1
|
Böttcher B, Kienast SD, Leufken J, Eggers C, Sharma P, Leufken CM, Morgner B, Drexler HCA, Schulz D, Allert S, Jacobsen ID, Vylkova S, Leidel SA, Brunke S. A highly conserved tRNA modification contributes to C. albicans filamentation and virulence. Microbiol Spectr 2024; 12:e0425522. [PMID: 38587411 PMCID: PMC11064501 DOI: 10.1128/spectrum.04255-22] [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: 10/18/2022] [Accepted: 01/18/2024] [Indexed: 04/09/2024] Open
Abstract
tRNA modifications play important roles in maintaining translation accuracy in all domains of life. Disruptions in the tRNA modification machinery, especially of the anticodon stem loop, can be lethal for many bacteria and lead to a broad range of phenotypes in baker's yeast. Very little is known about the function of tRNA modifications in host-pathogen interactions, where rapidly changing environments and stresses require fast adaptations. We found that two closely related fungal pathogens of humans, the highly pathogenic Candida albicans and its much less pathogenic sister species, Candida dubliniensis, differ in the function of a tRNA-modifying enzyme. This enzyme, Hma1, exhibits species-specific effects on the ability of the two fungi to grow in the hypha morphology, which is central to their virulence potential. We show that Hma1 has tRNA-threonylcarbamoyladenosine dehydratase activity, and its deletion alters ribosome occupancy, especially at 37°C-the body temperature of the human host. A C. albicans HMA1 deletion mutant also shows defects in adhesion to and invasion into human epithelial cells and shows reduced virulence in a fungal infection model. This links tRNA modifications to host-induced filamentation and virulence of one of the most important fungal pathogens of humans.IMPORTANCEFungal infections are on the rise worldwide, and their global burden on human life and health is frequently underestimated. Among them, the human commensal and opportunistic pathogen, Candida albicans, is one of the major causative agents of severe infections. Its virulence is closely linked to its ability to change morphologies from yeasts to hyphae. Here, this ability is linked-to our knowledge for the first time-to modifications of tRNA and translational efficiency. One tRNA-modifying enzyme, Hma1, plays a specific role in C. albicans and its ability to invade the host. This adds a so-far unknown layer of regulation to the fungal virulence program and offers new potential therapeutic targets to fight fungal infections.
Collapse
Affiliation(s)
- Bettina Böttcher
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Sandra D. Kienast
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Johannes Leufken
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Cristian Eggers
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Puneet Sharma
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Christine M. Leufken
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Bianka Morgner
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Hannes C. A. Drexler
- Bioanalytical Mass Spectrometry Unit, Max Planck Institute for Molecular Biomedicine, Münster, Germany
| | - Daniela Schulz
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Stefanie Allert
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Ilse D. Jacobsen
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Slavena Vylkova
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Sebastian A. Leidel
- Max Planck Research Group for RNA Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Research Group for Cellular RNA Biochemistry, Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| |
Collapse
|
2
|
Yang L, Cheng T, Shao J. Perspective on receptor-associated immune response to Candida albicans single and mixed infections: Implications for therapeutics in oropharyngeal candidiasis. Med Mycol 2023; 61:myad077. [PMID: 37533203 DOI: 10.1093/mmy/myad077] [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: 04/04/2023] [Revised: 07/11/2023] [Accepted: 07/25/2023] [Indexed: 08/04/2023] Open
Abstract
Oropharyngeal candidiasis (OPC), commonly known as 'thrush', is an oral infection that usually dismantles oral mucosal integrity and malfunctions local innate and adaptive immunities in compromised individuals. The major pathogen responsible for the occurrence and progression of OPC is the dimorphic opportunistic commensal Candida albicans. However, the incidence induced by non-albicans Candida species including C. glabrata, C. tropicalis, C. dubliniensis, C. parapsilosis, and C. krusei are increasing in company with several oral bacteria, such as Streptococcus mutans, S. gordonii, S. epidermidis, and S. aureus. In this review, the microbiological and infection features of C. albicans and its co-contributors in the pathogenesis of OPC are outlined. Since the invasion and concomitant immune response lie firstly on the recognition of oral pathogens through diverse cellular surface receptors, we subsequently emphasize the roles of epidermal growth factor receptor, ephrin-type receptor 2, human epidermal growth factor receptor 2, and aryl hydrocarbon receptor located on oral epithelial cells to delineate the underlying mechanism by which host immune recognition to oral pathogens is mediated. Based on these observations, the therapeutic approaches to OPC comprising conventional and non-conventional antifungal agents, fungal vaccines, cytokine and antibody therapies, and antimicrobial peptide therapy are finally overviewed. In the face of newly emerging life-threatening microbes (C. auris and SARS-CoV-2), risks (biofilm formation and interconnected translocation among diverse organs), and complicated clinical settings (HIV and oropharyngeal cancer), the research on OPC is still a challenging task.
Collapse
Affiliation(s)
- Liu Yang
- Laboratory of Anti-infection and Immunity, College of Integrated Chinese and Western Medicine (College of Life Science), Anhui University of Chinese Medicine, Zhijing Building, 350 Longzihu Road, Xinzhan District, Hefei 230012, P. R. China
| | - Ting Cheng
- Laboratory of Anti-infection and Immunity, College of Integrated Chinese and Western Medicine (College of Life Science), Anhui University of Chinese Medicine, Zhijing Building, 350 Longzihu Road, Xinzhan District, Hefei 230012, P. R. China
| | - Jing Shao
- Laboratory of Anti-infection and Immunity, College of Integrated Chinese and Western Medicine (College of Life Science), Anhui University of Chinese Medicine, Zhijing Building, 350 Longzihu Road, Xinzhan District, Hefei 230012, P. R. China
- Institute of Integrated Traditional Chinese and Western Medicine, Anhui Academy of Chinese Medicine, Zhijing Building, 350 Longzihu Road, Xinzhan District, Hefei 230012, P. R. China
| |
Collapse
|
3
|
Similarities and Differences among Species Closely Related to Candida albicans: C. tropicalis, C. dubliniensis, and C. auris. Cell Microbiol 2022. [DOI: 10.1155/2022/2599136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Although Candida species are widespread commensals of the microflora of healthy individuals, they are also among the most important human fungal pathogens that under certain conditions can cause diseases (candidiases) of varying severity ranging from mild superficial infections of the mucous membranes to life-threatening systemic infections. So far, the vast majority of research aimed at understanding the molecular basis of pathogenesis has been focused on the most common species—Candida albicans. Meanwhile, other closely related species belonging to the CTG clade, namely, Candida tropicalis and Candida dubliniensis, are becoming more important in clinical practice, as well as a relatively newly identified species, Candida auris. Despite the close relationship of these microorganisms, it seems that in the course of evolution, they have developed distinct biochemical, metabolic, and physiological adaptations, which they use to fit to commensal niches and achieve full virulence. Therefore, in this review, we describe the current knowledge on C. tropicalis, C. dubliniensis, and C. auris virulence factors, the formation of a mixed species biofilm and mutual communication, the environmental stress response and related changes in fungal cell metabolism, and the effect of pathogens on host defense response and susceptibility to antifungal agents used, highlighting differences with respect to C. albicans. Special attention is paid to common diagnostic problems resulting from similarities between these species and the emergence of drug resistance mechanisms. Understanding the different strategies to achieve virulence, used by important opportunistic pathogens of the genus Candida, is essential for proper diagnosis and treatment.
Collapse
|
4
|
Cvanova M, Ruzicka F, Kukletova M, Lipovy B, Gachova D, Izakovicova Holla L, Danek Z, Hola V, Bartosova M, Jarkovsky J, Dusek L, Borilova Linhartova P. Candida species and selected behavioral factors co-associated with severe early childhood caries: Case-control study. Front Cell Infect Microbiol 2022; 12:943480. [PMID: 35959372 PMCID: PMC9357982 DOI: 10.3389/fcimb.2022.943480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 07/04/2022] [Indexed: 11/25/2022] Open
Abstract
Severe Early Childhood Caries (sECC) is a multifactorial disease associated with the occurrence of specific oral microorganisms and other environmental, behavioral, and genetic factors. This study aimed to construct a multivariable model including the occurrence of Candida spp. and selected behavioral factors (length of breastfeeding, serving sweet beverages and beginning of brushing child’s teeth) to determine their relationships to the occurrence of sECC. In this case-control study 164 children with sECC and 147 children without dental caries were included. MALDI-TOF MS and multiplex qPCR were used to identify Candida spp. and selected bacteria in dental plaque samples, respectively. A questionnaire on oral hygiene, diet, and children’s health was filled in by the parents. The constructed multivariable logistic regression model showed an independent influence of the microbial and behavioral factors in sECC etiopathogenesis. The occurrence of C. albicans and C. dubliniensis was associated with higher odds of sECC development (odds ratio, OR: 9.62 and 16.93, respectively), together with breastfeeding of 6 months or less (OR: 2.71), exposure to sweet beverages (OR: 3.77), and starting to brush child’s teeth after the 12th month of age (OR: 4.10), all statistically significant (p < 0.01). Considering the high occurrence of C. albicans and C. dubliniensis in dental plaque in children with sECC, we propose them as “keystone pathogens” and risk factors for sECC. The models showed that presence of specific species of Candida in dental plaque may be a better descriptor of sECC than the mentioned behavioral factors.
Collapse
Affiliation(s)
- Michaela Cvanova
- RECETOX, Faculty of Science, Masaryk University Kotlarska 2, Brno, Czechia
- Institute of Biostatistics and Analyses, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Filip Ruzicka
- Clinic of Microbiology, Institution Shared with St. Anne´s University Hospital, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Martina Kukletova
- Clinic of Stomatology, Institution Shared with St. Anne´s University Hospital, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Bretislav Lipovy
- Clinic of Burns and Plastic Surgery, Institution shared with University Hospital Brno, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Daniela Gachova
- RECETOX, Faculty of Science, Masaryk University Kotlarska 2, Brno, Czechia
| | - Lydie Izakovicova Holla
- Clinic of Stomatology, Institution Shared with St. Anne´s University Hospital, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Zdenek Danek
- RECETOX, Faculty of Science, Masaryk University Kotlarska 2, Brno, Czechia
- Clinic of Maxillofacial Surgery, Institution shared with the University Hospital Brno, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Veronika Hola
- Clinic of Microbiology, Institution Shared with St. Anne´s University Hospital, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Michaela Bartosova
- Clinic of Stomatology, Institution Shared with St. Anne´s University Hospital, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Jiri Jarkovsky
- Institute of Biostatistics and Analyses, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Ladislav Dusek
- Institute of Biostatistics and Analyses, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Petra Borilova Linhartova
- RECETOX, Faculty of Science, Masaryk University Kotlarska 2, Brno, Czechia
- Clinic of Stomatology, Institution Shared with St. Anne´s University Hospital, Faculty of Medicine, Masaryk University, Brno, Czechia
- Clinic of Maxillofacial Surgery, Institution shared with the University Hospital Brno, Faculty of Medicine, Masaryk University, Brno, Czechia
- Department of Pathophysiology, Faculty of Medicine, Masaryk University, Brno, Czechia
- *Correspondence: Petra Borilova Linhartova,
| |
Collapse
|
5
|
Abstract
Candidalysin is the first cytolytic peptide toxin identified in any human fungal pathogen. Candidalysin is secreted by Candida albicans and is critical for driving infection and host immune responses in several model systems. However, Candida infections are also caused by non-C. albicans species. Here, we identify and characterize orthologs of C. albicans candidalysin in C. dubliniensis and C. tropicalis. The candidalysins have different amino acid sequences, are amphipathic, and adopt a predominantly α-helical secondary structure in solution. Comparative functional analysis demonstrates that each candidalysin causes epithelial damage and calcium influx and activates intracellular signaling pathways and cytokine secretion. Importantly, C. dubliniensis and C. tropicalis candidalysins have higher damaging and activation potential than C. albicans candidalysin and exhibit more rapid membrane binding and disruption, although both fungal species cause less damage to epithelial cells than C. albicans. This study identifies the first family of peptide cytolysins in human-pathogenic fungi. IMPORTANCE Pathogenic fungi kill an estimated 1.5 million people every year. Recently, we discovered that the fungal pathogen Candida albicans secretes a peptide toxin called candidalysin during mucosal infection. Candidalysin causes damage to host cells, a process that supports disease progression. However, fungal infections are also caused by Candida species other than C. albicans. In this work, we identify and characterize two additional candidalysin toxins present in the related fungal pathogens C. dubliniensis and C. tropicalis. While the three candidalysins have different amino acid sequences, all three toxins are α-helical and amphipathic. Notably, the candidalysins from C. dubliniensis and C. tropicalis are more potent at inducing cell damage, calcium influx, mitogen-activated protein kinase signaling, and cytokine responses than C. albicans candidalysin, with the C. dubliniensis candidalysin having the most rapid membrane binding kinetics. These observations identify the candidalysins as the first family of peptide toxins in human-pathogenic fungi.
