151
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Fabri JHTM, Godoy NL, Rocha MC, Munshi M, Cocio TA, von Zeska Kress MR, Fill TP, da Cunha AF, Del Poeta M, Malavazi I. The AGC Kinase YpkA Regulates Sphingolipids Biosynthesis and Physically Interacts With SakA MAP Kinase in Aspergillus fumigatus. Front Microbiol 2019; 9:3347. [PMID: 30692984 PMCID: PMC6339957 DOI: 10.3389/fmicb.2018.03347] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 12/28/2018] [Indexed: 12/12/2022] Open
Abstract
Sphingolipids (SL) are complex lipids and components of the plasma membrane which are involved in numerous cellular processes, as well as important for virulence of different fungal pathogens. In yeast, SL biosynthesis is regulated by the "AGC kinases" Ypk1 and Ypk2, which also seem to connect the SL biosynthesis with the cell wall integrity (CWI) and the High Osmolarity Glycerol (HOG) pathways. Here, we investigate the role of ypkA Y PK1 in SL biosynthesis and its relationship with the CWI and the HOG pathways in the opportunistic human pathogen Aspergillus fumigatus. We found that ypkA is important for fungal viability, since the ΔypkA strain presented a drastically sick phenotype and complete absence of conidiation. We observed that under repressive condition, the conditional mutant niiA::ypkA exhibited vegetative growth defects, impaired germination and thermosensitivity. In addition, the ypkA loss of function caused a decrease in glycosphingolipid (GSL) levels, especially the metabolic intermediates belonging to the neutral GSL branch including dihydroceramide (DHC), ceramide (Cer), and glucosylceramide (GlcCer), but interestingly a small increase in ergosterol content. Genetic analyzes showed that ypkA genetically interacts with the MAP kinases of CWI and HOG pathways, mpkA and sakA, respectively, while only SakA physically interacts with YpkA. Our results suggest that YpkA is important for fungal survival through the regulation of GSL biosynthesis and cross talks with A. fumigatus MAP kinase pathways.
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Affiliation(s)
| | - Naiane Lima Godoy
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Marina Campos Rocha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Mansa Munshi
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, United States
| | - Tiago Alexandre Cocio
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Marcia Regina von Zeska Kress
- Departamento de Análises Clínicas Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | | | - Anderson Ferreira da Cunha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Maurizio Del Poeta
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, United States.,Division of Infectious Diseases, School of Medicine, Stony Brook University, Stony Brook, NY, United States.,Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY, United States.,Veterans Administration Medical Center, Northport, NY, United States
| | - Iran Malavazi
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
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152
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Hokken MWJ, Zoll J, Coolen JPM, Zwaan BJ, Verweij PE, Melchers WJG. Phenotypic plasticity and the evolution of azole resistance in Aspergillus fumigatus; an expression profile of clinical isolates upon exposure to itraconazole. BMC Genomics 2019; 20:28. [PMID: 30626317 PMCID: PMC6327609 DOI: 10.1186/s12864-018-5255-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 11/15/2018] [Indexed: 01/26/2023] Open
Abstract
Background The prevalence of azole resistance in clinical and environmental Aspergillus fumigatus isolates is rising over the past decades, but the molecular basis of the development of antifungal drug resistance is not well understood. This study focuses on the role of phenotypic plasticity in the evolution of azole resistance in A. fumigatus. When A. fumigatus is challenged with a new stressful environment, phenotypic plasticity may allow A. fumigatus to adjust their physiology to still enable growth and reproduction, therefore allowing the establishment of genetic adaptations through natural selection on the available variation in the mutational and recombinational gene pool. To investigate these short-term physiological adaptations, we conducted time series transcriptome analyses on three clinical A. fumigatus isolates, during incubation with itraconazole. Results After analysis of expression patterns, we identified 3955, 3430, 1207, and 1101 differentially expressed genes (DEGs), after 30, 60, 120 and 240 min of incubation with itraconazole, respectively. We explored the general functions in these gene groups and we identified 186 genes that were differentially expressed during the whole time series. Additionally, we investigated expression patterns of potential novel drug-efflux transporters, genes involved in ergosterol and phospholipid biosynthesis, and the known MAPK proteins of A. fumigatus. Conclusions Our data suggests that A. fumigatus adjusts its transcriptome quickly within 60 min of exposure to itraconazole. Further investigation of these short-term adaptive phenotypic plasticity mechanisms might enable us to understand how the direct response of A. fumigatus to itraconazole promotes survival of the fungus in the patient, before any “hard-wired” genetic mutations arise. Electronic supplementary material The online version of this article (10.1186/s12864-018-5255-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Margriet W J Hokken
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands. .,Center of Expertise in Mycology Radboudumc/CWZ, Weg door Jonkerbos 100, 6532 SZ, Nijmegen, the Netherlands.
| | - Jan Zoll
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands.,Center of Expertise in Mycology Radboudumc/CWZ, Weg door Jonkerbos 100, 6532 SZ, Nijmegen, the Netherlands
| | - Jordy P M Coolen
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands.,Center of Expertise in Mycology Radboudumc/CWZ, Weg door Jonkerbos 100, 6532 SZ, Nijmegen, the Netherlands
| | - Bas J Zwaan
- Department of Plant Sciences, Laboratory of Genetics, Wageningen University, Droevendaalsesteeg 1, 6708PB, Wageningen, The Netherlands
| | - Paul E Verweij
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands.,Center of Expertise in Mycology Radboudumc/CWZ, Weg door Jonkerbos 100, 6532 SZ, Nijmegen, the Netherlands
| | - Willem J G Melchers
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands.,Center of Expertise in Mycology Radboudumc/CWZ, Weg door Jonkerbos 100, 6532 SZ, Nijmegen, the Netherlands
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153
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Azole Resistance Reduces Susceptibility to the Tetrazole Antifungal VT-1161. Antimicrob Agents Chemother 2018; 63:AAC.02114-18. [PMID: 30397057 DOI: 10.1128/aac.02114-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 10/29/2018] [Indexed: 01/07/2023] Open
Abstract
Tetrazole antifungals designed to target fungal lanosterol 14α-demethylase (LDM) appear to be effective against a range of fungal pathogens. In addition, a crystal structure of the catalytic domain of Candida albicans LDM in complex with the tetrazole VT-1161 has been obtained. We have addressed concern about artifacts that might arise from crystallizing VT-1161 with truncated recombinant CYP51s and measured the impact on VT-1161 susceptibility of genotypes known to confer azole resistance. A yeast system was used to overexpress recombinant full-length Saccharomyces cerevisiae LDM with a C-terminal hexahistidine tag (ScLDM6×His) for phenotypic analysis and crystallographic studies with VT-1161 or with the widely used triazole drug posaconazole (PCZ). We determined the effect of characterized mutations in LDM on VT-1161 activity and identified drug efflux pumps from fungi, including key fungal pathogens, that efflux VT-1161. The relevance of these yeast-based observations on drug efflux was verified using clinical isolates of C. albicans and Candida glabrata VT-1161 binding elicits a significant conformational difference between the full-length and truncated enzymes not found when posaconazole is bound. Susceptibility to VT-1161 is reduced by ATP-binding cassette (ABC) and major facilitator superfamily (MFS) drug efflux pumps, the overexpression of LDM, and mutations within the drug binding pocket of LDM that affect interaction with the tertiary alcohol of the drug.
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154
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Resendiz Sharpe A, Lagrou K, Meis JF, Chowdhary A, Lockhart SR, Verweij PE. Triazole resistance surveillance in Aspergillus fumigatus. Med Mycol 2018. [PMID: 29538741 DOI: 10.1093/mmy/myx144] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Triazole resistance is an increasing concern in the opportunistic mold Aspergillus fumigatus. Resistance can develop through exposure to azole compounds during azole therapy or in the environment. Resistance mutations are commonly found in the Cyp51A-gene, although other known and unknown resistance mechanisms may be present. Surveillance studies show triazole resistance in six continents, although the presence of resistance remains unknown in many countries. In most countries, resistance mutations associated with the environment dominate, but it remains unclear if these resistance traits predominately migrate or arise locally. Patients with triazole-resistant aspergillus disease may fail to antifungal therapy, but only a limited number of cohort studies have been performed that show conflicting results. Treatment failure might be due to diagnostic delay or due to the limited number of alternative treatment options. The ISHAM/ECMM Aspergillus Resistance Surveillance working group was set up to facilitate surveillance studies and stimulate international collaborations. Important aims are to determine the resistance epidemiology in countries where this information is currently lacking, to gain more insight in the clinical implications of triazole resistance through a registry and to unify nomenclature through consensus definitions.
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Affiliation(s)
- Agustin Resendiz Sharpe
- Department of Laboratory Medicine, University Hospitals Leuven, and Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
| | - Katrien Lagrou
- Department of Laboratory Medicine, University Hospitals Leuven, and Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
| | - Jacques F Meis
- Department of Medical Microbiology and Infectious Disease, Canisius Wilhelmina Hospital, Nijmegen, the Netherlands.,Center of Expertise in Mycology Radboudumc/CWZ, Nijmegen, the Netherlands
| | - Anuradha Chowdhary
- Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
| | - Shawn R Lockhart
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Paul E Verweij
- Center of Expertise in Mycology Radboudumc/CWZ, Nijmegen, the Netherlands.,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
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155
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Trovato L, Scalia G, Domina M, Oliveri S. Environmental Isolates of Multi-Azole-Resistant Aspergillus spp. in Southern Italy. J Fungi (Basel) 2018; 4:jof4040131. [PMID: 30563198 PMCID: PMC6308927 DOI: 10.3390/jof4040131] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/21/2018] [Accepted: 12/04/2018] [Indexed: 11/16/2022] Open
Abstract
Azole resistance in Aspergillus spp. has been increasingly reported worldwide. Acquired azole resistance is probably linked to environmental exposure to fungicides used in agriculture. We collected a total of 84 soil and leaf samples from eight farms in Southern Italy. Aspergillus isolates were tested for resistance to itraconazole, posaconazole, and voriconazole by the EUCAST method. Five out of 84 samples yielded A. fumigatus isolates: four of them were itraconazole-resistant and were identified as A. fumigatus sensu stricto, three of them were posaconazole-resistant, and two were also voriconazole-resistant. All three isolates harbored the TR34/L98H resistance mechanism, which was detected by DNA sequencing of the cyp51A gene. Fifteen out of 84 samples yielded Aspergillus spp. isolates and included 11 itraconazole-resistant isolates: Aspergillus section Nigri (9) and Aspergillus section Flavi (2). Our study reports for the first time the isolation of azole-resistant A. fumigatus harboring TR34/L98H mutation from the environment of Southern Italy. The present work provides a better understanding of the magnitude of the environmental spread of azole resistance in the context of a necessary effective surveillance program to improve the management of Aspergillus-related disease.
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Affiliation(s)
- Laura Trovato
- U.O.C. Laboratory Analysis Unit, A.O.U. "Policlinico-Vittorio Emanuele", 95123 Catania, Italy.
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy.
| | - Guido Scalia
- U.O.C. Laboratory Analysis Unit, A.O.U. "Policlinico-Vittorio Emanuele", 95123 Catania, Italy.
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy.
| | - Maria Domina
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy.
| | - Salvatore Oliveri
- U.O.C. Laboratory Analysis Unit, A.O.U. "Policlinico-Vittorio Emanuele", 95123 Catania, Italy.
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy.
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156
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Arikan-Akdagli S, Ghannoum M, Meis JF. Antifungal Resistance: Specific Focus on Multidrug Resistance in Candida auris and Secondary Azole Resistance in Aspergillus fumigatus. J Fungi (Basel) 2018; 4:jof4040129. [PMID: 30563053 PMCID: PMC6308933 DOI: 10.3390/jof4040129] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 11/29/2018] [Accepted: 12/03/2018] [Indexed: 12/20/2022] Open
Abstract
Antifungal resistance is a topic of concern, particularly for specific fungal species and drugs. Among these are the multidrug-resistant Candida auris and azole-resistant Aspergillus fumigatus. While the knowledge on molecular mechanisms of resistance is now accumulating, further data are also available for the clinical implications and the extent of correlation of in vitro resistance to clinical outcomes. This review article summarizes the epidemiology of C. auris infections, animal models focusing on the activity of novel antifungal compounds in C. auris infections, virulence factors, and the mechanisms of antifungal resistance for this multi-resistant Candida species. Regarding A. fumigatus, the significance of azoles in the treatment of A. fumigatus infections, reference methods available for the detection of resistance in vitro, molecular mechanisms of secondary azole resistance, routes of acquisition, and clinical implications of in vitro resistance are covered to provide guidance for the current status of azole resistance in A. fumigatus.
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Affiliation(s)
- Sevtap Arikan-Akdagli
- Department of Medical Microbiology, Mycology Laboratory, Hacettepe University Medical School, TR-06100 Ankara, Turkey.
| | - Mahmoud Ghannoum
- Center for Medical Mycology, Department of Dermatology, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Jacques F Meis
- Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital (CWZ), 6532 Nijmegen, The Netherlands.
