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Oda S, Karasawa S, Satoh K. A novel procedure for the quantification of antifungal activity against filamentous fungi, mycelial invasion distance (MID) method. J Microbiol Methods 2024; 222:106958. [PMID: 38777183 DOI: 10.1016/j.mimet.2024.106958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 05/17/2024] [Accepted: 05/19/2024] [Indexed: 05/25/2024]
Abstract
A novel method for the quantification of antifungal activity of fungicides and painted surfaces, mycelial invasion distance (MID) method, was developed and applied to the quantification of activities of parabens and an antifungal paint. In this method, the MID of aerial mycelia on a test paper or a panel placed on a nutrient agar plate was measured with a stereoscopic microscope and a micro-ruler. The antifungal activities of the parabens and painted surfaces were expressed as the MID. The higher the hydrophobicity of parabens, the longer the MID, that is the lower the antifungal activity, were observed. Conversely, relatively polar parabens, such as methyl and ethyl parabens, exhibited stronger antifungal activity, that is shorter MID. The most hydrophobic paraben, benzyl paraben, showed the weakest antifungal activity. Furthermore, it was confirmed that the MID method was effective for the evaluation of the painted surfaces.
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Affiliation(s)
- Shinobu Oda
- Genome Biotechnology Laboratory, Kanazawa Institute of Technology, 3-1 Yatsukaho, Hakusan, Ishikawa 924-0838, Japan; Research Laboratory for Integrated Technological Systems, Kanazawa Institute of Technology, 3-1 Yatsukaho, Hakusan, Ishikawa 924-0838, Japan.
| | - Sonomi Karasawa
- Genome Biotechnology Laboratory, Kanazawa Institute of Technology, 3-1 Yatsukaho, Hakusan, Ishikawa 924-0838, Japan
| | - Kurea Satoh
- Genome Biotechnology Laboratory, Kanazawa Institute of Technology, 3-1 Yatsukaho, Hakusan, Ishikawa 924-0838, Japan
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2
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Korkmaz E, Ergon MC. Investigation of antifungal susceptibility of Aspergillus species isolated from systemic clinical specimens by different methods. Indian J Med Microbiol 2024; 50:100642. [PMID: 38830536 DOI: 10.1016/j.ijmmb.2024.100642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 05/30/2024] [Accepted: 05/31/2024] [Indexed: 06/05/2024]
Abstract
PURPOSE Due to the potential for Aspergillus species to cause lethal infections and the rising rates of antifungal resistance, the significance of antifungal susceptibility tests has increased. We aimed to assess the sensitivities of Aspergillus species to amphotericin B (AMB), voriconazole (VOR), itraconazole (ITZ), and caspofungin (CAS) using disk diffusion (DD) and gradient diffusion (GD) methods and compare them with broth microdilution (BMD) as the reference susceptibility method. METHODS The study involved 62 Aspergillus fumigatus, 28 Aspergillus flavus, and 16 Aspergillus terreus isolates, totaling 106 Aspergillus isolates. BMD and DD methods were performed in accordance with CLSI M38-A2 and CLSI M51-A documents, respectively. The GD method utilized nonsupplemented Mueller Hinton agar (MHA) as the medium. RESULTS In the BMD method, the lowest minimal inhibitory concentration (MIC)90 or minimal effective concentration (MEC)90 values were observed for VOR and CAS (0.5 μg/mL and 0.06 μg/mL, respectively). AMB and ITZ MIC90 values were both 2 μg/mL. In our comparison of the GD method with the BMD method at ±2 dilution, we observed essential agreement rates of 91.6%, 99.1%, 100%, and 38.6% for AMB, VOR, ITZ, and CAS, respectively. When comparing DD and BMD methods, we found categorical agreement rates of 65.1%, 99.1%, 77.3%, and 100% for AMB, VOR, ITZ, and CAS, respectively. For GD and BMD methods, these rates were 79.2%, 99.1%, 87.8%, and 100%. CONCLUSIONS Given the high essential and categorical agreement rates, we posit that the GD method is a viable alternative to the BMD method for AMB, ITZ and VOR but not for CAS. In addition, the use of nonsupplemented MHA in the GD method proves advantageous due to its cost-effectiveness and widespread availability compared to other growth media.
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Affiliation(s)
- Emine Korkmaz
- Dokuz Eylül University Faculty of Medicine, Department of Medical Microbiology, İzmir, Turkey.
| | - M Cem Ergon
- Dokuz Eylül University Faculty of Medicine, Department of Medical Microbiology, İzmir, Turkey.
