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Azole-Resistance Development; How the Aspergillus fumigatus Lifecycle Defines the Potential for Adaptation. J Fungi (Basel) 2021; 7:jof7080599. [PMID: 34436138 PMCID: PMC8397044 DOI: 10.3390/jof7080599] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/16/2021] [Accepted: 07/20/2021] [Indexed: 01/15/2023] Open
Abstract
In order to successfully infect or colonize human hosts or survive changing environments, Aspergillus fumigatus needs to adapt through genetic changes or phenotypic plasticity. The genomic changes are based on the capacity of the fungus to produce genetic variation, followed by selection of the genotypes that are most fit to the new environment. Much scientific work has focused on the metabolic plasticity, biofilm formation or the particular genetic changes themselves leading to adaptation, such as antifungal resistance in the host. Recent scientific work has shown advances made in understanding the natural relevance of parasex and how both the asexual and sexual reproduction can lead to tandem repeat elongation in the target gene of the azoles: the cyp51A gene. In this review, we will explain how the fungus can generate genetic variation that can lead to adaptation. We will discuss recent advances that have been made in the understanding of the lifecycle of A. fumigatus to explain the differences observed in speed and type of mutations that are generated under different environments and how this can facilitate adaptation, such as azole-resistance selection.
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Ries LNA, Steenwyk JL, de Castro PA, de Lima PBA, Almeida F, de Assis LJ, Manfiolli AO, Takahashi-Nakaguchi A, Kusuya Y, Hagiwara D, Takahashi H, Wang X, Obar JJ, Rokas A, Goldman GH. Nutritional Heterogeneity Among Aspergillus fumigatus Strains Has Consequences for Virulence in a Strain- and Host-Dependent Manner. Front Microbiol 2019; 10:854. [PMID: 31105662 PMCID: PMC6492530 DOI: 10.3389/fmicb.2019.00854] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/03/2019] [Indexed: 01/09/2023] Open
Abstract
Acquisition and subsequent metabolism of different carbon and nitrogen sources have been shown to play an important role in virulence attributes of the fungal pathogen Aspergillus fumigatus, such as the secretion of host tissue-damaging proteases and fungal cell wall integrity. We examined the relationship between the metabolic processes of carbon catabolite repression (CCR), nitrogen catabolite repression (NCR) and virulence in a variety of A. fumigatus clinical isolates. A considerable amount of heterogeneity with respect to the degree of CCR and NCR was observed and a positive correlation between NCR and virulence in a neutropenic mouse model of pulmonary aspergillosis (PA) was found. Isolate Afs35 was selected for further analysis and compared to the reference strain A1163, with both strains presenting the same degree of virulence in a neutropenic mouse model of PA. Afs35 metabolome analysis in physiological-relevant carbon sources indicated an accumulation of intracellular sugars that also serve as cell wall polysaccharide precursors. Genome analysis showed an accumulation of missense substitutions in the regulator of protease secretion and in genes encoding enzymes required for cell wall sugar metabolism. Based on these results, the virulence of strains Afs35 and A1163 was assessed in a triamcinolone murine model of PA and found to be significantly different, confirming the known importance of using different mouse models to assess strain-specific pathogenicity. These results highlight the importance of nitrogen metabolism for virulence and provide a detailed example of the heterogeneity that exists between A. fumigatus isolates with consequences for virulence in a strain-specific and host-dependent manner.
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Affiliation(s)
| | - Jacob L. Steenwyk
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
| | - Patrícia Alves de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | | | - Fausto Almeida
- Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Leandro José de Assis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | | | | | - Yoko Kusuya
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Daisuke Hagiwara
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Hiroki Takahashi
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Xi Wang
- Department of Microbiology and Immunology, Dartmouth Geisel School of Medicine, Lebanon, NH, United States
| | - Joshua J. Obar
- Department of Microbiology and Immunology, Dartmouth Geisel School of Medicine, Lebanon, NH, United States
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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Restrepo CM, Llanes A, Lleonart R. Use of AFLP for the study of eukaryotic pathogens affecting humans. INFECTION GENETICS AND EVOLUTION 2017; 63:360-369. [PMID: 28935612 DOI: 10.1016/j.meegid.2017.09.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 09/13/2017] [Accepted: 09/15/2017] [Indexed: 12/29/2022]
Abstract
Amplified fragment length polymorphism (AFLP) is a genotyping technique based on PCR amplification of specific restriction fragments from a particular genome. The methodology has been extensively used in plant biology to solve a variety of scientific questions, including taxonomy, molecular epidemiology, systematics, population genetics, among many others. The AFLP share advantages and disadvantages with other types of molecular markers, being particularly useful in organisms with no previous DNA sequence knowledge. In eukaryotic pathogens, the technique has not been extensively used, although it has the potential to solve many important issues as it allows the simultaneous examination of hundreds or even thousands of polymorphic sites in the genome of the organism. Here we describe the main applications published on the use of AFLP in eukaryotic pathogens, with emphasis in species of the groups fungi, protozoa and helminths, and discuss the role of this methodology in the context of new techniques derived from the advances of the next generation sequencing.