- Centre of Expertise in Mycology Radboudumc/CWZ, 6532 Nijmegen, The Netherlands.
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157
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Yu LS, Rodriguez-Manzano J, Malpartida-Cardenas K, Sewell T, Bader O, Armstrong-James D, Fisher MC, Georgiou P. Rapid and Sensitive Detection of Azole-Resistant Aspergillus fumigatus by Tandem Repeat Loop-Mediated Isothermal Amplification. J Mol Diagn 2018; 21:286-295. [PMID: 30529128 DOI: 10.1016/j.jmoldx.2018.10.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 09/07/2018] [Accepted: 10/16/2018] [Indexed: 12/11/2022] Open
Abstract
Invasive fungal infections caused by multiazole-resistant Aspergillus fumigatus are associated with increasing rates of mortality in susceptible patients. Current methods of diagnosing infections caused by multiazole-resistant A. fumigatus are, however, not well suited for use in clinical point-of-care testing or in the field. Loop-mediated isothermal amplification (LAMP) is a widely used method of nucleic acid amplification with rapid and easy-to-use features, making it suitable for use in different resource settings. Here, we developed a LAMP assay to detect a 34 bp tandem repeat, named TR34-LAMP. TR34 is a high-prevalence allele that, in conjunction with the L98H single-nucleotide polymorphism, is associated with the occurrence of multiazole resistance in A. fumigatus in the environment and in patients. This process was validated with both synthetic double-stranded DNA and genomic DNA prepared from azole-resistant isolates of A. fumigatus. Use of our assay resulted in rapid and specific identification of the TR34 allele with high sensitivity, detecting down to 10 genomic copies per reaction within 25 minutes. Fluorescent and colorimetric detections were used for the analysis of 11 clinical isolates as cross validation. These results show that the TR34-LAMP assay has the potential to accelerate the screening of clinical and environmental A. fumigatus to provide a rapid and accurate diagnosis of azole resistance, which current methods struggle to achieve.
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Affiliation(s)
- Ling-Shan Yu
- Centre for Bio-Inspired Technology, Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering.
| | - Jesus Rodriguez-Manzano
- Centre for Bio-Inspired Technology, Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering.
| | - Kenny Malpartida-Cardenas
- Centre for Bio-Inspired Technology, Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering
| | - Thomas Sewell
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Oliver Bader
- Institute for Medical Microbiology, University Medical Center Göttingen, Göttingen, Germany
| | | | - Matthew C Fisher
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, United Kingdom
| | - Pantelis Georgiou
- Centre for Bio-Inspired Technology, Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering
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158
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Rocchi S, Ponçot M, Morin-Crini N, Laboissière A, Valot B, Godeau C, Léchenault-Bergerot C, Reboux G, Crini G, Millon L. Determination of azole fungal residues in soils and detection of Aspergillus fumigatus-resistant strains in market gardens of Eastern France. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:32015-32023. [PMID: 30215210 DOI: 10.1007/s11356-018-3177-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 09/06/2018] [Indexed: 06/08/2023]
Abstract
Medical azole antifungals are major compounds used to prevent and to treat invasive aspergillosis (IA). Azole fungicides, called DMI (14-alpha demethylase inhibitors), are also widely used for crop protection and have been reported to be linked to azole-resistant A. fumigatus (aR-Af) development in the environment. The aim of this study was to determine whether or not market gardens that spray DMIs in Eastern France are also affected by the presence of aR-Af. Forty aR-Afs were detected in soils in only two of the four market gardens using DMIs, with 23% (7/30) and 10% (3/30) of soils containing aR-Af. A total of 87.5% of these isolates had the TR34/L98H mutation and 22.5% the TR46/Y121F/T289A mutation on the cyp51A gene. Analyses of residual azole concentrations in soils showed the presence of difenoconazole for up to 2 years after spraying, but only in soils of market gardens where aR-Af was detected. It is very important to identify professional activities that could lead to aR-Af development and to develop preventive measures for at-risk patients living near professional activities using DMIs. We have to better understand why, in some cases, the use of DMI is not linked to aR-Af. Measures should be taken to avoid the use of DMI conferring cross-resistance to preserve the efficiency of human therapeutics.
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Affiliation(s)
- Steffi Rocchi
- Parasitology-Mycology Department, University Hospital, Besançon, France.
- Chrono-Environnement UMR 6249 CNRS, Bourgogne Franche-Comté University, Besançon, France.
| | - Manon Ponçot
- Chrono-Environnement UMR 6249 CNRS, Bourgogne Franche-Comté University, Besançon, France
| | - Nadia Morin-Crini
- Chrono-Environnement UMR 6249 CNRS, Bourgogne Franche-Comté University, Besançon, France
| | - Audrey Laboissière
- Chrono-Environnement UMR 6249 CNRS, Bourgogne Franche-Comté University, Besançon, France
| | - Benoit Valot
- Chrono-Environnement UMR 6249 CNRS, Bourgogne Franche-Comté University, Besançon, France
| | - Chloé Godeau
- Chrono-Environnement UMR 6249 CNRS, Bourgogne Franche-Comté University, Besançon, France
| | | | - Gabriel Reboux
- Parasitology-Mycology Department, University Hospital, Besançon, France
- Chrono-Environnement UMR 6249 CNRS, Bourgogne Franche-Comté University, Besançon, France
| | - Grégorio Crini
- Chrono-Environnement UMR 6249 CNRS, Bourgogne Franche-Comté University, Besançon, France
| | - Laurence Millon
- Parasitology-Mycology Department, University Hospital, Besançon, France
- Chrono-Environnement UMR 6249 CNRS, Bourgogne Franche-Comté University, Besançon, France
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159
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Ukai Y, Kuroiwa M, Kurihara N, Naruse H, Homma T, Maki H, Naito A. Contributions of yap1 Mutation and Subsequent atrF Upregulation to Voriconazole Resistance in Aspergillus flavus. Antimicrob Agents Chemother 2018; 62:AAC.01216-18. [PMID: 30126960 PMCID: PMC6201102 DOI: 10.1128/aac.01216-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/08/2018] [Indexed: 01/16/2023] Open
Abstract
Aspergillus flavus is the second most significant pathogenic cause of invasive aspergillosis; however, its emergence risks and mechanisms of voriconazole (VRC) resistance have not yet been elucidated in detail. Here, we demonstrate that repeated exposure of A. flavus to subinhibitory concentrations of VRC in vitro causes the emergence of a VRC-resistant mutant with a novel resistance mechanism. The VRC-resistant mutant shows a MIC of 16 μg/ml for VRC and of 0.5 μg/ml for itraconazole (ITC). Whole-genome sequencing analysis showed that the mutant possesses a point mutation in yap1, which encodes a bZIP transcription factor working as the master regulator of the oxidative stress response, but no mutations in the cyp51 genes. This point mutation in yap1 caused alteration of Leu558 to Trp (Yap1Leu558Trp) in the putative nuclear export sequence in the carboxy-terminal cysteine-rich domain of Yap1. This Yap1Leu558Trp substitution was confirmed as being responsible for the VRC-resistant phenotype, but not for that of ITC, by the revertant to Yap1wild type with homologous gene replacement. Furthermore, Yap1Leu558Trp caused marked upregulation of the atrF ATP-binding cassette transporter, and the deletion of atrF restored susceptibility to VRC in A. flavus These findings provide new insights into VRC resistance mechanisms via a transcriptional factor mutation that is independent of the cyp51 gene mutation in A. flavus.
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Affiliation(s)
- Yuuta Ukai
- Drug Discovery & Disease Research Laboratory, Shionogi and Co., Ltd., Toyonaka, Osaka, Japan
| | - Miho Kuroiwa
- Drug Discovery & Disease Research Laboratory, Shionogi and Co., Ltd., Toyonaka, Osaka, Japan
| | - Naoko Kurihara
- Drug Discovery & Disease Research Laboratory, Shionogi and Co., Ltd., Toyonaka, Osaka, Japan
| | - Hiroki Naruse
- Drug Discovery & Disease Research Laboratory, Shionogi and Co., Ltd., Toyonaka, Osaka, Japan
| | - Tomoyuki Homma
- Drug Discovery & Disease Research Laboratory, Shionogi and Co., Ltd., Toyonaka, Osaka, Japan
| | - Hideki Maki
- Drug Discovery & Disease Research Laboratory, Shionogi and Co., Ltd., Toyonaka, Osaka, Japan
| | - Akira Naito
- Drug Discovery & Disease Research Laboratory, Shionogi and Co., Ltd., Toyonaka, Osaka, Japan
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160
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Ali EM, Amiri A. Selection Pressure Pathways and Mechanisms of Resistance to the Demethylation Inhibitor-Difenoconazole in Penicillium expansum. Front Microbiol 2018; 9:2472. [PMID: 30429831 PMCID: PMC6220093 DOI: 10.3389/fmicb.2018.02472] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/27/2018] [Indexed: 11/13/2022] Open
Abstract
Penicillium expansum causes blue mold, the most economically important postharvest disease of pome fruit worldwide. Beside sanitation practices, the disease is managed through fungicide applications at harvest. Difenoconazole (DIF) is a new demethylation inhibitor (DMI) fungicide registered recently to manage postharvest diseases of pome fruit. Herein, we evaluated the sensitivity of 130 P. expansum baseline isolates never exposed to DIF and determined the effective concentration (EC50) necessary to inhibit 50% germination, germ tube length, and mycelial growth. The respective mean EC50 values of 0.32, 0.26, and 0.18 μg/ml indicate a high sensitivity of P. expansum baseline isolates to DIF. We also found full and extended control efficacy in vivo after 6 months of storage at 1°C. We conducted a risk assessment for DIF-resistance development using ultraviolet excitation combined with or without DIF-selection pressure to generate and characterize lab mutants. Fifteen DIF-resistant mutants were selected and showed EC50 values of 0.92 to 1.4 μg/ml and 1.7 to 3.8 μg/ml without and with a DIF selection pressure, respectively. Resistance to DIF was stable in vitro over a 10-week period without selection pressure. Alignment of the full CYP51 gene sequences from the three wild-type and 15 mutant isolates revealed a tyrosine to phenylalanine mutation at codon 126 (Y126F) in all of the 15 mutants but not in the wild-type parental isolates. Resistance factors increased 5 to 15-fold in the mutants compared to the wild-type-isolates. DIF-resistant mutants also displayed enhanced CYP51 expression by 2 to 14-fold and was positively correlated with the EC50 values (R 2 = 0.8264). Cross resistance between DIF and fludioxonil, the mixing-partner in the commercial product, was not observed. Our findings suggest P. expansum resistance to DIF is likely to emerge in commercial packinghouse when used frequently. Future studies will determine whether resistance to DIF is qualitative or quantitative which will be determinant in the speed at which resistance will develop and spread in commercial packinghouses and to develop appropriate strategies to extend the lifespan of this new fungicide.
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Affiliation(s)
| | - Achour Amiri
- Department of Plant Pathology, Tree Fruit Research and Extension Center, Washington State University, Wenatchee, WA, United States
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161
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Crystal Structures of Full-Length Lanosterol 14α-Demethylases of Prominent Fungal Pathogens Candida albicans and Candida glabrata Provide Tools for Antifungal Discovery. Antimicrob Agents Chemother 2018; 62:AAC.01134-18. [PMID: 30126961 DOI: 10.1128/aac.01134-18] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/08/2018] [Indexed: 01/10/2023] Open
Abstract
Targeting lanosterol 14α-demethylase (LDM) with azole drugs provides prophylaxis and treatments for superficial and disseminated fungal infections, but cure rates are not optimal for immunocompromised patients and individuals with comorbidities. The efficacy of azole drugs has also been reduced due to the emergence of drug-resistant fungal pathogens. We have addressed the need to improve the potency, spectrum, and specificity for azoles by expressing in Saccharomyces cerevisiae functional, recombinant, hexahistidine-tagged, full-length Candida albicans LDM (CaLDM6×His) and Candida glabrata LDM (CgLDM6×His) and determining their X-ray crystal structures. The crystal structures of CaLDM6×His, CgLDM6×His, and ScLDM6×His have the same fold and bind itraconazole in nearly identical conformations. The catalytic domains of the full-length LDMs have the same fold as the CaLDM6×His catalytic domain in complex with posaconazole, with minor structural differences within the ligand binding pocket. Our structures give insight into the LDM reaction mechanism and phenotypes of single-site CaLDM mutations. This study provides a practical basis for the structure-directed discovery of novel antifungals that target LDMs of fungal pathogens.