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Li Y, Dai M, Lu L, Zhang Y. The C 2H 2-Type Transcription Factor ZfpA, Coordinately with CrzA, Affects Azole Susceptibility by Regulating the Multidrug Transporter Gene atrF in Aspergillus fumigatus. Microbiol Spectr 2023; 11:e0032523. [PMID: 37318356 PMCID: PMC10434176 DOI: 10.1128/spectrum.00325-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 05/26/2023] [Indexed: 06/16/2023] Open
Abstract
The incidence of invasive aspergillosis caused by Aspergillus fumigatus has risen steadily over the past few decades due to the limited effective treatment options and the emergence of antifungal-resistant isolates. In clinic-isolated A. fumigatus, the azole resistance mechanism is primarily caused by mutations of the drug target and/or overexpression of drug efflux pumps. However, knowledge about how drug efflux pumps are transcriptionally regulated is limited. In this study, we found that loss of a C2H2 transcription factor ZfpA (zinc finger protein) results in the marked upregulation of a series of drug efflux pump-encoding genes, especially atrF, which contributes to azole drug resistance in A. fumigatus. CrzA is a previously identified positive transcription factor for genes of drug efflux pumps, and ZfpA transcriptionally inhibits expressions of drug efflux pumps in a CrzA-dependent way. Under the treatment of azoles, both ZfpA and CrzA transfer to nuclei and coregulate the expression of multidrug transporters and then keep normal drug susceptibility in fungal cells. Findings in this study demonstrated that ZfpA is not only involved in fungal growth and virulence potential but also negatively regulates antifungal drug susceptibility. IMPORTANCE Conserved across all kingdoms of life, ABC transporters comprise one of the largest protein families. They are associated with multidrug resistance, affecting aspects such as resistance to antimicrobials or anticancer drugs. Despite the importance of ABC transporters in multidrug resistance, the understanding of their regulatory network is still limited in A. fumigatus. Here, we found that the loss of the transcription factor ZfpA induces the expression of the ABC transporter gene atrF, altering azole susceptibility in A. fumigatus. ZfpA, coordinately with CrzA, affects the azole susceptibility by regulating the expression of the ABC transporter gene atrF. These findings reveal the regulatory mechanism of the ABC transporter gene atrF in A. fumigatus.
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Affiliation(s)
- Yeqi Li
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Centre for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Mengyao Dai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Centre for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Centre for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Yuanwei Zhang
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Centre for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, China
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Vahedi-Shahandashti R, Hahn L, Houbraken J, Lass-Flörl C. Aspergillus Section Terrei and Antifungals: From Broth to Agar-Based Susceptibility Testing Methods. J Fungi (Basel) 2023; 9:jof9030306. [PMID: 36983474 PMCID: PMC10056208 DOI: 10.3390/jof9030306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 02/23/2023] [Accepted: 02/27/2023] [Indexed: 03/04/2023] Open
Abstract
Providing timely antifungal treatment to patients suffering from life-threatening invasive fungal infections (IFIs) is essential. Due to the changing epidemiology and the emergence of antifungal resistance in Aspergillus, the most commonly responsible mold of IFIs, antifungal susceptibility testing (AFST) has become increasingly important to guide clinical decisions. This study assessed the essential agreement (EA) between broth microdilution methods (the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST)) and the Etest of amphotericin B (AmB), liposomal amphotericin B (L-AmB), and isavuconazole (ISA) against 112 Aspergillus section Terrei. An EA within ±2 dilutions of ≥90% between the two methods was considered acceptable. Excellent EA was found between EUCAST and CLSI of AmB and ISA (98.2% and 95.5%, respectively). The correlation of Etest results and EUCAST/CLSI was not acceptable (<90%) for any tested antifungal; however, Etest and CLSI for AmB (79.6%) and ISA (77.6%) showed a higher EA than Etest and EUCAST for AmB (49.5%) and ISA (46.4%). It was concluded that the Etest method requires its own clinical breakpoints (CBPs) and epidemiological cutoff values (ECVs), and interpreting Etest results using EUCAST and CLSI-adapted CBPs and ECVs could result in misinterpretation as Etest shows lower minimum inhibitory concentrations (MICs).
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Affiliation(s)
- Roya Vahedi-Shahandashti
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Lisa Hahn
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Jos Houbraken
- Westerdijk Fungal Biodiversity Institute, 3584 CT Utrecht, The Netherlands
| | - Cornelia Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, 6020 Innsbruck, Austria
- Correspondence:
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Opperman TJ, Dhingra S, Gutierrez-Perez C, Kwasny SM, Cramer RA. Luciferase-Based High-Throughput Screen with Aspergillus fumigatus to Identify Antifungal Small Molecules. Methods Mol Biol 2023; 2658:17-34. [PMID: 37024692 DOI: 10.1007/978-1-0716-3155-3_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
Only three classes of contemporary antifungal drugs are routinely utilized in the clinic against filamentous fungal pathogens such as Aspergillus fumigatus. High-throughput phenotypic screens to identify small molecules with activity against filamentous fungi remain challenging due to the hyphal, biofilm-like growth morphology of these important organisms. In this chapter, we describe a protocol for utilizing a bioluminescent A. fumigatus strain for identifying small molecules that potentiate the activity of the triazole antifungal drug fluconazole. The assay holds great promise for identifying small molecules with activity against filamentous fungal pathogens.
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Affiliation(s)
| | - Sourabh Dhingra
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
- Clemson University, Biological Sciences, Clemson, SC, USA
| | - Cecilia Gutierrez-Perez
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | | | - Robert A Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA.