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Affiliation(s)
- Carlos M Restrepo
- Center for Cellular and Molecular Biology of Diseases, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Edificio 219, Ciudad del Saber, Apartado 0843-01103, Ciudad de Panamá, Panama.; Department of Biotechnology, Acharya Nagarjuna University, Guntur, India..
| | - Alejandro Llanes
- Center for Cellular and Molecular Biology of Diseases, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Edificio 219, Ciudad del Saber, Apartado 0843-01103, Ciudad de Panamá, Panama.; Department of Biotechnology, Acharya Nagarjuna University, Guntur, India
| | - Ricardo Lleonart
- Center for Cellular and Molecular Biology of Diseases, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Edificio 219, Ciudad del Saber, Apartado 0843-01103, Ciudad de Panamá, Panama..
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Ashu EE, Korfanty GA, Xu J. Evidence of unique genetic diversity in Aspergillus fumigatus isolates from Cameroon. Mycoses 2017; 60:739-748. [PMID: 28730597 DOI: 10.1111/myc.12655] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 03/19/2017] [Accepted: 06/20/2017] [Indexed: 11/27/2022]
Abstract
Aspergillus fumigatus is a saprophytic fungus that can cause lethal invasive aspergillosis in immunocompromised patients. Recent studies have shown that Eurasian and North American populations of A. fumigatus often consist of genetically diverse strains. However, very little is known about African populations of A. fumigatus. Here, we characterise the genetic diversity and triazole susceptibility of A. fumigatus in Cameroon, West Africa. A total of 495 soil samples were obtained from nine collection sites in three Cameroonian regions. Nine microsatellite markers were used to genotype all 51 identified A. fumigatus isolates. In vitro susceptibility to itraconazole and voriconazole was tested using micro broth dilution. The 51 Cameroonian A. fumigatus isolates belonged to 45 genotypes. Consistent with recombination, 32 of 36 possible pairwise loci combinations are phylogenetically incompatible. Interestingly, evidence for geographic sub-structuring was found within Cameroon and the sub-population with the most evidence of recombination was also the least susceptible sub-population to the triazole antifungals tested. Furthermore, the Cameroonian sample was significantly differentiated from those in Eurasia and North America. Overall, our results indicate the genetic uniqueness of Cameroonian A. fumigatus populations and that additional novel genetic diversity likely exist in other parts of Africa.
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Affiliation(s)
- Eta E Ashu
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | | | - Jianping Xu
- Department of Biology, McMaster University, Hamilton, ON, Canada
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Giusiano GE, Piontelli E, Fernández MS, Mangiaterra ML, Cattana ME, Kocsubé S, Varga J. Biodiversity of species of Aspergillus section Fumigati in semi-desert soils in Argentina. Rev Argent Microbiol 2017; 49:247-254. [PMID: 28551307 DOI: 10.1016/j.ram.2017.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 01/23/2017] [Accepted: 02/20/2017] [Indexed: 11/19/2022] Open
Abstract
The distribution of Aspergillus species in soil has been widely studied all over the world. The aim of this study was the phenotypic and genotypic characterization of species Aspergillus belonging to section Fumigati present in soils from two Argentinian semi-desert areas having different geological conditions. Altogether, 23 isolates belonging to Aspergillus section Fumigati were recovered and identified using a polyphasic approach including phenotypic and molecular identifications. Aspergillus fumigatus sensu stricto and Aspergillus fumigatiaffinis had the highest frequency, of occurrence while isolates closely related to Aspergillus udagawae and Aspergillus felis were rarely observed. A. fumigatiaffinis and isolates closer to A. udagawae were isolated for the first time from Argentinian soils and this is the first report on the occurrence of species belonging to the A. felis clade in South America. Recent scientific interests in biodiversity, as well as the increasing importance of aspergilli as causative agents of human and animal diseases increase the need to understand the diversity and occurrence of these fungi in nature.