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162
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Valdes ID, van den Berg J, Haagsman A, Escobar N, Meis JF, Hagen F, Haas PJ, Houbraken J, Wösten HAB, de Cock H. Comparative genotyping and phenotyping of Aspergillus fumigatus isolates from humans, dogs and the environment. BMC Microbiol 2018; 18:118. [PMID: 30223790 PMCID: PMC6142626 DOI: 10.1186/s12866-018-1244-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 08/21/2018] [Indexed: 12/26/2022] Open
Abstract
Background Aspergillus fumigatus is a ubiquitous saprotrophic fungus and an opportunistic pathogen of humans and animals. Humans and animals can inhale hundreds of A. fumigatus spores daily. Normally this is harmless for humans, but in case of immunodeficiency, invasive pulmonary aspergillosis (IPA) can develop with a high mortality rate. A. fumigatus also causes non-invasive mycoses like sino-nasal aspergillosis (SNA) in dogs. Results In this study we compared A. fumigatus isolates from humans with suspected IPA, dogs with SNA, and a set of environmental isolates. Phylogenetic inference based on calmodulin (CaM) and beta-tubulin (benA) sequences did not reveal A. fumigatus sub-groups linked to the origin of the isolates. Genotyping and microsatellite analysis showed that each dog was infected by one A. fumigatus genotype, whereas human patients had mixed infections. Azole resistance was determined by antifungal susceptibility testing and sequencing of the cyp51A gene. A total of 12 out of 29 human isolates and 1 out of 27 environmental isolates were azole resistant. Of the azole resistant strains, 11 human isolates showed TR34/L98H (n = 6) or TR46/Y121F/T289A (n = 5). Phenotypically, isolates from dogs were more variable in growth speed and morphology when compared to those isolated from human and the environment. Conclusions A. fumigatus from dogs with SNA are phenotypically very diverse in contrast to their environmental and human counterparts. Phenotypic variability can be induced during the chronic infection process in the sinus of the dogs. The basis of this heterogeneity might be due to genomic differences and/or epigenetic variations. Differences in dogs is a could be a result of within-host adaption and might be triggered by environmental factors in the sinus, however this hypothesis still needs to be tested.
Electronic supplementary material The online version of this article (10.1186/s12866-018-1244-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ivan D Valdes
- Microbiology, Department of Biology, Utrecht University, Utrecht, The Netherlands.
| | - Joris van den Berg
- Microbiology, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Annika Haagsman
- Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Natalia Escobar
- Microbiology, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Jacques F Meis
- Department of Medical Microbiology and Infectious Diseases, Canisius-Wilhelmina Hospital, Nijmegen, The Netherlands.,Centre of Expertise in Mycology Radboudumc/CWZ, Nijmegen, The Netherlands
| | - Ferry Hagen
- Westerdijk Institute, Utrecht, The Netherlands
| | | | | | - Han A B Wösten
- Microbiology, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Hans de Cock
- Microbiology, Department of Biology, Utrecht University, Utrecht, The Netherlands
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163
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Sanguinetti M, Posteraro B. Susceptibility Testing of Fungi to Antifungal Drugs. J Fungi (Basel) 2018; 4:jof4030110. [PMID: 30223554 PMCID: PMC6162686 DOI: 10.3390/jof4030110] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 08/11/2018] [Accepted: 08/13/2018] [Indexed: 01/05/2023] Open
Abstract
Susceptibility testing of fungi against antifungal drugs commonly used for therapy is a key component of the care of patients with invasive fungal infections. Antifungal susceptibility testing (AFST) has progressed in recent decades to finally become standardized and available as both Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) reference methods and in commercial manual/automated phenotypic methods. In clinical practice, the Sensititre YeastOne and Etest methods are widely used for AFST, particularly for sterile site isolates of Candida. Nevertheless, AFST is moving toward new phenotypic methods, such as matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), that are capable of providing rapid, and potentially more actionable, results for the treating clinician. Our objective is to summarize updated data on phenotypic methods for AFST of Candida and Aspergillus species and to assess their significance in view of opposing, but emerging, molecular genotypic methods.
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Affiliation(s)
- Maurizio Sanguinetti
- Insititute of Micorbiology, Fondazione Policlinico Universitario A. Gemelli, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Università Cattolica del Sacro Cuore, 00168 Rome, Italy.
| | - Brunella Posteraro
- Insitutue of Public Health (Section of Hygiene), Fondazione Policlinico Universitario A. Gemelli, IRCCS, Università Cattolica del Sacro Cuore, 00168 Rome, Italy.
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164
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Güngör Ö, Sampaio-Maia B, Amorim A, Araujo R, Erturan Z. Determination of Azole Resistance and TR 34/L98H Mutations in Isolates of Aspergillus Section Fumigati from Turkish Cystic Fibrosis Patients. Mycopathologia 2018; 183:913-920. [PMID: 30187246 DOI: 10.1007/s11046-018-0297-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 08/24/2018] [Indexed: 02/05/2023]
Abstract
BACKGROUND Aspergillus fumigatus is the species section Fumigati most frequently isolated from the respiratory tract of cystic fibrosis (CF) patients. Recent studies suggest that mutations in the Cyp51 gene, particularly TR34/L98H, are responsible for azole resistance. OBJECTIVES AND METHODS The focus of this study was on section Fumigati isolates isolated from the respiratory tract samples of CF patients. More specifically, the goal was to detect A. fumigatus isolates, test their antifungal susceptibility to itraconazole, voriconazole and posaconazole, and finally determine the presence of TR34/L98H and other mutations in the isolates Cyp51A gene. RESULTS AND CONCLUSIONS A set of 31 isolates of Aspergillus section Fumigati were obtained from the sputum samples of 6 CF patients and subsequently identified to species level by microsatellite genotyping. All isolates were determined as A. fumigatus and involved 14 different genotypes. The minimal inhibitory concentrations to the three azoles were determined by the E-test method, and the Cyp51A gene was sequenced. One of the genotypes was found to be resistant to all azoles but no mutations were detected in the Cyp51A gene, especially the TR34/L98H mutation. Therefore, mutations in genes other than Cyp51A or other distinct mechanisms may be responsible for this reported multiazole resistance found in a Turkish CF patient.
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Affiliation(s)
- Özge Güngör
- Istanbul Medical Faculty, Department of Medical Microbiology, Istanbul University, 34093, Capa, Istanbul, Turkey.
| | - Benedita Sampaio-Maia
- Faculty of Dental Medicine, University of Porto, Porto, Portugal
- INEB, Instituto Nacional de Engenharia Biomédica da Universidade do Porto, Porto, Portugal
- i3S, Instituto de Investigação e Inovação em Saúde da Universidade do Porto, Porto, Portugal
| | - Antonio Amorim
- i3S, Instituto de Investigação e Inovação em Saúde da Universidade do Porto, Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal
- Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Ricardo Araujo
- i3S, Instituto de Investigação e Inovação em Saúde da Universidade do Porto, Porto, Portugal
- Department of Medical Biotechnology, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Zayre Erturan
- Istanbul Medical Faculty, Department of Medical Microbiology, Istanbul University, 34093, Capa, Istanbul, Turkey
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165
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Beardsley J, Halliday CL, Chen SCA, Sorrell TC. Responding to the emergence of antifungal drug resistance: perspectives from the bench and the bedside. Future Microbiol 2018; 13:1175-1191. [PMID: 30113223 PMCID: PMC6190174 DOI: 10.2217/fmb-2018-0059] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/01/2018] [Indexed: 12/15/2022] Open
Abstract
The incidence of serious fungal infections is increasing rapidly, and yet the rate of new drugs becoming available to treat them is slow. The limited therapeutic armamentarium is a challenge for clinicians, because the available drugs are often toxic, expensive, difficult to administer, ineffective or a combination of all four. Given this setting, the emergence of resistance is especially concerning, and a review of the topic is timely. Here we discuss antifungal drug resistance in Candida spp. and Aspergillus spp. with reference to the most commonly used first-line antifungal agents - azoles and echinocandins. We review the resistance mechanisms of the leading pathogens, how resistance can be identified in the diagnostic lab and the clinical implications of resistance once detected.
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Affiliation(s)
- Justin Beardsley
- Marie Bashir Institute for Infectious Diseases & Biosecurity, University of Sydney & Westmead Institute for Medical Research, Westmead, NSW, Australia
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Catriona L Halliday
- The Center for Infectious Diseases & Microbiology Laboratory Services, ICPMR Pathology West, New South Wales Health Pathology, Westmead, NSW, Australia
| | - Sharon C-A Chen
- Marie Bashir Institute for Infectious Diseases & Biosecurity, University of Sydney & Westmead Institute for Medical Research, Westmead, NSW, Australia
- The Center for Infectious Diseases & Microbiology Laboratory Services, ICPMR Pathology West, New South Wales Health Pathology, Westmead, NSW, Australia
| | - Tania C Sorrell
- Marie Bashir Institute for Infectious Diseases & Biosecurity, University of Sydney & Westmead Institute for Medical Research, Westmead, NSW, Australia
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166
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Lee HJ, Cho SY, Lee DG, Park C, Chun HS, Park YJ. TR34/L98H Mutation in CYP51A Gene in Aspergillus fumigatus Clinical Isolates During Posaconazole Prophylaxis: First Case in Korea. Mycopathologia 2018; 183:731-736. [PMID: 29858759 PMCID: PMC6096900 DOI: 10.1007/s11046-018-0271-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 05/12/2018] [Indexed: 12/03/2022]
Abstract
Azole resistance in Aspergillus fumigatus is an emerging problem, especially in immunocompromised patients. It has been reported worldwide, including in Asia, but has not yet been reported in Korea. Here, we report a case of invasive pulmonary aspergillosis (IPA) caused by azole-resistant A. fumigatus that developed in a hematopoietic stem cell transplantation recipient during posaconazole prophylaxis for immunosuppressive therapy of graft-versus-host diseases. We identified TR34/L98H/S297T/F495L mutation in the CYP51A gene of A. fumigatus clinical isolate obtained from bronchial washing fluid. Minimal inhibitory concentrations for itraconazole, voriconazole, and posaconazole were > 16, 1, and 4 μg/mL, respectively. While IPA improved partially under voriconazole treatment, the patient died from carbapenemase-producing Klebsiella pneumoniae bacteremia. Further epidemiological surveillance studies are warranted.
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Affiliation(s)
- Hyeon-Jeong Lee
- Division of Infectious Diseases, Department of Internal Medicine, The Catholic Blood and Marrow Transplantation Center, Vaccine Bio Research Institute, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 222, Banpo-daero, Seocho-gu, Seoul, 06591 Republic of Korea
- Vaccine Bio Research Institute, Seoul St. Mary’s Hospital, The Catholic University of Korea, 222, Banpo-daero, Seocho-gu, Seoul, Republic of Korea
| | - Sung-Yeon Cho
- Division of Infectious Diseases, Department of Internal Medicine, The Catholic Blood and Marrow Transplantation Center, Vaccine Bio Research Institute, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 222, Banpo-daero, Seocho-gu, Seoul, 06591 Republic of Korea
- Vaccine Bio Research Institute, Seoul St. Mary’s Hospital, The Catholic University of Korea, 222, Banpo-daero, Seocho-gu, Seoul, Republic of Korea
- The Catholic Blood and Marrow Transplantation Center, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 222, Banpo-daero, Seocho-gu, Seoul, 06591 Republic of Korea
| | - Dong-Gun Lee
- Division of Infectious Diseases, Department of Internal Medicine, The Catholic Blood and Marrow Transplantation Center, Vaccine Bio Research Institute, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 222, Banpo-daero, Seocho-gu, Seoul, 06591 Republic of Korea
- Vaccine Bio Research Institute, Seoul St. Mary’s Hospital, The Catholic University of Korea, 222, Banpo-daero, Seocho-gu, Seoul, Republic of Korea
- The Catholic Blood and Marrow Transplantation Center, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 222, Banpo-daero, Seocho-gu, Seoul, 06591 Republic of Korea
| | - Chulmin Park
- Vaccine Bio Research Institute, Seoul St. Mary’s Hospital, The Catholic University of Korea, 222, Banpo-daero, Seocho-gu, Seoul, Republic of Korea
| | - Hye-Sun Chun
- Vaccine Bio Research Institute, Seoul St. Mary’s Hospital, The Catholic University of Korea, 222, Banpo-daero, Seocho-gu, Seoul, Republic of Korea
| | - Yeon-Joon Park
- Department of Laboratory Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, 222, Banpo-daero, Seocho-gu, Seoul, 06591 Republic of Korea
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167
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Emerging Antifungal Drug Resistance in Aspergillus fumigatus and Among Other Species of Aspergillus. CURRENT FUNGAL INFECTION REPORTS 2018. [DOI: 10.1007/s12281-018-0318-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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168
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Emergence of Azole-Resistant Aspergillus fumigatus from Immunocompromised Hosts in India. Antimicrob Agents Chemother 2018; 62:AAC.02264-17. [PMID: 29891597 DOI: 10.1128/aac.02264-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 05/29/2018] [Indexed: 12/17/2022] Open
Abstract
This prospective study shows that the rate of azole-resistant Aspergillus fumigatus (ARAF) in an immunocompromised Indian patient population with invasive aspergillosis (IA) is low, 6/706 (0.8%). This low rate supports the continued use of voriconazole as the first line of treatment. However, the ARAF isolates from India in this study exhibited three kinds of unreported cyp51A mutations, of which two were at hot spots, G54R and P216L, while one was at codon Y431C.