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Melhem MSC, Coelho VC, Fonseca CA, de Oliveira L, Bonfietti LX, Szeszs MW, Magri MMC, Dorneles FS, Taguchi H, Moreira DVS, Motta AL, Batista MV, Kamei K, Shikanai-Yasuda MA. Evaluation of the Sensititre YeastOne and Etest in Comparison with CLSI M38-A2 for Antifungal Susceptibility Testing of Three Azoles, Amphotericin B, Caspofungin, and Anidulafungin, against Aspergillusfumigatus and Other Species, Using New Clinical Breakpoints and Epidemiological Cutoff Values. Pharmaceutics 2022; 14:pharmaceutics14102161. [PMID: 36297597 PMCID: PMC9607534 DOI: 10.3390/pharmaceutics14102161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/25/2022] [Accepted: 09/27/2022] [Indexed: 11/16/2022] Open
Abstract
Aspergillosis is an invasive fungal disease associated with high mortality. Antifungal susceptibility testing (AFST) is receiving increasing consideration for managing patients, as well as for surveilling emerging drug resistance, despite having time-consuming and technically complex reference methodologies. The Sensititre YeastOne (SYO) and Etest methods are widely utilized for yeasts but have not been extensively evaluated for Aspergillus isolates. We obtained Posaconazole (POS), Voriconazole (VCZ), Itraconazole (ITC), Amphotericin B (AMB), Caspofungin (CAS), and Anidulafungin (AND) minimum inhibitory concentrations (MICs) for both the Etest (n = 330) and SYO (n = 339) methods for 106 sequenced clinical strains. For 84 A. fumigatus, we analyzed the performance of both commercial methods in comparison with the CLSI-AFST, using available cutoff values. An excellent correlation could be demonstrated for Etest-AMB and Etest-VCZ (p < 0.01). SYO-MICs of AMB, VCZ, and POS resulted in excellent essential agreement (>93%), and >80% for AMB, VCZ, and ITC Etest-MICs. High categoric agreement was found for AMB, ITC, and CAS Etest-MICs (>85%) and AMB SYO-MICs (>90%). The considerable number of major/very major errors found using Etest and SYO, possibly related to the proposed cutoffs and associated with the less time-consuming processes, support the need for the improvement of commercial methods for Aspergillus strains.
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Affiliation(s)
- Marcia S. C. Melhem
- Mycology Unit, Parasitology and Mycology Department, Instituto Adolfo Lutz, Secretary of Health, Government of São Paulo State, São Paulo 01246-902, SP, Brazil
- Graduate Program in Sciences, Coordination of Diseases Control, Secretary of Health, Government of São Paulo State, São Paulo 01246-902, SP, Brazil
- Graduate Program in Infectious and Parasitic Diseases, Faculdade de Medicina, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil
- Correspondence: (M.S.C.M.); (M.A.S.-Y.); Tel.: +55-11-996855034 (M.S.C.M.); +55-11-30627049 (M.A.S.-Y.)
| | - Vivian C. Coelho
- Laboratório de Investigação Médica em Imunologia (LIM 48), Hospital das Clínicas, Faculdade de Medicina, University of São Paulo, São Paulo 05403-000, SP, Brazil
| | - Claudia A. Fonseca
- Laboratório de Investigação Médica em Imunologia (LIM 48), Hospital das Clínicas, Faculdade de Medicina, University of São Paulo, São Paulo 05403-000, SP, Brazil
| | - Lidiane de Oliveira
- Mycology Unit, Parasitology and Mycology Department, Instituto Adolfo Lutz, Secretary of Health, Government of São Paulo State, São Paulo 01246-902, SP, Brazil
| | - Lucas X. Bonfietti
- Mycology Unit, Parasitology and Mycology Department, Instituto Adolfo Lutz, Secretary of Health, Government of São Paulo State, São Paulo 01246-902, SP, Brazil
| | - Maria. W. Szeszs
- Mycology Unit, Parasitology and Mycology Department, Instituto Adolfo Lutz, Secretary of Health, Government of São Paulo State, São Paulo 01246-902, SP, Brazil
| | - Marcello M. C. Magri
- Laboratório de Investigação Médica em Imunologia (LIM 48), Hospital das Clínicas, Faculdade de Medicina, University of São Paulo, São Paulo 05403-000, SP, Brazil
- Division of Infectious Diseases, Hospital das Clínicas da Faculdade de Medicina, University of São Paulo, São Paulo 05403-000, SP, Brazil
| | - Francine S. Dorneles
- Graduate Program in Infectious and Parasitic Diseases, Faculdade de Medicina, Federal University of Mato Grosso do Sul, Campo Grande 79070-900, MS, Brazil
| | - Hideaki Taguchi
- Medical Mycology Research Center, Chiba University, Chiba 260-8673, Japan
| | - Daniel V. S. Moreira
- Laboratório de Investigação Médica em Imunologia (LIM 48), Hospital das Clínicas, Faculdade de Medicina, University of São Paulo, São Paulo 05403-000, SP, Brazil
| | - Adriana L. Motta
- Laboratory of Microbiology, Division of Central Laboratory—Laboratory of Medical Investigation—LIM 03, Hospital das Clínicas, Faculdade de Medicina, University of São Paulo, São Paulo 05403-000, SP, Brazil
| | - Marjorie V. Batista
- Division of Infectious Diseases, Hospital das Clínicas da Faculdade de Medicina, University of São Paulo, São Paulo 05403-000, SP, Brazil
| | - Katsuhiko Kamei
- Medical Mycology Research Center, Chiba University, Chiba 260-8673, Japan
| | - Maria A. Shikanai-Yasuda
- Laboratório de Investigação Médica em Imunologia (LIM 48), Hospital das Clínicas, Faculdade de Medicina, University of São Paulo, São Paulo 05403-000, SP, Brazil
- Department of Infectious and Parasitic Diseases, Faculdade de Medicina, University of São Paulo, São Paulo 05403-000, SP, Brazil
- Correspondence: (M.S.C.M.); (M.A.S.-Y.); Tel.: +55-11-996855034 (M.S.C.M.); +55-11-30627049 (M.A.S.-Y.)
