNC cells of C. neoformans showed that VBNC cells elicited a reduced transcriptional modification of the macrophage but retaining the ability to regulate genes important for immune response, such as NLRP3 inflammasome-related genes. We further confirmed the maintenance of the low immunostimulatory capacity of VBNC cells using multiplex cytokine profiling, and analysis of cell wall composition and dectin-1 ligands exposure. In addition, we evaluated the effects of classic (M1) or alternative (M2) macrophage polarization on VBNC cells. We observed that intracellular residence sustained dormancy, regardless of the polarization state of macrophages and despite indirect detection of pantothenic acid (or its derivatives), a known reactivator for VBNC cells, in the C. neoformans-containing phagolysosome. Notably, M0 and M2, but not M1 macrophages, induced extracellular reactivation of VBNC cells by the secretion of extracellular vesicles and non-lytic exocytosis. Our results indicate that VBNC cells retain the low immunostimulatory profile required for persistence of C. neoformans in the host. We also describe a pro-pathogen role of macrophage-derived extracellular vesicles in C. neoformans infection and reinforce the impact of non-lytic exocytosis and the macrophage profile on the pathophysiology of cryptococcosis.
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Affiliation(s)
- Raffael Júnio Araújo de Castro
- Translational Mycology Research Group, National Reference Center for Invasive Mycoses and Antifungals, Mycology Department, Institut Pasteur, Université Paris Cité, Paris, France
- Laboratory of Applied Immunology, Department of Cell Biology, Institute of Biological Sciences, University of Brasilia, Brasília, Distrito Federal, Brazil
| | - Clara Luna Marina
- Laboratory of Applied Immunology, Department of Cell Biology, Institute of Biological Sciences, University of Brasilia, Brasília, Distrito Federal, Brazil
| | - Aude Sturny-Leclère
- Translational Mycology Research Group, National Reference Center for Invasive Mycoses and Antifungals, Mycology Department, Institut Pasteur, Université Paris Cité, Paris, France
| | - Christian Hoffmann
- Food Research Center, Department of Food Sciences and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Pedro Henrique Bürgel
- Laboratory of Applied Immunology, Department of Cell Biology, Institute of Biological Sciences, University of Brasilia, Brasília, Distrito Federal, Brazil
| | - Sarah Sze Wah Wong
- Immunobiology of Aspergillus, Institut Pasteur, Université Paris Cité, Paris, France
| | - Vishukumar Aimanianda
- Immunobiology of Aspergillus, Institut Pasteur, Université Paris Cité, Paris, France
| | - Hugo Varet
- Plate-forme Technologique Biomics, Institut Pasteur, Université Paris Cité, Paris, France
| | - Ruchi Agrawal
- Translational Mycology Research Group, National Reference Center for Invasive Mycoses and Antifungals, Mycology Department, Institut Pasteur, Université Paris Cité, Paris, France
| | - Anamélia Lorenzetti Bocca
- Laboratory of Applied Immunology, Department of Cell Biology, Institute of Biological Sciences, University of Brasilia, Brasília, Distrito Federal, Brazil
| | - Alexandre Alanio
- Translational Mycology Research Group, National Reference Center for Invasive Mycoses and Antifungals, Mycology Department, Institut Pasteur, Université Paris Cité, Paris, France
- Laboratoire de parasitologie-mycologie, AP-HP, Hôpital Saint-Louis, Paris, France
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7
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Stuckey PV, Santiago-Tirado FH. Fungal mechanisms of intracellular survival: what can we learn from bacterial pathogens? Infect Immun 2023; 91:e0043422. [PMID: 37506189 PMCID: PMC10501222 DOI: 10.1128/iai.00434-22] [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: 11/28/2022] [Accepted: 06/23/2023] [Indexed: 07/30/2023] Open
Abstract
Fungal infections represent a major, albeit neglected, public health threat with serious medical and economic burdens globally. With unacceptably high mortality rates, invasive fungal pathogens are responsible for millions of deaths each year, with a steadily increasing incidence primarily in immunocompromised individuals. The poor therapeutic options and rise of antifungal drug resistance pose further challenges in controlling these infections. These fungal pathogens have adapted to survive within mammalian hosts and can establish intracellular niches to promote survival within host immune cells. To do that, they have developed diverse methods to circumvent the innate immune system attack. This includes strategies such as altering their morphology, counteracting macrophage antimicrobial action, and metabolic adaptation. This is reminiscent of how bacterial pathogens have adapted to survive within host cells and cause disease. However, relative to the great deal of information available concerning intracellular bacterial pathogenesis, less is known about the mechanisms fungal pathogens employ. Therefore, here we review our current knowledge and recent advances in our understanding of how fungi can evade and persist within host immune cells. This review will focus on the major fungal pathogens, including Cryptococcus neoformans, Candida albicans, and Aspergillus fumigatus, among others. As we discover and understand the strategies used by these fungi, similarities with their bacterial counterparts are becoming apparent, hence we can use the abundant information from bacteria to guide our studies in fungi. By understanding these strategies, new lines of research will open that can improve the treatments of these devastating fungal diseases.
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Affiliation(s)
- Peter V. Stuckey
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Felipe H. Santiago-Tirado
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
- Warren Center for Drug Discovery, University of Notre Dame, Notre Dame, Indiana, USA
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8
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Pham T, Li Y, Watford W, Lin X. Vaccination with a ZNF2oe Strain of Cryptococcus Provides Long-Lasting Protection against Cryptococcosis and Is Effective in Immunocompromised Hosts. Infect Immun 2023:e0019823. [PMID: 37338404 DOI: 10.1128/iai.00198-23] [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: 05/26/2023] [Accepted: 05/31/2023] [Indexed: 06/21/2023] Open
Abstract
Systemic cryptococcosis is fatal without treatment. Even with the current antifungal therapies, this disease kills 180,000 of 225,000 infected people annually. Exposure to the causative environmental fungus Cryptococcus neoformans is universal. Either reactivation of a latent infection or an acute infection after high exposure to cryptococcal cells can result in cryptococcosis. Currently, there is no vaccine to prevent cryptococcosis. Previously, we discovered that Znf2, a transcription factor that directs Cryptococcus yeast-to-hypha transition, profoundly affects cryptococcal interaction with the host. Overexpression of ZNF2 drives filamentous growth, attenuates cryptococcal virulence, and elicits protective host immune responses. Importantly, immunization with cryptococcal cells overexpressing ZNF2, in either live or heat-inactivated form, offers significant protection to the host from a subsequent challenge by the otherwise lethal clinical isolate H99. In this study, we found that the heat-inactivated ZNF2oe vaccine offered long-lasting protection with no relapse upon challenge with the wild-type H99. Vaccination with heat-inactivated ZNF2oe cells provides partial protection in hosts with preexisting asymptomatic cryptococcal infection. Importantly, once animals have been vaccinated with heat-inactivated or live short-lived ZNF2oe cells, they are protected against cryptococcosis even when their CD4+ T cells are depleted at the time of fungal challenge. Remarkably, vaccination with live, short-lived ZNF2oe cells in CD4-depleted hosts still provides strong protection to these hosts with preexisting immunodeficiency at the time of vaccination. This work raises hope for developing effective vaccines with long-lasting protection for individuals who are immunocompromised or could become immunocompromised later in life.
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Affiliation(s)
- Tuyetnhu Pham
- Department of Plant Biology, University of Georgia, Athens, Georgia, USA
| | - Yeqi Li
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Wendy Watford
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Xiaorong Lin
- Department of Plant Biology, University of Georgia, Athens, Georgia, USA
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
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9
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Hachey DM, Wood BR, Buitrago M, Burde A. Therapy for HIV-associated cryptococcal meningitis: a case report demonstrating a new treatment approach emphasizing updated treatment guidelines. DRUGS & THERAPY PERSPECTIVES 2023; 39:1-6. [PMID: 37361909 PMCID: PMC10258474 DOI: 10.1007/s40267-023-01001-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2023] [Indexed: 06/28/2023]
Abstract
Cryptococcal meningitis (CM) remains a significant global health burden, especially for persons living with HIV. Despite effective antiretroviral and antifungal therapy, mortality rates are still approximately 70% in low- and middle-income countries and 20-30% in high-income countries. Central nervous system symptoms range from mild to severe, depending on burden of disease, and prompt and appropriate therapy is critical to reducing mortality. Treatment consists of three phases: induction, consolidation, and maintenance. Although treatment regimens have largely remained unchanged for decades, recent clinical trials have led the World Health Organization to update guidelines to reflect best practices in resource-limited settings. We review the clinical presentation, diagnosis, and standard therapy for CM, present a case with a challenging diagnostic and treatment course complicated by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, and discuss the benefits of a new treatment dosing strategy highlighting potential advantages of adopting this novel dosing option in high-income countries.
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Affiliation(s)
- David M. Hachey
- Department of Family Medicine, Idaho State University, Pocatello, ID USA
| | - Brian R. Wood
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA USA
| | - Martha Buitrago
- Department of Family Medicine, Idaho State University, Pocatello, ID USA
| | - Anushka Burde
- Department of Pharmacy Practice and Administrative Sciences, College of Pharmacy, Idaho State University, Pocatello, ID USA
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10
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Yoon H, Wake RM, Nakouzi AS, Wang T, Agalliu I, Tiemessen CT, Govender NP, Jarvis JN, Harrison TS, Pirofski LA. Association of Antibody Immunity With Cryptococcal Antigenemia and Mortality in a South African Cohort With Advanced Human Immunodeficiency Virus Disease. Clin Infect Dis 2023; 76:649-657. [PMID: 35915964 PMCID: PMC10226730 DOI: 10.1093/cid/ciac633] [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: 05/31/2022] [Revised: 07/06/2022] [Accepted: 07/29/2022] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Asymptomatic cryptococcal antigenemia (positive blood cryptococcal antigen [CrAg]) is associated with increased mortality in individuals with human immunodeficiency virus (HIV) even after adjusting for CD4 count and despite receiving antifungal treatment. The association of antibody immunity with mortality in adults with HIV with cryptococcal antigenemia is unknown. METHODS Cryptococcal capsular glucuronoxylomannan (GXM)- and naturally occurring β-glucans (laminarin, curdlan)-binding antibodies were measured in blood samples of 197 South Africans with HIV who underwent CrAg screening and were followed up to 6 months. Associations between antibody titers, CrAg status, and all-cause mortality were sought using logistic and Cox regression, respectively. RESULTS Compared with CrAg-negative individuals (n = 130), CrAg-positive individuals (n = 67) had significantly higher IgG1 (median, 6672; interquartile range [IQR], 4696-10 414 vs 5343, 3808-7722 μg/mL; P = .007), IgG2 (1467, 813-2607 vs 1036, 519-2012 μg/mL; P = .01), and GXM-IgG (1:170, 61-412 vs 1:117, 47-176; P = .0009) and lower curdlan-IgG (1:47, 11-133 vs 1:93, 40-206; P = .01) titers. GXM-IgG was associated directly with cryptococcal antigenemia adjusted for CD4 count and antiretroviral therapy use (odds ratio, 1.64; 95% confidence interval [CI], 1.21 to 2.22). Among CrAg-positive individuals, GXM-IgG was inversely associated with mortality at 6 months adjusted for CD4 count and tuberculosis (hazard ratio, 0.50; 95% CI, .33 to .77). CONCLUSIONS The inverse association of GXM-IgG with mortality in CrAg-positive individuals suggests that GXM-IgG titer may have prognostic value in those individuals. Prospective longitudinal studies to investigate this hypothesis and identify mechanisms by which antibody may protect against mortality are warranted.