Collapse
|
6
|
The Interplay Between Neutral and Adaptive Processes Shapes Genetic Variation During Candida Species Evolution. CURRENT CLINICAL MICROBIOLOGY REPORTS 2021. [DOI: 10.1007/s40588-021-00171-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
7
|
Rizkalla C, Ottombrino J, Malik F. Colovesicular fistula from Candida dubliniensis in an immunocompetent resulting in poor outcome. J Community Hosp Intern Med Perspect 2020; 10:242-244. [PMID: 32850072 PMCID: PMC7426985 DOI: 10.1080/20009666.2020.1760444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
is a rare fungal opportunistic infection originally isolated from the oral cavity of severely immunocompromised individuals. We present a case of a candidiasis infection in a patient with only decompensated liver cirrhosis and diabetes mellitus as his immunocompromising risk factors, resulting in severe fungemia and death within 5 days despite being on antifungal therapy.
Collapse
|
8
|
Abu Khalaf S, Elkeeb A, Salzer W, Regunath H. Circumferential iris lesions in a male with cirrhosis caused by Candida dublinensis endophthalmitis. IDCases 2019; 18:e00621. [PMID: 31692598 PMCID: PMC6804899 DOI: 10.1016/j.idcr.2019.e00621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/08/2019] [Accepted: 08/08/2019] [Indexed: 11/03/2022] Open
Affiliation(s)
- Suha Abu Khalaf
- Department of Medicine, University of Missouri, Columbia, MO 65212, United States
| | - Ahmed Elkeeb
- Department of Ophthalmology, University of Missouri, Columbia, MO 65212, United States
| | - William Salzer
- Department of Medicine - Division of Infectious Diseases, University of Missouri, Columbia, MO 65212, United States
| | - Hariharan Regunath
- Department of Medicine - Divisions of Pulmonary, Critical Care Medicine and Infectious Diseases, University of Missouri, Columbia, MO 65212, United States
| |
Collapse
|
9
|
Combined Candida dubliniensis and Candida albicans Keratitis following a Chemical Injury. Case Rep Ophthalmol Med 2019; 2019:7628126. [PMID: 31214370 PMCID: PMC6535822 DOI: 10.1155/2019/7628126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 04/28/2019] [Indexed: 11/20/2022] Open
Abstract
Candida dubliniensis is an uncommon source of ocular infections and has only been reported in a single previous case of keratitis. This report documents the course of a combined Candida dubliniensis and Candida albicans keratitis following a chemical injury. Antifungal sensitivities of the two different Candida species are also demonstrated.
Collapse
|
10
|
Regulation of Candida albicans Hyphal Morphogenesis by Endogenous Signals. J Fungi (Basel) 2019; 5:jof5010021. [PMID: 30823468 PMCID: PMC6463138 DOI: 10.3390/jof5010021] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 02/25/2019] [Accepted: 02/26/2019] [Indexed: 12/15/2022] Open
Abstract
Candida albicans is a human commensal fungus that is able to assume several morphologies, including yeast, hyphal, and pseudohyphal. Under a range of conditions, C. albicans performs a regulated switch to the filamentous morphology, characterized by the emergence of a germ tube from the yeast cell, followed by a mold-like growth of branching hyphae. This transition from yeast to hyphal growth has attracted particular attention, as it has been linked to the virulence of C. albicans as an opportunistic human pathogen. Signal transduction pathways that mediate the induction of the hyphal transcription program upon the imposition of external stimuli have been extensively investigated. However, the hyphal morphogenesis transcription program can also be induced by internal cellular signals, such as inhibition of cell cycle progression, and conversely, the inhibition of hyphal extension can repress hyphal-specific gene expression, suggesting that endogenous cellular signals are able to modulate hyphal gene expression as well. Here we review recent developments in the regulation of the hyphal morphogenesis of C. albicans, with emphasis on endogenous morphogenetic signals.
Collapse
|
11
|
Chong PP, Chin VK, Wong WF, Madhavan P, Yong VC, Looi CY. Transcriptomic and Genomic Approaches for Unravelling Candida albicans Biofilm Formation and Drug Resistance-An Update. Genes (Basel) 2018; 9:genes9110540. [PMID: 30405082 PMCID: PMC6266447 DOI: 10.3390/genes9110540] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/29/2018] [Accepted: 10/30/2018] [Indexed: 11/17/2022] Open
Abstract
Candida albicans is an opportunistic fungal pathogen, which causes a plethora of superficial, as well as invasive, infections in humans. The ability of this fungus in switching from commensalism to active infection is attributed to its many virulence traits. Biofilm formation is a key process, which allows the fungus to adhere to and proliferate on medically implanted devices as well as host tissue and cause serious life-threatening infections. Biofilms are complex communities of filamentous and yeast cells surrounded by an extracellular matrix that confers an enhanced degree of resistance to antifungal drugs. Moreover, the extensive plasticity of the C. albicans genome has given this versatile fungus the added advantage of microevolution and adaptation to thrive within the unique environmental niches within the host. To combat these challenges in dealing with C. albicans infections, it is imperative that we target specifically the molecular pathways involved in biofilm formation as well as drug resistance. With the advent of the -omics era and whole genome sequencing platforms, novel pathways and genes involved in the pathogenesis of the fungus have been unraveled. Researchers have used a myriad of strategies including transcriptome analysis for C. albicans cells grown in different environments, whole genome sequencing of different strains, functional genomics approaches to identify critical regulatory genes, as well as comparative genomics analysis between C. albicans and its closely related, much less virulent relative, C. dubliniensis, in the quest to increase our understanding of the mechanisms underlying the success of C. albicans as a major fungal pathogen. This review attempts to summarize the most recent advancements in the field of biofilm and antifungal resistance research and offers suggestions for future directions in therapeutics development.
Collapse
Affiliation(s)
- Pei Pei Chong
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor's University Malaysia, Subang Jaya, 47500 Selangor, Malaysia.
| | - Voon Kin Chin
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor's University Malaysia, Subang Jaya, 47500 Selangor, Malaysia.
| | - Won Fen Wong
- Department of Microbiology, Faculty of Medicine, University Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Priya Madhavan
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University Malaysia, Subang Jaya, 47500 Selangor, Malaysia.
| | - Voon Chen Yong
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor's University Malaysia, Subang Jaya, 47500 Selangor, Malaysia.
| | - Chung Yeng Looi
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor's University Malaysia, Subang Jaya, 47500 Selangor, Malaysia.
| |
Collapse
|
12
|
Romo JA, Pierce CG, Esqueda M, Hung CY, Saville SP, Lopez-Ribot JL. In Vitro Characterization of a Biaryl Amide Anti-virulence Compound Targeting Candida albicans Filamentation and Biofilm Formation. Front Cell Infect Microbiol 2018; 8:227. [PMID: 30042929 PMCID: PMC6048184 DOI: 10.3389/fcimb.2018.00227] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 06/18/2018] [Indexed: 12/26/2022] Open
Abstract
We have previously identified a small molecule compound, N-[3-(allyloxy)-phenyl]-4-methoxybenzamide (9029936), that exerts potent inhibitory activity against filamentation and biofilm formation by the Candida albicans SC5314 strain and represents a lead candidate for the development of anti-virulence approaches against C. albicans infections. Here we present data from a series of experiments to further characterize its in vitro activity and drug-like characteristics. We demonstrate the activity of this compound against a panel of C. albicans clinical isolates, including several displaying resistance to current antifungals; as well as against a set of C. albicans gain of function strains in key transcriptional regulators of antifungal drug resistance. The compound also inhibits filamentation and biofilm formation in the closely related species C. dubliniensis, but not C. glabrata or C. tropicalis. Combinatorial studies reveal the potential of compound 9029936 to be used together with currently available conventional antifungals. Results of serial passage experiments indicate that repeated exposure to this compound does not elicit resistance. Viability staining of C. albicans in the presence of high concentrations of compound 9029936 confirms that the compound is not toxic to fungal cells, and cytological staining using image flow cytometry analysis reveals that treatment with the lead compound affects hyphal length, with additional effects on cell wall and integrity of the membrane system. In vitro pharmacological profiling provides further evidence that the lead compound displays a safe profile, underscoring its excellent “drug-like” characteristics. Altogether these results confirm the potential of this compound to be further developed as a true anti-virulence agent for the treatment of C. albicans infections, including those refractory to treatment with conventional antifungal agents.
Collapse
Affiliation(s)
- Jesus A Romo
- Department of Biology, South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Christopher G Pierce
- Department of Biology, University of the Incarnate Word, San Antonio, TX, United States
| | - Marisol Esqueda
- Department of Biology, South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Chiung-Yu Hung
- Department of Biology, South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Stephen P Saville
- Department of Biology, South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Jose L Lopez-Ribot
- Department of Biology, South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States
| |
Collapse
|
13
|
Kianipour S, Ardestani ME, Dehghan P. Identification of Candida albicans and Candida dubliniensis Species Isolated from Bronchoalveolar Lavage Samples Using Genotypic and Phenotypic Methods. Adv Biomed Res 2018; 7:66. [PMID: 29862215 PMCID: PMC5952538 DOI: 10.4103/abr.abr_138_17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Background Candida dubliniensis is a newly diagnosed species very similar to Candida albicans phenotypically and first discovered in the mouth of people with AIDS in 1995. Among the different phenotypic and genotypic methods, a cost-effective method should be selected which makes it possible to differentiate these similar species. Materials and Methods Polymerase chain reaction (PCR)-restriction fragment length polymorphism with MspI enzyme and the Duplex-PCR method were done by DNA extraction using boiling. The sequencing of the amplified ribosomal region was used to confirm the C. dubliniensis species. Direct examination and colony count of the yeasts were applied for bronchoalveolar lavage (BAL) samples and the growth rate of the yeasts were studied at 45°C. To understand the ability formation of chlamydoconidia in yeast isolates, they were separately cultured on the sunflower seed agar, wheat flour agar, and corn meal agar media. Results Fifty-nine (49.2%) yeast colonies were identified from the total of 120 BAL specimens. Twenty-nine isolated yeasts; including 17 (58.6%) of C. albicans/dubliniensis complex and 12 (41.4%) of nonalbicans isolates produced pseudohypha or blastoconidia in direct smear with a mean colony count of 42000 CFU/mL. C. albicans with the frequency of 15 (42.9%) were the most common isolated yeasts, whereas C. dubliniensis was identified in two nonHIV patients. Conclusion Sequencing of the replicated gene fragment is the best method for identifying the yeasts, but the determination of the species by phenotypic methods such as the creation of chlamydoconidia in sunflower seeds agar and wheat flour agar media can be cost-effective, have sensitivity and acceptable quality.
