DOCSLIB.ORG

The Evolution of Cryptococcus Neoformans Var. Grubii in the Context of Clinical Disease Using Multilocus Sequence Typing

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Evolution of Cryptococcus Neoformans Var. Grubii in the Context of Clinical Disease Using Multilocus Sequence Typing Imperial College London School of Public Health The evolution of Cryptococcus neoformans var. grubii in the context of clinical disease using multilocus sequence typing Sitali P. Simwami September 2011 Submitted in part fulfilment of the requirements for the degree of Doctor of Philosophy in the School of Public Health of Imperial College London and the Diploma of Imperial College London Declaration I herewith certify that all material in this dissertation which is not my own work has been properly acknowledged. Sitali P. Simwami 3 Abstract The global burden of HIV-associated cryptococcal meningitis (CM) is es- timated at one million cases per year, causing up to a third of all AIDS- related deaths. Cryptococcus neoformans variety grubii (Cng) is the most ubiquitous cause of cryptococcal meningitis worldwide, however patterns of molecular diversity are understudied across some geographical regions ex- periencing significant burdens of disease. Cryptococcus species are notable in the degree that virulence differs amongst lineages, and highly virulent emerging lineages are changing patterns of human disease both temporally and spatially. Molecular epidemiology constitutes the main methodology for understanding the factors underpinning the emergence of this under- studied, yet increasingly important, group of pathogenic fungi. A multilo- cus sequence typing (MLST) scheme was used to characterise a genetically depauperate Cng population in Thailand, and a contrastingly highly di- verse Cng population in Cape Town, South Africa. Sequence types (STs) from these populations were integrated into a dataset comprising global STs of Cng and patterns of range expansion were traced. Evidence from haplotypic networks and coalescent analyses revealed an ancestral African population of molecular type VNB, from which emerged a VNI lineage. This VNI lineage expanded globally out of Africa and led to the introduction of a limited number of genotypes in novel regions, including Asia. Bayesian inference estimated this spread of VNI to have occurred between 1 600 and 70 500 years ago, putatively vectored by the anthropogenically mediated spread of domesticated pigeons, historically native African birds. Clinical data collected from patients presenting with AIDS-associated CM showed that infecting African Cng isolates were associated with poorer long-term survival compared to Asian isolates. As mortality rates reported for these patients in Sub-Saharan Africa are higher than those seen in Asia, sup- ported by a Galleria mellonella virulence model, this apparently elevated virulence is postulated as being the result of recombinant progeny with di- verse phenotypes being created through frequent meiotic recombination. 5 Acknowledgments First, I would like to thank my principal supervisor, Dr. Matthew Fisher, for his vision for this project, guidance, and confidence in my abilities. I could not have asked for a better mentor. Thank you to the members of the Fisher Lab, past and present, and especially to Daniel who somehow knew the answers to all my questions. I also thank my second supervisor, Prof. Christl Donnelly, Dr. Jombart Thibaut and Dr. Miltiadis Mavrakakis for their valuable statistical advice, and the BBSRC for funding this work. Thank you to members of the CBS (Ferry and Ning), St. George's and Hammersmith Hospitals (Tom, Tihana, Jo, Anne-Marie and Michael), and Duke University (Ana), whose valuable collaborations made this work pos- sible. Thank you to the the University of Cape Town's Institute of Infectious Disease and Molecular Medicine for hosting me during my fieldwork in South Africa (Widaad, Robert, Graeme). I also extend an especially warm thank you to those who made my stay so memorable (Tsungai, Vee, Slee, Joanna, Banda and Lee) | I will be back! Thank you to my friends whose support never wavered, despite me reg- ularly disappearing for long periods of time. Bee and Shmi, knowing our relationships remained unchanged made this process a lot easier. I also thank my little sister Moono; our relationship kept me grounded and means more to me than you know. Thank you to my fiance, Milt, for being everything to me. As a wise Greek once said, 'A hungry bear does not dance'. Finally, I would like to thank my parents for their constant love, support and wisdom. I owe you everything. 6 To my parents, Jonathan and Sharon, and to Milt. Trust in the Lord with all your mind, in all your ways acknowledge him, and he shall direct your path. | Proverbs 3:5 7 Contents 1. Introduction 17 1.1. Cryptococcus ........................... 