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Affiliation(s)
- Hyunah Yoon
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York, USA
| | - Rachel M Wake
- Institute for Infection and Immunity, St George’s University Hospital NHS Foundation Trust, London, United Kingdom
- Centre for Healthcare-Associated Infections, Antimicrobial Resistance and Mycoses, National Institute for Communicable Diseases, Division of the National Health Laboratory Service, Johannesburg, South Africa
- Clinical Academic Group in Infection and Immunity, St George’s University Hospital NHS Foundation Trust, London, United Kingdom
| | - Antonio S Nakouzi
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York, USA
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Tao Wang
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, USA
| | - Ilir Agalliu
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, USA
- Department of Urology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, USA
| | - Caroline T Tiemessen
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Centre for HIV & STIs, National Institute for Communicable Diseases, Division of the National Health Laboratory Service, Johannesburg, South Africa
| | - Nelesh P Govender
- Institute for Infection and Immunity, St George’s University Hospital NHS Foundation Trust, London, United Kingdom
- Centre for Healthcare-Associated Infections, Antimicrobial Resistance and Mycoses, National Institute for Communicable Diseases, Division of the National Health Laboratory Service, Johannesburg, South Africa
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- MRC Center for Medical Mycology, University of Exeter, Exeter, United Kingdom
- Division of Medical Microbiology, University of Cape Town, Cape Town, South Africa
| | - Joseph N Jarvis
- Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Botswana Harvard AIDS Institute Partnership, Botswana, Southern Africa
| | - Thomas S Harrison
- Institute for Infection and Immunity, St George’s University Hospital NHS Foundation Trust, London, United Kingdom
- Clinical Academic Group in Infection and Immunity, St George’s University Hospital NHS Foundation Trust, London, United Kingdom
- MRC Center for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Liise-anne Pirofski
- Division of Infectious Diseases, Department of Medicine, Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, New York, USA
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
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11
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Wake RM, Molloy SF, Jarvis JN, Harrison TS, Govender NP. Cryptococcal Antigenemia in Advanced Human Immunodeficiency Virus Disease: Pathophysiology, Epidemiology, and Clinical Implications. Clin Infect Dis 2023; 76:764-770. [PMID: 35986670 PMCID: PMC9938740 DOI: 10.1093/cid/ciac675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 08/11/2022] [Accepted: 08/17/2022] [Indexed: 11/14/2022] Open
Abstract
Cryptococcal antigen (CrAg) is detectable in blood prior to the onset of symptomatic cryptococcal meningitis (CM), a leading cause of death among people with advanced human immunodeficiency virus (HIV) disease globally. Highly sensitive assays can detect CrAg in blood, and screening people with HIV with low CD4 counts, followed by preemptive antifungal treatment, is recommended and widely implemented as part of a global strategy to prevent CM and end cryptococcal-related deaths. Cryptococcal antigenemia encompasses a spectrum of conditions from preclinical asymptomatic infection (cerebrospinal fluid [CSF] CrAg-negative) through subclinical (CSF CrAg-positive without overt meningism) to clinical symptomatic cryptococcal disease, usually manifesting as CM. In this review, we summarize current understanding of the pathophysiology, risk factors for, and clinical implications of cryptococcal antigenemia within this spectrum. We also provide an update on global prevalence, recommended screening and treatment strategies, and future considerations for improving outcomes among patients with cryptococcal antigenemia.
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Affiliation(s)
- Rachel M Wake
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
- Clinical Academic Group in Infection and Immunity, St George’s University Hospitals National Health Service Foundation Trust, London, United Kingdom
| | - Síle F Molloy
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Joseph N Jarvis
- Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Botswana Harvard AIDS Institute Partnership, Gaborone, Botswana
| | - Thomas S Harrison
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
- Clinical Academic Group in Infection and Immunity, St George’s University Hospitals National Health Service Foundation Trust, London, United Kingdom
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Nelesh P Govender
- Institute for Infection and Immunity, St George’s University of London, London, United Kingdom
- Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
- Division of the National Health Laboratory Service, Centre for Healthcare-Associated Infections, Antimicrobial Resistance and Mycoses, National Institute for Communicable Diseases, Johannesburg, South Africa
- Division of Medical Microbiology, University of Cape Town, Cape Town, South Africa
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12
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Martins-Santana L, Rezende CP, Rossi A, Martinez-Rossi NM, Almeida F. Addressing Microbial Resistance Worldwide: Challenges over Controlling Life-Threatening Fungal Infections. Pathogens 2023; 12:pathogens12020293. [PMID: 36839565 PMCID: PMC9961291 DOI: 10.3390/pathogens12020293] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 02/02/2023] [Accepted: 02/03/2023] [Indexed: 02/12/2023] Open
Abstract
Fungal infections are a serious global concern because of their ability to spread and colonize host tissues in immunocompromised individuals. Such infections have been frequently reported worldwide and are currently gaining clinical research relevance owing to their resistant character, representing a bottleneck in treating affected people. Resistant fungi are an emergent public health threat. The upsurge of such pathogens has led to new research toward unraveling the destructive potential evoked by these species. Some fungi-grouped into Candida, Aspergillus, and Cryptococcus-are causative agents of severe and systemic infections. They are associated with high mortality rates and have recently been described as sources of coinfection in COVID-hospitalized patients. Despite the efforts to elucidate the challenges of colonization, dissemination, and infection severity, the immunopathogenesis of fungal diseases remains a pivotal characteristic in fungal burden elimination. The struggle between the host immune system and the physiological strategies of the fungi to maintain cellular viability is complex. In this brief review, we highlight the relevance of drug resistance phenotypes in fungi of clinical significance, taking into consideration their physiopathology and how the scientific community could orchestrate their efforts to avoid fungal infection dissemination and deaths.
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Affiliation(s)
- Leonardo Martins-Santana
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14040-900, Brazil
| | - Caroline Patini Rezende
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14040-900, Brazil
| | - Antonio Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14040-900, Brazil
| | - Nilce Maria Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14040-900, Brazil
| | - Fausto Almeida
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14040-900, Brazil
- Correspondence:
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13
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Del Poeta M, Wormley FL, Lin X. Host populations, challenges, and commercialization of cryptococcal vaccines. PLoS Pathog 2023; 19:e1011115. [PMID: 36757929 PMCID: PMC9910758 DOI: 10.1371/journal.ppat.1011115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
Vaccines are one of the most effective public health tools to prevent and manage infectious diseases. Since the first clinical use of vaccines in the late 18th century, many vaccines have been successfully developed to combat bacterial and viral infections, including the most recent Coronavirus Disease 2019 (COVID-19) pandemic. However, there remains no vaccine that is clinically available to treat or prevent invasive fungal diseases, including cryptococcal meningoencephalitis. This fungal disease is uniformly fatal without treatment and has a global mortality rate of over 70%. Despite a dire need for an effective cryptococcal vaccine, there are many scientific and economic challenges to overcome prior to making it a reality. Here, we discuss some of these challenges as well as steps that the community is taking for commercialization of effective cryptococcal vaccines.
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Affiliation(s)
- Maurizio Del Poeta
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, New York, United States of America,Division of Infectious Diseases, Stony Brook University, Stony Brook, New York, United States of America,Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, New York, United States of America,Veteran Administration Medical Center, Northport, New York, United States of America,* E-mail: (MDP); (FLW); (XL)
| | - Floyd L. Wormley
- Department of Biology, Texas Christian University, Fort Worth, Texas, United States of America,* E-mail: (MDP); (FLW); (XL)
| | - Xiaorong Lin
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America,* E-mail: (MDP); (FLW); (XL)
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14
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Immunological correlates of protection following vaccination with glucan particles containing Cryptococcus neoformans chitin deacetylases. NPJ Vaccines 2023; 8:6. [PMID: 36732332 PMCID: PMC9892683 DOI: 10.1038/s41541-023-00606-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 01/23/2023] [Indexed: 02/04/2023] Open
Abstract
Vaccination with glucan particles (GP) containing the Cryptococcus neoformans chitin deacetylases Cda1 and Cda2 protect mice against experimental cryptococcosis. Here, immunological correlates of vaccine-mediated protection were explored. Studies comparing knockout and wild-type mice demonstrated CD4+ T cells are crucial, while B cells and CD8+ T cells are dispensable. Protection was abolished following CD4+ T cell depletion during either vaccination or infection but was retained if CD4+ T cells were only partially depleted. Vaccination elicited systemic and durable antigen-specific immune responses in peripheral blood mononuclear cells (PBMCs), spleens, and lungs. Following vaccination and fungal challenge, robust T-helper (Th) 1 and Th17 responses were observed in the lungs. Protection was abrogated in mice congenitally deficient in interferon (IFN) γ, IFNγ receptor, interleukin (IL)-1β, IL-6, or IL-23. Thus, CD4+ T cells and specific proinflammatory cytokines are required for GP-vaccine-mediated protection. Importantly, retention of protection in the setting of partial CD4+ T depletion suggests a pathway for vaccinating at-risk immunocompromised individuals.
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15
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Sato K, Kawakami K. Mouse Model of Latent Cryptococcal Infection and Reactivation. Methods Mol Biol 2023; 2667:87-98. [PMID: 37145277 DOI: 10.1007/978-1-0716-3199-7_6] [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: 05/06/2023]
Abstract
AbstractCryptococcus neoformans is an opportunistic fungal pathogen that frequently causes fatal meningoencephalitis in patients with impaired immune responses. This fungus, an intracellularly growing microbe, evades host immunity, leading to a latent infection (latent C. neoformans infection: LCNI), and cryptococcal disease is developed by its reactivation when host immunity is suppressed. Elucidation of the pathophysiology of LCNI is difficult due to the lack of mouse models. Here we show the established methods for LCNI and reactivation.