Collapse
Affiliation(s)
- Sahar Kianipour
- Department of Parasitology and Mycology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammad Emami Ardestani
- Department of Internal Medicine, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Parvin Dehghan
- Department of Parasitology and Mycology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| |
Collapse
|
14
|
Ortega-Riveros M, De-la-Pinta I, Marcos-Arias C, Ezpeleta G, Quindós G, Eraso E. Usefulness of the Non-conventional Caenorhabditis elegans Model to Assess Candida Virulence. Mycopathologia 2017; 182:785-795. [PMID: 28523422 DOI: 10.1007/s11046-017-0142-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 05/08/2017] [Indexed: 12/20/2022]
Abstract
Invasive candidiasis is caused mainly by Candida albicans, but other Candida species have increasing etiologies. These species show different virulence and susceptibility levels to antifungal drugs. The aims of this study were to evaluate the usefulness of the non-conventional model Caenorhabditis elegans to assess the in vivo virulence of seven different Candida species and to compare the virulence in vivo with the in vitro production of proteinases and phospholipases, hemolytic activity and biofilm development capacity. One culture collection strain of each of seven Candida species (C. albicans, Candida dubliniensis, Candida glabrata, Candida krusei, Candida metapsilosis, Candida orthopsilosis and Candida parapsilosis) was studied. A double mutant C. elegans AU37 strain (glp-4;sek-1) was infected with Candida by ingestion, and the analysis of nematode survival was performed in liquid medium every 24 h until 120 h. Candida establishes a persistent lethal infection in the C. elegans intestinal tract. C. albicans and C. krusei were the most pathogenic species, whereas C. dubliniensis infection showed the lowest mortality. C. albicans was the only species with phospholipase activity, was the greatest producer of aspartyl proteinase and had a higher hemolytic activity. C. albicans and C. krusei caused higher mortality than the rest of the Candida species studied in the C. elegans model of candidiasis.
Collapse
Affiliation(s)
- Marcelo Ortega-Riveros
- Departamento de Inmunología, Microbiología y Parasitología, Unidad de formación e investigación multidisciplinar 'Microbios y Salud' (UFI 11/25), Facultad de Medicina y Enfermería, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Bilbao, Spain
| | - Iker De-la-Pinta
- Departamento de Inmunología, Microbiología y Parasitología, Unidad de formación e investigación multidisciplinar 'Microbios y Salud' (UFI 11/25), Facultad de Medicina y Enfermería, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Bilbao, Spain
| | - Cristina Marcos-Arias
- Departamento de Inmunología, Microbiología y Parasitología, Unidad de formación e investigación multidisciplinar 'Microbios y Salud' (UFI 11/25), Facultad de Medicina y Enfermería, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Bilbao, Spain
| | - Guillermo Ezpeleta
- Departamento de Medicina Preventiva y Salud Pública, Facultad de Medicina y Enfermería, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Bilbao, Spain.,Servicio de Medicina Preventiva e Higiene Hospitalaria, Complejo Hospitalario de Navarra, Pamplona, Spain
| | - Guillermo Quindós
- Departamento de Inmunología, Microbiología y Parasitología, Unidad de formación e investigación multidisciplinar 'Microbios y Salud' (UFI 11/25), Facultad de Medicina y Enfermería, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Bilbao, Spain
| | - Elena Eraso
- Departamento de Inmunología, Microbiología y Parasitología, Unidad de formación e investigación multidisciplinar 'Microbios y Salud' (UFI 11/25), Facultad de Medicina y Enfermería, Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), Bilbao, Spain.
| |
Collapse
|
15
|
Asadzadeh M, Ahmad S, Al-Sweih N, Khan Z. Molecular Fingerprinting Studies Do Not Support Intrahospital Transmission of Candida albicans among Candidemia Patients in Kuwait. Front Microbiol 2017; 8:247. [PMID: 28270801 PMCID: PMC5318450 DOI: 10.3389/fmicb.2017.00247] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 02/06/2017] [Indexed: 12/20/2022] Open
Abstract
Candida albicans, a constituent of normal microbial flora of human mucosal surfaces, is a major cause of candidemia in immunocompromised individuals and hospitalized patients with other debilitating diseases. Molecular fingerprinting studies have suggested nosocomial transmission of C. albicans based on the presence of clusters or endemic genotypes in some hospitals. However, intrahospital strain transmission or a common source of infection has not been firmly established. We performed multilocus sequence typing (MLST) on 102 C. albicans bloodstream isolates (representing 92% of all culture-confirmed candidemia patients over a 31-month period at seven major hospitals) to identify patient-to-patient transmission or infection from a common source in Kuwait, a small country in the Middle East where consanguineous marriages are common. Repeat bloodstream isolates from six patients and nine surveillance cultures from other anatomic sites from six patients were also analyzed. Fifty-five isolates belonged to unique genotypes. Forty-seven isolates from 47 patients formed 16 clusters, with each cluster containing 2–9 isolates. Multiple isolates from the same patient from bloodstream or other anatomical sites yielded identical genotypes. We identified four cases of potential patient-to-patient transmission or infection from a common source based on association analysis between patients' clinical/epidemiological data and the corresponding MLST genotypes of eight C. albicans isolates. However, further fingerprinting by whole genome-based amplified fragment length polymorphism (AFLP) analysis yielded 8 different genotypes, ruling out intrahospital transmission of infection. The findings suggest that related strains of C. albicans exist in the community and fingerprinting by MLST alone may complicate hospital infection control measures during outbreak investigations.
Collapse
Affiliation(s)
- Mohammad Asadzadeh
- Department of Microbiology, Faculty of Medicine, Kuwait University Kuwait, Kuwait
| | - Suhail Ahmad
- Department of Microbiology, Faculty of Medicine, Kuwait University Kuwait, Kuwait
| | - Noura Al-Sweih
- Department of Microbiology, Faculty of Medicine, Kuwait University Kuwait, Kuwait
| | - Ziauddin Khan
- Department of Microbiology, Faculty of Medicine, Kuwait University Kuwait, Kuwait
| |
Collapse
|
16
|
Biotin Auxotrophy and Biotin Enhanced Germ Tube Formation in Candida albicans. Microorganisms 2016; 4:microorganisms4030037. [PMID: 27681931 PMCID: PMC5039597 DOI: 10.3390/microorganisms4030037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 09/07/2016] [Accepted: 09/14/2016] [Indexed: 11/17/2022] Open
Abstract
Due to the increased number of immunocompromised patients, infections with the pathogen Candida albicans have significantly increased in recent years. C. albicans transition from yeast to germ tubes is one of the essential factors for virulence. In this study we noted that Lee's medium, commonly used to induce filamentation, contained 500-fold more biotin than needed for growth and 40-fold more biotin than is typically added to growth media. Thus, we investigated the effects of excess biotin on growth rate and filamentation by C. albicans in different media. At 37 °C, excess biotin (4 µM) enhanced germ tube formation (GTF) ca. 10-fold in both Lee's medium and a defined glucose-proline medium, and ca. 4-fold in 1% serum. Two biotin precursors, desthiobiotin and 7-keto-8-aminopelargonic acid (KAPA), also stimulated GTF. During these studies we also noted an inverse correlation between the number of times the inoculum had been washed and the concentration of serum needed to stimulate GTF. C. albicans cells that had been washed eight times achieved 80% GTF with only 0.1% sheep serum. The mechanism by which 1-4 µM biotin enhances GTF is still unknown except to note that equivalent levels of biotin are needed to create an internal supply of stored biotin and biotinylated histones. Biotin did not restore filamentation for any of the four known filamentation defective mutants tested. C. albicans is auxotrophic for biotin and this biotin auxotrophy was fulfilled by biotin, desthiobiotin, or KAPA. However, biotin auxotrophy is not temperature dependent or influenced by the presence of 5% CO₂. Biotin starvation upregulated the biotin biosynthetic genes BIO2, BIO3, and BIO4 by 11-, 1500-, and 150-fold, respectively, and BIO2p is predicted to be mitochondrion-localized. Based on our findings, we suggest that biotin has two roles in the physiology of C. albicans, one as an enzymatic cofactor and another as a morphological regulator. Finally, we found no evidence supporting prior claims that C. albicans only forms hyphae at very low biotin (0.1 nM) growth conditions.
Collapse
|
17
|
Caplice N, Moran GP. Candida albicans exhibits enhanced alkaline and temperature induction of Efg1-regulated transcripts relative to Candida dubliniensis. GENOMICS DATA 2015; 6:130-5. [PMID: 26697354 PMCID: PMC4664712 DOI: 10.1016/j.gdata.2015.08.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 08/27/2015] [Indexed: 11/18/2022]
Abstract
Filamentous growth is an important virulence trait of the human pathogenic fungi within the genus Candida, and the greater propensity of C. albicans to form hyphae has been proposed to account for the greater virulence of this species relative to the less pathogenic species C. dubliniensis. In this meta-analysis, we compare the transcriptional response of C. dubliniensis and C. albicans to the individual environmental stimuli that shape the gene expression profiles during filamentation in 10% serum, namely alkaline pH, 37 °C and reduced cell density. We could identify conserved core temperature and pH responses, however many signature Efg1-regulated, hypha-induced transcripts (e.g. ECE1, HWP1) exhibited reduced or lack of induction in C. dubliniensis. Comparison of the activity of the HWP1 and ECE1 promoters in both species using GFP fusions showed a lag in serum induced fluorescence in C. dubliniensis relative to C. albicans and nutrient depletion was required for maximal expression of these Efg1-regulated transcripts in C. dubliniensis.
Collapse
|
18
|
Comparison of Switching and Biofilm Formation between MTL-Homozygous Strains of Candida albicans and Candida dubliniensis. EUKARYOTIC CELL 2015; 14:1186-202. [PMID: 26432632 DOI: 10.1128/ec.00146-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 09/23/2015] [Indexed: 11/20/2022]
Abstract
Candida albicans and Candida dubliniensis are highly related species that share the same main developmental programs. In C. albicans, it has been demonstrated that the biofilms formed by strains heterozygous and homozygous at the mating type locus (MTL) differ functionally, but studies rarely identify the MTL configuration. This becomes a particular problem in studies of C. dubliniensis, given that one-third of natural strains are MTL homozygous. For that reason, we have analyzed MTL-homozygous strains of C. dubliniensis for their capacity to switch from white to opaque, the stability of the opaque phenotype, CO2 induction of switching, pheromone induction of adhesion, the effects of minority opaque cells on biofilm thickness and dry weight, and biofilm architecture in comparison with C. albicans. Our results reveal that C. dubliniensis strains switch to opaque at lower average frequencies, exhibit a far lower level of opaque phase stability, are not stimulated to switch by high CO2, exhibit more variability in biofilm architecture, and most notably, form mature biofilms composed predominately of pseudohyphae rather than true hyphae. Therefore, while several traits of MTL-homozygous strains of C. dubliniensis appear to be degenerating or have been lost, others, most notably several related to biofilm formation, have been conserved. Within this context, the possibility is considered that C. dubliniensis is transitioning from a hypha-dominated to a pseudohypha-dominated biofilm and that aspects of C. dubliniensis colonization may provide insights into the selective pressures that are involved.