17 1.2. Species classification and distribution . 18 1.3. Cryptococcus neoformans var grubii .............. 21 1.4. Life cycle and sexual cycle of Cn ................ 22 1.5. Infection and disease caused by Cng .............. 26 1.6. Cryptococcosis and HIV/AIDS . 28 1.6.1. AIDS in Thailand . 30 1.6.2. AIDS in South Africa . 31 1.7. Classical virulence phenotypes of Cn . 32 1.8. Animal Host Models . 36 1.8.1. Cn { Galleria mellonella pathosystem . 37 1.9. Rationale and importance of study . 38 1.10. Thesis overview . 42 1.11. Aims of the project . 43 2. Methodology and data analysis 44 2.1. Molecular sequencing of Cn ................... 44 2.1.1. Yeast cultivation and DNA extraction . 44 2.1.2. Polymerase Chain Reaction amplification (PCR) . 45 2.1.3. PCR cleanup . 45 2.1.4. Sequencing . 47 2.1.5. Precipitation of sequencing cycling products . 47 2.2. MLST determination . 48 2.3. Mating-type and serotype analyses . 48 2.4. Molecular data analyses . 49 2.4.1. Diversity indices . 49 2.4.2. Analysis of genetic structure based on allelic profiles . 51 2.4.3. Linkage disequilibrium and recombination . 53 9 2.4.4. Genetic differentiation between populations . 53 2.5. Phylogenetic analyses and molecular type determination . 54 2.6. Estimates of times of divergence and haplotype networks . 55 2.7. MLST website eBURST tool . 55 2.8. Clinical data and analysis . 56 2.9. Environmental fieldwork . 56 2.9.1. Sampling of Cn ...................... 56 2.9.2. Preparation of niger seed agar . 56 2.9.3. Isolation and identification . 57 2.10. Galleria mellonella wax moth model . 58 3. Multilocus Sequence Typing 60 3.1. Introduction . 60 3.2. History of the identification of fungi . 61 3.3. Rationale for the standardisation of the typing of Cn ..... 65 3.4. ISHAM, our aims . 66 3.4.1. Consensus genotype nomenclature . 67 3.4.2. Consensus standard strains . 67 3.4.3. Consensus typing scheme MLST . 72 3.5. MLST . 72 3.5.1. MLST loci . 73 3.5.2. MLST website and Cng Database . 75 3.6. Discussion . 77 4. Cng in Thailand 79 4.1. Introduction . 79 4.1.1. Cn in Thailand . 80 4.2. Aim . 81 4.3. Materials and Methods . 81 4.3.1. Isolates . 81 4.4. Ethics Statement . 87 4.5. Results . 88 4.5.1. Mating type, variety and MLST sequence type . 88 4.6. Discussion . 95 5. Cng in Cape Town 99 5.1. Introduction . 99 10 5.2. Aims . 100 5.3. Materials and Methods . 100 5.3.1. Isolates . 100 5.3.2. Molecular methods . 101 5.4. Ethics Statement . 103 5.5. Results . 103 5.5.1. Mating, molecular, and sequence types of isolates . 103 5.5.2. Molecular analyses . 108 5.6. Discussion . 113 6. Global Cng 119 6.1. Introduction . 119 6.2. Aim . 120 6.3. Materials and Methods . 120 6.3.1. Global Cng isolates . 120 6.3.2. Methods . 125 6.4. Results . 125 6.4.1. Structure of the global population of Cng isolates based on allelic profiles . 125 6.4.2. Phylogenetic analyses revealed three molecular groups within the global Cng population . 126 6.4.3. The African population exhibits the most genetic di- versity of the global Cng subpopulations . 130 6.4.4. Predominant clonality detected within the global Cng populations . 134 6.4.5. Divergence time estimates and haplotype networks support a hypothesis of African ancestry for global Cng isolates . 138 6.5. Discussion . 142 7. Clinical analysis 149 7.1. Introduction . 149 7.2. Aims . 150 7.3. Materials and methods . 150 7.4. Results . 153 7.4.1. Study population according to ST . 153 11 7.4.2. ST and baseline variables . 155 7.4.3. Death by weeks 2 and 10 . 157 7.4.4. Early fungicidal activity and treatment . 157 7.4.5. Genotypic effect on EFA at the allelic profile level but not ST level . 160 7.4.6. Survival analysis . 161 7.5. Discussion . 167 8. Environmental Cape Town isolates 175 8.1. Introduction . 175 8.2. Materials and Methods . 176 8.3. Results . 176 8.4. Discussion . 179 9. Galleria mellonella - Cng virulence assay 182 9.1. Introduction . 182 9.2. Aims . 182 9.3. Materials and Method . 183 9.3.1. Isolates . 183 9.4. Result . 183 9.5. Discussion . 188 10.Final Discussion 193 A. Published work 202 A.1. Meyer et al., 2009 . 203 A.2. Simwami et al., 2011 . 217 B. Additional tables and figures 239 C. R Code 251 C.1. PCA commands . 251 C.2. Inter-class PCA commands . 251 C.3. Clinical analysis . 252 C.4. Galleria mellonella assay anaylsis . 255 D. Glossary 257 12 List of Tables 1.1. Genes linked to the major virulence phenotypes of Cn..... 35 2.1. Mating-type primer sequences. 49 3.1. Relationships among different molecular groups in Cn var grubii................................ 66 3.2. Concordance of different molecular typing methods used for Cryptococcus ........................... 69 3.3. Standard reference strains for Cryptococcus neoformans typing. 70 3.4. Standard reference strains for Cryptococcus gattii typing. 71 3.5. Seven Multilocus Sequence Typing Loci. 75 4.1. Allelic profiles of the Thai Cng isolates. 83 4.2. Diversity indices, Thailand.