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Affiliation(s)
- Ko Sato
- Department of Medical Microbiology, Mycology and Immunology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
- Department of Intelligent Network for Infection Control, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
| | - Kazuyoshi Kawakami
- Department of Medical Microbiology, Mycology and Immunology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
- Department of Intelligent Network for Infection Control, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
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16
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Kassaza K, Wasswa F, Nielsen K, Bazira J. Cryptococcus neoformans Genotypic Diversity and Disease Outcome among HIV Patients in Africa. J Fungi (Basel) 2022; 8:jof8070734. [PMID: 35887489 PMCID: PMC9325144 DOI: 10.3390/jof8070734] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/24/2022] [Accepted: 07/06/2022] [Indexed: 11/16/2022] Open
Abstract
Cryptococcal meningoencephalitis, a disease with poor patient outcomes, remains the most prevalent invasive fungal infection worldwide, accounting for approximately 180,000 deaths each year. In several areas of sub-Saharan Africa with the highest HIV prevalence, cryptococcal meningitis is the leading cause of community-acquired meningitis, with a high mortality among HIV-infected individuals. Recent studies show that patient disease outcomes are impacted by the genetics of the infecting isolate. Yet, there is still limited knowledge of how these genotypic variations contribute to clinical disease outcome. Further, it is unclear how the genetic heterogeneity of C. neoformans and the extensive phenotypic variation observed between and within isolates affects infection and disease. In this review, we discuss current knowledge of how various genotypes impact disease progression and patient outcome in HIV-positive populations in sub-Saharan African, a setting with a high burden of cryptococcosis.
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Affiliation(s)
- Kennedy Kassaza
- Department of Microbiology and Parasitology, Mbarara University of Science and Technology, Mbarara P.O. Box 1410, Uganda; (K.K.); (F.W.)
| | - Fredrickson Wasswa
- Department of Microbiology and Parasitology, Mbarara University of Science and Technology, Mbarara P.O. Box 1410, Uganda; (K.K.); (F.W.)
| | - Kirsten Nielsen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN 55455, USA
- Correspondence: (K.N.); (J.B.)
| | - Joel Bazira
- Department of Microbiology and Parasitology, Mbarara University of Science and Technology, Mbarara P.O. Box 1410, Uganda; (K.K.); (F.W.)
- Correspondence: (K.N.); (J.B.)
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17
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Abstract
Cryptococcosis is a disease caused by the pathogenic fungi Cryptococcus neoformans and Cryptococcus gattii, both environmental fungi that cause severe pneumonia and may even lead to cryptococcal meningoencephalitis. Although C. neoformans affects more fragile individuals, such as immunocompromised hosts through opportunistic infections, C. gattii causes a serious indiscriminate primary infection in immunocompetent individuals. Typically seen in tropical and subtropical environments, C. gattii has increased its endemic area over recent years, largely due to climatic factors that favor contagion in warmer climates. It is important to point out that not only C. gattii, but the Cryptococcus species complex produces a polysaccharidic capsule with immunomodulatory properties, enabling the pathogenic species of Cryptococccus to subvert the host immune response during the establishment of cryptococcosis, facilitating its dissemination in the infected organism. C. gattii causes a more severe and difficult-to-treat infection, with few antifungals eliciting an effective response during chronic treatment. Much of the immunopathology of this cryptococcosis is still poorly understood, with most studies focusing on cryptococcosis caused by the species C. neoformans. C. gattii became more important in the epidemiological scenario with the outbreaks in the Pacific Northwest of the United States, which resulted in phylogenetic studies of the virulent variant responsible for the severe infection in the region. Since then, the study of cryptococcosis caused by C. gattii has helped researchers understand the immunopathological aspects of different variants of this pathogen.
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18
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Bionized Nanoferrite Particles Alter the Course of Experimental Cryptococcus neoformans Pneumonia. Antimicrob Agents Chemother 2022; 66:e0239921. [PMID: 35293784 PMCID: PMC9017294 DOI: 10.1128/aac.02399-21] [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: 01/09/2023] Open
Abstract
Cryptococcosis is a devastating fungal disease associated with high morbidity and mortality even when treated with antifungal drugs. Bionized nanoferrite (BNF) nanoparticles are powerful immunomodulators, but their efficacy for infectious diseases has not been investigated. Administration of BNF nanoparticles to mice with experimental cryptococcal pneumonia altered the outcome of infection in a dose response manner as measured by CFU and survival. The protective effects were higher at lower doses, with reductions in IL-2, IL-4, and TNF-α, consistent with immune modulation whereby reductions in inflammation translate into reduced host damage, clearance of infection, and longer survival.
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19
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Fungal Infections of Implantation: More Than Five Years of Cases of Subcutaneous Fungal Infections Seen at the UK Mycology Reference Laboratory. J Fungi (Basel) 2022; 8:jof8040343. [PMID: 35448574 PMCID: PMC9028115 DOI: 10.3390/jof8040343] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/22/2022] [Accepted: 03/24/2022] [Indexed: 01/20/2023] Open
Abstract
Subcutaneous fungal infections, which typically result from traumatic introduction (implantation) of fungal elements into the skin or underlying tissues, can present as a range of different clinical entities including phaeohyphomycosis, chromoblastomycosis, subcutaneous nodules or masses, and genuine eumycetoma. Here, we mined our laboratory information management system for such infections in humans and domestic animals for the period 2016–2022, including (i) fungal isolates referred for identification and/or susceptibility testing; (ii) infections diagnosed at our laboratory using panfungal PCR approaches on infected tissue; and (iii) organisms cultured in our laboratory from biopsies. In total, 106 cases were retrieved, involving 39 fungal species comprising 26 distinct genera. Subcutaneous infections with Alternaria species were the most frequent (36 cases), which possibly reflects the ubiquitous nature of this common plant pathogen. A substantial proportion of Alternaria spp. isolates exhibited reduced in vitro susceptibility to voriconazole. Notably, a significant number of subcutaneous infections were diagnosed in renal and other solid organ transplant recipients post transplantation, suggesting that humans may harbour “inert” subcutaneous fungal elements from historical minor injuries that present as clinical infections upon later immunosuppression. The current study underscores the diversity of fungi that can cause subcutaneous infections. While most organisms catalogued here were responsible for occasional infections, several genera (Alternaria, Exophiala, Phaeoacremonuim, Scedosporium) were more frequently recovered in our searches, suggesting that they possess virulence factors that facilitate subcutaneous infections and/or inhabit natural niches that make them more likely to be traumatically inoculated.
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20
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Ding M, Smith KD, Wiesner DL, Nielsen JN, Jackson KM, Nielsen K. Use of Clinical Isolates to Establish Criteria for a Mouse Model of Latent Cryptococcus neoformans Infection. Front Cell Infect Microbiol 2022; 11:804059. [PMID: 35186781 PMCID: PMC8847453 DOI: 10.3389/fcimb.2021.804059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 12/10/2021] [Indexed: 12/15/2022] Open
Abstract
The mechanisms of latency in the context of C. neoformans infection remain poorly understood. Two reasons for this gap in knowledge are: 1) the lack of standardized criteria for defining latent cryptococcosis in animal models and 2) limited genetic and immunological tools available for studying host parameters against C. neoformans in non-murine models of persistent infection. In this study, we defined criteria required for latency in C. neoformans infection models and used these criteria to develop a murine model of persistent C. neoformans infection using clinical isolates. We analyzed infections with two clinical C. neoformans strains, UgCl223 and UgCl552, isolated from advanced HIV patients with cryptococcal meningitis. Our data show that the majority of C57BL/6 mice infected with the clinical C. neoformans isolates had persistent, stable infections with low fungal burden, survived beyond 90 days-post infection, exhibited weight gain, had no clinical signs of disease, and had yeast cells contained within pulmonary granulomas with no generalized alveolar inflammation. Infected mice exhibited stable relative frequencies of pulmonary immune cells during the course of the infection. Upon CD4+ T-cell depletion, the CD4DTR mice had significantly increased lung and brain fungal burden that resulted in lethal infection, indicating that CD4+ T-cells are important for control of the pulmonary infection and to prevent dissemination. Cells expressing the Tbet transcription factor were the predominant activated CD4 T-cell subset in the lungs during the latent infection. These Tbet-expressing T-cells had decreased IFNγ production, which may have implications in the capacity of the cells to orchestrate the pulmonary immune response. Altogether, these results indicate that clinical C. neoformans isolates can establish a persistent controlled infection that meets most criteria for latency; highlighting the utility of this new mouse model system for studies of host immune responses that control C. neoformans infections.
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Affiliation(s)
- Minna Ding
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, United States
| | - Kyle D. Smith
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, United States
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN, United States
| | - Darin L. Wiesner
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, United States
- Department of Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, NJ, United States
| | - Judith N. Nielsen
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC, United States
| | - Katrina M. Jackson
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, United States
| | - Kirsten Nielsen
- Department of Microbiology and Immunology, University of Minnesota Medical School, Minneapolis, MN, United States
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21
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Mohamed SH, Nyazika TK, Ssebambulidde K, Lionakis MS, Meya DB, Drummond RA. Fungal CNS Infections in Africa: The Neuroimmunology of Cryptococcal Meningitis. Front Immunol 2022; 13:804674. [PMID: 35432326 PMCID: PMC9010970 DOI: 10.3389/fimmu.2022.804674] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 03/03/2022] [Indexed: 01/13/2023] Open
Abstract
Cryptococcal meningitis (CM) is the leading cause of central nervous system (CNS) fungal infections in humans, with the majority of cases reported from the African continent. This is partly due to the high burden of HIV infection in the region and reduced access to standard-of-care including optimal sterilising antifungal drug treatments. As such, CM is responsible for 10-15% of all HIV-related mortality, with a large proportion being preventable. Immunity to the causative agent of CM, Cryptococcus neoformans, is only partially understood. IFNγ producing CD4+ T-cells are required for the activation of myeloid cells, especially macrophages, to enable fungal killing and clearance. However, macrophages may also act as a reservoir of the fungal yeast cells, shielding them from host immune detection thus promoting latent infection or persistent chronic inflammation. In this chapter, we review the epidemiology and pathogenesis of CNS fungal infections in Africa, with a major focus on CM, and the antifungal immune pathways operating to protect against C. neoformans infection. We also highlight the areas of research and policy that require prioritisation to help reduce the burden of CNS fungal diseases in Africa.