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Affiliation(s)
- Gustavo E Giusiano
- Universidad Nacional del Nordeste, CONICET, Instituto de Medicina Regional, Departamento de Micología, Resistencia, Chaco, Argentina.
| | - Eduardo Piontelli
- Universidad de Valparaíso, Escuela de Medicina, Cátedra de Micología, Valparaíso, Chile
| | - Mariana S Fernández
- Universidad Nacional del Nordeste, CONICET, Instituto de Medicina Regional, Departamento de Micología, Resistencia, Chaco, Argentina
| | - Magdalena L Mangiaterra
- Universidad Nacional del Nordeste, CONICET, Instituto de Medicina Regional, Departamento de Micología, Resistencia, Chaco, Argentina
| | - María E Cattana
- Universidad Nacional del Nordeste, CONICET, Instituto de Medicina Regional, Departamento de Micología, Resistencia, Chaco, Argentina
| | - Sándor Kocsubé
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - János Varga
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
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Global Population Genetic Analysis of Aspergillus fumigatus. mSphere 2017; 2:mSphere00019-17. [PMID: 28168221 PMCID: PMC5288565 DOI: 10.1128/msphere.00019-17] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 01/13/2017] [Indexed: 01/17/2023] Open
Abstract
The genetic diversity and geographic structure of the human fungal pathogen A. fumigatus have been the subject of many studies. However, most previous studies had relatively limited sample ranges and sizes and/or used genetic markers with low-level polymorphisms. In this paper, we characterize a global collection of strains of A. fumigatus using a panel of 9 highly polymorphic microsatellite markers. Using these markers, we analyze 2,026 isolates, which is ~3 times the number of isolates reported so far in previous studies. Our analyses suggest that A. fumigatus contains historically differentiated genetic populations but that its evolution is significantly impacted by contemporary forces such as widespread gene flow and local antifungal drug pressure. In the wake of a global rise in resistance to azoles in fungal pathogens, our findings should aid in developing management strategies to mitigate current increases to azole resistance. Aspergillus fumigatus is a ubiquitous opportunistic fungal pathogen capable of causing invasive aspergillosis, a globally distributed disease with a mortality rate of up to 90% in high-risk populations. Effective control and prevention of this disease require a thorough understanding of its epidemiology. However, despite significant efforts, the global molecular epidemiology of A. fumigatus remains poorly understood. In this study, we analyzed 2,026 A. fumigatus isolates from 13 countries in four continents using nine highly polymorphic microsatellite markers. Genetic cluster analyses suggest that our global sample of A. fumigatus isolates belonged to eight genetic clusters, with seven of the eight clusters showing broad geographic distributions. We found common signatures of sexual recombination within individual genetic clusters and clear evidence of hybridization between several clusters. Limited but statistically significant genetic differentiations were found among geographic and ecological populations. However, there was abundant evidence for gene flow at the local, regional, and global scales. Interestingly, the triazole-susceptible and triazole-resistant populations showed different population structures, consistent with antifungal drug pressure playing a significant role in local adaptation. Our results suggest that global populations of A. fumigatus are shaped by historical differentiation, contemporary gene flow, sexual reproduction, and the localized antifungal drug selection that is driving clonal expansion of genotypes resistant to multiple triazole drugs. IMPORTANCE The genetic diversity and geographic structure of the human fungal pathogen A. fumigatus have been the subject of many studies. However, most previous studies had relatively limited sample ranges and sizes and/or used genetic markers with low-level polymorphisms. In this paper, we characterize a global collection of strains of A. fumigatus using a panel of 9 highly polymorphic microsatellite markers. Using these markers, we analyze 2,026 isolates, which is ~3 times the number of isolates reported so far in previous studies. Our analyses suggest that A. fumigatus contains historically differentiated genetic populations but that its evolution is significantly impacted by contemporary forces such as widespread gene flow and local antifungal drug pressure. In the wake of a global rise in resistance to azoles in fungal pathogens, our findings should aid in developing management strategies to mitigate current increases to azole resistance.
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Heterogeneity among Isolates Reveals that Fitness in Low Oxygen Correlates with Aspergillus fumigatus Virulence. mBio 2016; 7:mBio.01515-16. [PMID: 27651366 PMCID: PMC5040115 DOI: 10.1128/mbio.01515-16] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED Previous work has shown that environmental and clinical isolates of Aspergillus fumigatus represent a diverse population that occupies a variety of niches, has extensive genetic diversity, and exhibits virulence heterogeneity in a number of animal models of invasive pulmonary aspergillosis (IPA). However, mechanisms explaining differences in virulence among A. fumigatus isolates remain enigmatic. Here, we report a significant difference in virulence of two common lab strains, CEA10 and AF293, in the murine triamcinolone immunosuppression model of IPA, in which we previously identified severe low oxygen microenvironments surrounding fungal lesions. Therefore, we hypothesize that the ability to thrive within these lesions of low oxygen promotes virulence of A. fumigatus in this model. To test this hypothesis, we performed in vitro fitness and in vivo virulence analyses in the triamcinolone murine model of IPA with 14 environmental and clinical isolates of A. fumigatus Among these isolates, we observed a strong correlation between fitness in low oxygen in vitro and virulence. In further support of our hypothesis, experimental evolution of AF293, a strain that exhibits reduced fitness in low oxygen and reduced virulence in the triamcinolone model of IPA, results in a strain (EVOL20) that has increased hypoxia fitness and a corresponding increase in virulence. Thus, the ability to thrive in low oxygen correlates with virulence of A. fumigatus isolates in the context of steroid-mediated murine immunosuppression. IMPORTANCE Aspergillus fumigatus occupies multiple environmental niches, likely contributing to the genotypic and phenotypic heterogeneity among isolates. Despite reports of virulence heterogeneity, pathogenesis studies often utilize a single strain for the identification and characterization of virulence and immunity factors. Here, we describe significant variation between A. fumigatus isolates in hypoxia fitness and virulence, highlighting the advantage of including multiple strains in future studies. We also illustrate that hypoxia fitness correlates strongly with increased virulence exclusively in the nonleukopenic murine triamcinolone immunosuppression model of IPA. Through an experimental evolution experiment, we observe that chronic hypoxia exposure results in increased virulence of A. fumigatus We describe here the first observation of a model-specific virulence phenotype correlative with in vitro fitness in hypoxia and pave the way for identification of hypoxia-mediated mechanisms of virulence in the fungal pathogen A. fumigatus.