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169
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Zoll J, Verweij PE, Melchers WJG. Discovery and characterization of novel Aspergillus fumigatus mycoviruses. PLoS One 2018; 13:e0200511. [PMID: 30044844 PMCID: PMC6059430 DOI: 10.1371/journal.pone.0200511] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 06/27/2018] [Indexed: 11/20/2022] Open
Abstract
In the last few years, increasing numbers of viruses infecting fungi have been identified. In this study, we used an in silico approach for the analysis of deep RNA sequencing data in order to discover and characterize putative genomic ssRNA or dsRNA mycovirus sequences in Aspergillus fumigatus. RNA sequencing reads of A. fumigatus strains were mapped against the A. fumigatus Af293 reference genome. Unmapped reads were collected for de novo assembly. Contigs were analyzed by Blastx comparison with a mycovirus protein database. Assembled viral genomes were used as template for remapping of RNA sequencing reads. In total, deep RNA sequencing results from 11 A. fumigatus strains were analyzed for the presence of mycoviral genomic RNAs. In 9 out of 11 strains, putative mycoviral RNA genomes were identified. Three strains were infected with two different mycovirus species. Two strains were infected with Aspergillus fumigatus polymycovirus type-1 (AfuPmV-1). Four strains contained fully recovered genomic RNA of unknown narna-like viruses designated as Aspergillus fumigatus narnavirus-1 and Aspergillus fumigatus narnavirus-2 (AfuNV-1 and AfuNV-2). Both viruses showed 38% amino acid sequence identity to Beihai narna-like virus-21. Three strains contained partially recovered genomic RNA of an unknown narna-like virus. Two strains contained fully recovered genomic RNAs of an unknown partitivirus designated as Aspergillus fumigatus partitivirus-2 (AfuPV-2) which showed 50% amino acid sequence identity to Alternaria alternata partitivirus-1. Finally, one strain contained fully recovered genomic RNA of an unknown mitovirus designated as Aspergillus fumigatus mitovirus-1 (AfuMV-1) which showed 34% amino acid sequence identity to Sclerotina sclerotiorum mitovirus. In silico analysis of deep RNA sequencing results showed that a majority of the A. fumigatus strains used here were infected with mycoviruses. Four novel A. fumigatus RNA mycoviruses could be identified: two different Aspergillus fumigatus narna-like viruses, one Aspergillus fumigatus partitivirus, and one Aspergillus fumigatus mitovirus.
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Affiliation(s)
- Jan Zoll
- Department of Medical Microbiology, Radboud University Medical Center, and Center of Expertise in Mycology Radboudumc/CWZ, Nijmegen, The Netherlands
- * E-mail:
| | - Paul E. Verweij
- Department of Medical Microbiology, Radboud University Medical Center, and Center of Expertise in Mycology Radboudumc/CWZ, Nijmegen, The Netherlands
| | - Willem J. G. Melchers
- Department of Medical Microbiology, Radboud University Medical Center, and Center of Expertise in Mycology Radboudumc/CWZ, Nijmegen, The Netherlands
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170
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Garcia-Rubio R, Escribano P, Gomez A, Guinea J, Mellado E. Comparison of Two Highly Discriminatory Typing Methods to Analyze Aspergillus fumigatus Azole Resistance. Front Microbiol 2018; 9:1626. [PMID: 30079058 PMCID: PMC6062602 DOI: 10.3389/fmicb.2018.01626] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 06/28/2018] [Indexed: 11/24/2022] Open
Abstract
Aspergillus fumigatus molecular typing has become increasingly more important for detecting outbreaks as well as for local and global epidemiological investigations and surveillance. Over the years, many different molecular methods have been described for genotyping this species. Some outstanding approaches are based on microsatellite markers (STRAf assay, which is the current gold standard), or based on sequencing data (TRESP typing improved in this work with a new marker and was renamed TRESPERG). Both methodologies were used to type a collection of 212 A. fumigatus isolates that included 70 azole resistant strains with diverse resistance mechanisms from different geographic locations. Our results showed that both methods are totally reliable for epidemiological investigations showing similar stratification of the A. fumigatus population. STRAf assay offered higher discriminatory power (D = 0.9993) than the TRESPERG typing method (D = 0.9972), but the latter does not require specific equipment or skilled personnel, allowing for a prompt integration into any clinical microbiology laboratory. Among azole resistant isolates, two groups were differentiated considering their resistance mechanisms: cyp51A single point mutations (G54, M220, or G448), and promoter tandem repeat integrations with or without cyp51A modifications (TR34/L98H, TR46/Y121F/A289T, or TR53). The genotypic differences were assessed to explore the population structure as well as the genetic relationship between strains and their azole resistance profile. Genetic cluster analyses suggested that our A. fumigatus population was formed by 6–7 clusters, depending on the methodology. Also, the azole susceptible and resistance population showed different structure and organization. The combination of both methodologies resolved the population structure in a similar way to what has been described in whole-genome sequencing works.
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Affiliation(s)
- Rocio Garcia-Rubio
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Madrid, Spain
| | - Pilar Escribano
- Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Ana Gomez
- Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Jesus Guinea
- Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.,Department of Medicine, School of Medicine, Complutense University of Madrid, Madrid, Spain
| | - Emilia Mellado
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Madrid, Spain
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171
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Miura D, Sugiyama K, Ito A, Ohba-Tanaka A, Tanaka M, Shintani T, Gomi K. The PDR-type ABC transporters AtrA and AtrG are involved in azole drug resistance in Aspergillus oryzae. Biosci Biotechnol Biochem 2018; 82:1840-1848. [PMID: 30011258 DOI: 10.1080/09168451.2018.1497941] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
For strain improvement of Aspergillus oryzae, development of the transformation system is essential, wherein dominant selectable markers, including drug-resistant genes, are available. However, A. oryzae generally has a relatively high resistance to many antifungal drugs effective against yeasts and other filamentous fungi. In the course of the study, while investigating azole drug resistance in A. oryzae, we isolated a spontaneous mutant that exhibited high resistance to azole fungicides and found that pleiotropic drug resistance (PDR)-type ATP-binding cassette (ABC) transporter genes were upregulated in the mutant; their overexpression in the wild-type strain increased azole drug resistance. While deletion of the gene designated atrG resulted in increased azole susceptibility, double deletion of atrG and another gene (atrA) resulted in further azole hypersensitivity. Overall, these results indicate that the ABC transporters AtrA and AtrG are involved in azole drug resistance in A. oryzae.
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Affiliation(s)
- Daisuke Miura
- a Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
| | - Kohei Sugiyama
- a Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
| | - Atsushi Ito
- a Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
| | - Ayumi Ohba-Tanaka
- a Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
| | - Mizuki Tanaka
- a Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
| | - Takahiro Shintani
- a Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science , Tohoku University , Sendai , Japan
| | - Katsuya Gomi
- a Laboratory of Bioindustrial Genomics, Graduate School of Agricultural Science , Tohoku University , Sendai , Japan.,b Biomolecular Engineering Laboratory, School of Food and Nutritional Science , University of Shizuoka , Shizuoka , Japan
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172
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MOHAMMADI F, HASHEMI SJ, SEYEDMOUSAVI SM, AKBARZADE D. Isolation and Characterization of Clinical Triazole Resistance Aspergillus fumigatus in Iran. IRANIAN JOURNAL OF PUBLIC HEALTH 2018; 47:994-1000. [PMID: 30181998 PMCID: PMC6119562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Aspergillus fumigatus is a major cause of allergic syndromes, aspergilloma and life-threatening invasive infections in immunocompromised hosts. To date, a wide range of mutations in A. fumigatushave been described conferring azole-resistance, which commonly involves modifications in the cyp51A-gene (substitutions at codons G54, G138, P216, F219, M220, G448 and specifically codon L98 in combination with a 34-bp tandem repeat in the promoter region of the gene), the target for azole antifungals. We investigated the prevalence of azole-resistance in clinical A. fumigatus isolates obtained from patients in Iran during 2010 to 2014. METHODS Overall, 172 clinical A. fumigatus isolates obtained from patients with underlying disease including transplantation, granulocytopenia, chronic liver disease, chronic obstructive pulmonary disease (COPD) and allergic bronchopulmonary aspergillosis (ABPA). Samples were collected between Jan 2009 and Nov 2014 from five provinces of Iran (Tehran, Shiraz, Isfahan, Khorasan razavi and East Azerbaijan). Antifungal susceptibility test was determined according to EUCAST reference method for itraconazole (ITC), voriconazole (VRC) and posaconazole (POS). All isolates were confirmed by amplification of the partial tubulin gene. RESULTS Of 172 A. fumigatus isolates tested, six isolates (3.5%) had high MIC values of ITC (>16 mg/L) and VRC (≥4 mg/L). All six isolates showed a multi-resistant phenotype with high MICs of ITC and VRC. CONCLUSION We determined in-vitro susceptibility a profile of 172 clinically isolates of A. fumigatus against triazole in Iran. Azole-resistance is an emerging problem in A. fumigatus and international surveillance is warranted.
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Affiliation(s)
- Faezezeh MOHAMMADI
- Dep. of Medical Parasitology and Mycology, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Seyed Jamal HASHEMI
- Dept. of Medical Mycology and Parasitology, School of Public Hygiene, Tehran University of Medical Sciences, Tehran, Iran, Food Microbiology Research Center, Tehran University of Medical Sciences, Tehran, Iran,Corresponding Author:
| | | | - Dorna AKBARZADE
- School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
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173
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D'Agostino M, Lemmet T, Dufay C, Luc A, Frippiat JP, Machouart M, Debourgogne A. Overinduction of CYP51A Gene After Exposure to Azole Antifungals Provides a First Clue to Resistance Mechanism in Fusarium solani Species Complex. Microb Drug Resist 2018; 24:768-773. [DOI: 10.1089/mdr.2017.0311] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Maurine D'Agostino
- Laboratoire Stress Immunité Pathogènes, EA7300, Faculté de Médecine, Vandoeuvre-les-Nancy, France
| | - Thomas Lemmet
- Laboratoire Stress Immunité Pathogènes, EA7300, Faculté de Médecine, Vandoeuvre-les-Nancy, France
| | - Claire Dufay
- Laboratoire Stress Immunité Pathogènes, EA7300, Faculté de Médecine, Vandoeuvre-les-Nancy, France
| | - Amandine Luc
- Unité de Méthodologie, Data Management et Statistique, PARC, CHRU de Nancy, Hôpitaux de Brabois, Vandoeuvre-les-Nancy, France
| | - Jean Pol Frippiat
- Laboratoire Stress Immunité Pathogènes, EA7300, Faculté de Médecine, Vandoeuvre-les-Nancy, France
| | - Marie Machouart
- Laboratoire Stress Immunité Pathogènes, EA7300, Faculté de Médecine, Vandoeuvre-les-Nancy, France
- Service de Parasitologie-Mycologie, CHRU de Nancy, Hôpitaux de Brabois, Vandoeuvre-les-Nancy, France
| | - Anne Debourgogne
- Laboratoire Stress Immunité Pathogènes, EA7300, Faculté de Médecine, Vandoeuvre-les-Nancy, France
- Service de Parasitologie-Mycologie, CHRU de Nancy, Hôpitaux de Brabois, Vandoeuvre-les-Nancy, France
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174
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Kemoi EK, Nyerere A, Bii CC. Triazole-Resistant Aspergillus fumigatus from Fungicide-Experienced Soils in Naivasha Subcounty and Nairobi County, Kenya. Int J Microbiol 2018; 2018:7147938. [PMID: 30046310 PMCID: PMC6038473 DOI: 10.1155/2018/7147938] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/06/2017] [Accepted: 05/03/2018] [Indexed: 11/18/2022] Open
Abstract
The mainstay in prevention and treatment of aspergillosis is the use triazole drugs. In Kenya, the use of agricultural azole is one of the predisposing factors in development of resistance. One hundred fifty-six (156) experienced soils were collected from agricultural farms and cultured on Sabouraud DextroseAagar. The study isolated 48 yielded Aspergillus fumigatus and 2 A. flavus. All the isolates were subjected to antifungal susceptibility testing against three triazoles: posaconazole, voriconazole, and itraconazole. Out of the isolates, 3 had MIC of 32 and 1 had MIC of 16 against itraconazole, and 1 isolate had MIC of 32 against posaconazole. CYP51A gene was sequenced, and TR34/L98H mutation was identified. Triazole resistance existing in Kenya calls for rational use of azole-based fungicides in agriculture over concerns of emerging antifungal resistance in clinical practice.