Load more

Recommended publications
  • Cryptococcus Neoformans</Em>
    Clemson University TigerPrints All Dissertations Dissertations December 2019 Role of Cryptococcus neoformans Pyruvate Decarboxylase and Aldehyde Dehydrogenase Enzymes in Acetate Production and Virulence Mufida Ahmed Nagi Ammar Clemson University, [email protected] Follow this and additional works at: https://tigerprints.clemson.edu/all_dissertations Recommended Citation Ammar, Mufida Ahmed Nagi, "Role of Cryptococcus neoformans Pyruvate Decarboxylase and Aldehyde Dehydrogenase Enzymes in Acetate Production and Virulence" (2019). All Dissertations. 2488. https://tigerprints.clemson.edu/all_dissertations/2488 This Dissertation is brought to you for free and open access by the Dissertations at TigerPrints. It has been accepted for inclusion in All Dissertations by an authorized administrator of TigerPrints. For more information, please contact [email protected]. Role of Cryptococcus neoformans Pyruvate Decarboxylase and Aldehyde Dehydrogenase Enzymes in Acetate Production and Virulence A Dissertation Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Biochemistry and Molecular Biology by Mufida Ahmed Nagi Ammar December 2019 Accepted by: Dr. Kerry Smith, Committee Chair Dr. Julia Frugoli Dr. Cheryl Ingram-Smith Dr. Lukasz Kozubowski ABSTRACT The basidiomycete Cryptococcus neoformans is is an invasive opportunistic pathogen of the central nervous system and the most frequent cause of fungal meningitis. C. neoformans enters the host by inhalation and protects itself from immune assault in the lungs by producing hydrolytic enzymes, immunosuppressants, and other virulence factors. C. neoformans also adapts to the environment inside the host, including producing metabolites that may confer survival advantages. One of these, acetate, can be kept in reserve as a carbon source or can be used to weaken the immune response by lowering local pH or as a key part of immunomodulatory molecules.
    [Show full text]
  • Safety Precautions for Working with Cryptococcus Neoformans
    Safety Precautions for Working with Cryptococcus neoformans The basidiomycete fungus Cryptococcus neoformans is an invasive opportunistic pathogen of the central nervous system and the most frequent cause of fungal meningitis worldwide. Although Cryptococcus is a problem in the United States, it is significantly more prevalent and especially devastating in the developing world, such as sub-Saharan Africa, resulting in in more than 625,000 deaths per year worldwide. C. neoformans survives in the environment within soil, trees, and bird guano, where it can interact with wild animals or microbial predators, maintaining its virulence. Human infection is thought to be acquired by inhalation of desiccated yeast cells or spores from an environmental source. C. neoformans can colonize the host respiratory tract without producing any disease. Infection is typically asymptomatic, and it can be either cleared or enter a dormant, latent form. When host immunity is compromised, the dormant form can be reactivated and disseminate hematogenously to cause systemic infection. C. neoformans can infect or spread to any organ to cause localized infections involving the skin, eyes, myocardium, bones, joints, lungs, prostate gland, or urinary tract, in addition to its propensity to infect the central nervous systems. The following diseases and medications are risk factors for C. neoformans infection and are associated with at least some degree of immunosuppression: Ø HIV/AIDs (CD4 < 100cells/mm) Ø Corticosteroids or other immunosuppressive medications for cancer, chemotherapy, or organ transplants Ø Solid organ transplantations Ø Diabetes mellitus Ø Heart, lung, or liver disease Ø Pregnancy Even otherwise healthy, fully immunocompetent individuals can develop cryptococcosis, as may well be the case in a lab accident.