Collapse
|
19
|
Huyke J, Martin R, Walther G, Weber M, Kaerger K, Bougnoux ME, Elias J, Kurzai O. Candida albicans bloodstream isolates in a German university hospital are genetically heterogenous and susceptible to commonly used antifungals. Int J Med Microbiol 2015; 305:742-7. [PMID: 26324013 DOI: 10.1016/j.ijmm.2015.08.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
From an eight-year-span, 99 Candida bloodstream isolates were collected at the University Hospital Wuerzburg, Germany. In this study, all strains were analyzed using molecular and phenotypic typing methods. Confirmatory species identification revealed three isolates that were initially diagnosed as C. albicans to be actually C. dubliniensis. Two isolates contained a mixed culture of C. albicans and C. glabrata, in one of the specimens both species could be separated while it was not possible to recover C. albicans in the other sample. The remaining 95 C. albicans isolates were profiled by multilocus sequence typing (MLST). Phylogenetic analyses showed a highly heterogenous collection of strains, associated with many different clades and constituting a set of new diploid sequence types (DST). For all strains with identical DST, patient data were reviewed for potential nosocomial transmission. In addition, all isolates were tested for their susceptibility to amphotericin B, caspofungin, fluconazole, itraconazole, posaconazole and voriconazole. No clinically relevant resistance could be detected. Furthermore, these data underline that correlation between minimal inhibitory concentrations for caspofungin and anidulafungin is low.
Collapse
Affiliation(s)
- Johanna Huyke
- National Reference Center for Invasive Mycoses, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knoell Institute, Jena, Germany; Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology - Hans Knoell Institute, Jena, Germany
| | - Ronny Martin
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology - Hans Knoell Institute, Jena, Germany
| | - Grit Walther
- National Reference Center for Invasive Mycoses, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knoell Institute, Jena, Germany
| | - Michael Weber
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology - Hans Knoell Institute, Jena, Germany
| | - Kerstin Kaerger
- National Reference Center for Invasive Mycoses, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knoell Institute, Jena, Germany
| | - Marie-Elisabeth Bougnoux
- Institut Pasteur, Unité Biologie et Pathogénicité Fongiques INRA USC2019 Laboratoire de Parasitologie-Mycologie, Service de Microbiologie, Hôpital Necker-Enfants Malades, Université Paris Descartes, Faculté de Médecine, Paris, France
| | - Johannes Elias
- University of Wuerzburg, Institute of Hygiene and Microbiology, Wuerzburg, Germany
| | - Oliver Kurzai
- National Reference Center for Invasive Mycoses, Leibniz Institute for Natural Product Research and Infection Biology - Hans Knoell Institute, Jena, Germany; Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology - Hans Knoell Institute, Jena, Germany.
| |
Collapse
|
20
|
Whibley N, Gaffen SL. Beyond Candida albicans: Mechanisms of immunity to non-albicans Candida species. Cytokine 2015; 76:42-52. [PMID: 26276374 DOI: 10.1016/j.cyto.2015.07.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 07/27/2015] [Accepted: 07/28/2015] [Indexed: 12/29/2022]
Abstract
The fungal genus Candida encompasses numerous species that inhabit a variety of hosts, either as commensal microbes and/or pathogens. Candida species are a major cause of fungal infections, yet to date there are no vaccines against Candida or indeed any other fungal pathogen. Our knowledge of immunity to Candida mainly comes from studies on Candida albicans, the most frequent species associated with disease. However, non-albicans Candida (NAC) species also cause disease and their prevalence is increasing. Although research into immunity to NAC species is still at an early stage, it is becoming apparent that immunity to C. albicans differs in important ways from non-albicans species, with important implications for treatment, therapy and predicted demographic susceptibility. This review will discuss the current understanding of immunity to NAC species in the context of immunity to C. albicans, and highlight as-yet unanswered questions.
Collapse
Affiliation(s)
- Natasha Whibley
- Division of Rheumatology & Clinical Immunology, Dept. of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Sarah L Gaffen
- Division of Rheumatology & Clinical Immunology, Dept. of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA; Division of Rheumatology & Clinical Immunology, BST S702, 200 Lothrop St., Pittsburgh, PA 15261, USA.
| |
Collapse
|
21
|
Structure-based functional annotation of hypothetical proteins from Candida dubliniensis: a quest for potential drug targets. 3 Biotech 2015; 5:561-576. [PMID: 28324558 PMCID: PMC4522726 DOI: 10.1007/s13205-014-0256-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 09/30/2014] [Indexed: 12/24/2022] Open
Abstract
Candida dubliniensis is an emerging pathogenic yeast in humans and infections are usually restricted to mucosal parts of the body. However, its presence in specimens of immunocompromised individuals, especially in HIV-positive patients, is of major medical concern. There is a large fraction of genomes of C. dubliniensis in the database which are uncharacterized for their biochemical, biophysical, and/or cellular functions, and are identified as hypothetical proteins (HPs). Function annotation of Candida genome is, therefore, essentially required to facilitate the understanding of mechanisms of pathogenesis and biochemical pathways important for selecting novel therapeutic target. Here, we carried out an extensive analysis to explain the functional properties of genome, using available protein structure and function analysis tools. We successfully modeled the structures of eight HPs for which a template with moderate sequence similarity was available in the protein data bank. All modeled structures were analyzed and we found that these proteins may act as transporter, kinase, transferase, ketosteroid, isomerase, hydrolase, oxidoreductase, and binding targets for DNA and RNA. Since these unique HPs of Candida showed no homologs in humans, these proteins are expected to be a potential target for future antifungal therapy.
Collapse
|
22
|
Csr1/Zap1 Maintains Zinc Homeostasis and Influences Virulence in Candida dubliniensis but Is Not Coupled to Morphogenesis. EUKARYOTIC CELL 2015; 14:661-70. [PMID: 26002718 PMCID: PMC4486669 DOI: 10.1128/ec.00078-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 05/09/2015] [Indexed: 01/10/2023]
Abstract
The supply and intracellular homeostasis of trace metals are essential for every living organism. Therefore, the struggle for micronutrients between a pathogen and its host is an important determinant in the infection process. In this work, we focus on the acquisition of zinc by Candida dubliniensis, an emerging pathogen closely related to Candida albicans. We show that the transcription factor Csr1 is essential for C. dubliniensis to regulate zinc uptake mechanisms under zinc limitation: it governs the expression of the zinc transporter genes ZRT1, ZRT2, and ZRT3 and of the zincophore gene PRA1. Exclusively, artificial overexpression of ZRT2 partially rescued the growth defect of a csr1Δ/Δ mutant in a zinc-restricted environment. Importantly, we found that, in contrast to what is seen in C. albicans, Csr1 (also called Zap1) is not a major regulator of dimorphism in C. dubliniensis. However, although a csr1Δ/Δ strain showed normal germ tube formation, we detected a clear attenuation in virulence using an embryonated chicken egg infection model. We conclude that, unlike in C. albicans, Csr1 seems to be a virulence factor of C. dubliniensis that is not coupled to filamentation but is strongly linked to zinc acquisition during pathogenesis.
Collapse
|
23
|
Salzer HJF, Rolling T, Klupp EM, Schmiedel S. Hematogenous dissemination of Candida dubliniensis causing spondylodiscitis and spinal abscess in a HIV-1 and HCV-coinfected patient. Med Mycol Case Rep 2015; 8:17-20. [PMID: 25750857 PMCID: PMC4348452 DOI: 10.1016/j.mmcr.2015.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 01/31/2015] [Accepted: 02/23/2015] [Indexed: 12/15/2022] Open
Abstract
We report a case of spondylodiscitis and spinal abscess following haematogenous dissemination of the emerging yeast Candida dubliniensis in a human immunodeficiency virus-1 (HIV-1) and hepatitis C virus (HCV)-coinfected patient. Although C. dubliniensis is considered less virulent compared to its closest known relative Candida albicans, reports of severe fungal infections are increasing. This case indicates that the pathogenicity of C. dubliniensis may be higher than previously believed. Therefore fungal infections caused by this dimorph fungus should be kept in mind in immunocompromised patients with spondylodiscitis and spinal abscess.
Collapse
Affiliation(s)
- Helmut J F Salzer
- Department of Internal Medicine I, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Thierry Rolling
- Department of Internal Medicine I, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Eva-Maria Klupp
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Stefan Schmiedel
- Department of Internal Medicine I, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| |
Collapse
|
24
|
Haran J, Boyle H, Hokamp K, Yeomans T, Liu Z, Church M, Fleming AB, Anderson MZ, Berman J, Myers LC, Sullivan DJ, Moran GP. Telomeric ORFs (TLOs) in Candida spp. Encode mediator subunits that regulate distinct virulence traits. PLoS Genet 2014; 10:e1004658. [PMID: 25356803 PMCID: PMC4214616 DOI: 10.1371/journal.pgen.1004658] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 08/11/2014] [Indexed: 11/18/2022] Open
Abstract
The TLO genes are a family of telomere-associated ORFs in the fungal pathogens Candida albicans and C. dubliniensis that encode a subunit of the Mediator complex with homology to Med2. The more virulent pathogen C. albicans has 15 copies of the gene whereas the less pathogenic species C. dubliniensis has only two (CdTLO1 and CdTLO2). In this study we used C. dubliniensis as a model to investigate the role of TLO genes in regulating virulence and also to determine whether TLO paralogs have evolved to regulate distinct functions. A C. dubliniensis tlo1Δ/tlo2Δ mutant is unable to form true hyphae, has longer doubling times in galactose broth, is more susceptible to oxidative stress and forms increased levels of biofilm. Transcript profiling of the tlo1Δ/tlo2Δ mutant revealed increased expression of starvation responses in rich medium and retarded expression of hypha-induced transcripts in serum. ChIP studies indicated that Tlo1 binds to many ORFs including genes that exhibit high and low expression levels under the conditions analyzed. The altered expression of these genes in the tlo1Δ/tlo2Δ null mutant indicates roles for Tlo proteins in transcriptional activation and repression. Complementation of the tlo1Δ/tlo2Δ mutant with TLO1, but not TLO2, restored wild-type filamentous growth, whereas only TLO2 fully suppressed biofilm growth. Complementation with TLO1 also had a greater effect on doubling times in galactose broth. The different abilities of TLO1 and TLO2 to restore wild-type functions was supported by transcript profiling studies that showed that only TLO1 restored expression of hypha-specific genes (UME6, SOD5) and galactose utilisation genes (GAL1 and GAL10), whereas TLO2 restored repression of starvation-induced gene transcription. Thus, Tlo/Med2 paralogs encoding Mediator subunits regulate different virulence properties in Candida spp. and their expansion may account for the increased adaptability of C. albicans relative to other Candida species.