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Affiliation(s)
- Sally H Mohamed
- Institute of Immunology & Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Tinashe K Nyazika
- Department of Clinical Science, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Kenneth Ssebambulidde
- College of Health Sciences, Infectious Diseases Institute, Makerere University, Kampala, Uganda
| | - Michail S Lionakis
- Fungal Pathogenesis Section, Laboratory of Clinical Immunology & Microbiology, National Institute of Allergy & Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - David B Meya
- College of Health Sciences, Infectious Diseases Institute, Makerere University, Kampala, Uganda
| | - Rebecca A Drummond
- Institute of Immunology & Immunotherapy, University of Birmingham, Birmingham, United Kingdom.,Institute of Microbiology & Infection, University of Birmingham, Birmingham, United Kingdom
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22
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Striking Back against Fungal Infections: The Utilization of Nanosystems for Antifungal Strategies. Int J Mol Sci 2021; 22:ijms221810104. [PMID: 34576268 PMCID: PMC8466259 DOI: 10.3390/ijms221810104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/13/2021] [Accepted: 09/15/2021] [Indexed: 12/19/2022] Open
Abstract
Fungal infections have become a major health concern, given that invasive infections by Candida, Cryptococcus, and Aspergillus species have led to millions of mortalities. Conventional antifungal drugs including polyenes, echinocandins, azoles, allylamins, and antimetabolites have been used for decades, but their limitations include off-target toxicity, drug-resistance, poor water solubility, low bioavailability, and weak tissue penetration, which cannot be ignored. These drawbacks have led to the emergence of novel antifungal therapies. In this review, we discuss the nanosystems that are currently utilized for drug delivery and the application of antifungal therapies.
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23
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Accounting for the Biological Complexity of Pathogenic Fungi in Phylogenetic Dating. J Fungi (Basel) 2021; 7:jof7080661. [PMID: 34436200 PMCID: PMC8400180 DOI: 10.3390/jof7080661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 08/11/2021] [Accepted: 08/11/2021] [Indexed: 11/17/2022] Open
Abstract
In the study of pathogen evolution, temporal dating of phylogenies provides information on when species and lineages may have diverged in the past. When combined with spatial and epidemiological data in phylodynamic models, these dated phylogenies can also help infer where and when outbreaks occurred, how pathogens may have spread to new geographic locations and/or niches, and how virulence or drug resistance has developed over time. Although widely applied to viruses and, increasingly, to bacterial pathogen outbreaks, phylogenetic dating is yet to be widely used in the study of pathogenic fungi. Fungi are complex organisms with several biological processes that could present issues with appropriate inference of phylogenies, clock rates, and divergence times, including high levels of recombination and slower mutation rates although with potentially high levels of mutation rate variation. Here, we discuss some of the key methodological challenges in accurate phylogeny reconstruction for fungi in the context of the temporal analyses conducted to date and make recommendations for future dating studies to aid development of a best practices roadmap in light of the increasing threat of fungal outbreaks and antifungal drug resistance worldwide.
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24
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Gressler AE, Volke D, Firacative C, Schnabel CL, Müller U, Krizsan A, Schulze-Richter B, Brock M, Brombacher F, Escandón P, Hoffmann R, Alber G. Identification of Disease-Associated Cryptococcal Proteins Reactive With Serum IgG From Cryptococcal Meningitis Patients. Front Immunol 2021; 12:709695. [PMID: 34367172 PMCID: PMC8342929 DOI: 10.3389/fimmu.2021.709695] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 06/21/2021] [Indexed: 01/16/2023] Open
Abstract
Cryptococcus neoformans, an opportunistic fungal pathogen ubiquitously present in the environment, causes cryptococcal meningitis (CM) mainly in immunocompromised patients, such as AIDS patients. We aimed to identify disease-associated cryptococcal protein antigens targeted by the human humoral immune response. Therefore, we used sera from Colombian CM patients, with or without HIV infection, and from healthy individuals living in the same region. Serological analysis revealed increased titers of anti-cryptococcal IgG in HIV-negative CM patients, but not HIV-positive CM patients, compared to healthy controls. In contrast, titers of anti-cryptococcal IgM were not affected by CM. Furthermore, we detected pre-existing IgG and IgM antibodies even in sera from healthy individuals. The observed induction of anti-cryptococcal IgG but not IgM during CM was supported by analysis of sera from C. neoformans-infected mice. Stronger increase in IgG was found in wild type mice with high lung fungal burden compared to IL-4Rα-deficient mice showing low lung fungal burden. To identify the proteins targeted by human anti-cryptococcal IgG antibodies, we applied a quantitative 2D immunoproteome approach identifying cryptococcal protein spots preferentially recognized by sera from CM patients or healthy individuals followed by mass spectrometry analysis. Twenty-three cryptococcal proteins were recombinantly expressed and confirmed to be immunoreactive with human sera. Fourteen of them were newly described as immunoreactive proteins. Twelve proteins were classified as disease-associated antigens, based on significantly stronger immunoreactivity with sera from CM patients compared to healthy individuals. The proteins identified in our screen significantly expand the pool of cryptococcal proteins with potential for (i) development of novel anti-cryptococcal agents based on implications in cryptococcal virulence or survival, or (ii) development of an anti-cryptococcal vaccine, as several candidates lack homology to human proteins and are localized extracellularly. Furthermore, this study defines pre-existing anti-cryptococcal immunoreactivity in healthy individuals at a molecular level, identifying target antigens recognized by sera from healthy control persons.
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Affiliation(s)
- A Elisabeth Gressler
- Institute of Immunology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Daniela Volke
- Institute of Bioanalytical Chemistry, Leipzig University, Leipzig, Germany
| | - Carolina Firacative
- Studies in Translational Microbiology and Emerging Diseases (MICROS) Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Bogota, Colombia
| | - Christiane L Schnabel
- Institute of Immunology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Uwe Müller
- Institute of Immunology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Andor Krizsan
- Institute of Bioanalytical Chemistry, Leipzig University, Leipzig, Germany
| | - Bianca Schulze-Richter
- Institute of Immunology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Matthias Brock
- Fungal Genetics and Biology Group, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Frank Brombacher
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town Component, Cape Town, South Africa
| | | | - Ralf Hoffmann
- Institute of Bioanalytical Chemistry, Leipzig University, Leipzig, Germany
| | - Gottfried Alber
- Institute of Immunology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
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25
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Rezende CP, Brito PKMO, Da Silva TA, Pessoni AM, Ramalho LNZ, Almeida F. Influence of Galectin-3 on the Innate Immune Response during Experimental Cryptococcosis. J Fungi (Basel) 2021; 7:jof7060492. [PMID: 34203011 PMCID: PMC8234158 DOI: 10.3390/jof7060492] [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: 05/11/2021] [Revised: 06/11/2021] [Accepted: 06/16/2021] [Indexed: 11/16/2022] Open
Abstract
Cryptococcus neoformans, the causative agent of cryptococcosis, is the primary fungal pathogen that affects the immunocompromised individuals. Galectin-3 (Gal-3) is an animal lectin involved in both innate and adaptive immune responses. The present study aimed to evaluate the influence of Gal-3 on the C. neoformans infection. We performed histopathological and gene profile analysis of the innate antifungal immunity markers in the lungs, spleen, and brain of the wild-type (WT) and Gal-3 knockout (KO) mice during cryptococcosis. These findings suggest that Gal-3 absence does not cause significant histopathological alterations in the analyzed tissues. The expression profile of the genes related to innate antifungal immunity showed that the presence of cryptococcosis in the WT and Gal-3 KO animals, compared to their respective controls, promoted the upregulation of the pattern recognition receptor (PRR) responsive to mannose/chitin (mrc1) and a gene involved in inflammation (ccr5), as well as the downregulation of the genes related to signal transduction (card9, fos, ikbkb, jun) and PRRs (cd209a, colec12, nptx1). The absence of Gal-3, in fungal infection, a positively modulated gene involved in phagocytosis (sftpd) and negatively genes involved in signal transduction (syk and myd88), proinflammatory cytokines il-1β and il-12b and cd209a receptor. Therefore, our results suggest that Gal-3 may play an essential role in the development of antifungal immune responses against cryptococcosis.
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Affiliation(s)
- Caroline Patini Rezende
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil; (C.P.R.); (A.M.P.)
| | - Patricia Kellen Martins Oliveira Brito
- Department of Cellular and Molecular Biology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil; (P.K.M.O.B.); (T.A.D.S.)
| | - Thiago Aparecido Da Silva
- Department of Cellular and Molecular Biology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil; (P.K.M.O.B.); (T.A.D.S.)
| | - Andre Moreira Pessoni
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil; (C.P.R.); (A.M.P.)
| | | | - Fausto Almeida
- Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, SP, Brazil; (C.P.R.); (A.M.P.)
- Correspondence:
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26
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Maufrais C, de Oliveira L, Bastos RW, Moyrand F, Reis FCG, Valero C, Gimenez B, Josefowicz LJ, Goldman GH, Rodrigues ML, Janbon G. Population genomic analysis of Cryptococcus Brazilian isolates reveals an African type subclade distribution. G3 (BETHESDA, MD.) 2021; 11:jkab107. [PMID: 33822048 PMCID: PMC8495746 DOI: 10.1093/g3journal/jkab107] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/29/2021] [Indexed: 12/22/2022]
Abstract
The genomes of a large number of Cryptococcus neoformans isolates have been sequenced and analyzed in recent years. These genomes have been used to understand the global population structure of this opportunistic pathogen. However, only a small number of South American isolates have been considered in these studies, and the population structure of C. neoformans in this part of the world remains elusive. Here, we analyzed the genomic sequences of 53 Brazilian Cryptococcus isolates and deciphered the C. neoformans population structure in this country. Our data reveal an African-like structure that suggested repeated intercontinental transports from Africa to South America. We also identified a mutator phenotype in one VNBII Brazilian isolate, exemplifying how fast-evolving isolates can shape the Cryptococcus population structure. Finally, phenotypic analyses revealed wide diversity but not lineage specificity in the expression of classical virulence traits within the set of isolates.