    [Show full text]
  • Chronic Mucocutaneous Candidiasis Associated with Paracoccidioidomycosis in a Patient with Mannose Receptor Deficiency: First Case Reported in the Literature
    Revista da Sociedade Brasileira de Medicina Tropical Journal of the Brazilian Society of Tropical Medicine Vol.:54:(e0008-2021): 2021 https://doi.org/10.1590/0037-8682-0008-2021 Case Report Chronic mucocutaneous candidiasis associated with paracoccidioidomycosis in a patient with mannose receptor deficiency: First case reported in the literature Dewton de Moraes Vasconcelos[1], Dalton Luís Bertolini[1] and Maurício Domingues Ferreira[1] [1]. Universidade de São Paulo, Faculdade de Medicina, Hospital das Clinicas, Departamento de Dermatologia, Ambulatório das Manifestações Cutâneas das Imunodeficiências Primárias, São Paulo, SP, Brasil. Abstract We describe the first report of a patient with chronic mucocutaneous candidiasis associated with disseminated and recurrent paracoccidioidomycosis. The investigation demonstrated that the patient had a mannose receptor deficiency, which would explain the patient’s susceptibility to chronic infection by Candida spp. and systemic infection by paracoccidioidomycosis. Mannose receptors are responsible for an important link between macrophages and fungal cells during phagocytosis. Deficiency of this receptor could explain the susceptibility to both fungal species, suggesting the impediment of the phagocytosis of these fungi in our patient. Keywords: Chronic mucocutaneous candidiasis. Paracoccidioidomycosis. Mannose receptor deficiency. INTRODUCTION “chronic mucocutaneous candidiasis and mannose receptor deficiency,” “chronic mucocutaneous candidiasis and paracoccidioidomycosis,” Chronic mucocutaneous
    [Show full text]
  • Identification of Culture-Negative Fungi in Blood and Respiratory Samples
    IDENTIFICATION OF CULTURE-NEGATIVE FUNGI IN BLOOD AND RESPIRATORY SAMPLES Farida P. Sidiq A Dissertation Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY May 2014 Committee: Scott O. Rogers, Advisor W. Robert Midden Graduate Faculty Representative George Bullerjahn Raymond Larsen Vipaporn Phuntumart © 2014 Farida P. Sidiq All Rights Reserved iii ABSTRACT Scott O. Rogers, Advisor Fungi were identified as early as the 1800’s as potential human pathogens, and have since been shown as being capable of causing disease in both immunocompetent and immunocompromised people. Clinical diagnosis of fungal infections has largely relied upon traditional microbiological culture techniques and examination of positive cultures and histopathological specimens utilizing microscopy. The first has been shown to be highly insensitive and prone to result in frequent false negatives. This is complicated by atypical phenotypes and organisms that are morphologically indistinguishable in tissues. Delays in diagnosis of fungal infections and inaccurate identification of infectious organisms contribute to increased morbidity and mortality in immunocompromised patients who exhibit increased vulnerability to opportunistic infection by normally nonpathogenic fungi. In this study we have retrospectively examined one-hundred culture negative whole blood samples and one-hundred culture negative respiratory samples obtained from the clinical microbiology lab at the University of Michigan Hospital in Ann Arbor, MI. Samples were obtained from randomized, heterogeneous patient populations collected between 2005 and 2006. Specimens were tested utilizing cetyltrimethylammonium bromide (CTAB) DNA extraction and polymerase chain reaction amplification of internal transcribed spacer (ITS) regions of ribosomal DNA utilizing panfungal ITS primers.