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Shittu OB, Adelaja OM, Obuotor TM, Sam-Wobo SO, Adenaike AS. PCR-Internal Transcribed Spacer (ITS) genes sequencing and phylogenetic analysis of clinical and environmental Aspergillus species associated with HIV-TB co infected patients in a hospital in Abeokuta, southwestern Nigeria. Afr Health Sci 2016; 16:141-8. [PMID: 27358625 DOI: 10.4314/ahs.v16i1.19] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Aspergillosis has been identified as one of the hospital acquired infections but the contribution of water and inhouse air as possible sources of Aspergillus infection in immunocompromised individuals like HIV-TB patients have not been studied in any hospital setting in Nigeria. OBJECTIVE To identify and investigate genetic relationship between clinical and environmental Aspergillus sp. associated with HIV-TB co infected patients. METHODS DNA extraction, purification, amplification and sequencing of Internal Transcribed Spacer (ITS) genes were performed using standard protocols. Similarity search using BLAST on NCBI was used for species identification and MEGA 5.0 was used for phylogenetic analysis. RESULTS Analyses of sequenced ITS genes of selected fourteen (14) Aspergillus isolates identified in the GenBank database revealed Aspergillus niger (28.57%), A. tubingensis (7.14%), A. flavus (7.14%) and A. fumigatus (57.14%). Aspergillus in sputum of HIV patients were Aspergillus niger, A. fumigatus, A. tubingensis and A. flavus. Also, A. niger and A. fumigatus were identified from water and open-air. Phylogenetic analysis of sequences yielded genetic relatedness between clinical and environmental isolates. CONCLUSION Water and air in health care settings in Nigeria are important sources of Aspergillus sp. for HIV-TB patients.
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Affiliation(s)
- Olufunke Bolatito Shittu
- Department of Microbiology, College of Biosciences, Federal University of Agriculture, Abeokuta, Nigeria
| | - Oluwabunmi Molade Adelaja
- Department of Microbiology, College of Biosciences, Federal University of Agriculture, Abeokuta, Nigeria
| | - Tolulope Mobolaji Obuotor
- Department of Microbiology, College of Biosciences, Federal University of Agriculture, Abeokuta, Nigeria
| | - Sam Olufemi Sam-Wobo
- Department of Pure and Applied Zoology, Federal University of Agriculture, Abeokuta, Nigeria
| | - Adeyemi Sunday Adenaike
- Department of Animal Breeding and Genetics, Federal University of Agriculture, Abeokuta, Nigeria
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Teixeira J, Amorim A, Araujo R. Recombination detection in Aspergillus fumigatus through single nucleotide polymorphisms typing. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:881-886. [PMID: 26189756 DOI: 10.1111/1758-2229.12321] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 06/27/2015] [Accepted: 07/10/2015] [Indexed: 06/04/2023]
Abstract
The first evidence of sexual reproduction in Aspergillus fumigatus was reported in 2009. Nevertheless, it remains difficult to understand how A. fumigatus is able to reproduce through this mode in its natural environment and how frequently this occurs. The aim of this study was to analyse single nucleotide polymorphisms (SNPs) in a set of environmental and clinical isolates of A. fumigatus to detect signatures of recombination. A group of closely related Portuguese A. fumigatus isolates was characterized by mating type and the genetic diversity of the intergenic regions, microsatellites and multilocus sequence typing (MLST) genes. A group of 19 SNPs, organized in nine association groups and inherited in blocks, was identified and compared. Several variations on the association panel were detected on reference isolates of A. fumigatus AF293 and A1163, the sequence types available at MLST database and six clinical and environmental Portuguese isolates. About one to four haplotype disruptions were observed per isolate. Considering clinical and environmental isolates, sexual reproduction seems to occur more frequently than previously admitted in A. fumigatus. In this study, a practical SNP approach is proposed for detection of recombination events in larger collections of A. fumigatus.