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Affiliation(s)
- Corinne Maufrais
- Unité Biologie des ARN des Pathogènes Fongiques, Département de Mycologie, Institut Pasteur, F-75015 Paris, France
- Institut Pasteur, HUB Bioinformatique et Biostatistique, C3BI, USR 3756 IP CNRS, F-75015 Paris, France
| | - Luciana de Oliveira
- Unité Biologie des ARN des Pathogènes Fongiques, Département de Mycologie, Institut Pasteur, F-75015 Paris, France
| | - Rafael W Bastos
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903 Ribeirão Preto, Brazil
| | - Frédérique Moyrand
- Unité Biologie des ARN des Pathogènes Fongiques, Département de Mycologie, Institut Pasteur, F-75015 Paris, France
| | - Flavia C G Reis
- Instituto Carlos Chagas, Fundação Oswaldo Cruz (FIOCRUZ), 81310-020 Curitiba, Brazil
- Centro de Desenvolvimento Tecnologico em Saude (CDTS-Fiocruz), 21040-361 Rio de Janeiro, Brazil
| | - Clara Valero
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903 Ribeirão Preto, Brazil
| | - Bianca Gimenez
- Instituto Carlos Chagas, Fundação Oswaldo Cruz (FIOCRUZ), 81310-020 Curitiba, Brazil
| | - Luisa J Josefowicz
- Instituto Carlos Chagas, Fundação Oswaldo Cruz (FIOCRUZ), 81310-020 Curitiba, Brazil
| | - Gustavo H Goldman
- Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, 14040-903 Ribeirão Preto, Brazil
| | - Marcio L Rodrigues
- Instituto Carlos Chagas, Fundação Oswaldo Cruz (FIOCRUZ), 81310-020 Curitiba, Brazil
- Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro, 21941-902 Rio de Janeiro, Brazil
| | - Guilhem Janbon
- Unité Biologie des ARN des Pathogènes Fongiques, Département de Mycologie, Institut Pasteur, F-75015 Paris, France
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The interplay of phenotype and genotype in Cryptococcus neoformans disease. Biosci Rep 2021; 40:226594. [PMID: 33021310 PMCID: PMC7569153 DOI: 10.1042/bsr20190337] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 09/23/2020] [Accepted: 10/06/2020] [Indexed: 12/17/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen that causes life-threatening meningitis primarily in immunocompromised individuals. In order to survive and proliferate during infection, C. neoformans must adapt to a variety of stresses it encounters within the host. Patient outcome depends on the interaction between the pathogen and the host. Understanding the mechanisms that C. neoformans uses to facilitate adaptation to the host and promote pathogenesis is necessary to better predict disease severity and establish proper treatment. Several virulence phenotypes have been characterized in C. neoformans, but the field still lacks a complete understanding of how genotype and phenotype contribute to clinical outcome. Furthermore, while it is known that C. neoformans genotype impacts patient outcome, the mechanisms remain unknown. This lack of understanding may be due to the genetic heterogeneity of C. neoformans and the extensive phenotypic variation observed between and within isolates during infection. In this review, we summarize the current understanding of how the various genotypes and phenotypes observed in C. neoformans correlate with human disease progression in the context of patient outcome and recurrence. We also postulate the mechanisms underlying the genetic and phenotypic changes that occur in vivo to promote rapid adaptation in the host.
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Associations between Cryptococcus Genotypes, Phenotypes, and Clinical Parameters of Human Disease: A Review. J Fungi (Basel) 2021; 7:jof7040260. [PMID: 33808500 PMCID: PMC8067209 DOI: 10.3390/jof7040260] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 03/25/2021] [Accepted: 03/25/2021] [Indexed: 12/11/2022] Open
Abstract
The genus Cryptococcus contains two primary species complexes that are significant opportunistic human fungal pathogens: C. neoformans and C. gattii. In humans, cryptococcosis can manifest in many ways, but most often results in either pulmonary or central nervous system disease. Patients with cryptococcosis can display a variety of symptoms on a spectrum of severity because of the interaction between yeast and host. The bulk of our knowledge regarding Cryptococcus and the mechanisms of disease stem from in vitro experiments and in vivo animal models that make a fair attempt, but do not recapitulate the conditions inside the human host. To better understand the dynamics of initiation and progression in cryptococcal disease, it is important to study the genetic and phenotypic differences in the context of human infection to identify the human and fungal risk factors that contribute to pathogenesis and poor clinical outcomes. In this review, we summarize the current understanding of the different clinical presentations and health outcomes that are associated with pathogenicity and virulence of cryptococcal strains with respect to specific genotypes and phenotypes.
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Abstract
Although we have recognized cryptococcosis as a disease entity for well over 100 years, there are many details about its pathogenesis which remain unknown. A major barrier to better understanding is the very broad range of clinical and pathological forms cryptococcal infections can take. One such form has been historically called the cryptococcal granuloma, or the cryptococcoma. These words have been used to describe essentially any mass lesion associated with infection, due to their presumed similarity to the quintessential granuloma, the tubercle in tuberculosis. Although clear distinctions between tuberculosis and cryptococcal disease have been discovered, cellular and molecular studies still confirm some important parallels between these 2 diseases and what we now call granulomatous inflammation. In this review, we shall sketch out some of the history behind the term “granuloma” as it pertains to cryptococcal disease, explore our current understanding of the biology of granuloma formation, and try to place that understanding in the context of the myriad pathological presentations of this infection. Finally, we shall summarize the role of the granuloma in cryptococcal latency and present opportunities for future investigations.
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Affiliation(s)
- Laura C. Ristow
- Stead Family Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - J. Muse Davis
- Stead Family Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- * E-mail:
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The Transcription Factor Pdr802 Regulates Titan Cell Formation and Pathogenicity of Cryptococcus neoformans. mBio 2021; 12:mBio.03457-20. [PMID: 33688010 PMCID: PMC8092302 DOI: 10.1128/mbio.03457-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The pathogenic yeast Cryptococcus neoformans presents a worldwide threat to human health, especially in the context of immunocompromise, and current antifungal therapy is hindered by cost, limited availability, and inadequate efficacy. After the infectious particle is inhaled, C. neoformans initiates a complex transcriptional program that integrates cellular responses and enables adaptation to the host lung environment. Cryptococcus neoformans is a ubiquitous, opportunistic fungal pathogen that kills almost 200,000 people worldwide each year. It is acquired when mammalian hosts inhale the infectious propagules; these are deposited in the lung and, in the context of immunocompromise, may disseminate to the brain and cause lethal meningoencephalitis. Once inside the host, C. neoformans undergoes a variety of adaptive processes, including secretion of virulence factors, expansion of a polysaccharide capsule that impedes phagocytosis, and the production of giant (Titan) cells. The transcription factor Pdr802 is one regulator of these responses to the host environment. Expression of the corresponding gene is highly induced under host-like conditions in vitro and is critical for C. neoformans dissemination and virulence in a mouse model of infection. Direct targets of Pdr802 include the quorum sensing proteins Pqp1, Opt1, and Liv3; the transcription factors Stb4, Zfc3, and Bzp4, which regulate cryptococcal brain infectivity and capsule thickness; the calcineurin targets Had1 and Crz1, important for cell wall remodeling and C. neoformans virulence; and additional genes related to resistance to host temperature and oxidative stress, and to urease activity. Notably, cryptococci engineered to lack Pdr802 showed a dramatic increase in Titan cells, which are not phagocytosed and have diminished ability to directly cross biological barriers. This explains the limited dissemination of pdr802 mutant cells to the central nervous system and the consequently reduced virulence of this strain. The role of Pdr802 as a negative regulator of Titan cell formation is thus critical for cryptococcal pathogenicity.
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31
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Farrer RA, Borman AM, Inkster T, Fisher MC, Johnson EM, Cuomo CA. Genomic epidemiology of a Cryptococcus neoformans case cluster in Glasgow, Scotland, 2018. Microb Genom 2021; 7:mgen000537. [PMID: 33620303 PMCID: PMC8190611 DOI: 10.1099/mgen.0.000537] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/01/2021] [Indexed: 12/16/2022] Open
Abstract
In 2018, a cluster of two cases of cryptococcosis occurred at the Queen Elizabeth University Hospital (QEUH) in Glasgow, Scotland (UK). It was postulated that these cases may have been linked to pigeon droppings found on the hospital site, given there have been previous reports of Cryptococcus neoformans associated with pigeon guano. Although some samples of pigeon guano taken from the site yielded culturable yeast from genera related to Cryptococcus, they have since been classified as Naganishia or Papiliotrema spp., and no isolates of C. neoformans were recovered from either the guano or subsequent widespread air sampling. In an attempt to further elucidate any possible shared source of the clinical isolates, we used whole-genome sequencing and phylogenetic analysis to examine the relationship of the two Cryptococcus isolates from the QEUH cases, along with two isolates from sporadic cases treated at a different Glasgow hospital earlier in 2018. Our work demonstrated that these four clinical isolates were not clonally related; while all isolates were from the VNI global lineage and of the same mating type (MATα), the genotypes of the two QEUH isolates were separated by 1885 base changes and belonged to different sub-lineages, recently described as the intercontinental sub-clades VNIa-93 and VNIa-5. In contrast, one of the two sporadic 2018 clinical isolates was determined to belong to the VNIb sub-lineage and the other classified as a VNIV/VNI hybrid. Our work demonstrated that the two 2018 QEUH isolates and the two prior C. neoformans clinical isolates were all genetically distinct. It was not possible to determine whether the QEUH genotypes stemmed from independent sources or from the same source, i.e. pigeons carrying different genotypes, but it should be noted that whilst members of allied genera within the Tremellomycetes were isolated from the hospital environment, there were no environmental isolations of C. neoformans.
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Affiliation(s)
- Rhys A. Farrer
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter EX4 4PY, UK
| | - Andrew M. Borman
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter EX4 4PY, UK
- Public Health England National Mycology Reference Laboratory, Science Quarter, Southmead Hospital, Bristol BS10 5NB, UK
| | - Teresa Inkster
- Department of Microbiology, Queen Elizabeth University Hospital, Glasgow, UK
| | - Matthew C. Fisher
- Medical Research Council Centre for Global Infectious Disease Analysis, Imperial College London, London, UK
| | - Elizabeth M. Johnson
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter EX4 4PY, UK
- Public Health England National Mycology Reference Laboratory, Science Quarter, Southmead Hospital, Bristol BS10 5NB, UK
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32
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Alanio A. Dormancy in Cryptococcus neoformans: 60 years of accumulating evidence. J Clin Invest 2021; 130:3353-3360. [PMID: 32484459 DOI: 10.1172/jci136223] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic yeast that is present worldwide and interacts with various organisms. In humans, it is responsible for cryptococcosis, a deadly invasive fungal infection that represents around 220,000 cases per year worldwide. Starting from the natural history of the disease in humans, there is accumulating evidence on the capacity of this organism to enter dormancy. In response to the harsh host environment, the yeast is able to adapt dramatically and escape the vigilance of the host's immune cells to survive. Indeed, the yeast exposed to the host takes on pleiotropic phenotypes, enabling the generation of populations in heterogeneous states, including dormancy, to eventually survive at low metabolic cost and revive in favorable conditions. The concept of dormancy has been validated in C. neoformans from both epidemiological and genotyping data, and more recently from the biological point of view with the characterization of dormancy through the description of viable but nonculturable cells.