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Affiliation(s)
- Edson K. Kemoi
- Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
- University of Kabianga, Kericho, Kenya
| | - Andrew Nyerere
- Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
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175
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Does the use of antifungal agents in agriculture and food foster polyene resistance development? A reason for concern. J Glob Antimicrob Resist 2018; 13:40-48. [DOI: 10.1016/j.jgar.2017.10.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 10/03/2017] [Accepted: 10/30/2017] [Indexed: 01/11/2023] Open
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176
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Zarrin M, Faramarzi S. Study of Azole - Resistant and Cyp51a Gene in Aspergillus Fumigatus. Open Access Maced J Med Sci 2018; 6:747-750. [PMID: 29875840 PMCID: PMC5985858 DOI: 10.3889/oamjms.2018.171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/19/2018] [Accepted: 03/23/2018] [Indexed: 11/30/2022] Open
Abstract
AIM The main goal of the present study was to find azole-resistant and molecular analysis of cyp51A gene in Aspergillus fumigatus. MATERIALS AND METHODS Fifty-eight A. fumigatus strains including environmental, clinical and reference isolates were assessed in this investigation. Azole susceptibility testing for itraconazole and voriconazole was carried out for A. fumigatus isolates. PCR was performed based on cyp51A gene sequence for all isolates. RESULTS Susceptibility testing verified the minimum inhibitory concentrations (MICs) for itraconazole (0.125 to 2 µg/ml) and voriconazole (0.125 to 4 µg/ml). Nine (15.5%) A. fumigatus isolates were resistant to voriconazole with MIC 4 µg/ml. A 1500 bp DNA fragment was amplified using cyp51A gene for all tested Aspergillus isolates. The sequences of the fragments showed 99% identity with A. fumigatus cyp51A gene in the GenBank. No point mutation was found at cyp51A gene codons. CONCLUSION In the current study, we detected the voriconazile resistant in A. fumigatus isolates. Susceptibility tests should be considered in patients who infected by A. fumigatus.
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Affiliation(s)
- Majid Zarrin
- Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Sama Faramarzi
- Department of Medical Mycology, Medical School, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
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177
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Geddes-McAlister J, Shapiro RS. New pathogens, new tricks: emerging, drug-resistant fungal pathogens and future prospects for antifungal therapeutics. Ann N Y Acad Sci 2018; 1435:57-78. [DOI: 10.1111/nyas.13739] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/19/2018] [Accepted: 03/28/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Jennifer Geddes-McAlister
- Department of Molecular and Cellular Biology; University of Guelph; Guelph Ontario Canada
- Department of Proteomics and Signal Transduction; Max Planck Institute of Biochemistry; Munich Germany
| | - Rebecca S. Shapiro
- Department of Molecular and Cellular Biology; University of Guelph; Guelph Ontario Canada
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178
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The burden of Invasive Aspergillosis in patients with haematological malignancy: A meta-analysis and systematic review. J Infect 2018; 76:550-562. [PMID: 29727605 DOI: 10.1016/j.jinf.2018.02.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 02/13/2018] [Accepted: 02/16/2018] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Successful treatment of haematological malignancies is frequently complicated by Invasive Aspergillosis (IA), a life-threatening fungal infection that occurs in at least 10% of haemato-oncological patients. Case fatality rates (CFR) may fluctuate over time, depending on host pathogen interactions as well as on treatment and quality of patient care. We conducted a systematic review and metaanalysis of current - i.e. 2008-revised EORTC-MSG criteria era - incidence and case fatality rates (CFR) of IA in patients with haematological malignancy. METHODS A systematic search according to PRISMA guidelines was performed to identify all literature reporting populations with a haematological malignancy and the incidence of IA, defined according to the EORTC/MSG 2008 criteria. Pooled cumulative incidences and CFR within 100 days were estimated using a random effects model for predefined patient populations and stratified by use of prophylaxis. RESULTS The systematic literature search yielded 1285 publications of which n = 49 met the inclusion criteria. Overall, 16.815 patients were involved of which 1056 (6.3%) developed IA. IA risk ranged from 4% (during remission-induction, with prophylaxis) to 11% (during remission-induction, without prophylaxis). Antifungal prophylaxis was associated with a lower rate of IA, especially in the pre-HSCT population. The pooled CFR within 100 days was 29% (95% CI: 20-38%). DISCUSSION This study confirms that IA is a relevant threat in the treatment of haematological cancer despite the universal use of antifungal prophylaxis. These outcomes inform scientists and other stakeholders about the current burden of IA and may be used to direct, implement and improve antifungal stewardship programs.
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179
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Ullmann AJ, Aguado JM, Arikan-Akdagli S, Denning DW, Groll AH, Lagrou K, Lass-Flörl C, Lewis RE, Munoz P, Verweij PE, Warris A, Ader F, Akova M, Arendrup MC, Barnes RA, Beigelman-Aubry C, Blot S, Bouza E, Brüggemann RJM, Buchheidt D, Cadranel J, Castagnola E, Chakrabarti A, Cuenca-Estrella M, Dimopoulos G, Fortun J, Gangneux JP, Garbino J, Heinz WJ, Herbrecht R, Heussel CP, Kibbler CC, Klimko N, Kullberg BJ, Lange C, Lehrnbecher T, Löffler J, Lortholary O, Maertens J, Marchetti O, Meis JF, Pagano L, Ribaud P, Richardson M, Roilides E, Ruhnke M, Sanguinetti M, Sheppard DC, Sinkó J, Skiada A, Vehreschild MJGT, Viscoli C, Cornely OA. Diagnosis and management of Aspergillus diseases: executive summary of the 2017 ESCMID-ECMM-ERS guideline. Clin Microbiol Infect 2018; 24 Suppl 1:e1-e38. [PMID: 29544767 DOI: 10.1016/j.cmi.2018.01.002] [Citation(s) in RCA: 828] [Impact Index Per Article: 138.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/02/2018] [Accepted: 01/03/2018] [Indexed: 02/06/2023]
Abstract
The European Society for Clinical Microbiology and Infectious Diseases, the European Confederation of Medical Mycology and the European Respiratory Society Joint Clinical Guidelines focus on diagnosis and management of aspergillosis. Of the numerous recommendations, a few are summarized here. Chest computed tomography as well as bronchoscopy with bronchoalveolar lavage (BAL) in patients with suspicion of pulmonary invasive aspergillosis (IA) are strongly recommended. For diagnosis, direct microscopy, preferably using optical brighteners, histopathology and culture are strongly recommended. Serum and BAL galactomannan measures are recommended as markers for the diagnosis of IA. PCR should be considered in conjunction with other diagnostic tests. Pathogen identification to species complex level is strongly recommended for all clinically relevant Aspergillus isolates; antifungal susceptibility testing should be performed in patients with invasive disease in regions with resistance found in contemporary surveillance programmes. Isavuconazole and voriconazole are the preferred agents for first-line treatment of pulmonary IA, whereas liposomal amphotericin B is moderately supported. Combinations of antifungals as primary treatment options are not recommended. Therapeutic drug monitoring is strongly recommended for patients receiving posaconazole suspension or any form of voriconazole for IA treatment, and in refractory disease, where a personalized approach considering reversal of predisposing factors, switching drug class and surgical intervention is also strongly recommended. Primary prophylaxis with posaconazole is strongly recommended in patients with acute myelogenous leukaemia or myelodysplastic syndrome receiving induction chemotherapy. Secondary prophylaxis is strongly recommended in high-risk patients. We strongly recommend treatment duration based on clinical improvement, degree of immunosuppression and response on imaging.
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Affiliation(s)
- A J Ullmann
- Department of Infectious Diseases, Haematology and Oncology, University Hospital Würzburg, Würzburg, Germany; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - J M Aguado
- Infectious Diseases Unit, University Hospital Madrid, Madrid, Spain; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - S Arikan-Akdagli
- Department of Medical Microbiology, Hacettepe University Medical School, Ankara, Turkey; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - D W Denning
- The National Aspergillosis Centre, Wythenshawe Hospital, Mycology Reference Centre Manchester, Manchester University NHS Foundation Trust, ECMM Excellence Centre of Medical Mycology, Manchester, UK; The University of Manchester, Manchester, UK; Manchester Academic Health Science Centre, Manchester, UK; European Confederation of Medical Mycology (ECMM)
| | - A H Groll
- Department of Paediatric Haematology/Oncology, Centre for Bone Marrow Transplantation, University Children's Hospital Münster, Münster, Germany; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - K Lagrou
- Department of Microbiology and Immunology, ECMM Excellence Centre of Medical Mycology, University Hospital Leuven, Leuven, Belgium; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - C Lass-Flörl
- Institute of Hygiene, Microbiology and Social Medicine, ECMM Excellence Centre of Medical Mycology, Medical University Innsbruck, Innsbruck, Austria; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - R E Lewis
- Infectious Diseases Clinic, Sant'Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy; ESCMID Fungal Infection Study Group (EFISG)
| | - P Munoz
- Department of Medical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain; CIBER Enfermedades Respiratorias - CIBERES (CB06/06/0058), Madrid, Spain; Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - P E Verweij
- Department of Medical Microbiology, Radboud University Medical Centre, Centre of Expertise in Mycology Radboudumc/CWZ, ECMM Excellence Centre of Medical Mycology, Nijmegen, Netherlands; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - A Warris
- MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - F Ader
- Department of Infectious Diseases, Hospices Civils de Lyon, Lyon, France; Inserm 1111, French International Centre for Infectious Diseases Research (CIRI), Université Claude Bernard Lyon 1, Lyon, France; European Respiratory Society (ERS)
| | - M Akova
- Department of Medicine, Section of Infectious Diseases, Hacettepe University Medical School, Ankara, Turkey; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - M C Arendrup
- Department Microbiological Surveillance and Research, Statens Serum Institute, Copenhagen, Denmark; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - R A Barnes
- Department of Medical Microbiology and Infectious Diseases, Institute of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, UK; European Confederation of Medical Mycology (ECMM)
| | - C Beigelman-Aubry
- Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland; European Respiratory Society (ERS)
| | - S Blot
- Department of Internal Medicine, Ghent University, Ghent, Belgium; Burns, Trauma and Critical Care Research Centre, University of Queensland, Brisbane, Australia; European Respiratory Society (ERS)
| | - E Bouza
- Department of Medical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain; CIBER Enfermedades Respiratorias - CIBERES (CB06/06/0058), Madrid, Spain; Medicine Department, School of Medicine, Universidad Complutense de Madrid, Madrid, Spain; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - R J M Brüggemann
- Radboud Centre for Infectious Diseases, Radboud University Medical Centre, Centre of Expertise in Mycology Radboudumc/CWZ, ECMM Excellence Centre of Medical Mycology, Nijmegen, Netherlands; ESCMID Fungal Infection Study Group (EFISG)
| | - D Buchheidt
- Medical Clinic III, University Hospital Mannheim, Mannheim, Germany; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - J Cadranel
- Department of Pneumology, University Hospital of Tenon and Sorbonne, University of Paris, Paris, France; European Respiratory Society (ERS)
| | - E Castagnola
- Infectious Diseases Unit, Istituto Giannina Gaslini Children's Hospital, Genoa, Italy; ESCMID Fungal Infection Study Group (EFISG)
| | - A Chakrabarti
- Department of Medical Microbiology, Postgraduate Institute of Medical Education & Research, Chandigarh, India; European Confederation of Medical Mycology (ECMM)
| | - M Cuenca-Estrella
- Instituto de Salud Carlos III, Madrid, Spain; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - G Dimopoulos
- Department of Critical Care Medicine, Attikon University Hospital, National and Kapodistrian University of Athens, Medical School, Athens, Greece; European Respiratory Society (ERS)
| | - J Fortun
- Infectious Diseases Service, Ramón y Cajal Hospital, Madrid, Spain; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - J-P Gangneux
- Univ Rennes, CHU Rennes, Inserm, Irset (Institut de Recherche en santé, environnement et travail) - UMR_S 1085, Rennes, France; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - J Garbino
- Division of Infectious Diseases, University Hospital of Geneva, Geneva, Switzerland; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - W J Heinz
- Department of Infectious Diseases, Haematology and Oncology, University Hospital Würzburg, Würzburg, Germany; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - R Herbrecht
- Department of Haematology and Oncology, University Hospital of Strasbourg, Strasbourg, France; ESCMID Fungal Infection Study Group (EFISG)
| | - C P Heussel
- Diagnostic and Interventional Radiology, Thoracic Clinic, University Hospital Heidelberg, Heidelberg, Germany; European Confederation of Medical Mycology (ECMM)
| | - C C Kibbler
- Centre for Medical Microbiology, University College London, London, UK; European Confederation of Medical Mycology (ECMM)
| | - N Klimko
- Department of Clinical Mycology, Allergy and Immunology, North Western State Medical University, St Petersburg, Russia; European Confederation of Medical Mycology (ECMM)
| | - B J Kullberg
- Radboud Centre for Infectious Diseases, Radboud University Medical Centre, Centre of Expertise in Mycology Radboudumc/CWZ, ECMM Excellence Centre of Medical Mycology, Nijmegen, Netherlands; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - C Lange
- International Health and Infectious Diseases, University of Lübeck, Lübeck, Germany; Clinical Infectious Diseases, Research Centre Borstel, Leibniz Center for Medicine & Biosciences, Borstel, Germany; German Centre for Infection Research (DZIF), Tuberculosis Unit, Hamburg-Lübeck-Borstel-Riems Site, Lübeck, Germany; European Respiratory Society (ERS)
| | - T Lehrnbecher
- Division of Paediatric Haematology and Oncology, Hospital for Children and Adolescents, Johann Wolfgang Goethe-University, Frankfurt, Germany; European Confederation of Medical Mycology (ECMM)
| | - J Löffler
- Department of Infectious Diseases, Haematology and Oncology, University Hospital Würzburg, Würzburg, Germany; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - O Lortholary
- Department of Infectious and Tropical Diseases, Children's Hospital, University of Paris, Paris, France; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - J Maertens
- Department of Haematology, ECMM Excellence Centre of Medical Mycology, University Hospital Leuven, Leuven, Belgium; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - O Marchetti
- Infectious Diseases Service, Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland; Department of Medicine, Ensemble Hospitalier de la Côte, Morges, Switzerland; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - J F Meis
- Department of Medical Microbiology and Infectious Diseases, Canisius-Wilhelmina Hospital, Centre of Expertise in Mycology Radboudumc/CWZ, ECMM Excellence Centre of Medical Mycology, Nijmegen, Netherlands; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - L Pagano
- Department of Haematology, Universita Cattolica del Sacro Cuore, Roma, Italy; European Confederation of Medical Mycology (ECMM)
| | - P Ribaud
- Quality Unit, Pôle Prébloc, Saint-Louis and Lariboisière Hospital Group, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - M Richardson
- The National Aspergillosis Centre, Wythenshawe Hospital, Mycology Reference Centre Manchester, Manchester University NHS Foundation Trust, ECMM Excellence Centre of Medical Mycology, Manchester, UK; The University of Manchester, Manchester, UK; Manchester Academic Health Science Centre, Manchester, UK; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - E Roilides
- Infectious Diseases Unit, 3rd Department of Paediatrics, Faculty of Medicine, Aristotle University School of Health Sciences, Thessaloniki, Greece; Hippokration General Hospital, Thessaloniki, Greece; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - M Ruhnke
- Department of Haematology and Oncology, Paracelsus Hospital, Osnabrück, Germany; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - M Sanguinetti
- Institute of Microbiology, Fondazione Policlinico Universitario A. Gemelli - Università Cattolica del Sacro Cuore, Rome, Italy; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - D C Sheppard
- Division of Infectious Diseases, Department of Medicine, Microbiology and Immunology, McGill University, Montreal, Canada; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - J Sinkó
- Department of Haematology and Stem Cell Transplantation, Szent István and Szent László Hospital, Budapest, Hungary; ESCMID Fungal Infection Study Group (EFISG)
| | - A Skiada
- First Department of Medicine, Laiko Hospital, National and Kapodistrian University of Athens, Athens, Greece; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - M J G T Vehreschild
- Department I of Internal Medicine, ECMM Excellence Centre of Medical Mycology, University Hospital of Cologne, Cologne, Germany; Centre for Integrated Oncology, Cologne-Bonn, University of Cologne, Cologne, Germany; German Centre for Infection Research (DZIF) partner site Bonn-Cologne, Cologne, Germany; European Confederation of Medical Mycology (ECMM)
| | - C Viscoli
- Ospedale Policlinico San Martino and University of Genova (DISSAL), Genova, Italy; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM)
| | - O A Cornely
- First Department of Medicine, Laiko Hospital, National and Kapodistrian University of Athens, Athens, Greece; German Centre for Infection Research (DZIF) partner site Bonn-Cologne, Cologne, Germany; CECAD Cluster of Excellence, University of Cologne, Cologne, Germany; Clinical Trials Center Cologne, University Hospital of Cologne, Cologne, Germany; ESCMID Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology (ECMM); ESCMID European Study Group for Infections in Compromised Hosts (ESGICH).