Collapse
Affiliation(s)
- John Haran
- Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Hannah Boyle
- Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Karsten Hokamp
- School of Genetics and Microbiology, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Tim Yeomans
- Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Zhongle Liu
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Michael Church
- School of Genetics and Microbiology, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Alastair B. Fleming
- School of Genetics and Microbiology, University of Dublin, Trinity College Dublin, Dublin, Ireland
| | - Matthew Z. Anderson
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Judith Berman
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel
| | - Lawrence C. Myers
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Derek J. Sullivan
- Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
- * E-mail: (DJS); (GPM)
| | - Gary P. Moran
- Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin, Ireland
- * E-mail: (DJS); (GPM)
| |
Collapse
|
25
|
Abstract
Candida species are the most common causes of fungal infection. Approximately 90% of infections are caused by five species: Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, and Candida krusei. Three (C. albicans, C. tropicalis, and C. parapsilosis) belong to the CTG clade, in which the CTG codon is translated as serine and not leucine. C. albicans remains the most commonly isolated but is decreasing relative to the other species. The increasing incidence of C. glabrata is related to its reduced susceptibility to azole drugs. Genome analysis suggests that virulence in the CTG clade is associated with expansion of gene families, particularly of cell wall genes. Similar independent processes took place in the C. glabrata species group. Gene loss and expansion in an ancestor of C. glabrata may have resulted in preadaptations that enabled pathogenicity.
Collapse
Affiliation(s)
- Siobhán A Turner
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Geraldine Butler
- School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| |
Collapse
|
26
|
Jordan RPC, Williams DW, Moran GP, Coleman DC, Sullivan DJ. Comparative adherence of Candida albicans and Candida dubliniensis to human buccal epithelial cells and extracellular matrix proteins. Med Mycol 2014; 52:254-63. [PMID: 24625677 DOI: 10.1093/mmy/myt032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Candida albicans and Candida dubliniensis are very closely related pathogenic yeast species. Despite their close relationship, C. albicans is a far more successful colonizer and pathogen of humans. The purpose of this study was to determine if the disparity in the virulence of the two species is attributed to differences in their ability to adhere to human buccal epithelial cells (BECs) and/or extracellular matrix proteins. When grown overnight at 30°C in yeast extract peptone dextrose, genotype 1 C. dubliniensis isolates were found to be significantly more adherent to human BECs than C. albicans or C. dubliniensis genotypes 2-4 (P < 0.001). However, when the yeast cells were grown at 37°C, no significant difference between the adhesion of C. dubliniensis genotype 1 and C. albicans to human BECs was observed, and C. dubliniensis genotype 1 and C. albicans adhered to BECs in significantly greater numbers than the other C. dubliniensis genotypes (P < 0.001). Using surface plasmon resonance analysis, C. dubliniensis isolates were found to adhere in significantly greater numbers than C. albicans to type I and IV collagen, fibronectin, laminin, vitronectin, and proline-rich peptides. These data suggest that C. albicans is not more adherent to epithelial cells or matrix proteins than C. dubliniensis and therefore other factors must contribute to the greater levels of virulence exhibited by C. albicans.
Collapse
Affiliation(s)
- Rachael P C Jordan
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental University Hospital, University of Dublin, Trinity College, Dublin 2, Ireland
| | | | | | | | | |
Collapse
|
27
|
Molecular epidemiology, phylogeny and evolution of Candida albicans. INFECTION GENETICS AND EVOLUTION 2013; 21:166-78. [PMID: 24269341 DOI: 10.1016/j.meegid.2013.11.008] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 10/31/2013] [Accepted: 11/01/2013] [Indexed: 11/21/2022]
Abstract
A small number of Candida species form part of the normal microbial flora of mucosal surfaces in humans and may give rise to opportunistic infections when host defences are impaired. Candida albicans is by far the most prevalent commensal and pathogenic Candida species. Several different molecular typing approaches including multilocus sequence typing, multilocus microsatellite typing and DNA fingerprinting using C. albicans-specific repetitive sequence-containing DNA probes have yielded a wealth of information regarding the epidemiology and population structure of this species. Such studies revealed that the C. albicans population structure consists of multiple major and minor clades, some of which exhibit geographical or phenotypic enrichment and that C. albicans reproduction is predominantly clonal. Despite this, losses of heterozygosity by recombination, the existence of a parasexual cycle, toleration of a wide range of aneuploidies and the recent description of viable haploid strains have all demonstrated the extensive plasticity of the C. albicans genome. Recombination and gross chromosomal rearrangements are more common under stressful environmental conditions, and have played a significant role in the evolution of this opportunistic pathogen. Surprisingly, Candida dubliniensis, the closest relative of C. albicans exhibits more karyotype variability than C. albicans, but is significantly less adaptable to unfavourable environments. This disparity most likely reflects the evolutionary processes that occurred during or soon after the divergence of both species from their common ancestor. Whilst C. dubliniensis underwent significant gene loss and pseudogenisation, C. albicans expanded gene families considered to be important in virulence. It is likely that technological developments in whole genome sequencing and data analysis in coming years will facilitate its routine use for population structure, epidemiological investigations, and phylogenetic analyses of Candida species. These are likely to reveal more minor C. albicans clades and to enhance our understanding of the population biology of this versatile organism.
Collapse
|
28
|
Wan Harun WHA, Jamil NA, Jamaludin NH, Nordin MAF. Effect of Piper betle and Brucea javanica on the Differential Expression of Hyphal Wall Protein (HWP1) in Non-Candida albicans Candida (NCAC) Species. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2013; 2013:397268. [PMID: 23853657 PMCID: PMC3703345 DOI: 10.1155/2013/397268] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 05/28/2013] [Indexed: 11/18/2022]
Abstract
The study aimed to identify the HWP1 gene in non-Candida albicans Candida species and the differential expression of HWP1 following treatment with Piper betle and Brucea javanica aqueous extracts. All candidal suspensions were standardized to 1 × 10(6) cells/mL. The suspension was incubated overnight at 37 °C (C. parapsilosis, 35°C). Candidal cells were treated with each respective extract at 1, 3, and 6 mg/mL for 24 h. The total RNA was extracted and reverse transcription-polymerase chain reaction was carried out with a specific primer of HWP1. HWP1 mRNAs were only detected in C. albicans, C. parapsilosis, and C. tropicalis. Exposing the cells to the aqueous extracts has affected the expression of HWP1 transcripts. C. albicans, C. parapsilosis, and C. tropicalis have demonstrated different intensity of mRNA. Compared to P. betle, B. javanica demonstrated a higher suppression on the transcript levels of HWP1 in all samples. HWP1 was not detected in C. albicans following the treatment of B. javanica at 1 mg/mL. In contrast, C. parapsilosis and C. tropicalis were shown to have HWP1 regulation. However, the expression levels were reduced upon the addition of higher concentration of B. javanica extract. P. betle and B. javanica have potential to be developed as oral health product.
Collapse
Affiliation(s)
| | - Nur Alyaa Jamil
- Department of Oral Biology, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Nor Hazwani Jamaludin
- Department of Oral Biology, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Mohd-Al-Faisal Nordin
- Department of Oral Biology, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| |
Collapse
|
29
|
Grumaz C, Lorenz S, Stevens P, Lindemann E, Schöck U, Retey J, Rupp S, Sohn K. Species and condition specific adaptation of the transcriptional landscapes in Candida albicans and Candida dubliniensis. BMC Genomics 2013; 14:212. [PMID: 23547856 PMCID: PMC3626586 DOI: 10.1186/1471-2164-14-212] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 03/18/2013] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Although Candida albicans and Candida dubliniensis are most closely related, both species behave significantly different with respect to morphogenesis and virulence. In order to gain further insight into the divergent routes for morphogenetic adaptation in both species, we investigated qualitative along with quantitative differences in the transcriptomes of both organisms by cDNA deep sequencing. RESULTS Following genome-associated assembly of sequence reads we were able to generate experimentally verified databases containing 6016 and 5972 genes for C. albicans and C. dubliniensis, respectively. About 95% of the transcriptionally active regions (TARs) contain open reading frames while the remaining TARs most likely represent non-coding RNAs. Comparison of our annotations with publically available gene models for C. albicans and C. dubliniensis confirmed approximately 95% of already predicted genes, but also revealed so far unknown novel TARs in both species. Qualitative cross-species analysis of these databases revealed in addition to 5802 orthologs also 399 and 49 species-specific protein coding genes for C. albicans and C. dubliniensis, respectively. Furthermore, quantitative transcriptional profiling using RNA-Seq revealed significant differences in the expression of orthologs across both species. We defined a core subset of 84 hyphal-specific genes required for both species, as well as a set of 42 genes that seem to be specifically induced during hyphal morphogenesis in C. albicans. CONCLUSIONS Species-specific adaptation in C. albicans and C. dubliniensis is governed by individual genetic repertoires but also by altered regulation of conserved orthologs on the transcriptional level.
Collapse
Affiliation(s)
- Christian Grumaz
- University of Stuttgart, IGVT, Nobelstr. 12 70569 Stuttgart, Germany
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Porman AM, Hirakawa MP, Jones SK, Wang N, Bennett RJ. MTL-independent phenotypic switching in Candida tropicalis and a dual role for Wor1 in regulating switching and filamentation. PLoS Genet 2013; 9:e1003369. [PMID: 23555286 PMCID: PMC3605238 DOI: 10.1371/journal.pgen.1003369] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 01/22/2013] [Indexed: 01/09/2023] Open
Abstract
Phenotypic switching allows for rapid transitions between alternative cell states and is important in pathogenic fungi for colonization and infection of different host niches. In Candida albicans, the white-opaque phenotypic switch plays a central role in regulating the program of sexual mating as well as interactions with the mammalian host. White-opaque switching is controlled by genes encoded at the MTL (mating-type-like) locus that ensures that only a or α cells can switch from the white state to the mating-competent opaque state, while a/α cells are refractory to switching. Here, we show that the related pathogen C. tropicalis undergoes white-opaque switching in all three cell types (a, α, and a/α), and thus switching is independent of MTL control. We also demonstrate that C. tropicalis white cells are themselves mating-competent, albeit at a lower efficiency than opaque cells. Transcriptional profiling of C. tropicalis white and opaque cells reveals significant overlap between switch-regulated genes in MTL homozygous and MTL heterozygous cells, although twice as many genes are white-opaque regulated in a/α cells as in a cells. In C. albicans, the transcription factor Wor1 is the master regulator of the white-opaque switch, and we show that Wor1 also regulates switching in C. tropicalis; deletion of WOR1 locks a, α, and a/α cells in the white state, while WOR1 overexpression induces these cells to adopt the opaque state. Furthermore, we show that WOR1 overexpression promotes both filamentous growth and biofilm formation in C. tropicalis, independent of the white-opaque switch. These results demonstrate an expanded role for C. tropicalis Wor1, including the regulation of processes necessary for infection of the mammalian host. We discuss these findings in light of the ancestral role of Wor1 as a transcriptional regulator of the transition between yeast form and filamentous growth. The white-opaque phenotypic switch has been extensively characterized in the human fungal pathogen Candida albicans, where it plays a central role in regulating entry into sexual reproduction. This epigenetic switch is strictly regulated by the MTL locus so that only a or α cell types can switch to the opaque state, whereas a/α cells are locked in the white state. In contrast, we show that in the related pathogen C. tropicalis white cells are capable of sexual mating and that the white-opaque switch is independent of MTL control. Thus, MTLa, α, and a/α cells all undergo reversible switching between white and opaque states. Despite these differences, switching in both C. tropicalis and C. albicans is dependent on the expression of the Wor1 transcription factor. This factor is conserved amongst fungal ascomycetes and, in several species, acts as a master regulator of the yeast-to-filament transition. We show that, in addition to regulating the white-opaque switch in C. tropicalis, Wor1 expression also promotes filamentation and biofilm formation in this species. We therefore propose that C. tropicalis Wor1 has retained the ancestral role of this family of transcription factors while also gaining control over the more recently evolved white-opaque phenotypic switch.