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Affiliation(s)
- Alexandre Alanio
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.,Molecular Mycology Unit, CNRS UMR 2000, National Reference Center for Invasive Mycoses and Antifungals (NRCMA), Institut Pasteur, Paris, France.,Université de Paris, Paris, France
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33
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Berry SB, Haack AJ, Theberge AB, Brighenti S, Svensson M. Host and Pathogen Communication in the Respiratory Tract: Mechanisms and Models of a Complex Signaling Microenvironment. Front Med (Lausanne) 2020; 7:537. [PMID: 33015094 PMCID: PMC7511576 DOI: 10.3389/fmed.2020.00537] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 07/29/2020] [Indexed: 01/15/2023] Open
Abstract
Chronic lung diseases are a leading cause of morbidity and mortality across the globe, encompassing a diverse range of conditions from infections with pathogenic microorganisms to underlying genetic disorders. The respiratory tract represents an active interface with the external environment having the primary immune function of resisting pathogen intrusion and maintaining homeostasis in response to the myriad of stimuli encountered within its microenvironment. To perform these vital functions and prevent lung disorders, a chemical and biological cross-talk occurs in the complex milieu of the lung that mediates and regulates the numerous cellular processes contributing to lung health. In this review, we will focus on the role of cross-talk in chronic lung infections, and discuss how different cell types and signaling pathways contribute to the chronicity of infection(s) and prevent effective immune clearance of pathogens. In the lung microenvironment, pathogens have developed the capacity to evade mucosal immunity using different mechanisms or virulence factors, leading to colonization and infection of the host; such mechanisms include the release of soluble and volatile factors, as well as contact dependent (juxtracrine) interactions. We explore the diverse modes of communication between the host and pathogen in the lung tissue milieu in the context of chronic lung infections. Lastly, we review current methods and approaches used to model and study these host-pathogen interactions in vitro, and the role of these technological platforms in advancing our knowledge about chronic lung diseases.
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Affiliation(s)
- Samuel B Berry
- Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.,Department of Chemistry, University of Washington, Seattle, WA, United States
| | - Amanda J Haack
- Department of Chemistry, University of Washington, Seattle, WA, United States
| | - Ashleigh B Theberge
- Department of Chemistry, University of Washington, Seattle, WA, United States
| | - Susanna Brighenti
- Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Mattias Svensson
- Department of Medicine, Center for Infectious Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
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34
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Garcia-Hermoso D, Hamane S, Fekkar A, Jabet A, Denis B, Siguier M, Galeazzi G, Haddad E, Brun S, Vidal V, Nevez G, Le Berre R, Gits-Muselli M, Lanternier F, Bretagne S. Invasive Infections with Nannizziopsis obscura Species Complex in 9 Patients from West Africa, France, 2004-2020 1. Emerg Infect Dis 2020; 26. [PMID: 32819454 PMCID: PMC7454062 DOI: 10.3201/eid2609.200276] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Nine new human invasive infections caused by the keratinophilic fungi Nannizziopsis obscura have been reported in France since 2004. The patients had variable clinical manifestations, had frequent dissemination, were mainly T-cell immunocompromised, and all originated from sub-Saharan West Africa. Before collection of the isolates, the etiologies of these infections were often misidentified, underscoring the extent of microscopic and cultural polymorphisms. All isolates but 1 had low MICs for the 8 antifungal drugs tested. When treated, patients received mainly azole therapy. Two of 7 patients with a known outcome died. We performed multilocus sequence analysis of N. obscura clinical strains and several strains of Nannizziopsis spp. isolated from reptiles. The human strains were clearly differentiated from the animal strains. N. obscura might be endemic to West Africa and responsible for undetected infections, which might become reactivated when immunosuppression occurs. N. obscura infection is probably underestimated because only sequencing enables proper identification.
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Okurut S, Boulware DR, Olobo J, Meya DB. Landmark clinical observations and immunopathogenesis pathways linked to HIV and Cryptococcus fatal central nervous system co-infection. Mycoses 2020; 63:840-853. [PMID: 32472727 PMCID: PMC7416908 DOI: 10.1111/myc.13122] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 12/13/2022]
Abstract
Cryptococcal meningitis remains one of the leading causes of death among HIV-infected adults in the fourth decade of HIV era in sub-Saharan Africa, contributing to 10%-20% of global HIV-related deaths. Despite widespread use and early induction of ART among HIV-infected adults, incidence of cryptococcosis remains significant in those with advanced HIV disease. Cryptococcus species that causes fatal infection follows systemic spread from initial environmental acquired infection in lungs to antigenaemia and fungaemia in circulation prior to establishment of often fatal disease, cryptococcal meningitis in the CNS. Cryptococcus person-to-person transmission is uncommon, and deaths related to blood infection without CNS involvement are rare. Keen to the persistent high mortality associated with HIV-cryptococcal meningitis, seizures are common among a third of the patients, altered mental status is frequent, anaemia is prevalent with ensuing brain hypoxia and at autopsy, brain fibrosis and infarction are evident. In addition, fungal burden is 3-to-4-fold higher in those with seizures. And high immune activation together with exacerbated inflammation and elevated PD-1/PD-L immune checkpoint expression is immunomodulated phenotypes elevated in CSF relative to blood. Lastly, though multiple Cryptococcus species cause disease in this setting, observations are mostly generalised to cryptococcal infection/meningitis or regional dominant species (C neoformans or gattii complex) that may limit our understanding of interspecies differences in infection, progression, treatment or recovery outcome. Together, these factors and underlying mechanisms are hypotheses generating for research to find targets to prevent infection or adequate therapy to prevent persistent high mortality with current optimal therapy.
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Affiliation(s)
- Samuel Okurut
- Research DepartmentInfectious Diseases InstituteMakerere UniversityKampalaUganda
- Department of MicrobiologySchool of Biomedical SciencesCollege of Health SciencesMakerere UniversityKampalaUganda
| | - David R. Boulware
- Division of Infectious Diseases and International MedicineDepartment of MedicineUniversity of MinnesotaMinneapolisMinnesota
| | - Joseph Olobo
- Department of Immunology and Molecular BiologySchool of Biomedical SciencesCollege of Health SciencesMakerere UniversityKampalaUganda
| | - David B. Meya
- Research DepartmentInfectious Diseases InstituteMakerere UniversityKampalaUganda
- Division of Infectious Diseases and International MedicineDepartment of MedicineUniversity of MinnesotaMinneapolisMinnesota
- Department of MedicineSchool of MedicineCollege of Health SciencesMakerere UniversityKampalaUganda
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36
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Greene G, Lawrence DS, Jordan A, Chiller T, Jarvis JN. Cryptococcal meningitis: a review of cryptococcal antigen screening programs in Africa. Expert Rev Anti Infect Ther 2020; 19:233-244. [PMID: 32567406 DOI: 10.1080/14787210.2020.1785871] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
INTRODUCTION Cryptococcal meningitis remains a significant contributor to AIDS-related mortality despite widened access to antiretroviral therapy. Cryptococcal antigen (CrAg) can be detected in the blood prior to development of meningitis. Development of highly sensitive and specific rapid diagnostic CrAg tests has helped facilitate the adoption of CrAg screening programs in 19 African countries. AREAS COVERED The biological rationale for CrAg screening and the programmatic strategies for its implementation are reviewed. We describe the approach to the investigation of patients with cryptococcal antigenemia and the importance of lumbar puncture to identify individuals who may have cryptococcal meningitis in the absence of symptoms. The limitations of current treatment recommendations and the potential role of newly defined combination antifungal therapies are discussed. A literature review was conducted using a broad database search for cryptococcal antigen screening and related terms in published journal articles dating up to December 2019. Conference abstracts, publicly available guidelines, and project descriptions were also incorporated. EXPERT OPINION As we learn more about the risks of cryptococcal antigenemia, it has become clear that the current management paradigm is inadequate. More intensive investigation and management are required to prevent the development of cryptococcal meningitis and reduce mortality associated with cryptococcal antigenemia.
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Affiliation(s)
- Greg Greene
- Centre for Healthcare-Associated Infections, Antimicrobial Resistance and Mycoses, National Institute for Communicable Diseases, a Division of the NHLS , Johannesburg, South Africa.,Department of Clinical Research, Faculty of Infectious & Tropical Diseases, London School of Hygiene and Tropical Medicine , London, UK
| | - David S Lawrence
- Department of Clinical Research, Faculty of Infectious & Tropical Diseases, London School of Hygiene and Tropical Medicine , London, UK.,Botswana Harvard AIDS Institute Partnership , Gaborone, Botswana
| | - Alex Jordan
- Mycotic Diseases Branch, Centers for Disease Control and Prevention , Atlanta, USA
| | - Tom Chiller
- Mycotic Diseases Branch, Centers for Disease Control and Prevention , Atlanta, USA
| | - Joseph N Jarvis
- Department of Clinical Research, Faculty of Infectious & Tropical Diseases, London School of Hygiene and Tropical Medicine , London, UK.,Botswana Harvard AIDS Institute Partnership , Gaborone, Botswana
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37
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Mann S, Tobolowsky F, Purohit S, Henao-Martínez A, Bajrovic V, Ramanan P, Wolfel E, Khazanie P, Barron M, Madinger N, Benamu E. Cryptococcal pericarditis in a heart transplant recipient. Transpl Infect Dis 2020; 22:e13366. [PMID: 32533755 DOI: 10.1111/tid.13366] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/17/2020] [Accepted: 05/27/2020] [Indexed: 12/27/2022]
Abstract
We present a case of Cryptococcus neoformans pericarditis in a cardiac transplant recipient. This article reviews the diagnosis, treatment, and complications of cryptococcosis specifically in transplant patients. While pericarditis is a rare manifestation of Cryptococcus infection, this case highlights that cryptococcosis should be considered in the differential diagnosis for solid organ transplant and immunocompromised patients presenting with pericardial effusions.