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Baltussen TJH, Coolen JPM, Zoll J, Verweij PE, Melchers WJG. Gene co-expression analysis identifies gene clusters associated with isotropic and polarized growth in Aspergillus fumigatus conidia. Fungal Genet Biol 2018; 116:62-72. [PMID: 29705402 DOI: 10.1016/j.fgb.2018.04.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 12/18/2022]
Abstract
Aspergillus fumigatus is a saprophytic fungus that extensively produces conidia. These microscopic asexually reproductive structures are small enough to reach the lungs. Germination of conidia followed by hyphal growth inside human lungs is a key step in the establishment of infection in immunocompromised patients. RNA-Seq was used to analyze the transcriptome of dormant and germinating A. fumigatus conidia. Construction of a gene co-expression network revealed four gene clusters (modules) correlated with a growth phase (dormant, isotropic growth, polarized growth). Transcripts levels of genes encoding for secondary metabolites were high in dormant conidia. During isotropic growth, transcript levels of genes involved in cell wall modifications increased. Two modules encoding for growth and cell cycle/DNA processing were associated with polarized growth. In addition, the co-expression network was used to identify highly connected intermodular hub genes. These genes may have a pivotal role in the respective module and could therefore be compelling therapeutic targets. Generally, cell wall remodeling is an important process during isotropic and polarized growth, characterized by an increase of transcripts coding for hyphal growth and cell cycle/DNA processing when polarized growth is initiated.
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Affiliation(s)
- Tim J H Baltussen
- (a)Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands; (b)Centre of Expertise in Mycology, Radboudumc/CWZ, Nijmegen, The Netherlands.
| | - Jordy P M Coolen
- (a)Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands; (b)Centre of Expertise in Mycology, Radboudumc/CWZ, Nijmegen, The Netherlands
| | - Jan Zoll
- (a)Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands; (b)Centre of Expertise in Mycology, Radboudumc/CWZ, Nijmegen, The Netherlands
| | - Paul E Verweij
- (a)Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands; (b)Centre of Expertise in Mycology, Radboudumc/CWZ, Nijmegen, The Netherlands
| | - Willem J G Melchers
- (a)Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands; (b)Centre of Expertise in Mycology, Radboudumc/CWZ, Nijmegen, The Netherlands
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181
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Elevated MIC Values of Imidazole Drugs against Aspergillus fumigatus Isolates with TR 34/L98H/S297T/F495I Mutation. Antimicrob Agents Chemother 2018; 62:AAC.01549-17. [PMID: 29507067 DOI: 10.1128/aac.01549-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 02/25/2018] [Indexed: 11/20/2022] Open
Abstract
The use of azole fungicides in agriculture is believed to be one of the main reasons for the emergence of azole resistance in Aspergillus fumigatus Though widely used in agriculture, imidazole fungicides have not been linked to resistance in A. fumigatus This study showed that elevated MIC values of imidazole drugs were observed against A. fumigatus isolates with TR34/L98H/S297T/F495I mutation, but not among isolates with TR34/L98H mutation. Short-tandem-repeat (STR) typing analysis of 580 A. fumigatus isolates from 20 countries suggested that the majority of TR34/L98H/S297T/F495I strains from China were genetically different from the predominant major clade comprising most of the azole-resistant strains and the strains with the same mutation from the Netherlands and Denmark. Alignments of sterol 14α-demethylase sequences suggested that F495I in A. fumigatus was orthologous to F506I in Penicillium digitatum and F489L in Pyrenophora teres, which have been reported to be associated with imidazole resistance. In vitro antifungal susceptibility testing of different recombinants with cyp51A mutations further confirmed the association of the F495I mutation with imidazole resistance. In conclusion, this study suggested that environmental use of imidazole fungicides might confer selection pressure for the emergence of azole resistance in A. fumigatus.
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Ballard E, Melchers WJG, Zoll J, Brown AJP, Verweij PE, Warris A. In-host microevolution of Aspergillus fumigatus: A phenotypic and genotypic analysis. Fungal Genet Biol 2018; 113:1-13. [PMID: 29477713 PMCID: PMC5883321 DOI: 10.1016/j.fgb.2018.02.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 02/06/2018] [Accepted: 02/21/2018] [Indexed: 01/23/2023]
Abstract
In order to survive, Aspergillus fumigatus must adapt to specific niche environments. Adaptation to the human host includes modifications facilitating persistent colonisation and the development of azole resistance. The aim of this study is to advance understanding of the genetic and physiological adaptation of A. fumigatus in patients during infection and treatment. Thirteen A. fumigatus strains were isolated from a single chronic granulomatous disease patient suffering from persistent and recurrent invasive aspergillosis over a period of 2 years. All strains had identical microsatellite genotypes and were considered isogenic. Whole genome comparisons identified 248 non-synonymous single nucleotide polymorphisms. These non-synonymous mutations have potential to play a role in in-host adaptation. The first 2 strains isolated were azole susceptible, whereas later isolates were itraconazole, voriconazole and/or posaconazole resistant. Growth assays in the presence and absence of various antifungal stressors highlighted minor changes in growth rate and stress resistance, with exception of one isolate showing a significant growth defect. Poor conidiation was observed in later isolates. In certain drug resistant isolates conidiation was restored in the presence of itraconazole. Differences in virulence were observed as demonstrated in a Galleria mellonella infection model. We conclude that the microevolution of A. fumigatus in this patient has driven the emergence of both Cyp51A-independent and Cyp51A-dependent, azole resistance mechanisms, and additional phenotypes that are likely to have promoted fungal persistence.
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Affiliation(s)
- Eloise Ballard
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Aberdeen, UK
| | - Willem J G Melchers
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands; Centre of Expertise in Mycology, Radboudumc/CWZ, Nijmegen, The Netherlands
| | - Jan Zoll
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands; Centre of Expertise in Mycology, Radboudumc/CWZ, Nijmegen, The Netherlands
| | - Alistair J P Brown
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Aberdeen, UK
| | - Paul E Verweij
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands; Centre of Expertise in Mycology, Radboudumc/CWZ, Nijmegen, The Netherlands
| | - Adilia Warris
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Aberdeen, UK.
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183
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Azole Resistance of Environmental and Clinical Aspergillus fumigatus Isolates from Switzerland. Antimicrob Agents Chemother 2018; 62:AAC.02088-17. [PMID: 29437612 PMCID: PMC5913999 DOI: 10.1128/aac.02088-17] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 01/22/2018] [Indexed: 11/21/2022] Open
Abstract
Aspergillus fumigatus is a ubiquitous opportunistic pathogen. This fungus can acquire resistance to azole antifungals due to mutations in the azole target (cyp51A). Recently, cyp51A mutations typical for environmental azole resistance acquisition (for example, TR34/L98H) have been reported. These mutations can also be found in isolates recovered from patients. Environmental azole resistance acquisition has been reported on several continents. Here we describe, for the first time, the occurrence of azole-resistant A. fumigatus isolates of environmental origin in Switzerland with cyp51A mutations, and we show that these isolates can also be recovered from a few patients. While the TR34/L98H mutation was dominant, a single azole-resistant isolate exhibited a cyp51A mutation (G54R) that was reported only for clinical isolates. In conclusion, our study demonstrates that azole resistance with an environmental signature is present in environments and patients of Swiss origin and that mutations believed to be unique to clinical settings are now also observed in the environment.
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184
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Reichert-Lima F, Lyra L, Pontes L, Moretti ML, Pham CD, Lockhart SR, Schreiber AZ. Surveillance for azoles resistance in Aspergillus spp. highlights a high number of amphotericin B-resistant isolates. Mycoses 2018; 61:360-365. [PMID: 29468746 DOI: 10.1111/myc.12759] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 12/14/2017] [Accepted: 02/15/2018] [Indexed: 11/27/2022]
Abstract
Aspergillus spp. are the most common invasive mould infection and are responsible for high mortality. Aspergillus fumigatus is currently of interest because resistance to azole antifungals has emerged. The Campinas University Hospital (HC-UNICAMP) receives high-risk patients susceptible to opportunistic infections but there have been no reports of resistant A. fumigatus. This study aimed to assess the susceptibility profile of Aspergillus isolates, specifically looking for azole resistance. ITS and β-tubulin DNA sequencing was performed on 228 sequential clinical isolates. Broth microdilution susceptibility testing was performed for all isolates. A. fumigatus represented 74% of the isolates followed by Aspergillus flavus (12%). Nine A. fumigatus isolates from 9 different patients showed high MIC values to at least 1 azole, but cyp51A polymorphisms were detected in only 6 isolates and none correlated with known resistance mutations. The most troubling observation was that the minimum inhibitory concentration for amphotericin B was elevated (≥2 mg L-1 ) in 87% of patients with A. flavus isolates and 43% with Aspergillus fumigatus isolates. Given that amphotericin B is used to treat azole-resistant infections, these data highlight the need for continuous surveillance in Aspergillus for all antifungal resistance to implement correct treatment strategies for the management of these pathogens.