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Heuer C, Bahnemann J, Scheper T, Segal E. Paving the Way to Overcome Antifungal Drug Resistance: Current Practices and Novel Developments for Rapid and Reliable Antifungal Susceptibility Testing. SMALL METHODS 2021; 5:e2100713. [PMID: 34927979 DOI: 10.1002/smtd.202100713] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 09/05/2021] [Indexed: 06/14/2023]
Abstract
The past year has established the link between the COVID-19 pandemic and the global spread of severe fungal infections; thus, underscoring the critical need for rapid and realizable fungal disease diagnostics. While in recent years, health authorities, such as the Centers for Disease Control and Prevention, have reported the alarming emergence and spread of drug-resistant pathogenic fungi and warned against the devastating consequences, progress in the diagnosis and treatment of fungal infections is limited. Early diagnosis and patient-tailored therapy are established to be key in reducing morbidity and mortality associated with fungal (and cofungal) infections. As such, antifungal susceptibility testing (AFST) is crucial in revealing susceptibility or resistance of these pathogens and initiating correct antifungal therapy. Today, gold standard AFST methods require several days for completion, and thus this much delayed time for answer limits their clinical application. This review focuses on the advancements made in developing novel AFST techniques and discusses their implications in the context of the practiced clinical workflow. The aim of this work is to highlight the advantages and drawbacks of currently available methods and identify the main gaps hindering their progress toward clinical application.
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Affiliation(s)
- Christopher Heuer
- Institute of Technical Chemistry, Leibniz University Hannover, 30167, Hannover, Germany
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, 320003, Israel
| | - Janina Bahnemann
- Institute of Technical Chemistry, Leibniz University Hannover, 30167, Hannover, Germany
| | - Thomas Scheper
- Institute of Technical Chemistry, Leibniz University Hannover, 30167, Hannover, Germany
| | - Ester Segal
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, 320003, Israel
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Comparison of Disc Diffusion, Etest, and a Modified CLSI Broth Microdilution Method for In Vitro Susceptibility Testing of Itraconazole, Posaconazole, and Voriconazole against Madurella mycetomatis. Antimicrob Agents Chemother 2021; 65:e0043321. [PMID: 34181477 DOI: 10.1128/aac.00433-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
For many fungal infections, in vitro susceptibility testing is used to predict if an isolate is resistant or susceptible to the antifungal agent used to treat the infection. For Madurella mycetomatis, the main causative agent of mycetoma, in vitro susceptibility testing currently is not performed on a routine basis. The current in vitro susceptibility testing method is labor-intensive, and sonication must be done to generate a hyphal inoculum. For endpoint visualization, expensive viability dyes are needed. Here, we investigated if the currently used in vitro susceptibility method could be adapted to make it amendable for use in a routine setting which can be used in low-income countries, where mycetoma is endemic. First, we developed a methodology in which hyphal fragments can be generated without the need for sonication, by comparing different bead beating methodologies. Next, in vitro susceptibility was assessed using standard broth microdilution assays as well as disc diffusion, Etest, and VIPcheck methodologies. We demonstrate that after a hyphal suspension is generated by glass bead beating, disc diffusion, Etest, and VIPcheck can be used to determine susceptibility of Madurella mycetomatis to itraconazole, posaconazole, and voriconazole. The MICs found with Etest were comparable to those obtained with our modified CLSI-based broth microdilution in vitro susceptibility assay for itraconazole and posaconazole. Furthermore, we found an inverse relationship between the zones of inhibition and MICs obtained with the Etest and those obtained by the modified CLSI broth microdilution technique.