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Affiliation(s)
- Joana Teixeira
- IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - António Amorim
- IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Faculty of Sciences, University of Porto, Porto, Portugal
| | - Ricardo Araujo
- IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
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Dogi C, Alonso V, Fochesato A, Poloni V, Cavaglieri L. Comparison of toxicogenic and immunosuppressive capacity of Aspergillus fumigatus
strains isolated from clinical and corn silage samples. J Appl Microbiol 2014; 118:175-81. [DOI: 10.1111/jam.12673] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/15/2014] [Accepted: 10/19/2014] [Indexed: 11/29/2022]
Affiliation(s)
- C. Dogi
- Departamento de Microbiología e Inmunología; Universidad Nacional de Río Cuarto; Río Cuarto Córdoba Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Buenos Aires Argentina
| | - V. Alonso
- Departamento de Microbiología e Inmunología; Universidad Nacional de Río Cuarto; Río Cuarto Córdoba Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Buenos Aires Argentina
| | - A. Fochesato
- Departamento de Microbiología e Inmunología; Universidad Nacional de Río Cuarto; Río Cuarto Córdoba Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET); Buenos Aires; Argentina
| | - V. Poloni
- Departamento de Microbiología e Inmunología; Universidad Nacional de Río Cuarto; Río Cuarto Córdoba Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET); Buenos Aires; Argentina
| | - L. Cavaglieri
- Departamento de Microbiología e Inmunología; Universidad Nacional de Río Cuarto; Río Cuarto Córdoba Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Buenos Aires Argentina
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Alshareef F, Robson GD. Genetic and virulence variation in an environmental population of the opportunistic pathogen Aspergillus fumigatus. MICROBIOLOGY-SGM 2014; 160:742-751. [PMID: 24464798 DOI: 10.1099/mic.0.072520-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Environmental populations of the opportunistic pathogen Aspergillus fumigatus have been shown to be genotypically diverse and to contain a range of isolates with varying pathogenic potential. In this study, we combined two RAPD primers to investigate the genetic diversity of environmental isolates from Manchester collected monthly over 1 year alongside Dublin environmental isolates and clinical isolates from patients. RAPD analysis revealed a diverse genotype, but with three major clinical isolate clusters. When the pathogenicity of clinical and Dublin isolates was compared with a random selection of Manchester isolates in a Galleria mellonella larvae model, as a group, clinical isolates were significantly more pathogenic than environmental isolates. Moreover, when relative pathogenicity of individual isolates was compared, clinical isolates were the most pathogenic, Dublin isolates were the least pathogenic and Manchester isolates showed a range in pathogenicity. Overall, this suggests that the environmental population is genetically diverse, displaying a range in pathogenicity, and that the most pathogenic strains from the environment are selected during patient infection.
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Affiliation(s)
- Fadwa Alshareef
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Manchester M16 8QW, UK
| | - Geoffrey D Robson
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Manchester M16 8QW, UK
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Duarte-Escalante E, Zúñiga G, Frías-De-León MG, Canteros C, Castañón-Olivares LR, Reyes-Montes MDR. AFLP analysis reveals high genetic diversity but low population structure in Coccidioides posadasii isolates from Mexico and Argentina. BMC Infect Dis 2013; 13:411. [PMID: 24004977 PMCID: PMC3766708 DOI: 10.1186/1471-2334-13-411] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 08/30/2013] [Indexed: 01/29/2023] Open
Abstract
Background Coccidioides immitis and C. posadasii cause coccidioidomycosis, a disease that is endemic to North and South America, but for Central America, the incidence of coccidioidomycosis has not been clearly established. Several studies suggest genetic variability in these fungi; however, little definitive information has been discovered about the variability of Coccidioides fungi in Mexico (MX) and Argentina (AR). Thus, the goals for this work were to study 32 Coccidioides spp. isolates from MX and AR, identify the species of these Coccidioides spp. isolates, analyse their phenotypic variability, examine their genetic variability and investigate the Coccidioides reproductive system and its level of genetic differentiation. Methods Coccidioides spp. isolates from MX and AR were taxonomically identified by phylogenetic inference analysis using partial sequences of the Ag2/PRA gene and their phenotypic characteristics analysed. The genetic variability, reproductive system and level of differentiation were estimated using AFLP markers. The level of genetic variability was assessed measuring the percentage of polymorphic loci, number of effective allele, expected heterocygosity and Index of Association (IA). The degree of genetic differentiation was determined by AMOVA. Genetic similarities among isolates were estimated using Jaccard index. The UPGMA was used to contsruct the corresponding dendrogram. Finally, a network of haplotypes was built to evaluate the genealogical relationships among AFLP haplotypes. Results All isolates of Coccidioides spp. from MX and AR were identified as C. posadasii. No phenotypic variability was observed among the C. posadasii isolates from MX and AR. Analyses of genetic diversity and population structure were conducted using AFLP markers. Different estimators of genetic variability indicated that the C. posadasii isolates from MX and AR had high genetic variability. Furthermore, AMOVA, dendrogram and haplotype network showed a small genetic differentiation among the C. posadasii populations analysed from MX and AR. Additionally, the IA calculated for the isolates suggested that the species has a recombinant reproductive system. Conclusions No phenotypic variability was observed among the C. posadasii isolates from MX and AR. The high genetic variability observed in the isolates from MX and AR and the small genetic differentiation observed among the C. posadasii isolates analysed, suggest that this species could be distributed as a single genetic population in Latin America.