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Affiliation(s)
- Franqueline Reichert-Lima
- Clinical Pathology Department, School of Medical Sciences, State University of Campinas, Sao Paulo, Brazil
| | - Luzia Lyra
- Clinical Pathology Department, School of Medical Sciences, State University of Campinas, Sao Paulo, Brazil
| | - Lais Pontes
- Clinical Pathology Department, School of Medical Sciences, State University of Campinas, Sao Paulo, Brazil
| | - Maria Luiza Moretti
- Internal Medicine Department, School of Medical Sciences, State University of Campinas, Sao Paulo, Brazil
| | - Cau D Pham
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Shawn R Lockhart
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
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185
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Aspergillus fumigatus Afssn3-Afssn8 Pair Reverse Regulates Azole Resistance by Conferring Extracellular Polysaccharide, Sphingolipid Pathway Intermediates, and Efflux Pumps to Biofilm. Antimicrob Agents Chemother 2018; 62:AAC.01978-17. [PMID: 29311083 DOI: 10.1128/aac.01978-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Accepted: 12/21/2017] [Indexed: 11/20/2022] Open
Abstract
Antifungal treatment is often ineffectual, partly because of biofilm formation. In this study, by using a combined forward and reverse genetic strategy, we identified that nucleus-localized AfSsn3 and its partner AfSsn8, which constitute a Cdk8-cyclin pair, are required for azole resistance in Aspergillus fumigatus Deletion of Afssn3 led to increased absorption and utilization of glucose and amino acids. Interestingly, absorption and utilization of glucose accelerated the extracellular polysaccharide formation, while utilization of the amino acids serine, threonine, and glycine increased sphingolipid pathway intermediate accumulation. In addition, the absence of Afssn3 induced the activity of the efflux pump proteins. These factors indicate the mature biofilm is responsible for the major mechanisms of A. fumigatus resistance to azoles in the ΔAfssn3 mutant. Collectively, the loss of Afssn3 led to two "barrier" layers between the intracellular and extracellular spaces, which consequently decreased drug penetration into the cell.
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186
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Tangwattanachuleeporn M, Minarin N, Saichan S, Sermsri P, Mitkornburee R, Groß U, Chindamporn A, Bader O. Prevalence of azole-resistant Aspergillus fumigatus in the environment of Thailand. Med Mycol 2018; 55:429-435. [PMID: 27664994 DOI: 10.1093/mmy/myw090] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 08/07/2016] [Indexed: 12/18/2022] Open
Abstract
Occurrence of azole-resistant Aspergillus fumigatus (ARAF) in the environment is an emerging problem worldwide, likely impacting on patient treatment. Several resistance mutations are thought to have initially arisen through triazole-based fungicide use in agriculture and subsequently being propagated in a similar manner. Here we investigated the prevalence of ARAF in the environment of Thailand and characterized their susceptibility profiles toward clinically used azole compounds along with underlying resistance mutations. Three hundred and eight soil samples were collected and analyzed, out of which 3.25% (n = 10) were positive for ARAF. All isolates obtained were resistant to itraconazole (MIC ≥ 8 μg/ml), two showed additional increased MIC values toward posaconazole (MIC = 0.5 μg/ml), and one other toward voriconazole (MIC = 2 μg/ml). Sequencing of the respective cyp51A genes revealed that eight of the isolates carried the TR34/L98H allele and those two with elevated MIC values to posaconazole the G54R substitution. Although a clear correlation between the use of triazole-based fungicides and isolation of ARAF strains from agricultural lands could not be established for Thailand, but this study clearly demonstrates the spread of globally observed ARAF strains to the environment of South East Asia.
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Affiliation(s)
| | - Nanthakan Minarin
- Medical Technology Unit, Faculty of Allied Health Sciences, Burapha University, Chon Buri, Thailand
| | - Saranya Saichan
- Biomedical Sciences Unit, Faculty of Allied Health Sciences, Burapha University, Chon Buri, Thailand
| | - Pornsuda Sermsri
- Biomedical Sciences Unit, Faculty of Allied Health Sciences, Burapha University, Chon Buri, Thailand
| | - Ruthairat Mitkornburee
- Biomedical Sciences Unit, Faculty of Allied Health Sciences, Burapha University, Chon Buri, Thailand
| | - Uwe Groß
- Institute for Medical Microbiology, University Medical Center Göttingen, Kreuzbergring 57, 37075 Göttingen, Germany
| | - Ariya Chindamporn
- Mycology Unit, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Oliver Bader
- Institute for Medical Microbiology, University Medical Center Göttingen, Kreuzbergring 57, 37075 Göttingen, Germany
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187
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188
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Gamaletsou MN, Walsh TJ, Sipsas NV. Invasive Fungal Infections in Patients with Hematological Malignancies: Emergence of Resistant Pathogens and New Antifungal Therapies. Turk J Haematol 2018; 35:1-11. [PMID: 29391334 PMCID: PMC5843768 DOI: 10.4274/tjh.2018.0007] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Invasive fungal infections caused by drug-resistant organisms are an emerging threat to heavily immunosuppressed patients with hematological malignancies. Modern early antifungal treatment strategies, such as prophylaxis and empirical and preemptive therapy, result in long-term exposure to antifungal agents, which is a major driving force for the development of resistance. The extended use of central venous catheters, the nonlinear pharmacokinetics of certain antifungal agents, neutropenia, other forms of intense immunosuppression, and drug toxicities are other contributing factors. The widespread use of agricultural and industrial fungicides with similar chemical structures and mechanisms of action has resulted in the development of environmental reservoirs for some drug-resistant fungi, especially azole-resistant Aspergillus species, which have been reported from four continents. The majority of resistant strains have the mutation TR34/L98H, a finding suggesting that the source of resistance is the environment. The global emergence of new fungal pathogens with inherent resistance, such as Candida auris, is a new public health threat. The most common mechanism of antifungal drug resistance is the induction of efflux pumps, which decrease intracellular drug concentrations. Overexpression, depletion, and alteration of the drug target are other mechanisms of resistance. Mutations in the ERG11 gene alter the protein structure of C-demethylase, reducing the efficacy of antifungal triazoles. Candida species become echinocandin-resistant by mutations in FKS genes. A shift in the epidemiology of Candida towards resistant non-albicans Candida spp. has emerged among patients with hematological malignancies. There is no definite association between antifungal resistance, as defined by elevated minimum inhibitory concentrations, and clinical outcomes in this population. Detection of genes or mutations conferring resistance with the use of molecular methods may offer better predictive values in certain cases. Treatment options for resistant fungal infections are limited and new drugs with novel mechanisms of actions are needed. Prevention of resistance through antifungal stewardship programs is of paramount importance.
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Affiliation(s)
- Maria N Gamaletsou
- The Leeds Teaching Hospitals NHS Trust, St James University Hospital, Department of Infection and Travel Medicine, Leeds, United Kingdom
| | - Thomas J Walsh
- Weill Cornell Medicine of Cornell University, Department of Medicine, Pediatrics, and Microbiology and Immunology, New York, United States of America
| | - Nikolaos V Sipsas
- National and Kapodistrian University of Athens Faculty of Medicine, Department of Pathophysiology, Athens, Greece
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189
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190
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Meis JF, Chowdhary A, Rhodes JL, Fisher MC, Verweij PE. Clinical implications of globally emerging azole resistance in Aspergillus fumigatus. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0460. [PMID: 28080986 DOI: 10.1098/rstb.2015.0460] [Citation(s) in RCA: 209] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 08/05/2016] [Indexed: 01/23/2023] Open
Abstract
Aspergillus fungi are the cause of an array of diseases affecting humans, animals and plants. The triazole antifungal agents itraconazole, voriconazole, isavuconazole and posaconazole are treatment options against diseases caused by Aspergillus However, resistance to azoles has recently emerged as a new therapeutic challenge in six continents. Although de novo azole resistance occurs occasionally in patients during azole therapy, the main burden is the aquisition of resistance through the environment. In this setting, the evolution of resistance is attributed to the widespread use of azole-based fungicides. Although ubiquitously distributed, A. fumigatus is not a phytopathogen. However, agricultural fungicides deployed against plant pathogenic moulds such as Fusarium, Mycospaerella and A. flavus also show activity against A. fumigatus in the environment and exposure of non-target fungi is inevitable. Further, similarity in molecule structure between azole fungicides and antifungal drugs results in cross-resistance of A. fumigatus to medical azoles. Clinical studies have shown that two-thirds of patients with azole-resistant infections had no previous history of azole therapy and high mortality rates between 50% and 100% are reported in azole-resistant invasive aspergillosis. The resistance phenotype is associated with key mutations in the cyp51A gene, including TR34/L98H, TR53 and TR46/Y121F/T289A resistance mechanisms. Early detection of resistance is of paramount importance and if demonstrated, either with susceptibility testing or through molecular analysis, azole monotherapy should be avoided. Liposomal amphotericin B or a combination of voriconazole and an echinocandin are recomended for azole-resistant aspergillosis.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'.
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Affiliation(s)
- Jacques F Meis
- Department of Medical Microbiology and Infectious Diseases, Canisius Wihelmina Hospital (CWZ), Nijmegen, The Netherlands .,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboudumc/CWZ Centre of Excellence in Mycology, Nijmegen, The Netherlands
| | - Anuradha Chowdhary
- Department of Medical Microbiology, Division of Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
| | - Johanna L Rhodes
- Department of Infectious Disease Epidemiology, Imperial College School of Public Health, St Mary's Campus, London, UK
| | - Matthew C Fisher
- Department of Infectious Disease Epidemiology, Imperial College School of Public Health, St Mary's Campus, London, UK
| | - Paul E Verweij
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboudumc/CWZ Centre of Excellence in Mycology, Nijmegen, The Netherlands
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191
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Monteiro MC, Garcia-Rubio R, Alcazar-Fuoli L, Peláez T, Mellado E. Could the determination of Aspergillus fumigatus mating type have prognostic value in invasive aspergillosis? Mycoses 2017; 61:172-178. [PMID: 29082564 DOI: 10.1111/myc.12720] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/19/2017] [Accepted: 10/19/2017] [Indexed: 11/30/2022]
Abstract
A clear link between mating type and virulence has been demonstrated for some fungal pathogens, but not for Aspergillus fumigatus as of yet. An association between mating type and invasiveness has recently been established. The mating type proportion (MAT1-1:MAT1-2) of 213 A. fumigatus strains was determined (48.5%:51.5%) and results were in agreement with previous studies. However, these percentages changed when the strain collection was divided into azole-susceptible and -resistant strains. The 163 susceptible strains kept these proportions, but among the 50 azole-resistant strains 60.0% MAT1-1 and 40% MAT1-2 were found. Moreover, looking at the clinical outcome associated to 27 azole-resistant strains, we found that MAT1-1 was linked to a high mortality rate (64%), whereas the rate associated to MAT1-2 genotype was markedly lower (15%). The pathogenicity linked to the Mat type was tested in a Galleria mellonella model of infection, showing that MAT1-1 strains were consistently more pathogenic than MAT1-2, independently of their susceptibility phenotype. This data would suggest that A. fumigatus mating type determination at the time of diagnosis could have a prognostic value in invasive aspergillosis.
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Affiliation(s)
- Maria Candida Monteiro
- Mycology Reference Laboratory, Centro Nacional de Microbiologia, Instituto de Salud Carlos III, Madrid, Spain
| | - Rocio Garcia-Rubio
- Mycology Reference Laboratory, Centro Nacional de Microbiologia, Instituto de Salud Carlos III, Madrid, Spain
| | - Laura Alcazar-Fuoli
- Mycology Reference Laboratory, Centro Nacional de Microbiologia, Instituto de Salud Carlos III, Madrid, Spain
| | - Teresa Peláez
- Clinical Microbiology and Infectious Diseases Department, Hospital General Universitario Gregorio Marañon, Instituto de Investigacion Biomedica, Madrid, Spain.,Faculty of Medicine, Department of Medicine, Universidad Complutense, Madrid, Spain
| | - Emilia Mellado
- Mycology Reference Laboratory, Centro Nacional de Microbiologia, Instituto de Salud Carlos III, Madrid, Spain
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192
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Development and Validation of a High-Resolution Melting Assay To Detect Azole Resistance in Aspergillus fumigatus. Antimicrob Agents Chemother 2017; 61:AAC.01083-17. [PMID: 28893791 DOI: 10.1128/aac.01083-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 09/03/2017] [Indexed: 01/04/2023] Open
Abstract
The global emergence of azole-resistant Aspergillus fumigatus strains is a growing public health concern. Different patterns of azole resistance are linked to mutations in cyp51A Therefore, accurate characterization of the mechanisms underlying azole resistance is critical to guide selection of the most appropriate antifungal agent for patients with aspergillosis. This study describes a new sequencing-free molecular screening tool for early detection of the most frequent mutations known to be associated with azole resistance in A. fumigatus PCRs targeting cyp51A mutations at positions G54, Y121, G448, and M220 and targeting different tandem repeats (TRs) in the promoter region were designed. All PCRs were performed simultaneously, using the same cycling conditions. Amplicons were then distinguished using a high-resolution melting assay. For standardization, 30 well-characterized azole-resistant A. fumigatus strains were used, yielding melting curve clusters for different resistance mechanisms for each target and allowing detection of the most frequent azole resistance mutations, i.e., G54E, G54V, G54R, G54W, Y121F, M220V, M220I, M220T, M220K, and G448S, and the tandem repeats TR34, TR46, and TR53 Validation of the method was performed using a blind panel of 80 A. fumigatus azole-susceptible or azole-resistant strains. All strains included in the blind panel were properly classified as susceptible or resistant with the developed method. The implementation of this screening method can reduce the time needed for the detection of azole-resistant A. fumigatus isolates and therefore facilitate selection of the best antifungal therapy in patients with aspergillosis.