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Souza ACO, Martin-Vicente A, Nywening AV, Ge W, Lowes DJ, Peters BM, Fortwendel JR. Loss of Septation Initiation Network (SIN) kinases blocks tissue invasion and unlocks echinocandin cidal activity against Aspergillus fumigatus. PLoS Pathog 2021; 17:e1009806. [PMID: 34370772 PMCID: PMC8376064 DOI: 10.1371/journal.ppat.1009806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/19/2021] [Accepted: 07/16/2021] [Indexed: 11/18/2022] Open
Abstract
Although considered effective treatment for many yeast fungi, the therapeutic efficacy of the echinocandin class of antifungals for invasive aspergillosis (IA) is limited. Recent studies suggest intense kinase- and phosphatase-mediated echinocandin adaptation in A. fumigatus. To identify A. fumigatus protein kinases required for survival under echinocandin stress, we employed CRISPR/Cas9-mediated gene targeting to generate a protein kinase disruption mutant library in a wild type genetic background. Cell wall and echinocandin stress screening of the 118 disruption mutants comprising the library identified only five protein kinase disruption mutants displaying greater than 4-fold decreased echinocandin minimum effective concentrations (MEC) compared to the parental strain. Two of these mutated genes, the previously uncharacterized A. fumigatus sepL and sidB genes, were predicted to encode protein kinases functioning as core components of the Septation Initiation Network (SIN), a tripartite kinase cascade that is necessary for septation in fungi. As the A. fumigatus SIN is completely uncharacterized, we sought to explore these network components as effectors of echinocandin stress survival. Our data show that mutation of any single SIN kinase gene caused complete loss of hyphal septation and increased susceptibility to cell wall stress, as well as widespread hyphal damage and loss of viability in response to echinocandin stress. Strikingly, mutation of each SIN kinase gene also resulted in a profound loss of virulence characterized by lack of tissue invasive growth. Through the deletion of multiple novel regulators of hyphal septation, we show that the non-invasive growth phenotype is not SIN-kinase dependent, but likely due to hyphal septation deficiency. Finally, we also find that echinocandin therapy is highly effective at eliminating residual tissue burden in mice infected with an aseptate strain of A. fumigatus. Together, our findings suggest that inhibitors of septation could enhance echinocandin-mediated killing while simultaneously limiting the invasive potential of A. fumigatus hyphae.
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Affiliation(s)
- Ana Camila Oliveira Souza
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Adela Martin-Vicente
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Ashley V. Nywening
- Integrated Program in Biomedical Sciences, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Wenbo Ge
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - David J. Lowes
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Brian M. Peters
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
- Department of Microbiology, Immunology, and Biochemistry, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Jarrod R. Fortwendel
- Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
- Department of Microbiology, Immunology, and Biochemistry, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
- * E-mail:
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Improvement of the pharmacokinetic/pharmacodynamic relationship in the treatment of invasive aspergillosis with voriconazole. Reduced drug toxicity through novel rapid release formulations. Colloids Surf B Biointerfaces 2020; 193:111119. [PMID: 32464356 DOI: 10.1016/j.colsurfb.2020.111119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 04/05/2020] [Accepted: 05/06/2020] [Indexed: 12/17/2022]
Abstract
Voriconazole (VCZ) is currently the first-line treatment for invasive aspergillosis, although the doses are limited by its poor solubility and high hepatic toxicity. The aim of this study was to develop a solid self-dispersing micellar system of VCZ to improve the pharmacokinetic/pharmacodynamic (PK/PD) relationship and reduce hepatotoxicity. In this work, solid micellar systems of VCZ are formulated with different polysorbate 80 ratios using mannitol as a hydrophilic carrier. The novel micellar systems were characterized by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and dissolution studies. Self-dispersing micellar systems reduced VCZ crystallinity, leading to an improvement in its dissolution rate. The in vitro susceptibility test also revealed that the most common microorganisms in invasive aspergillosis exhibited low minimum inhibitory concentration (MIC) values for micellar systems. Pharmacokinetic studies indicated an improvement in bioavailability for MS-1:3:0.05, and changes in its biodistribution to different organs. MS-1:3:0.05 showed an increased concentration in lungs and a significant decrease in VCZ accumulated in the liver.
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Abstract
Although not as ubiquitous as antibacterial susceptibility testing, antifungal susceptibility testing (AFST) is a tool of increasing importance in clinical microbiology laboratories. The goal of AFST is to reliably produce MIC values that may be used to guide patient therapy, inform epidemiological studies, and track rates of antifungal drug resistance. There are three methods that have been standardized by standards development organizations: broth dilution, disk diffusion, and azole agar screening for Aspergillus Other commonly used methods include gradient diffusion and the use of rapid automated instruments. Novel methodologies for susceptibility testing are in development. It is important for laboratories to consider not only the method of testing but also the interpretation (or lack thereof) of in vitro data.
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Dannaoui E, Espinel-Ingroff A. Antifungal Susceptibly Testing by Concentration Gradient Strip Etest Method for Fungal Isolates: A Review. J Fungi (Basel) 2019; 5:jof5040108. [PMID: 31766762 PMCID: PMC6958406 DOI: 10.3390/jof5040108] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 11/13/2019] [Accepted: 11/16/2019] [Indexed: 12/23/2022] Open
Abstract
Antifungal susceptibility testing is an important tool for managing patients with invasive fungal infections, as well as for epidemiological surveillance of emerging resistance. For routine testing in clinical microbiology laboratories, ready-to-use commercial methods are more practical than homemade reference techniques. Among commercially available methods, the concentration gradient Etest strip technique is widely used. It combines an agar-based diffusion method with a dilution method that determinates a minimal inhibitory concentration (MIC) in µg/mL. Many studies have evaluated the agreement between the gradient strip method and the reference methods for both yeasts and filamentous fungi. This agreement has been variable depending on the antifungal, the species, and the incubation time. It has also been shown that the gradient strip method could be a valuable alternative for detection of emerging resistance (non-wild-type isolates) as Etest epidemiological cutoff values have been recently defined for several drug-species combinations. Furthermore, the Etest could be useful for direct antifungal susceptibility testing on blood samples and basic research studies (e.g., the evaluation of the in vitro activity of antifungal combinations). This review summarizes the available data on the performance and potential use of the gradient strip method.