    [Show full text]
  • Pulmonary Cryptococcosis Secondary To
    & My gy co lo lo ro g i y V Ramana et al., Virol Mycol 2012, 1:3 Virology & Mycology DOI: 10.4172/2161-0517.1000107 ISSN: 2161-0517 Case Report Open Access Pulmonary Cryptococcosis Secondary to Bronchial Asthma Presenting as Type I Respiratory Failure- A Case Report with Review of Literature KV Ramana*, Moses Vinay Kumar, Sanjeev D Rao, Akhila R, Sandhya, Shruthi P, Pranuthi M, Krishnappa M, Anand K Department of Microbiology, Prathima Inst of Medical Sciences, Nagunur, Karimnagar, Andhrapradesh, India Introduction mellitus, pleuritis, systemic lupus erythematus, cushings syndrome, Continous Ambulatory Peritoneal Dialysis (CAPD), liver cirrhosis, Cryptococcus spp, was first isolated and described in 1894 by cancer, organ transplants, spleenectomy, malnutrition, leprosy, Sanfelice F in Italy from peach juice and named it as Saccharomyces pulmonary tuberculosis and those on cortico steroid therapy [13-20]. neoformans, is an yeast like fungus [1], first isolated from a clinical Pulmonary Cryptococcosis may be presenting as pleural effusions, specimen by Busse in the same year from Germany [2]. Cryptococci solitary or multiple masses, glass-ground interstitial opacities, dense are a saprophytic fungi present in soil contaminated with bird consolidations, patchy, segmented or lobar air space consolidation droppings mainly of pigeons, roosting sites and decaying vegetables (cryptococcal pneumonia) and nodular and reticulonodular cavities. [3]. Previous reports have also showed the presence of Cryptococcus Differential diagnosis of pulmonary cryptococcosis should be done spp colonized in the nasopharynx and on skin of healthy individuals with pneumonia [21,22]. Review of literature showed only two previous [4]. Belonging to Basidiomyctes group of fungi Cryptococcus spp reported cases of pulmonary cryptococcosis presenting as acute primarily infects central nervous system causing meningoencephalitis respiratory failure [7,23,24].
    [Show full text]
  • Environmental Factors That Contribute to the Maintenance of Cryptococcus Neoformans Pathogenesis
    microorganisms Review Environmental Factors That Contribute to the Maintenance of Cryptococcus neoformans Pathogenesis Maphori Maliehe, Mathope A. Ntoi, Shayanki Lahiri, Olufemi S. Folorunso , Adepemi O. Ogundeji , Carolina H. Pohl and Olihile M. Sebolai * Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein 9301, Free State, South Africa; [email protected] (M.M.); [email protected] (M.A.N.); [email protected] (S.L.); [email protected] (O.S.F.); [email protected] (A.O.O.); [email protected] (C.H.P.) * Correspondence: [email protected]; Tel.: +27-(0)51-401-2004 Received: 15 November 2019; Accepted: 11 December 2019; Published: 28 January 2020 Abstract: The ability of microorganisms to colonise and display an intracellular lifestyle within a host body increases their fitness to survive and avoid extinction. This host–pathogen association drives microbial evolution, as such organisms are under selective pressure and can become more pathogenic. Some of these microorganisms can quickly spread through the environment via transmission. The non-transmittable fungal pathogens, such as Cryptococcus, probably return into the environment upon decomposition of the infected host. This review analyses whether re-entry of the pathogen into the environment causes restoration of its non-pathogenic state or whether environmental factors and parameters assist them in maintaining pathogenesis. Cryptococcus (C.) neoformans is therefore used as a model organism to evaluate the impact of environmental stress factors that aid the survival and pathogenesis of C. neoformans intracellularly and extracellularly. Keywords: Cryptococcus; environmental factors; pathogenesis; survival; virulence factors; transcriptional factors; signalling factors 1. Introduction The genus Cryptococcus is defined by basidiomycetous fungi that can transform into a yeast state [1].
    [Show full text]
  • Laboratory Manual for Diagnosis of Fungal Opportunistic Infections in HIV/AIDS Patients
    The human immunodeficiency virus per se does not kill the infected individuals. Instead, it weakens the body's ability to fight disease. Infections which are rarely seen in those with normal immune systems can be deadly to those with HIV. People with HIV can get many infections (known as opportunistic infections, or OIs). Many of these illnesses are very serious and require treatment. Some can be prevented. Of the several OIs that cause morbidity and mortality in HIV infected individuals those belonging to various genera of fungi have assumed great importance in recent past. Since these OIs were earlier considered as nonpathogenic, the diagnostic services for confirmation of their causative role need to be strengthened. This document is an endeavour in this direction and hopefully shall be useful in establishing early diagnosis of fungal OIs in HIV infected people thus assuring rapid institution of specific treatment. Laboratory manual for diagnosis of fungal opportunistic infections World Health House Indraprastha Estate, in HIV/AIDS patients Mahatma Gandhi Marg, New Delhi-110002, India Website: www.searo.who.int SEA-HLM-401 SEA-HLM-401 Distribution: General Laboratory manual for diagnosis of fungal opportunistic infections in HIV/AIDS patients Regional Office for South-East Asia © World Health Organization 2009 All rights reserved. Requests for publications, or for permission to reproduce or translate WHO publications – whether for sale or for noncommercial distribution – can be obtained from Publishing and Sales, World Health Organization, Regional Office for South-East Asia, Indraprastha Estate, Mahatma Gandhi Marg, New Delhi 110 002, India (fax: +91 11 23370197; e-mail: [email protected]).