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193
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Single-Center Evaluation of an Agar-Based Screening for Azole Resistance in Aspergillus fumigatus by Using VIPcheck. Antimicrob Agents Chemother 2017; 61:AAC.01250-17. [PMID: 28923874 DOI: 10.1128/aac.01250-17] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 09/04/2017] [Indexed: 11/20/2022] Open
Abstract
Antifungal susceptibility testing is an essential tool for guiding therapy, although EUCAST and CLSI reference methods are often available only in specialized centers. We studied the performance of an agar-based screening method for the detection of azole resistance in Aspergillus fumigatus cultures. The VIPcheck consists of four wells containing voriconazole, itraconazole, posaconazole, or a growth control. Ninety-six A. fumigatus isolates were used. Thirty-three isolates harbored a known resistance mechanism: TR34/L98H (11 isolates), TR46/Y121F/T289A (6 isolates), TR53 (2 isolates), and 14 isolates with other cyp51A gene point mutations. Eighteen resistant isolates had no cyp51A-mediated azole resistance. Forty-five isolates had a wild-type (WT) azole phenotype. Four technicians and two inexperienced interns, blinded to the genotype/phenotype, read the plates visually after 24 h and 48 h and documented minimal growth, uninhibited growth, and no growth. The performance was compared to the EUCAST method. After 24 h of incubation, the mean sensitivity and specificity were 0.54 and 1.00, respectively, with uninhibited growth as the threshold. After 48 h of incubation, the performance mean sensitivity and specificity were 0.98 and 0.93, respectively, with minimal growth. The performance was not affected by observer experience in mycology. The interclass correlation coefficient was 0.87 after 24 h and 0.85 after 48 h. VIPcheck enabled the selection of azole-resistant A. fumigatus colonies, with a mean sensitivity and specificity of 0.98 and 0.93, respectively. Uninhibited growth on any azole-containing well after 24 h and minimal growth after 48 h were indicative of resistance. These results indicate that the VIPcheck is an easy-to-use tool for azole resistance screening and the selection of colonies that require MIC testing.
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194
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Bedin Denardi L, Hoch Dalla-Lana B, Pantella Kunz de Jesus F, Bittencourt Severo C, Morais Santurio J, Zanette RA, Hartz Alves S. In vitro antifungal susceptibility of clinical and environmental isolates of Aspergillus fumigatus and Aspergillus flavus in Brazil. Braz J Infect Dis 2017; 22:30-36. [PMID: 29172033 PMCID: PMC9425663 DOI: 10.1016/j.bjid.2017.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 10/20/2017] [Accepted: 10/22/2017] [Indexed: 11/17/2022] Open
Abstract
The in vitro susceptibility of 105 clinical and environmental strains of Aspergillus fumigatus and Aspergillus flavus to antifungal drugs, such as amphotericin B, azoles, and echinocandins was evaluated by the broth microdilution method proposed by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Following the EUCAST-proposed breakpoints, 20% and 25% of the clinical and environmental isolates of A. fumigatus, respectively, were found to be resistant to itraconazole (Minimal Inhibitory Concentration, MIC > 2.0 mg/L). Voriconazole showed good activity against A. fumigatus and A. flavus strains, except for one clinical strain of A. fumigatus whose MIC was 4.0 mg/L. Posaconazole (≤0.25 mg/L) also showed appreciable activity against both species of Aspergillus, except for six A. fumigatus strains with relatively higher MICs (0.5 mg/L). The MICs for Amphotericin B ranged from 0.06 to 1.0 mg/L for A. fumigatus, but were much higher (0.5–8.0 mg/L) for A. flavus. Among the echinocandins, caspofungin showed a geometric mean of 0.078 and 0.113 against the clinical and environmental strains of A. flavus, respectively, but had elevated minimal effective concentrations (MECs) for seven of the A. fumigatus strains. Anidulafungin and micafungin exhibited considerable activity against both A. fumigatus and A. flavus isolates, except for one environmental isolate of A. fumigatus that showed an MEC of 1 mg/L to micafungin. Our study proposes that a detailed investigation of the antifungal susceptibility of the genus Aspergillus from different regions of Brazil is necessary for establishing a response profile against the different classes of antifungal agents used in the treatment of aspergillosis.
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Affiliation(s)
- Laura Bedin Denardi
- Universidade Federal de Santa Maria (UFSM), Centro de Ciências da Saúde, Programa de Pós-Graduação em Ciências Farmacêuticas, Santa Maria, RS, Brazil; Universidade Federal de Santa Maria (UFSM), Centro de Ciências da Saúde, Departamento de Microbiologia e Parasitologia, Laboratório de Pesquisas Micológicas, Santa Maria, RS, Brazil.
| | - Bianca Hoch Dalla-Lana
- Universidade Federal de Santa Maria (UFSM), Centro de Ciências da Saúde, Departamento de Microbiologia e Parasitologia, Laboratório de Pesquisas Micológicas, Santa Maria, RS, Brazil
| | - Francielli Pantella Kunz de Jesus
- Universidade Federal de Santa Maria (UFSM), Centro de Ciências da Saúde, Departamento de Microbiologia e Parasitologia, Laboratório de Pesquisas Micológicas, Santa Maria, RS, Brazil; Universidade Federal de Santa Maria (UFSM), Centro de Ciências da Saúde, Programa de Pós-Graduação em Farmacologia, Santa Maria, RS, Brazil
| | | | - Janio Morais Santurio
- Universidade Federal de Santa Maria (UFSM), Centro de Ciências da Saúde, Departamento de Microbiologia e Parasitologia, Laboratório de Pesquisas Micológicas, Santa Maria, RS, Brazil; Universidade Federal de Santa Maria (UFSM), Centro de Ciências da Saúde, Programa de Pós-Graduação em Farmacologia, Santa Maria, RS, Brazil
| | - Régis Adriel Zanette
- Universidade Federal do Rio Grande do Sul, Programa de Pós Graduação em Ciências Biológicas: Farmacologia e Terapêutica, Porto Alegre, RS, Brazil
| | - Sydney Hartz Alves
- Universidade Federal de Santa Maria (UFSM), Centro de Ciências da Saúde, Programa de Pós-Graduação em Ciências Farmacêuticas, Santa Maria, RS, Brazil; Universidade Federal de Santa Maria (UFSM), Centro de Ciências da Saúde, Departamento de Microbiologia e Parasitologia, Laboratório de Pesquisas Micológicas, Santa Maria, RS, Brazil
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195
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Molecular Tools for the Detection and Deduction of Azole Antifungal Drug Resistance Phenotypes in Aspergillus Species. Clin Microbiol Rev 2017; 30:1065-1091. [PMID: 28903985 DOI: 10.1128/cmr.00095-16] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The incidence of azole resistance in Aspergillus species has increased over the past years, most importantly for Aspergillus fumigatus. This is partially attributable to the global spread of only a few resistance alleles through the environment. Secondary resistance is a significant clinical concern, as invasive aspergillosis with drug-susceptible strains is already difficult to treat, and exclusion of azole-based antifungals from prophylaxis or first-line treatment of invasive aspergillosis in high-risk patients would dramatically limit drug choices, thus increasing mortality rates for immunocompromised patients. Management options for invasive aspergillosis caused by azole-resistant A. fumigatus strains were recently reevaluated by an international expert panel, which concluded that drug resistance testing of cultured isolates is highly indicated when antifungal therapy is intended. In geographical regions with a high environmental prevalence of azole-resistant strains, initial therapy should be guided by such analyses. More environmental and clinical screening studies are therefore needed to generate the local epidemiologic data if such measures are to be implemented on a sound basis. Here we propose a first workflow for evaluating isolates from screening studies, and we compile the MIC values correlating with individual amino acid substitutions in the products of cyp51 genes for interpretation of DNA sequencing data, especially in the absence of cultured isolates.
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Investigating Clinical Issues by Genotyping of Medically Important Fungi: Why and How? Clin Microbiol Rev 2017; 30:671-707. [PMID: 28490578 DOI: 10.1128/cmr.00043-16] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Genotyping studies of medically important fungi have addressed elucidation of outbreaks, nosocomial transmissions, infection routes, and genotype-phenotype correlations, of which secondary resistance has been most intensively investigated. Two methods have emerged because of their high discriminatory power and reproducibility: multilocus sequence typing (MLST) and microsatellite length polymorphism (MLP) using short tandem repeat (STR) markers. MLST relies on single-nucleotide polymorphisms within the coding regions of housekeeping genes. STR polymorphisms are based on the number of repeats of short DNA fragments, mostly outside coding regions, and thus are expected to be more polymorphic and more rapidly evolving than MLST markers. There is no consensus on a universal typing system. Either one or both of these approaches are now available for Candida spp., Aspergillus spp., Fusarium spp., Scedosporium spp., Cryptococcus neoformans, Pneumocystis jirovecii, and endemic mycoses. The choice of the method and the number of loci to be tested depend on the clinical question being addressed. Next-generation sequencing is becoming the most appropriate method for fungi with no MLP or MLST typing available. Whatever the molecular tool used, collection of clinical data (e.g., time of hospitalization and sharing of similar rooms) is mandatory for investigating outbreaks and nosocomial transmission.
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197
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Sharma C, Chowdhary A. Molecular bases of antifungal resistance in filamentous fungi. Int J Antimicrob Agents 2017; 50:607-616. [DOI: 10.1016/j.ijantimicag.2017.06.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Revised: 06/16/2017] [Accepted: 06/24/2017] [Indexed: 01/15/2023]
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198
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Menotti J, Alanio A, Sturny-Leclère A, Vitry S, Sauvage F, Barratt G, Bretagne S. A cell impedance-based real-time in vitro assay to assess the toxicity of amphotericin B formulations. Toxicol Appl Pharmacol 2017; 334:18-23. [DOI: 10.1016/j.taap.2017.08.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 08/02/2017] [Accepted: 08/29/2017] [Indexed: 10/18/2022]
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199
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Triazole Resistance Is Still Not Emerging in Aspergillus fumigatus Isolates Causing Invasive Aspergillosis in Brazilian Patients. Antimicrob Agents Chemother 2017; 61:AAC.00608-17. [PMID: 28893772 DOI: 10.1128/aac.00608-17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 08/26/2017] [Indexed: 11/20/2022] Open
Abstract
Aspergillus fumigatus azole resistance has emerged as a global health problem. We evaluated the in vitro antifungal susceptibility of 221 clinical A. fumigatus isolates according to CLSI guidelines. Sixty-one isolates exhibiting MICs at the epidemiological cutoff value (ECV) for itraconazole or above the ECV for any triazole were checked for CYP51A mutations. No mutations were documented, even for the isolates (1.8%) with high voriconazole MICs, indicating that triazoles may be used safely to treat aspergillosis in Brazil.
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A CTG Clade Candida Yeast Genetically Engineered for the Genotype-Phenotype Characterization of Azole Antifungal Resistance in Human-Pathogenic Yeasts. Antimicrob Agents Chemother 2017; 62:AAC.01483-17. [PMID: 29038279 DOI: 10.1128/aac.01483-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/12/2017] [Indexed: 11/20/2022] Open
Abstract
A strain of the opportunistic pathogenic yeast Candida lusitaniae was genetically modified for use as a cellular model for assessing by allele replacement the impact of lanosterol C14α-demethylase ERG11 mutations on azole resistance. Candida lusitaniae was chosen because it is susceptible to azole antifungals, it belongs to the CTG clade of yeast, which includes most of the Candida species pathogenic for humans, and it is haploid and easily amenable to genetic transformation and molecular modeling. In this work, allelic replacement is targeted at the ERG11 locus by the reconstitution of a functional auxotrophic marker in the 3' intergenic region of ERG11 Homologous and heterologous ERG11 alleles are expressed from the resident ERG11 promoter of C. lusitaniae, allowing accurate comparison of the phenotypic change in azole susceptibility. As a proof of concept, we successfully expressed in C. lusitaniae different ERG11 alleles, either bearing or not bearing mutations retrieved from a clinical context, from two phylogenetically distant yeasts, C. albicans and Kluyveromyces marxianusCandida lusitaniae constitutes a high-fidelity expression system, giving specific Erg11p-dependent fluconazole MICs very close to those observed with the ERG11 donor strain. This work led us to characterize the phenotypic effect of two kinds of mutation: mutation conferring decreased fluconazole susceptibility in a species-specific manner and mutation conferring fluconazole resistance in several yeast species. In particular, a missense mutation affecting amino acid K143 of Erg11p in Candida species, and the equivalent position K151 in K. marxianus, plays a critical role in fluconazole resistance.
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