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Affiliation(s)
- Eric Dannaoui
- Paris-Descartes University, Faculty of Medicine, 75006 Paris, France
- APHP, European Georges Pompidou Hospital, Parasitology-Mycology Unit, Microbiology Department, 75015 Paris, France
- Correspondence: ; Tel.: +33-15-6093-948; Fax: +33-15-6092-446
| | - Ana Espinel-Ingroff
- Virginia Commonwealth University (VCU) Medical Center, Richmond, VA 23219, USA;
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Jenks JD, Spiess B, Buchheidt D, Hoenigl M. (New) Methods for Detection of Aspergillus fumigatus Resistance in Clinical Samples. CURRENT FUNGAL INFECTION REPORTS 2019; 13:129-136. [PMID: 31552129 PMCID: PMC6759225 DOI: 10.1007/s12281-019-00342-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
PURPOSE OF REVIEW The incidence of invasive aspergillosis has increased substantially over the past few decades, accompanied by a change in susceptibility patterns of Aspergillus fumigatus with increasing resistance observed against triazole antifungals, including voriconazole and isavuconazole, the most commonly used antifungal agents for the disease. Culture-based methods for determining triazole resistance are still the gold standard but are time consuming and lack sensitivity. We sought to provide an update on non-culture-based methods for detecting resistance patterns to Aspergillus. RECENT FINDINGS New molecular-based approaches for detecting triazole resistance to Aspergillus, real-time polymerase chain reaction (PCR) to detect mutations to the Cyp51A protein, have been developed which are able to detect most triazole-resistant A. fumigatus strains in patients with invasive aspergillosis. SUMMARY Over the last few years, a number of non-culture-based methods for molecular detection of Aspergillus triazole resistance have been developed that may overcome some of the limitations of culture. These molecular methods are therefore of high epidemiological and clinical relevance, mainly in immunocompromised patients with hematological malignancies, where culture has particularly limited sensitivity. These assays are now able to detect most triazole-resistant Aspergillus fumigatus strains. Given that resistance rates vary, clinical utility for these assays still depends on regional resistance patterns.
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Affiliation(s)
- Jeffrey D. Jenks
- Department of Medicine, University of California San Diego, San Diego, CA 92103, USA
| | - Birgit Spiess
- Department of Hematology and Oncology, Scientific Laboratory, University Hospital Mannheim, Heidelberg University, Pettenkoferstraße 22, 68169 Mannheim, Germany
| | - Dieter Buchheidt
- Department of Hematology and Oncology, Scientific Laboratory, University Hospital Mannheim, Heidelberg University, Pettenkoferstraße 22, 68169 Mannheim, Germany
| | - Martin Hoenigl
- Department of Medicine, University of California San Diego, San Diego, CA 92103, USA
- Section of Infectious Diseases and Tropical Medicine, Medical University of Graz, Graz, Austria
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Method-Dependent Epidemiological Cutoff Values for Detection of Triazole Resistance in Candida and Aspergillus Species for the Sensititre YeastOne Colorimetric Broth and Etest Agar Diffusion Methods. Antimicrob Agents Chemother 2018; 63:AAC.01651-18. [PMID: 30323038 DOI: 10.1128/aac.01651-18] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 10/03/2018] [Indexed: 11/20/2022] Open
Abstract
Although the Sensititre Yeast-One (SYO) and Etest methods are widely utilized, interpretive criteria are not available for triazole susceptibility testing of Candida or Aspergillus species. We collected fluconazole, itraconazole, posaconazole, and voriconazole SYO and Etest MICs from 39 laboratories representing all continents for (method/agent-dependent) 11,171 Candida albicans, 215 C. dubliniensis, 4,418 C. glabrata species complex, 157 C. guilliermondii (Meyerozyma guilliermondii), 676 C. krusei (Pichia kudriavzevii), 298 C. lusitaniae (Clavispora lusitaniae), 911 C. parapsilosis sensu stricto, 3,691 C. parapsilosis species complex, 36 C. metapsilosis, 110 C. orthopsilosis, 1,854 C. tropicalis, 244 Saccharomyces cerevisiae, 1,409 Aspergillus fumigatus, 389 A. flavus, 130 A. nidulans, 233 A. niger, and 302 A. terreus complex isolates. SYO/Etest MICs for 282 confirmed non-wild-type (non-WT) isolates were included: ERG11 (C. albicans), ERG11 and MRR1 (C. parapsilosis), cyp51A (A. fumigatus), and CDR2 and CDR1 overexpression (C. albicans and C. glabrata, respectively). Interlaboratory modal agreement was superior by SYO for yeast species and by the Etest for Aspergillus spp. Distributions fulfilling CLSI criteria for epidemiological cutoff value (ECV) definition were pooled, and we proposed SYO ECVs for S. cerevisiae and 9 yeast and 3 Aspergillus species and Etest ECVs for 5 yeast and 4 Aspergillus species. The posaconazole SYO ECV of 0.06 µg/ml for C. albicans and the Etest itraconazole ECV of 2 µg/ml for A. fumigatus were the best predictors of non-WT isolates. These findings support the need for method-dependent ECVs, as, overall, the SYO appears to perform better for susceptibility testing of yeast species and the Etest appears to perform better for susceptibility testing of Aspergillus spp. Further evaluations should be conducted with more Candida mutants.