    [Show full text]
  • Kwon-Chung Et Al (2014)
    Downloaded from http://perspectivesinmedicine.cshlp.org/ at The University of Manchester Library on July 5, 2018 - Published by Cold Spring Harbor Laboratory Press Cryptococcus neoformans and Cryptococcus gattii, the Etiologic Agents of Cryptococcosis Kyung J. Kwon-Chung1, James A. Fraser2, Tamara L. Doering3, Zhuo A. Wang3, Guilhem Janbon4, Alexander Idnurm5, and Yong-Sun Bahn6 1Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892 2Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland 4072, Australia 3Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110 4Unite´ Biologie et Pathoge´nicite´ Fongiques, Institut Pasteur, 75015 Paris, France 5Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri, Kansas City, Missouri 64110 6Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 120–749, Republic of Korea Correspondence: [email protected] Cryptococcus neoformans and Cryptococcus gattii are the two etiologic agents of crypto- coccosis. They belong to the phylum Basidiomycota and can be readily distinguished from other pathogenic yeasts such as Candida by the presence of a polysaccharide capsule, formation of melanin, and urease activity, which all function as virulence determinants. Infection proceeds via inhalation and subsequent dissemination to the central nervous
    [Show full text]
  • Biology, Systematics and Clinical Manifestations of Zygomycota Infections
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by IBB PAS Repository Biology, systematics and clinical manifestations of Zygomycota infections Anna Muszewska*1, Julia Pawlowska2 and Paweł Krzyściak3 1 Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawiskiego 5a, 02-106 Warsaw, Poland; [email protected], [email protected], tel.: +48 22 659 70 72, +48 22 592 57 61, fax: +48 22 592 21 90 2 Department of Plant Systematics and Geography, University of Warsaw, Al. Ujazdowskie 4, 00-478 Warsaw, Poland 3 Department of Mycology Chair of Microbiology Jagiellonian University Medical College 18 Czysta Str, PL 31-121 Krakow, Poland * to whom correspondence should be addressed Abstract Fungi cause opportunistic, nosocomial, and community-acquired infections. Among fungal infections (mycoses) zygomycoses are exceptionally severe with mortality rate exceeding 50%. Immunocompromised hosts, transplant recipients, diabetic patients with uncontrolled keto-acidosis, high iron serum levels are at risk. Zygomycota are capable of infecting hosts immune to other filamentous fungi. The infection follows often a progressive pattern, with angioinvasion and metastases. Moreover, current antifungal therapy has often an unfavorable outcome. Zygomycota are resistant to some of the routinely used antifungals among them azoles (except posaconazole) and echinocandins. The typical treatment consists of surgical debridement of the infected tissues accompanied with amphotericin B administration. The latter has strong nephrotoxic side effects which make it not suitable for prophylaxis. Delayed administration of amphotericin and excision of mycelium containing tissues worsens survival prognoses. More than 30 species of Zygomycota are involved in human infections, among them Mucorales are the most abundant.