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Affiliation(s)
- Esperanza Duarte-Escalante
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria No, 3000, México, D, F, 04510, México.
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Refojo N, Duarte-Escalante E, Dignani MC, Hevia AI, Abrantes RA, Davel G, Canteros C, Frías de León MG, Acosta-Altamirano G, Zúñiga G, Reyes-Montes MDR. [Genotyping of clinical isolates of Aspergillus flavus and its relationship with environmental isolates of an oncohematological center]. Rev Iberoam Micol 2012; 30:25-30. [PMID: 23036749 DOI: 10.1016/j.riam.2012.09.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 08/09/2012] [Accepted: 09/10/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND During 4 months, and while conducting an environmental sampling of air, 2 cases of aspergillosis by Aspergillus flavus (A. flavus) were diagnosed at an oncohematological center in Buenos Aires, Argentina. AIMS The aim of this study was to know the variability and the genetic relationship between the clinical and environmental isolates, obtained in the oncohematological center. METHODS Two genotyping techniques of different discriminatory power (RAPD and AFLP) were used. A genetic similarity matrix was calculated using Jaccard method and was the basis for the construction of a dendrogram by UPGMA. The level of genetic variability was assessed by measuring the percentage of polymorphic loci, number of effective allele, expected heterocygozity and association index test (I(A)). RESULTS The dendrogram reveals that the A. flavus isolates recovered from the patients were not genetically related to those gotten from the rooms occupied by the patients. The environmental isolates had higher values of genetic diversity than the clinical isolates. The I(A) estimated for all the isolates suggest that recombination events occurred. CONCLUSIONS Patients 1 and 2 were not infected with isolates from the nosocomial environment. Clinical and environmental isolates of A. flavus showed high genetic variability among them.
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Affiliation(s)
- Nicolás Refojo
- Departamento de Micología, INEI ANLIS Dr. Carlos G. Malbrán, Buenos Aires, Argentina
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Al-Qarawi A, Hashem A, Abd-Allah E. Seed mycoflora of Ephedra aphylla and amino acid profile of seed-borne Aspergillus flavus. Acta Microbiol Immunol Hung 2012; 59:311-20. [PMID: 22982635 DOI: 10.1556/amicr.59.2012.3.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Twenty-seven seed samples of Ephedra aphylla were collected from different rangelands in Riyadh region, Saudi Arabia during seed production season of 2010. They were assessed to determine the incidence of seedborne fungal flora using both agar plate and blotter paper methods. The investigation of the seeds yielded thirty four fungal species belonging to twelve genera, which are new record to seed-brone mycoflora of E. aphylla in Saudi Arabia. The agar plate method was found superior over blotter methods. The genus Aspergillus was the most prevalent one followed by Fusarium, Penicillium, Alternaria, and Chaetomium. Only eighteen isolates of A. flavus (∼ 28.6% of total isolates) were able to produce aflatoxins. Mycelial amino acids profile of selected aflatoxigenic isolates of A. flavus was investigated and five amino acids, namely cystein, lysine, praline, tryptophan and valine were common in mycelia and all of them were aflatoxins producers. Based on the dissimilarity coefficient between the isolates and their amino acids patterns, high diversity among the population of A. flavus has been recorded.