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Sensibilidad in vitro de especies crípticas de Aspergillus fumigatus a isavuconazol, itraconazol y voriconazol mediante E-test. Rev Iberoam Micol 2018; 35:113-114. [DOI: 10.1016/j.riam.2017.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 07/04/2017] [Accepted: 10/23/2017] [Indexed: 11/21/2022] Open
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FUNGICIDAL AND INHIBITORY EFFECTS OF OF MONARDA FISTULOSA ESSENTIAL OIL AND EUGENOL AGAINST FUNGI OF ASPERGILLUS GENUS. WORLD OF MEDICINE AND BIOLOGY 2018. [DOI: 10.26724/2079-8334-2017-4-62-169-173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Denardi LB, Keller JT, de Azevedo MI, Oliveira V, Piasentin FB, Severo CB, Santurio JM, Alves SH. Comparison Between Etest and Broth Microdilution Methods for Testing Itraconazole-Resistant Aspergillus fumigatus Susceptibility to Antifungal Combinations. Mycopathologia 2017; 183:359-370. [PMID: 28994001 DOI: 10.1007/s11046-017-0208-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 10/02/2017] [Indexed: 11/30/2022]
Abstract
The checkerboard broth microdilution assay (BMD) is the most frequently used method for the in vitro evaluation of drug combinations. However, its use to evaluate the effect of antifungal drugs on filamentous fungi is sometimes associated with endpoint-reading difficulties, and different degrees of interaction are assigned to the same drug combination. We evaluated combinations of the azoles, itraconazole, posaconazole, and voriconazole, with the echinocandins, anidulafungin, caspofungin, and micafungin, against 15 itraconazole-resistant Aspergillus fumigatus clinical strains via the checkerboard BMD and Etest assay. Readings after 24 and 48 h, considering the two reading endpoints, the minimum inhibitory concentration (MIC) and minimum effective concentration (MEC), were performed for both methods. Our results showed that the correlation coefficients between the BMD and Etest methods were quite diverse to the drug combinations tested. The highest correlation coefficients of the Etest with the BMD assays (MEC and MIC reading) were the Etest-MIC reading at 24 h and the Etest-MEC reading at 48 h. Improvements in experimental conditions may increase the correlation between the two methods and ensure that Etest assay can be safely used in the evaluation of antifungal combinations against Aspergillus species.
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Affiliation(s)
- Laura Bedin Denardi
- Postgraduate Program in Pharmaceutical Sciences, Health Sciences Center, Federal University of Santa Maria, Santa Maria, RS, 97105-900, Brazil.
- Mycological Research Laboratory, Federal University of Santa Maria, UFSM, Santa Maria, RS, Brazil.
| | - Jéssica Tairine Keller
- Postgraduate Program in Pharmaceutical Sciences, Health Sciences Center, Federal University of Santa Maria, Santa Maria, RS, 97105-900, Brazil
- Mycological Research Laboratory, Federal University of Santa Maria, UFSM, Santa Maria, RS, Brazil
| | - Maria Isabel de Azevedo
- Postgraduate Program in Pharmacology, Health Sciences Center, Federal University of Santa Maria (UFSM), Santa Maria, RS, Brazil
- Mycological Research Laboratory, Federal University of Santa Maria, UFSM, Santa Maria, RS, Brazil
| | - Vanessa Oliveira
- Mycological Research Laboratory, Federal University of Santa Maria, UFSM, Santa Maria, RS, Brazil
| | - Fernanda Baldissera Piasentin
- Postgraduate Program in Pharmaceutical Sciences, Health Sciences Center, Federal University of Santa Maria, Santa Maria, RS, 97105-900, Brazil
- Mycological Research Laboratory, Federal University of Santa Maria, UFSM, Santa Maria, RS, Brazil
| | | | - Janio Morais Santurio
- Postgraduate Program in Pharmacology, Health Sciences Center, Federal University of Santa Maria (UFSM), Santa Maria, RS, Brazil
- Mycological Research Laboratory, Federal University of Santa Maria, UFSM, Santa Maria, RS, Brazil
| | - Sydney Hartz Alves
- Postgraduate Program in Pharmaceutical Sciences, Health Sciences Center, Federal University of Santa Maria, Santa Maria, RS, 97105-900, Brazil
- Mycological Research Laboratory, Federal University of Santa Maria, UFSM, Santa Maria, RS, Brazil