Collapse
Affiliation(s)
- Allison M. Porman
- Department of Microbiology and Immunology, Brown University, Providence, Rhode Island, United States of America
| | - Matthew P. Hirakawa
- Department of Microbiology and Immunology, Brown University, Providence, Rhode Island, United States of America
| | - Stephen K. Jones
- Department of Microbiology and Immunology, Brown University, Providence, Rhode Island, United States of America
| | - Na Wang
- Department of Microbiology and Immunology, Brown University, Providence, Rhode Island, United States of America
| | - Richard J. Bennett
- Department of Microbiology and Immunology, Brown University, Providence, Rhode Island, United States of America
- * E-mail:
| |
Collapse
|
31
|
Epidemiology, antifungal susceptibility, and pathogenicity of Candida africana isolates from the United Kingdom. J Clin Microbiol 2013; 51:967-72. [PMID: 23303503 DOI: 10.1128/jcm.02816-12] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Candida africana was previously proposed as a new species within the Candida albicans species complex, together with C. albicans and C. dubliniensis, although further phylogenetic analyses better support its status as an unusual variant within C. albicans. Here we show that C. africana can be distinguished from C. albicans and C. dubliniensis by pyrosequencing of a short region of ITS2, and we have evaluated its occurrence in clinical samples by pyrosequencing all presumptive isolates of C. albicans submitted to the Mycology Reference Laboratory over a 9-month period. The C. albicans complex constituted 826/1,839 (44.9%) of yeast isolates received over the study period and included 783 isolates of C. albicans, 28 isolates of C. dubliniensis, and 15 isolates of C. africana. In agreement with previous reports, C. africana was isolated exclusively from genital specimens, in women in the 18-to-35-year age group. Indeed, C. africana constituted 15/251 (6%) of "C. albicans" isolates from female genital specimens during the study period. C. africana isolates were germ tube positive, grew significantly more slowly than C. albicans and C. dubliniensis on conventional mycological media, could be distinguished from the other members of the C. albicans complex by appearance on chromogenic agar, and were incapable of forming chlamydospores. Here we present the detailed evaluation of epidemiological, phenotypic, and clinical features and antifungal susceptibility profiles of United Kingdom isolates of C. africana. Furthermore, we demonstrate that C. africana is significantly less pathogenic than C. albicans and C. dubliniensis in the Galleria mellonella insect systemic infection model.
Collapse
|
32
|
Zhang J, Heitman J, Chen YL. Comparative analysis of calcineurin signaling between Candida dubliniensis and Candida albicans. Commun Integr Biol 2012; 5:122-6. [PMID: 22808313 PMCID: PMC3376044 DOI: 10.4161/cib.18833] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Candida dubliniensis, an emerging fungal pathogen, is the closest known species to the established pathogenic species Candida albicans. Despite the fact that these two species share > 80% genome sequence identity, they exhibit distinct properties such as less hyphal growth, reduced pathogenicity and increased sensitivity to sodium stress and elevated temperatures in C. dubliniensis compared with C. albicans. It is, however, largely unknown whether signaling pathways are conserved in the two Candida species. Calcineurin signaling is known to be required for hyphal growth in Cryptococcus neoformans and Aspergillus fumigatus but remains elusive in C. albicans. Our recent study showed that calcineurin plays a clearly demonstrable role in controlling hyphal growth, drug tolerance and virulence in C. dubliniensis. Here, we extend our studies and show that calcineurin is conserved in controlling endoplasmic reticulum stress but distinct in governing pH homeostasis. Furthermore, we demonstrate that azole or echinocandin drugs in combination with the calcineurin inhibitor FK506 exhibit a synergistic effect against C. dubliniensis wild-type and echinocandin-resistant strains. The involvement of calcineurin in a variety of fungal virulence attributes and as a target for fungicidal synergism with azoles and echinocandins highlights the potential of combination therapy with calcineurin inhibitors for treating Candida infections.
Collapse
|
33
|
Moran GP. Transcript profiling reveals rewiring of iron assimilation gene expression in Candida albicans and C. dubliniensis. FEMS Yeast Res 2012; 12:918-23. [PMID: 22888912 DOI: 10.1111/j.1567-1364.2012.00841.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 07/17/2012] [Accepted: 08/07/2012] [Indexed: 11/28/2022] Open
Abstract
Hyphal growth is repressed in Candida albicans and Candida dubliniensis by the transcription factor Nrg1. Transcript profiling of a C. dubliniensis NRG1 mutant identified a common group of 28 NRG1-repressed genes in both species, including the hypha-specific genes HWP1, ECE1 and the regulator of cell elongation UME6. Unexpectedly, C. dubliniensis NRG1 was required for wild-type levels of expression of 10 genes required for iron uptake including seven ferric reductases, SIT1, FTR1 and RBT5. However, at alkaline pH and during filamentous growth in 10% serum, most of these genes were highly induced in C. dubliniensis. Conversely, RBT5, PGA10, FRE10 and FRP1 did not exhibit induction during hyphal growth when NRG1 is downregulated, indicating that in C. dubliniensis NRG1 is also required for optimal expression of these genes in alkaline environments. In iron-depleted medium at pH 4.5, reduced growth of the NRG1 mutant relative to wild type was observed; however, growth was restored to wild-type levels or greater at pH 6.5, indicating that alkaline induction of iron assimilation gene expression could rescue this phenotype. These data indicate that transcriptional control of iron assimilation and pseudohypha formation has been separated in C. albicans, perhaps promoting growth in a wider range of niches.
Collapse
Affiliation(s)
- Gary P Moran
- Division of Oral Biosciences, Dublin Dental School and Hospital, Trinity College Dublin, University of Dublin, Ireland.
| |
Collapse
|
34
|
Zhang J, Silao FGS, Bigol UG, Bungay AAC, Nicolas MG, Heitman J, Chen YL. Calcineurin is required for pseudohyphal growth, virulence, and drug resistance in Candida lusitaniae. PLoS One 2012; 7:e44192. [PMID: 22952924 PMCID: PMC3432075 DOI: 10.1371/journal.pone.0044192] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 07/30/2012] [Indexed: 11/19/2022] Open
Abstract
Candida lusitaniae is an emerging fungal pathogen that infects immunocompromised patients including HIV/AIDS, cancer, and neonatal pediatric patients. Though less prevalent than other Candida species, C. lusitaniae is unique in its ability to develop resistance to amphotericin B. We investigated the role of the calcium-activated protein phosphatase calcineurin in several virulence attributes of C. lusitaniae including pseudohyphal growth, serum survival, and growth at 37°C. We found that calcineurin and Crz1, a C. albicans Crz1 homolog acting as a downstream target of calcineurin, are required for C. lusitaniae pseudohyphal growth, a process for which the underlying mechanism remains largely unknown in C. lusitaniae but hyphal growth is fundamental to C. albicans virulence. We demonstrate that calcineurin is required for cell wall integrity, ER stress response, optimal growth in serum, virulence in a murine systemic infection model, and antifungal drug tolerance in C. lusitaniae. To further examine the potential of targeting the calcineurin signaling cascade for antifungal drug development, we examined the activity of a calcineurin inhibitor FK506 in combination with caspofungin against echinocandin resistant C. lusitaniae clinical isolates. Broth microdilution and drug disk diffusion assays demonstrate that FK506 has synergistic fungicidal activity with caspofungin against echinocandin resistant isolates. Our findings reveal that pseudohyphal growth is controlled by the calcineurin signaling cascade, and highlight the potential use of calcineurin inhibitors and caspofungin for emerging drug-resistant C. lusitaniae infections.
Collapse
Affiliation(s)
- Jing Zhang
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, United States of America
- Department of Chemistry, Duke University, Durham, North Carolina, United States of America
| | - Fitz Gerald S. Silao
- Department of Microbiology and Parasitology, University of Perpetual Help – Dr. Jose G. Tamayo Medical University, Biñan, Laguna, Philippines
| | - Ursela G. Bigol
- Environment and Biotechnology Division, Department of Science and Technology, Bicutan, Philippines
| | - Alice Alma C. Bungay
- Department of Microbiology and Parasitology, University of Perpetual Help – Dr. Jose G. Tamayo Medical University, Biñan, Laguna, Philippines
- National Institutes of Health-Philippines, University of the Philippines, Manila, Philippines
| | - Marilou G. Nicolas
- National Institutes of Health-Philippines, University of the Philippines, Manila, Philippines
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, United States of America
- * E-mail: (JH); (Y-LC)
| | - Ying-Lien Chen
- Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, United States of America
- * E-mail: (JH); (Y-LC)
| |
Collapse
|
35
|
Svobodová E, Staib P, Losse J, Hennicke F, Barz D, Józsi M. Differential interaction of the two related fungal species Candida albicans and Candida dubliniensis with human neutrophils. THE JOURNAL OF IMMUNOLOGY 2012; 189:2502-11. [PMID: 22851712 DOI: 10.4049/jimmunol.1200185] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Candida albicans, the most common facultative human pathogenic fungus is of major medical importance, whereas the closely related species Candida dubliniensis is less virulent and rarely causes life-threatening, systemic infections. Little is known, however, about the reasons for this difference in pathogenicity, and especially on the interactions of C. dubliniensis with the human immune system. Because innate immunity and, in particular, neutrophil granulocytes play a major role in host antifungal defense, we studied the responses of human neutrophils to clinical isolates of both C. albicans and C. dubliniensis. C. dubliniensis was found to support neutrophil migration and fungal cell uptake to a greater extent in comparison with C. albicans, whereas inducing less neutrophil damage and extracellular trap formation. The production of antimicrobial reactive oxygen species, myeloperoxidase, and lactoferrin, as well as the inflammatory chemokine IL-8 by neutrophils was increased when stimulated with C. dubliniensis as compared with C. albicans. However, most of the analyzed macrophage-derived inflammatory and regulatory cytokines and chemokines, such as IL-1α, IL-1β, IL-1ra, TNF-α, IL-10, G-CSF, and GM-CSF, were less induced by C. dubliniensis. Similarly, the amounts of the antifungal immunity-related IL-17A produced by PBMCs was significantly lower when challenged with C. dubliniensis than with C. albicans. These data indicate that C. dubliniensis triggers stronger early neutrophil responses than C. albicans, thus providing insight into the differential virulence of these two closely related fungal species, and suggest that this is, in part, due to their differential capacity to form hyphae.
Collapse
Affiliation(s)
- Eliska Svobodová
- Junior Research Group Cellular Immunobiology, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute, D-07745 Jena, Germany
| | | | | | | | | | | |
Collapse
|
36
|
Yoshioka H, Ito-Kuwa S, Nakamura K, Mataga I. [Virulence of Candida dubliniensis in comparison with Candida albicans using an experimental model of mouse oral candiddiasis]. Med Mycol J 2012; 53:135-45. [PMID: 22728597 DOI: 10.3314/mmj.53.135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Certain species of Candida are known as opportunistic fungal pathogens and Candida albicans has especially been isolated oral candidiasis patients at high frequency as a result of its strong pathogenicity. Recently C. dubliniensis is isolated mainly from immunocompromised patients, but is also detected from healthy persons. C. dubliniensis has similar cell morphology and molecular biological properties to C. albicans. Thus, in order to clarify the pathogenicity of C. dubliniensis, the activities of two extracellular enzymes, phospholipase (PL) and proteinase (PT), were measured, and pathological features were compared using mice. PL activity was examined in the improved Price's PL activity assay. In brief, the white precipitation zone was detected by spraying NaCl on egg yold plates without NaCl after colonies had grown. PL activity was no detected in any of the 31 C. dubliniensis strains tested. On the other hand, PT acitivty of C. dubliniensis was almost equivalent to that of C. albicans. Although we attempted to make an experimental model of mouse oral candidiasis using C. dubliniensis in yeast form as an inoculum following the conventional method, oral candidiasis did not develop in any mice. Thrush was successfully developed after inoculation with mycelial form cells, and there was no significant difference in histopathological findings of the thrush in comparison with C. albicans. These results strongly suggest that the two enzymes, PT and PL, do not play a crusial role in the establishment of mouse oral experimental candidiasis by C. dubliniensis.