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Affiliation(s)
- Abdulaziz Al-Qarawi
- 1 King Saud University Plant Production Department, Faculty of Food Science and Agriculture P.O. Box 2460 Riyadh 11451 Saudi Arabia
| | - Abeer Hashem
- 2 King Saud University Botany and Microbiology Department, Faculty of Science P.O. Box 2460 Riyadh 11451 Saudi Arabia
| | - Elsayed Abd-Allah
- 1 King Saud University Plant Production Department, Faculty of Food Science and Agriculture P.O. Box 2460 Riyadh 11451 Saudi Arabia
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Burco JD, Etienne KA, Massey JG, Ziccardi MH, Balajee SA. Molecular sub-typing suggests that the environment of rehabilitation centers may be a potential source ofAspergillus fumigatusinfecting rehabilitating seabirds. Med Mycol 2012; 50:91-8. [DOI: 10.3109/13693786.2011.592860] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Frías-De León MG, Zavala-Ramírez M, Córdoba S, Zúñiga G, Duarte-Escalante E, Pérez-Torres A, Zepeda-Rodríguez A, López-Martínez I, Buitrago MJ, del Rocío Reyes-Montes M. Phenotypic characteristics of isolates of Aspergillus section Fumigati from different geographic origins and their relationships with genotypic characteristics. BMC Infect Dis 2011; 11:116. [PMID: 21554728 PMCID: PMC3115867 DOI: 10.1186/1471-2334-11-116] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 05/09/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Epidemiological studies worldwide have shown that A. fumigatus exhibits important phenotypic and genotypic diversity, and these findings have been of great importance in improving the diagnosis and treatment of diseases caused by this fungus. However, few studies have been carried out related to the epidemiology of this fungus in Latin America. This study's aim is to report on the epidemiology of the fungus by analyzing the phenotypic variability of Aspergillus section Fumigati isolates from different Latin American countries and the relationship between this variability, the geographical origin and genotypic characteristics. METHODS We analyzed the phenotypic characteristics (macro- and micromorphology, conidial size, vesicles size, antifungal susceptibility and thermotolerance at 28, 37 and 48°C) of A. section Fumigati isolates from Mexico (MX), Argentina (AR), Peru (PE) and France (FR). The results were analyzed using analysis of variance (ANOVA) and Tukey's multiple comparison test to detect significant differences. Two dendrograms among isolates were obtained with UPGMA using the Euclidean distance index. One was drawn for phenotypic data, and the other for phenotypic and genotypic data. A PCoA was done for shown isolates in a space of reduced dimensionality. In order to determine the degree of association between the phenotypic and genotypic characteristics AFLP, we calculated the correlation between parwise Euclidean distance matrices of both data sets with the nonparametric Mantel test. RESULTS No variability was found in the macromorphology of the studied isolates; however, the micromorphology and growth rate showed that the PE isolates grew at a faster rate and exhibited the widest vesicles in comparison to the isolates from MX, AR and FR. The dendrogram constructed with phenotypic data showed three distinct groups. The group I and II were formed with isolates from PE and FR, respectively, while group III was formed with isolates from MX and AR. The dendrogram with phenotypic and genotypic data showed the same cluster, except for an isolate from FR that formed a separate cluster. This cluster was confirmed using PCoA. The correlation between the phenotypic and genotypic data of the isolates revealed a statistically significant association between these characteristics. CONCLUSIONS The PE isolates showed specific phenotypic characteristics that clearly differentiate them from the rest of the isolates, which matches the genotypic data. The correlation between the phenotypic and genotypic characteristics showed a statistically significant association. In conclusion, phenotypic and genotypic methods together increase the power of correlation between isolates.
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Affiliation(s)
- María Guadalupe Frías-De León
- Laboratorio de Micología Molecular Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad Universitaria No, 3000, México D.F., 04360, Mexico
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Thierry S, Wang D, Arné P, Deville M, De Bruin B, Nieguitsila A, Pourcel C, Laroucau K, Chermette R, Huang W, Botterel F, Guillot J. Multiple-locus variable-number tandem repeat analysis for molecular typing of Aspergillus fumigatus. BMC Microbiol 2010; 10:315. [PMID: 21143842 PMCID: PMC3004892 DOI: 10.1186/1471-2180-10-315] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 12/08/2010] [Indexed: 11/30/2022] Open
Abstract
Background Multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA) is a prominent subtyping method to resolve closely related microbial isolates to provide information for establishing genetic patterns among isolates and to investigate disease outbreaks. The usefulness of MLVA was recently demonstrated for the avian major pathogen Chlamydophila psittaci. In the present study, we developed a similar method for another pathogen of birds: the filamentous fungus Aspergillus fumigatus. Results We selected 10 VNTR markers located on 4 different chromosomes (1, 5, 6 and 8) of A. fumigatus. These markers were tested with 57 unrelated isolates from different hosts or their environment (53 isolates from avian species in France, China or Morocco, 3 isolates from humans collected at CHU Henri Mondor hospital in France and the reference strain CBS 144.89). The Simpson index for individual markers ranged from 0.5771 to 0.8530. A combined loci index calculated with all the markers yielded an index of 0.9994. In a second step, the panel of 10 markers was used in different epidemiological situations and tested on 277 isolates, including 62 isolates from birds in Guangxi province in China, 95 isolates collected in two duck farms in France and 120 environmental isolates from a turkey hatchery in France. A database was created with the results of the present study http://minisatellites.u-psud.fr/MLVAnet/. Three major clusters of isolates were defined by using the graphing algorithm termed Minimum Spanning Tree (MST). The first cluster comprised most of the avian isolates collected in the two duck farms in France, the second cluster comprised most of the avian isolates collected in poultry farms in China and the third one comprised most of the isolates collected in the turkey hatchery in France. Conclusions MLVA displayed excellent discriminatory power. The method showed a good reproducibility. MST analysis revealed an interesting clustering with a clear separation between isolates according to their geographic origin rather than their respective hosts.