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Affiliation(s)
- Sarah Mann
- Division of Infectious Diseases, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Farrell Tobolowsky
- Division of Infectious Diseases, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Suneet Purohit
- Division of Cardiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Andres Henao-Martínez
- Division of Infectious Diseases, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Valida Bajrovic
- Division of Infectious Diseases, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Poornima Ramanan
- Division of Infectious Diseases, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Eugene Wolfel
- Division of Cardiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Prateeti Khazanie
- Division of Cardiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Michelle Barron
- Division of Infectious Diseases, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Nancy Madinger
- Division of Infectious Diseases, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Esther Benamu
- Division of Infectious Diseases, University of Colorado School of Medicine, Aurora, Colorado, USA
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Samarasinghe H, Aljohani R, Jimenez C, Xu J. Fantastic yeasts and where to find them: the discovery of a predominantly clonal Cryptococcus deneoformans population in Saudi Arabian soils. FEMS Microbiol Ecol 2020; 95:5538757. [PMID: 31344232 DOI: 10.1093/femsec/fiz122] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 07/20/2019] [Indexed: 12/15/2022] Open
Abstract
Cryptococcus deneoformans is an opportunist yeast pathogen and causative agent of meningoencephalitis in humans. It is known to be mainly distributed in temperate climates. Most of our current understanding of this species has come from clinical isolates, leaving environmental populations largely unexplored. The Middle East remains one such underexplored area with no published study to date investigating cryptococcal diversity in soil. In this study, we identified 76 C. deneoformans isolates from a survey of 562 soil samples collected from six cities in Saudi Arabia. Multilocus sequence typing revealed the presence of two major sequence types (STs), ST160 (n = 63) and ST294 (n = 9), along with four singleton STs, three of which were novel. One novel ST, ST613, was likely a recombinant product between ST160 and ST294. Among the 76 isolates, 75 belonged to mating type (MAT)α while one isolate was MATa. Our analyses suggest that the Saudi Arabian C. deneoformans population likely reproduces both asexually and sexually in nature. Our study is the first to report the occurrence of C. deneoformans in a desert climate, representing a novel expansion to this species' currently known ecological niche.
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Affiliation(s)
| | - Renad Aljohani
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Carlene Jimenez
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Jianping Xu
- Department of Biology, McMaster University, Hamilton, ON, Canada
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Crawford CJ, Cordero RJB, Guazzelli L, Wear MP, Bowen A, Oscarson S, Casadevall A. Exploring Cryptococcus neoformans capsule structure and assembly with a hydroxylamine-armed fluorescent probe. J Biol Chem 2020; 295:4327-4340. [PMID: 32005661 PMCID: PMC7105310 DOI: 10.1074/jbc.ra119.012251] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/30/2020] [Indexed: 11/06/2022] Open
Abstract
Chemical biology is an emerging field that enables the study and manipulation of biological systems with probes whose reactivities provide structural insights. The opportunistic fungal pathogen Cryptococcus neoformans possesses a polysaccharide capsule that is a major virulence factor, but is challenging to study. We report here the synthesis of a hydroxylamine-armed fluorescent probe that reacts with reducing glycans and its application to study the architecture of the C. neoformans capsule under a variety of conditions. The probe signal localized intracellularly and at the cell wall-membrane interface, implying the presence of reducing-end glycans at this location where the capsule is attached to the cell body. In contrast, no fluorescence signal was detected in the capsule body. We observed vesicle-like structures containing the reducing-end probe, both intra- and extracellularly, consistent with the importance of vesicles in capsular assembly. Disrupting the capsule with DMSO, ultrasound, or mechanical shear stress resulted in capsule alterations that affected the binding of the probe, as reducing ends were exposed and cell membrane integrity was compromised. Unlike the polysaccharides in the assembled capsule, isolated exopolysaccharides contained reducing ends. The reactivity of the hydroxylamine-armed fluorescent probe suggests a model for capsule assembly whereby reducing ends localize to the cell wall surface, supporting previous findings suggesting that this is an initiation point for capsular assembly. We propose that chemical biology is a promising approach for studying the C. neoformans capsule and its associated polysaccharides to unravel their roles in fungal virulence.
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Affiliation(s)
- Conor J Crawford
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland; Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland 21205
| | - Radamés J B Cordero
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland 21205
| | - Lorenzo Guazzelli
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Maggie P Wear
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland 21205
| | - Anthony Bowen
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland 21205
| | - Stefan Oscarson
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland 21205.
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Coelho C, Farrer RA. Pathogen and host genetics underpinning cryptococcal disease. ADVANCES IN GENETICS 2020; 105:1-66. [PMID: 32560785 DOI: 10.1016/bs.adgen.2020.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cryptococcosis is a severe fungal disease causing 220,000 cases of cryptococcal meningitis yearly. The etiological agents of cryptococcosis are taxonomically grouped into at least two species complexes belonging to the genus Cryptococcus. All of these yeasts are environmentally ubiquitous fungi (often found in soil, leaves and decaying wood, tree hollows, and associated with bird feces especially pigeon guano). Infection in a range of animals including humans begins following inhalation of spores or aerosolized yeasts. Recent advances provide fundamental insights into the factors from both the pathogen and its hosts which influence pathogenesis and disease. The complex interactions leading to disease in mammalian hosts have also updated from the availability of better genomic tools and datasets. In this review, we discuss recent genetic research on Cryptococcus, covering the epidemiology, ecology, and evolution of Cryptococcus pathogenic species. We also discuss the insights into the host immune response obtained from the latest genetic modified host models as well as insights from monogenic disorders in humans. Finally we highlight outstanding questions that can be answered in the near future using bioinformatics and genomic tools.
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Affiliation(s)
- Carolina Coelho
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - Rhys A Farrer
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom.
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Alemayehu T, Ayalew S, Buzayehu T, Daka D. Magnitude of Cryptococcosis among HIV patients in sub-Saharan Africa countries: a systematic review and meta-analysis. Afr Health Sci 2020; 20:114-121. [PMID: 33402899 PMCID: PMC7750036 DOI: 10.4314/ahs.v20i1.16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Background Cryptococcus is encapsulated opportunistic yeast that causes life threatening meningoencephalitis of patients with human immunodeficiency virus (HIV). The magnitude of Cryptococcosis among HIV patients varies from 1–10% in Western countries as opposed to almost a one third of HIV-infected individuals in sub-Saharan Africa where it is associated with high mortality. Methodology By using key terms “Cryptococcosis among HIV patients in sub-saharan Africa countries”, articles that published in different journals from 2010–2017 searched on Pub-Med and Google scholar database. Those freely accessible and included the prevalence of Cryptococcosis in the result section, their PDF file was downloaded and the result extracted manually and presented in table. Articles that did not report the prevalence of Cryptococcosis, with a study design otherthan cross sectional, or a sample size less than 100, and those duplicated in the same study area and period by the same authors were excluded. The article selection followed the PRISMA guidelines and meta- analysis was performed using OpenMeta(analyst). Results The overall pooled magnitude of Cryptococcosis among HIV patients in sub saharan African countries was 8.3% (95%CI 6.1–10.5%). The highest prevalence was from Uganda (19%) and the least was from Ethiopia at 1.6%. There was 87.2 % of substantial heterogeneity among the studies with p-value<0.001. The symmetry ofthe forest plot showed that there was little publication bias. The most commonly used method for diagnosis of Cryptococcosis was lateral flow assay and latex agglutination test and culture was the least method employed. Conclusion The overall pooled magnitude of Cryptococcosisis high among HIV patients in sub-Saharan African countries. The studies showed substantial heterogeneity, and little publication bias. Most of the studies relied on LFA & LA that showed the scarcity of facilities for fungal culture. Therefore, paying attention to screening HIV patients; those with signs and symptoms of meningitis may help to reduce the loss of HIV patients.
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Affiliation(s)
- Tsegaye Alemayehu
- School of Medical Laboratory Science Hawassa University College of medicine and health sciences
| | | | - Temesgen Buzayehu
- School of Medical Laboratory Science Hawassa University College of medicine and health sciences
| | - Deresse Daka
- School of Medical Laboratory Science Hawassa University College of medicine and health sciences
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Cryptococcal Immune Reconstitution Inflammatory Syndrome: a Paradoxical Response to a Complex Organism. CURRENT TREATMENT OPTIONS IN INFECTIOUS DISEASES 2020. [DOI: 10.1007/s40506-020-00210-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Stingone C, Sarmati L, Andreoni M. The Clinical Spectrum of Human Immunodeficiency Virus Infection. Sex Transm Infect 2020. [DOI: 10.1007/978-3-030-02200-6_15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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Zafar H, Altamirano S, Ballou ER, Nielsen K. A titanic drug resistance threat in Cryptococcus neoformans. Curr Opin Microbiol 2019; 52:158-164. [PMID: 31765991 DOI: 10.1016/j.mib.2019.11.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 10/01/2019] [Accepted: 11/01/2019] [Indexed: 10/25/2022]
Abstract
Increasing resistance to frontline antifungals is a growing threat to global health. In the face of high rates of relapse for patients with cryptococcal meningitis and frequent drug resistance in clinical isolates, recent insights into Cryptococcus neoformans morphogenesis and genome plasticity take on new and urgent meaning. Here we review the state of the understanding of mechanisms of drug resistance in the context of host-relevant changes in Cryptococcus morphology and cell ploidy.
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Affiliation(s)
- Hanna Zafar
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Sophie Altamirano
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, 55455 USA
| | - Elizabeth R Ballou
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Kirsten Nielsen
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN, 55455 USA.
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Abstract
PURPOSE OF REVIEW Defective cell-mediated immunity is a major risk factor for cryptococcosis, a fatal disease if untreated. Cryptococcal meningitis (CM), the main presentation of disseminated disease, occurs through hematogenous spread to the brain from primary pulmonary foci, facilitated by yeast virulence factors. We revisit remarkable recent improvements in the prevention, diagnosis and management of CM. RECENT FINDINGS Cryptococcal antigen (CrAg), main capsular polysaccharide of Cryptococcus spp. is detectable in blood and cerebrospinal fluid of infected patients with point of care lateral flow assays. Recent World Health Organization guidelines recommend 7-day amphotericin B plus flucytosine, then 7-day high dose (1200 mg/day) fluconazole for induction treatment of HIV-associated CM. Management of raised intracranial pressure, a consequence of CM, should rely mainly on daily therapeutic lumbar punctures until normalisation. In HIV-associated CM, following introduction of antifungal therapy, (re)initiation of antiretroviral therapy should be delayed by 4-6 weeks to prevent immune reconstitution inflammatory syndrome, common in CM. CM is a fatal disease whose diagnosis has recently been simplified. Treatment should always include antifungal combination therapy and management of raised intracranial pressure. Screening for immune deficiency should be mandatory in all patients with cryptococcosis.
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Engelthaler DM, Casadevall A. On the Emergence of Cryptococcus gattii in the Pacific Northwest: Ballast Tanks, Tsunamis, and Black Swans. mBio 2019; 10:e02193-19. [PMID: 31575770 PMCID: PMC6775458 DOI: 10.1128/mbio.02193-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The appearance of Cryptococcus gattii in the North American Pacific Northwest (PNW) in 1999 was an unexpected and is still an unexplained event. Recent phylogenomic analyses strongly suggest that this pathogenic fungus arrived in the PNW approximately 7 to 9 decades ago. In this paper, we theorize that the ancestors of the PNW C. gattii clones arrived in the area by shipborne transport, possibly in contaminated ballast, and established themselves in coastal waters early in the 20th century. In 1964, a tsunami flooded local coastal regions, transporting C. gattii to land. The occurrence of cryptococcosis in animals and humans 3 decades later suggests that adaptation to local environs took time, possibly requiring an increase in virulence and further dispersal. Tsunamis as a mechanism for the seeding of land with pathogenic waterborne microbes may have important implications for our understanding of how infectious diseases emerge in certain regions. This hypothesis suggests experimental work for its validation or refutation.