Collapse
Affiliation(s)
- Hiroo Yoshioka
- Oral and Maxillofacial Surgery and Systemic Medicine, Graduate School of Life Dentistry, Nippon Dental University at Niigata
| | | | | | | |
Collapse
|
37
|
Sequence and analysis of the genome of the pathogenic yeast Candida orthopsilosis. PLoS One 2012; 7:e35750. [PMID: 22563396 PMCID: PMC3338533 DOI: 10.1371/journal.pone.0035750] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 03/24/2012] [Indexed: 01/09/2023] Open
Abstract
Candida orthopsilosis is closely related to the fungal pathogen Candida parapsilosis. However, whereas C. parapsilosis is a major cause of disease in immunosuppressed individuals and in premature neonates, C. orthopsilosis is more rarely associated with infection. We sequenced the C. orthopsilosis genome to facilitate the identification of genes associated with virulence. Here, we report the de novo assembly and annotation of the genome of a Type 2 isolate of C. orthopsilosis. The sequence was obtained by combining data from next generation sequencing (454 Life Sciences and Illumina) with paired-end Sanger reads from a fosmid library. The final assembly contains 12.6 Mb on 8 chromosomes. The genome was annotated using an automated pipeline based on comparative analysis of genomes of Candida species, together with manual identification of introns. We identified 5700 protein-coding genes in C. orthopsilosis, of which 5570 have an ortholog in C. parapsilosis. The time of divergence between C. orthopsilosis and C. parapsilosis is estimated to be twice as great as that between Candida albicans and Candida dubliniensis. There has been an expansion of the Hyr/Iff family of cell wall genes and the JEN family of monocarboxylic transporters in C. parapsilosis relative to C. orthopsilosis. We identified one gene from a Maltose/Galactoside O-acetyltransferase family that originated by horizontal gene transfer from a bacterium to the common ancestor of C. orthopsilosis and C. parapsilosis. We report that TFB3, a component of the general transcription factor TFIIH, undergoes alternative splicing by intron retention in multiple Candida species. We also show that an intein in the vacuolar ATPase gene VMA1 is present in C. orthopsilosis but not C. parapsilosis, and has a patchy distribution in Candida species. Our results suggest that the difference in virulence between C. parapsilosis and C. orthopsilosis may be associated with expansion of gene families.
Collapse
|
38
|
Khan Z, Ahmad S, Joseph L, Chandy R. Candida dubliniensis: an appraisal of its clinical significance as a bloodstream pathogen. PLoS One 2012; 7:e32952. [PMID: 22396802 PMCID: PMC3292580 DOI: 10.1371/journal.pone.0032952] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 02/06/2012] [Indexed: 11/18/2022] Open
Abstract
A nine-year prospective study (2002–2010) on the prevalence of Candida dubliniensis among Candida bloodstream isolates is presented. The germ tube positive isolates were provisionally identified as C. dubliniensis by presence of fringed and rough colonies on sunflower seed agar. Subsequently, their identity was confirmed by Vitek2 Yeast identification system and/or by amplification and sequencing of the ITS region of rDNA. In all, 368 isolates were identified as C. dubliniensis; 67.1% came from respiratory specimens, 11.7% from oral swabs, 9.2% from urine, 3.8% from blood, 2.7% from vaginal swabs and 5.4% from other sources. All C. dubliniensis isolates tested by Etest were susceptible to voriconazole and amphotericin B. Resistance to fluconazole (≥8 µg/ml) was observed in 2.5% of C. dubliniensis isolates, 7 of which occurred between 2008–2010. Of note was the diagnosis of C. dubliniensis candidemia in 14 patients, 11 of them occurring between 2008–2010. None of the bloodstream isolate was resistant to fluconazole, while a solitary isolate showed increased MIC to 5-flucytosine (>32 µg/ml) and belonged to genotype 4. A review of literature since 1999 revealed 28 additional cases of C. dubliniensis candidemia, and 167 isolates identified from blood cultures since 1982. In conclusion, this study highlights a greater role of C. dubliniensis in bloodstream infections than hitherto recognized.
Collapse
Affiliation(s)
- Ziauddin Khan
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait.
| | | | | | | |
Collapse
|
39
|
Biofilm formation and adhesive/invasive properties of Candida dubliniensis in comparison with Candida albicans. Open Life Sci 2011. [DOI: 10.2478/s11535-011-0087-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractCandida dubliniensis and Candida albicans are closely related spp. exhibiting differences in their virulence potency. This study compared clinical isolates of C. dubliniensis with C. albicans from HIV patients with oropharyngeal candidiasis (OPC) and standard strains in power to form biofilm and their adhesive and invasive properties. Members of both spp. were able to form strong biofilms. However, SEM microscopy confirmed that C. albicans undergoes the more effective yeast-to-hyphae transition than C. dubliniensis with prevalent yeast form and limited ability to form filaments. Kinetic patterns indicated that while the first 30 min are critical for sufficient attachment to a polystyrene surface, adhesion to human carcinoma cell lines (Caco-2 and TR 146) needs additional time with maximal saturation observed at 240 min for both spp. The invasion process was tested on 3D RHE (reconstituted human epithelium) with Caco-2 or TR 146 on the collagen surface. C. albicans rapidly produced hyphae that penetrated the tissue layer, demonstrating substantive invasion within 21 h. In contrast, C. dubliniensis attached to the tissue surface and proliferated, suggesting the formation of a biofilm-like structure. After 21 h, C. dubliniensis was able to penetrate the RHE layer and invade unusually, with a cluster of the yeast cells.
Collapse
|
40
|
Villa F, Pitts B, Stewart PS, Giussani B, Roncoroni S, Albanese D, Giordano C, Tunesi M, Cappitelli F. Efficacy of zosteric acid sodium salt on the yeast biofilm model Candida albicans. MICROBIAL ECOLOGY 2011; 62:584-598. [PMID: 21614460 DOI: 10.1007/s00248-011-9876-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 05/04/2011] [Indexed: 05/30/2023]
Abstract
Candida albicans is the most notorious and the most widely studied yeast biofilm former. Design of experiments (DoE) showed that 10 mg/L zosteric acid sodium salt reduced C. albicans adhesion and the subsequent biofilm formation by at least 70%, on both hydrophilic and hydrophobic surfaces of 96-well plates. Indeed, biofilm imaging revealed the dramatic impact of zosteric acid sodium salt on biofilm thickness and morphology, due to the inability of the cells to form filamentous structures while remaining metabolically active. In the same way, 10 mg/L zosteric acid sodium salt inhibited C. albicans biofilm formation when added after the adhesion phase. Contrary to zosteric acid sodium salt, methyl zosterate did not affect yeast biofilm. In addition, zosteric acid sodium salt enhanced sensitivity to chlorhexidine, chlorine, hydrogen peroxide, and cis-2-decenoic acid, with a reduction of 0.5 to 8 log units. Preliminary in vitro studies using suitable primary cell based models revealed that zosteric acid sodium salt did not compromise the cellular activity, adhesion, proliferation or morphology of either the murine fibroblast line L929 or the human osteosarcoma line MG-63. Thus the use of zosteric acid sodium salt could provide a suitable, innovative, preventive, and integrative approach to preventing yeast biofilm formation.
Collapse
Affiliation(s)
- Federica Villa
- Dipartimento di Scienze e Tecnologie Alimentari e Microbiologiche, Università degli Studi di Milano, via Celoria 2, 20133 Milan, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Ahmad S, Khan ZU, Joseph L, Asadzadeh M, Theyyathel A. Genotypic heterogeneity and molecular basis of 5-flucytosine resistance among Candida dubliniensis isolates recovered from clinical specimens in Kuwait. Med Mycol 2011; 50:244-51. [PMID: 21895416 DOI: 10.3109/13693786.2011.597446] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
There is a paucity of information about genotypic heterogeneity among Candida dubliniensis isolates recovered from different geographic regions. This study explored genotypic heterogeneity among 103 C. dubliniensis strains obtained over a six-year period from clinical specimens in Kuwait. Genotype assignment was based on amplification with genotype-specific primers and sequencing of rDNA. Susceptibility to 5-flucytosine was determined by means of the Etest. DNA sequencing of cytosine deaminase was performed to determine the molecular basis of resistance to 5-flucytosine. DNA sequencing of rDNA identified seven different genotypes, i.e., 68 (66%) isolates were found to belong to genotype 1, 25 to genotype 4, six to genotype 5 and one each to genotypes 6-9. Strains of genotype 2 or genotype 3 were not detected. All isolates of genotype 4 but none of other genotypes were resistant to 5-flucytosine and the resistant strains all contained S29L mutation. Isolates of all other genotypes contained wild-type codon 29 in cytosine deaminase. A simple, PCR-RFLP-based method has been developed to facilitate rapid detection of S29L mutation in cytosine deaminase. A noteworthy observation of our study is the identification of five new genotypes of C. dubliniensis isolates, recovered from oral/respiratory specimens from patients of Middle Eastern origin. Furthermore, all 5-flucytosine resistant C. dubliniensis isolates in Kuwait belonged to genotype 4 only.
Collapse
Affiliation(s)
- Suhail Ahmad
- Department of Microbiology, Kuwait University, Kuwait
| | | | | | | | | |
Collapse
|
42
|
Candida albicans versus Candida dubliniensis: Why Is C. albicans More Pathogenic? Int J Microbiol 2011; 2012:205921. [PMID: 21904553 PMCID: PMC3166774 DOI: 10.1155/2012/205921] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 06/28/2011] [Indexed: 11/29/2022] Open
Abstract
Candida albicans and Candida dubliniensis are highly related pathogenic yeast species. However, C. albicans is far more prevalent in human infection and has been shown to be more pathogenic in a wide range of infection models. Comparison of the genomes of the two species has revealed that they are very similar although there are some significant differences, largely due to the expansion of virulence-related gene families (e.g., ALS and SAP) in C. albicans, and increased levels of pseudogenisation in C. dubliniensis. Comparative global gene expression analyses have also been used to investigate differences in the ability of the two species to tolerate environmental stress and to produce hyphae, two traits that are likely to play a role in the lower virulence of C. dubliniensis. Taken together, these data suggest that C. dubliniensis is in the process of undergoing reductive evolution and may have become adapted for growth in a specialized anatomic niche.