    [Show full text]
  • Inositol Polyphosphate Kinases, Fungal Virulence and Drug Discovery
    Journal of Fungi Review Inositol Polyphosphate Kinases, Fungal Virulence and Drug Discovery Cecilia Li 1, Sophie Lev 1, Adolfo Saiardi 2, Desmarini Desmarini 1, Tania C. Sorrell 1,3,4 and Julianne T. Djordjevic 1,3,4,* 1 Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145, Australia; [email protected] (C.L.); [email protected] (S.L.); [email protected] (D.D.); [email protected] (T.C.S.) 2 Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK; [email protected] 3 Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Westmead, NSW 2145, Australia 4 Westmead Hospital, Westmead, NSW 2145, Australia * Correspondence: [email protected]; Tel.: +61-2-8627-3420 Academic Editor: Maurizio Del Poeta Received: 22 July 2016; Accepted: 30 August 2016; Published: 6 September 2016 Abstract: Opportunistic fungi are a major cause of morbidity and mortality world-wide, particularly in immunocompromised individuals. Developing new treatments to combat invasive fungal disease is challenging given that fungal and mammalian host cells are eukaryotic, with similar organization and physiology. Even therapies targeting unique fungal cell features have limitations and drug resistance is emerging. New approaches to the development of antifungal drugs are therefore needed urgently. Cryptococcus neoformans, the commonest cause of fungal meningitis worldwide, is an accepted model for studying fungal pathogenicity and driving drug discovery. We recently characterized a phospholipase C (Plc1)-dependent pathway in C. neoformans comprising of sequentially-acting inositol polyphosphate kinases (IPK), which are involved in synthesizing inositol polyphosphates (IP).
    [Show full text]
  • Multiple GAL Pathway Gene Clusters Evolved Independently and by Different Mechanisms in Fungi
    Multiple GAL pathway gene clusters evolved independently and by different mechanisms in fungi Jason C. Slot and Antonis Rokas1 Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235 Edited* by John Doebley, University of Wisconsin, Madison, WI, and approved April 23, 2010 (received for review December 14, 2009) A notable characteristic of fungal genomes is that genes involved in 4-epimerase) domain, but not in other fungal lineages. In the successive steps of a metabolic pathway are often physically linked second step, α-D-galactose is phosphorylated into α-D-galactose- or clustered. To investigate how such clusters of functionally related 1-phosphate by Gal1p (galactokinase), whereas in the third step, genes are assembled and maintained, we examined the evolution of UDP is transferred from UDP-α-D-glucose-1-phosphate to α-D- gene sequences and order in the galactose utilization (GAL)pathway galactose-1-phosphate via Gal7p (galactose-1-phosphate uridylyl in whole-genome data from 80 diverse fungi. We found that GAL transferase), thereby freeing glucose-1-phosphate. In the fourth gene clusters originated independently and by different mechanisms and final step, UDP-α-D-galactose-1-phosphate is used to regen- in three unrelated yeast lineages. Specifically, the GAL cluster found erate UDP-α-D-glucose-1-phosphate by the epimerase domain in Saccharomyces and Candida yeasts originated through the reloca- of Gal10p. tion of native unclustered genes, whereas the GAL cluster of Schiz- Whereas GAL1, GAL7, and GAL10 are unclustered in most osaccharomyces yeasts was acquired through horizontal gene trans- fungi (23–27), they are clustered in S.
    [Show full text]
  • The Host Immune Response to Scedosporium/Lomentospora
    Journal of Fungi Review The Host Immune Response to Scedosporium/Lomentospora Idoia Buldain, Leire Martin-Souto , Aitziber Antoran, Maialen Areitio , Leire Aparicio-Fernandez , Aitor Rementeria * , Fernando L. Hernando and Andoni Ramirez-Garcia * Fungal and Bacterial Biomics Research Group, Department of Immunology, Microbiology and Parasitology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain; [email protected] (I.B.); [email protected] (L.M.-S.); [email protected] (A.A.); [email protected] (M.A.); [email protected] (L.A.-F.); fl[email protected] (F.L.H.) * Correspondence: [email protected] (A.R.); [email protected] (A.R.-G.) Abstract: Infections caused by the opportunistic pathogens Scedosporium/Lomentospora are on the rise. This causes problems in the clinic due to the difficulty in diagnosing and treating them. This review collates information published on immune response against these fungi, since an understanding of the mechanisms involved is of great interest in developing more effective strategies against them. Sce- dosporium/Lomentospora cell wall components, including peptidorhamnomannans (PRMs), α-glucans and glucosylceramides, are important immune response activators following their recognition by TLR2, TLR4 and Dectin-1 and through receptors that are yet unknown. After recognition, cytokine synthesis and antifungal activity of different phagocytes and epithelial cells is species-specific, high- lighting the poor response by microglial cells against L. prolificans. Moreover, a great number of Scedosporium/Lomentospora antigens have been identified, most notably catalase, PRM and Hsp70 for their potential medical applicability. Against host immune response, these fungi contain evasion mechanisms, inducing host non-protective response, masking fungal molecular patterns, destructing host defense proteins and decreasing oxidative killing.
    [Show full text]