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Hommel B, Sturny-Leclère A, Volant S, Veluppillai N, Duchateau M, Yu CH, Hourdel V, Varet H, Matondo M, Perfect JR, Casadevall A, Dromer F, Alanio A. Cryptococcus neoformans resists to drastic conditions by switching to viable but non-culturable cell phenotype. PLoS Pathog 2019; 15:e1007945. [PMID: 31356623 PMCID: PMC6687208 DOI: 10.1371/journal.ppat.1007945] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 08/08/2019] [Accepted: 06/27/2019] [Indexed: 01/22/2023] Open
Abstract
Metabolically quiescent pathogens can persist in a viable non-replicating state for months or even years. For certain infectious diseases, such as tuberculosis, cryptococcosis, histoplasmosis, latent infection is a corollary of this dormant state, which has the risk for reactivation and clinical disease. During murine cryptococcosis and macrophage uptake, stress and host immunity induce Cryptococcus neoformans heterogeneity with the generation of a sub-population of yeasts that manifests a phenotype compatible with dormancy (low stress response, latency of growth). In this subpopulation, mitochondrial transcriptional activity is regulated and this phenotype has been considered as a hallmark of quiescence in stem cells. Based on these findings, we worked to reproduce this phenotype in vitro and then standardize the experimental conditions to consistently generate this dormancy in C. neoformans. We found that incubation of stationary phase yeasts (STAT) in nutriment limited conditions and hypoxia for 8 days (8D-HYPOx) was able to produced cells that mimic the phenotype obtained in vivo. In these conditions, mortality and/or apoptosis occurred in less than 5% of the yeasts compared to 30-40% of apoptotic or dead yeasts upon incubation in normoxia (8D-NORMOx). Yeasts in 8D-HYPOx harbored a lower stress response, delayed growth and less that 1% of culturability on agar plates, suggesting that these yeasts are viable but non culturable cells (VBNC). These VBNC were able to reactivate in the presence of pantothenic acid, a vitamin that is known to be involved in quorum sensing and a precursor of acetyl-CoA. Global metabolism of 8D-HYPOx cells showed some specific requirements and was globally shut down compared to 8D-NORMOx and STAT conditions. Mitochondrial analyses showed that the mitochondrial mass increased with mitochondria mostly depolarized in 8D-HYPOx compared to 8D-NORMox, with increased expression of mitochondrial genes. Proteomic and transcriptomic analyses of 8D-HYPOx revealed that the number of secreted proteins and transcripts detected also decreased compared to 8D-NORMOx and STAT, and the proteome, secretome and transcriptome harbored specific profiles that are engaged as soon as four days of incubation. Importantly, acetyl-CoA and the fatty acid pathway involving mitochondria are required for the generation and viability maintenance of VBNC. Altogether, these data show that we were able to generate for the first time VBNC phenotype in C. neoformans. This VBNC state is associated with a specific metabolism that should be further studied to understand dormancy/quiescence in this yeast.
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Affiliation(s)
- Benjamin Hommel
- Institut Pasteur, CNRS, Molecular Mycology Unit, UMR2000, Paris, France
- Laboratoire de Parasitologie-Mycologie, Hôpital Saint-Louis, Groupe Hospitalier Lariboisière, Saint-Louis, Fernand Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | | | - Stevenn Volant
- Institut Pasteur - Bioinformatics and Biostatistics Hub - C3BI, USR 3756 IP CNRS, Paris, France
| | | | - Magalie Duchateau
- Institut Pasteur, Unité de spectrométrie de masse et Protéomique, Paris, France
| | - Chen-Hsin Yu
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Véronique Hourdel
- Institut Pasteur, Unité de spectrométrie de masse et Protéomique, Paris, France
| | - Hugo Varet
- Institut Pasteur - Bioinformatics and Biostatistics Hub - C3BI, USR 3756 IP CNRS, Paris, France
- Institut Pasteur - Transcriptome and Epigenome Platform - Biomics Pole - C2RT, Paris, France
| | - Mariette Matondo
- Institut Pasteur, Unité de spectrométrie de masse et Protéomique, Paris, France
| | - John R. Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Arturo Casadevall
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Françoise Dromer
- Institut Pasteur, CNRS, Molecular Mycology Unit, UMR2000, Paris, France
| | - Alexandre Alanio
- Institut Pasteur, CNRS, Molecular Mycology Unit, UMR2000, Paris, France
- Laboratoire de Parasitologie-Mycologie, Hôpital Saint-Louis, Groupe Hospitalier Lariboisière, Saint-Louis, Fernand Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Paris, France
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- * E-mail:
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Denham ST, Wambaugh MA, Brown JCS. How Environmental Fungi Cause a Range of Clinical Outcomes in Susceptible Hosts. J Mol Biol 2019; 431:2982-3009. [PMID: 31078554 PMCID: PMC6646061 DOI: 10.1016/j.jmb.2019.05.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 04/18/2019] [Accepted: 05/01/2019] [Indexed: 12/11/2022]
Abstract
Environmental fungi are globally ubiquitous and human exposure is near universal. However, relatively few fungal species are capable of infecting humans, and among fungi, few exposure events lead to severe systemic infections. Systemic infections have mortality rates of up to 90%, cost the US healthcare system $7.2 billion annually, and are typically associated with immunocompromised patients. Despite this reputation, exposure to environmental fungi results in a range of outcomes, from asymptomatic latent infections to severe systemic infection. Here we discuss different exposure outcomes for five major fungal pathogens: Aspergillus, Blastomyces, Coccidioides, Cryptococcus, and Histoplasma species. These fungi include a mold, a budding yeast, and thermal dimorphic fungi. All of these species must adapt to dramatically changing environments over the course of disease. These dynamic environments include the human lung, which is the first exposure site for these organisms. Fungi must defend themselves against host immune cells while germinating and growing, which risks further exposing microbe-associated molecular patterns to the host. We discuss immune evasion strategies during early infection, from disruption of host immune cells to major changes in fungal cell morphology.
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Affiliation(s)
- Steven T Denham
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Morgan A Wambaugh
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Jessica C S Brown
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
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Abstract
Purpose of review To perform an extensive review of recent literature and provide an update on the current epidemiology, clinical features and management of cryptococcal disease with a focus on the differences between patients depending on their immune status. Recent findings Emerging literature has highlighted the inflammatory pathophysiology and varied manifestations of cryptococcal infections in patients who are apparently healthy but paradoxically have a more critical clinical course compared to their immunosuppressed counterparts. Summary Non-HIV cryptococcal meningitis has greater mortality compared to that seen in HIV patients. Basic science experiments closely analyzing the underlying pathophysiological response to this infection have demonstrated the predominant role of T cell-mediated inflammatory injury in causing worse clinical outcomes. Further studies are needed to define the need for immunosuppressive agents in the treatment of this illness.
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Affiliation(s)
- Seher Anjum
- Laboratory of Clinical Immunology and Microbiology (LCIM), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Peter R Williamson
- Laboratory of Clinical Immunology and Microbiology (LCIM), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, MD, USA
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Nakajima T, Oba Y, Takashima J, Ueno K, Kikuchi A, Yamada T, Fukunami M. Cryptococcus endocarditis: A case report and review of the literature. J Infect Chemother 2019; 25:901-905. [PMID: 31182330 DOI: 10.1016/j.jiac.2019.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/23/2019] [Accepted: 05/07/2019] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Cryptococcus neoformans is known to be a cause of meningitis. However, as cryptococcal endocarditis is rare, it is not well understood. Here, we describe a case with Implantable Cardioverter Defibrillator associated endocarditis and meningitis caused by Cryptococcus neoformans and we review the literature associated cryptococcal endocarditis. CASE PRESENTATION A 72 years old Japanese male presented in emergency department with non-productive cough and respiratory discomfort. His past medical history was ischemic heart disease four years ago and ICD was implanted. Physical examination was unremarkable. Chest computer tomography revealed ground glass opacity in the right lung. He received a diagnosis of amiodarone-induced interstitial pneumonitis and high dose steroid pulse therapy. Septic shock and acute respiratory failure occurred after steroid therapy. Cryptococcus neoformans was identified by blood culture and cerebral spinal fluid. Intravenous liposomal Amphotericin B and oral flucytosine were initiated. Transesophageal echocardiography revealed vegetation on the lead of the ICD. Diagnosis of cryptococcal endocarditis was made. The patient died despite antifungal therapy was continued. DISCUSSION We analyzed our case and 8 cases of cryptococcal endocarditis in the literature for 40 years. Almost all of the patients had previous valve replacement surgery or immunocompromised state. Three cases had meningitis. Surgery performed in 3 cases. The overall mortality rate were 44.4%. CONCLUSIONS Cryptococcal endocarditis is rare and carries a high mortality. Almost all of the patients had underlying diseases. Diagnosis needs repeating blood culture and echocardiogram, sometimes. Cryptococcal endocarditis needs lumber puncture for rule out meningitis.
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Affiliation(s)
- Takahiro Nakajima
- Division of General Internal Medicine, Akashi Medical Center, 743-33, Okubocho-Yagi, Akashi City, Hyogo, 674-0063, Japan.
| | - Yuichirou Oba
- Department of General Internal Medicine, Osaka General Medical Center, 3-1-56, Mandai-Higashi, Sumiyoshi-ku, Osaka, 558-8558, Japan
| | - Junpei Takashima
- Department of Respiratory Medicine, Sakai City Medical Center, 1-1-1, Eharaji, Nishi-ku, Sakai City, Osaka, 593-8304, Japan
| | - Kiyonobu Ueno
- Department of Respiratory Medicine, Osaka General Medical Center 3-1-56, Mandai-Higashi, Sumiyoshi-ku, Osaka, 558-8558, Japan
| | - Atsushi Kikuchi
- Department of Cardiology, Osaka General Medical Center, Mandai-Higashi, Sumiyoshi-ku, Osaka, 558-8558, Japan
| | - Takahisa Yamada
- Department of Cardiology, Osaka General Medical Center, Mandai-Higashi, Sumiyoshi-ku, Osaka, 558-8558, Japan
| | - Masatake Fukunami
- Department of Cardiology, Osaka General Medical Center, Mandai-Higashi, Sumiyoshi-ku, Osaka, 558-8558, Japan
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