Collapse
|
43
|
Chen YL, Brand A, Morrison EL, Silao FGS, Bigol UG, Malbas FF, Nett JE, Andes DR, Solis NV, Filler SG, Averette A, Heitman J. Calcineurin controls drug tolerance, hyphal growth, and virulence in Candida dubliniensis. EUKARYOTIC CELL 2011; 10:803-19. [PMID: 21531874 PMCID: PMC3127677 DOI: 10.1128/ec.00310-10] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 04/11/2011] [Indexed: 01/09/2023]
Abstract
Candida dubliniensis is an emerging pathogenic yeast species closely related to Candida albicans and frequently found colonizing or infecting the oral cavities of HIV/AIDS patients. Drug resistance during C. dubliniensis infection is common and constitutes a significant therapeutic challenge. The calcineurin inhibitor FK506 exhibits synergistic fungicidal activity with azoles or echinocandins in the fungal pathogens C. albicans, Cryptococcus neoformans, and Aspergillus fumigatus. In this study, we show that calcineurin is required for cell wall integrity and wild-type tolerance of C. dubliniensis to azoles and echinocandins; hence, these drugs are candidates for combination therapy with calcineurin inhibitors. In contrast to C. albicans, in which the roles of calcineurin and Crz1 in hyphal growth are unclear, here we show that calcineurin and Crz1 play a clearly demonstrable role in hyphal growth in response to nutrient limitation in C. dubliniensis. We further demonstrate that thigmotropism is controlled by Crz1, but not calcineurin, in C. dubliniensis. Similar to C. albicans, C. dubliniensis calcineurin enhances survival in serum. C. dubliniensis calcineurin and crz1/crz1 mutants exhibit attenuated virulence in a murine systemic infection model, likely attributable to defects in cell wall integrity, hyphal growth, and serum survival. Furthermore, we show that C. dubliniensis calcineurin mutants are unable to establish murine ocular infection or form biofilms in a rat denture model. That calcineurin is required for drug tolerance and virulence makes fungus-specific calcineurin inhibitors attractive candidates for combination therapy with azoles or echinocandins against emerging C. dubliniensis infections.
Collapse
Affiliation(s)
- Ying-Lien Chen
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina
| | - Alexandra Brand
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Emma L. Morrison
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Fitz Gerald S. Silao
- Department of Microbiology and Parasitology, University of Perpetual Help-Dr. Jose G. Tamayo Medical University, Biñan, Laguna, Philippines
| | - Ursela G. Bigol
- Environment and Biotechnology Division, Department of Science and Technology, Bicutan, Philippines
| | | | - Jeniel E. Nett
- Departments of Medicine
- Medical Microbiology and Immunology, University of Wisconsin
- William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - David R. Andes
- Departments of Medicine
- Medical Microbiology and Immunology, University of Wisconsin
- William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Norma V. Solis
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California
| | - Scott G. Filler
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California
- David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Anna Averette
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina
| |
Collapse
|
44
|
Falgier C, Kegley S, Podgorski H, Heisel T, Storey K, Bendel CM, Gale CA. Candida species differ in their interactions with immature human gastrointestinal epithelial cells. Pediatr Res 2011; 69:384-9. [PMID: 21283049 PMCID: PMC3078174 DOI: 10.1203/pdr.0b013e31821269d5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Life-threatening gastrointestinal (GI) diseases of prematurity are highly associated with systemic candidiasis. This implicates the premature GI tract as an important site for invasion by Candida. Invasive interactions of Candida spp. with immature enterocytes have heretofore not been analyzed. Using a primary immature human enterocyte line, we compared the ability of multiple isolates of different Candida spp. to penetrate, injure, and induce a cytokine response from host cells. Of all the Candida spp. analyzed, C. albicans had the greatest ability to penetrate and injure immature enterocytes and to elicit IL-8 release (p < 0.01). In addition, C. albicans was the only Candida spp. to form filamentous hyphae when in contact with immature enterocytes. Similarly, a C. albicans mutant with defective hyphal morphogenesis and invasiveness had attenuated cytotoxicity for immature enterocytes (p < 0.003). Thus, hyphal morphogenesis correlates with immature enterocyte penetration, injury, and inflammatory responses. Furthermore, variability in enterocyte injury was observed among hyphal-producing C. albicans strains, suggesting that individual organism genotypes also influence host-pathogen interactions. Overall, the finding that Candida spp. differed in their interactions with immature enterocytes implicates that individual spp. may use different pathogenesis mechanisms.
Collapse
Affiliation(s)
- Christina Falgier
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, Minnesota, USA
| | | | | | | | | | | | | |
Collapse
|
45
|
Comparative genomics and the evolution of pathogenicity in human pathogenic fungi. EUKARYOTIC CELL 2010; 10:34-42. [PMID: 21076011 DOI: 10.1128/ec.00242-10] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Because most fungi have evolved to be free-living in the environment and because the infections they cause are usually opportunistic in nature, it is often difficult to identify specific traits that contribute to fungal pathogenesis. In recent years, there has been a surge in the number of sequenced genomes of human fungal pathogens, and comparison of these sequences has proved to be an excellent resource for exploring commonalities and differences in how these species interact with their hosts. In order to survive in the human body, fungi must be able to adapt to new nutrient sources and environmental stresses. Therefore, genes involved in carbohydrate and amino acid metabolism and transport and genes encoding secondary metabolites tend to be overrepresented in pathogenic species (e.g., Aspergillus fumigatus). However, it is clear that human commensal yeast species such as Candida albicans have also evolved a range of specific factors that facilitate direct interaction with host tissues. The evolution of virulence across the human pathogenic fungi has occurred largely through very similar mechanisms. One of the most important mechanisms is gene duplication and the expansion of gene families, particularly in subtelomeric regions. Unlike the case for prokaryotic pathogens, horizontal transfer of genes between species and other genera does not seem to have played a significant role in the evolution of fungal virulence. New sequencing technologies promise the prospect of even greater numbers of genome sequences, facilitating the sequencing of multiple genomes and transcriptomes within individual species, and will undoubtedly contribute to a deeper insight into fungal pathogenesis.
Collapse
|
46
|
Boyle M, O’Donnell M, Russell R, Coleman D. Lack of cytotoxicity by Trustwater Ecasol™ used to maintain good quality dental unit waterline output water in keratinocyte monolayer and reconstituted human oral epithelial tissue models. J Dent 2010; 38:930-40. [DOI: 10.1016/j.jdent.2010.08.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 08/05/2010] [Accepted: 08/06/2010] [Indexed: 11/16/2022] Open
|
47
|
Coleman DC, Moran GP, McManus BA, Sullivan DJ. Mechanisms of antifungal drug resistance in Candida dubliniensis. Future Microbiol 2010; 5:935-49. [PMID: 20521937 DOI: 10.2217/fmb.10.51] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Candida dubliniensis was first described in 1995 and is the most closely related species to the predominant human fungal pathogen Candida albicans. C. dubliniensis is significantly less prevalent and less pathogenic than C. albicans and is primarily associated with infections in HIV-infected individuals and other immunocompromised cohorts. The population structure of C. dubliniensis consists of three well-defined major clades and is significantly less diverse than C. albicans. The majority of C. dubliniensis isolates are susceptible to antifungal drugs commonly used to treat Candida infections. To date only two major patterns of antifungal drug resistance have been identified and the molecular mechanisms of these are very similar to the resistance mechanisms that have been described previously in C. albicans. However, significant differences are evident in the predominant antifungal drug mechanisms employed by C. dubliniensis, differences that reflect its more clonal nature, its lower prevalence and characteristics of its genome, the complete sequence of which has only recently been determined.
Collapse
Affiliation(s)
- David C Coleman
- Microbiology Research Unit, Division of Oral Biosciences, Dublin Dental School & Hospital, University of Dublin, Trinity College Dublin, Dublin 2, Republic of Ireland.
| | | | | | | |
Collapse
|
48
|
Differential filamentation of Candida albicans and Candida dubliniensis Is governed by nutrient regulation of UME6 expression. EUKARYOTIC CELL 2010; 9:1383-97. [PMID: 20639413 DOI: 10.1128/ec.00042-10] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Candida dubliniensis is closely related to Candida albicans; however, it is responsible for fewer infections in humans and is less virulent in animal models of infection. C. dubliniensis forms fewer hyphae in vivo, and this may contribute to its reduced virulence. In this study we show that, unlike C. albicans, C. dubliniensis fails to form hyphae in yeast extract-peptone-dextrose (YPD) medium supplemented with 10% (vol/vol) fetal calf serum (YPDS medium). However, C. dubliniensis filaments in water plus 10% (vol/vol) fetal calf serum (WS), and this filamentation is inhibited by the addition of peptone and glucose. Repression of filamentation in YPDS medium could be partly overcome by preculture in synthetic Lee's medium. Unlike C. albicans, inoculation of C. dubliniensis in YPDS medium did not result in increased UME6 transcription. However, >100-fold induction of UME6 was observed when C. dubliniensis was inoculated in nutrient-poor WS medium. The addition of increasing concentrations of peptone to WS medium had a dose-dependent effect on reducing UME6 expression. Transcript profiling of C. dubliniensis hyphae in WS medium identified a starvation response involving expression of genes in the glyoxylate cycle and fatty acid oxidation. In addition, a core, shared transcriptional response with C. albicans could be identified, including expression of virulence-associated genes including SAP456, SAP7, HWP1, and SOD5. Preculture in nutrient-limiting medium enhanced adherence of C. dubliniensis, epithelial invasion, and survival following coculture with murine macrophages. In conclusion, C. albicans, unlike C. dubliniensis, appears to form hyphae in liquid medium regardless of nutrient availability, which may account for its increased capacity to cause disease in humans.
Collapse
|
49
|
Koga-Ito CY, Komiyama EY, Martins CADP, Vasconcellos TC, Jorge AOC, Carvalho YR, do Prado RF, Balducci I. Experimental systemic virulence of oral Candida dubliniensis isolates in comparison with Candida albicans, Candida tropicalis and Candida krusei. Mycoses 2010; 54:e278-85. [PMID: 20492535 DOI: 10.1111/j.1439-0507.2010.01899.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
There are no previous studies on the comparative virulence of Candida dubliniensis with other non-albicans species. The aim of this study was to compare the virulence and infection kinetics of C. dubliniensis and other species. Candida albicans, C. dubliniensis, Candida tropicalis and Candida krusei (reference strains) were inoculated intravenously in mice. For infection kinetics evaluation, a group of five animals were sacrificed after 6 h, 3, 7, 14 and 21 days. Microbiological evaluations (liver, spleen, kidneys, lungs and brain) and histopathological examination of the kidney were performed. The results of virulence evaluation were analysed using Kaplan-Meier survival analysis (5%). Candida dubliniensis-inoculated mice survived for longer periods compared with those with C. albicans (P = 0.005). No differences were detected in relation to C. tropicalis (P = 0.326) and C. krusei (P = 0.317). Most of the organs were persistently colonised by C. albicans and C. dubliniensis even by day 21. Tendency of C. krusei clearance was observed in all organs. Fungal masses and renal lesions were observed after inoculation of C. albicans, C. dubliniensis and C. tropicalis. Within the limits of the study, data on survival rate and dissemination capacity suggest that C. dubliniensis is less virulent than C. albicans.
Collapse
Affiliation(s)
- Cristiane Yumi Koga-Ito
- Laboratory of Microbiology, Department of Oral Biosciences and Diagnosis, São José dos Campos Dental School, Univ. Estadual Paulista (UNESP), São José dos Campos - SP, Brazil.
| | | | | | | | | | | | | | | |
Collapse
|
50
|
Lindemann E, Rohde B, Rupp S, Regenbogen J, Sohn K. A multidimensional electrophoretic system of separation for the analysis of gene expression (MESSAGE). Electrophoresis 2010; 31:1330-43. [DOI: 10.1002/elps.200900624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|