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Affiliation(s)
- Simon Thierry
- ENVA, UMR BIPAR, Ecopham, Ecole nationale vétérinaire d'Alfort, Maisons-Alfort, France
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What makes Aspergillus fumigatus a successful pathogen? Genes and molecules involved in invasive aspergillosis. Rev Iberoam Micol 2010; 27:155-82. [PMID: 20974273 DOI: 10.1016/j.riam.2010.10.003] [Citation(s) in RCA: 273] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 10/06/2010] [Accepted: 10/07/2010] [Indexed: 11/21/2022] Open
Abstract
Aspergillus fumigatus is an opportunistic pathogen that causes 90% of invasive aspergillosis (IA) due to Aspergillus genus, with a 50-95% mortality rate. It has been postulated that certain virulence factors are characteristic of A. fumigatus, but the "non-classical" virulence factors seem to be highly variable. Overall, published studies have demonstrated that the virulence of this fungus is multifactorial, associated with its structure, its capacity for growth and adaptation to stress conditions, its mechanisms for evading the immune system and its ability to cause damage to the host. In this review we intend to give a general overview of the genes and molecules involved in the development of IA. The thermotolerance section focuses on five genes related with the capacity of the fungus to grow at temperatures above 30°C (thtA, cgrA, afpmt1, kre2/afmnt1, and hsp1/asp f 12). The following sections discuss molecules and genes related to interaction with the host and with the immune responses. These sections include β-glucan, α-glucan, chitin, galactomannan, galactomannoproteins (afmp1/asp f 17 and afmp2), hydrophobins (rodA/hyp1 and rodB), DHN-melanin, their respective synthases (fks1, rho1-4, ags1-3, chsA-G, och1-4, mnn9, van1, anp1, glfA, pksP/alb1, arp1, arp2, abr1, abr2, and ayg1), and modifying enzymes (gel1-7, bgt1, eng1, ecm33, afpigA, afpmt1-2, afpmt4, kre2/afmnt1, afmnt2-3, afcwh41 and pmi); several enzymes related to oxidative stress protection such as catalases (catA, cat1/catB, cat2/katG, catC, and catE), superoxide dismutases (sod1, sod2, sod3/asp f 6, and sod4), fatty acid oxygenases (ppoA-C), glutathione tranferases (gstA-E), and others (afyap1, skn7, and pes1); and efflux transporters (mdr1-4, atrF, abcA-E, and msfA-E). In addition, this review considers toxins and related genes, such as a diffusible toxic substance from conidia, gliotoxin (gliP and gliZ), mitogillin (res/mitF/asp f 1), hemolysin (aspHS), festuclavine and fumigaclavine A-C, fumitremorgin A-C, verruculogen, fumagillin, helvolic acid, aflatoxin B1 and G1, and laeA. Two sections cover genes and molecules related with nutrient uptake, signaling and metabolic regulations involved in virulence, including enzymes, such as serine proteases (alp/asp f 13, alp2, and asp f 18), metalloproteases (mep/asp f 5, mepB, and mep20), aspartic proteases (pep/asp f 10, pep2, and ctsD), dipeptidylpeptidases (dppIV and dppV), and phospholipases (plb1-3 and phospholipase C); siderophores and iron acquisition (sidA-G, sreA, ftrA, fetC, mirB-C, and amcA); zinc acquisition (zrfA-H, zafA, and pacC); amino acid biosynthesis, nitrogen uptake, and cross-pathways control (areA, rhbA, mcsA, lysF, cpcA/gcn4p, and cpcC/gcn2p); general biosynthetic pathway (pyrG, hcsA, and pabaA), trehalose biosynthesis (tpsA and tpsB), and other regulation pathways such as those of the MAP kinases (sakA/hogA, mpkA-C, ste7, pbs2, mkk2, steC/ste11, bck1, ssk2, and sho1), G-proteins (gpaA, sfaD, and cpgA), cAMP-PKA signaling (acyA, gpaB, pkaC1, and pkaR), His kinases (fos1 and tcsB), Ca(2+) signaling (calA/cnaA, crzA, gprC and gprD), and Ras family (rasA, rasB, and rhbA), and others (ace2, medA, and srbA). Finally, we also comment on the effect of A. fumigatus allergens (Asp f 1-Asp f 34) on IA. The data gathered generate a complex puzzle, the pieces representing virulence factors or the different activities of the fungus, and these need to be arranged to obtain a comprehensive vision of the virulence of A. fumigatus. The most recent gene expression studies using DNA-microarrays may be help us to understand this complex virulence, and to detect targets to develop rapid diagnostic methods and new antifungal agents.
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