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Norton TS, Al Abdallah Q, Hill AM, Lovingood RV, Fortwendel JR. The Aspergillus fumigatus farnesyltransferase β-subunit, RamA, mediates growth, virulence, and antifungal susceptibility. Virulence 2017; 8:1401-1416. [PMID: 28489963 PMCID: PMC5711395 DOI: 10.1080/21505594.2017.1328343] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Post-translational prenylation mechanisms, including farnesylation and geranylgeranylation, mediate both subcellular localization and protein-protein interaction in eukaryotes. The prenyltransferase complex is an αβ heterodimer in which the essential α-subunit is common to both the farnesyltransferase and the geranylgeranyltransferase type-I enzymes. The β-subunit is unique to each enzyme. Farnesyltransferase activity is an important mediator of protein localization and subsequent signaling for multiple proteins, including Ras GTPases. Here, we examined the importance of protein farnesylation in the opportunistic fungal pathogen Aspergillus fumigatus through generation of a mutant lacking the farnesyltransferase β-subunit, ramA. Although farnesyltransferase activity was found to be non-essential in A. fumigatus, diminished hyphal outgrowth, delayed polarization kinetics, decreased conidial viability, and irregular distribution of nuclei during polarized growth were noted upon ramA deletion (ΔramA). Although predicted to be a target of the farnesyltransferase enzyme complex, we found that localization of the major A. fumigatus Ras GTPase protein, RasA, was only partially regulated by farnesyltransferase activity. Furthermore, the farnesyltransferase-deficient mutant exhibited attenuated virulence in a murine model of invasive aspergillosis, characterized by decreased tissue invasion and development of large, swollen hyphae in vivo. However, loss of ramA also led to a Cyp51A/B-independent increase in resistance to triazole antifungal drugs. Our findings indicate that protein farnesylation underpins multiple cellular processes in A. fumigatus, likely due to the large body of proteins affected by ramA deletion.
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Affiliation(s)
- Tiffany S Norton
- a Department of Microbiology and Immunology , University of South Alabama , Mobile , AL , USA
| | - Qusai Al Abdallah
- b Department of Clinical Pharmacy , University of Tennessee Health Science Center , Memphis , TN , USA
| | - Amy M Hill
- a Department of Microbiology and Immunology , University of South Alabama , Mobile , AL , USA
| | - Rachel V Lovingood
- a Department of Microbiology and Immunology , University of South Alabama , Mobile , AL , USA
| | - Jarrod R Fortwendel
- b Department of Clinical Pharmacy , University of Tennessee Health Science Center , Memphis , TN , USA
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James JE, Santhanam J, Lee MC, Wong CX, Sabaratnam P, Yusoff H, Tzar MN, Razak MFA. In Vitro Antifungal Susceptibility of Neoscytalidium dimidiatum Clinical Isolates from Malaysia. Mycopathologia 2016; 182:305-313. [DOI: 10.1007/s11046-016-0085-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 10/24/2016] [Indexed: 11/29/2022]
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Comparing Etest and Broth Microdilution for Antifungal Susceptibility Testing of the Most-Relevant Pathogenic Molds. J Clin Microbiol 2015. [PMID: 26202113 DOI: 10.1128/jcm.00925-15] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Invasive mold infections are life-threatening diseases for which appropriate antifungal therapy is crucial. Their epidemiology is evolving, with the emergence of triazole-resistant Aspergillus spp. and multidrug-resistant non-Aspergillus molds. Despite the lack of interpretive criteria, antifungal susceptibility testing of molds may be useful in guiding antifungal therapy. The standard broth microdilution method (BMD) is demanding and requires expertise. We assessed the performance of a commercialized gradient diffusion method (Etest method) as an alternative to BMD. The MICs or minimal effective concentrations (MECs) of amphotericin B, voriconazole, posaconazole, caspofungin, and micafungin were assessed for 290 clinical isolates of the most representative pathogenic molds (154 Aspergillus and 136 non-Aspergillus isolates) with the BMD and Etest methods. Essential agreements (EAs) within ±2 dilutions of ≥90% between the two methods were considered acceptable. EAs for amphotericin B and voriconazole were >90% for most potentially susceptible species. For posaconazole, the correlation was acceptable for Mucoromycotina but Etest MIC values were consistently lower for Aspergillus spp. (EAs of <90%). Excellent EAs were found for echinocandins with highly susceptible (MECs of <0.015 μg/ml) or intrinsically resistant (MECs of >16 μg/ml) strains. However, MEC determinations lacked consistency between methods for strains exhibiting mid-range MECs for echinocandins. We concluded that the Etest method is an appropriate alternative to BMD for antifungal susceptibility testing of molds under specific circumstances, including testing with amphotericin B or triazoles for non-Aspergillus molds (Mucoromycotina and Fusarium spp.). Additional study of molecularly characterized triazole-resistant Aspergillus isolates is required to confirm the ability of the Etest method to detect voriconazole and posaconazole resistance among Aspergillus spp.
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The molecular mechanism of azole resistance in Aspergillus fumigatus: from bedside to bench and back. J Microbiol 2015; 53:91-9. [PMID: 25626363 DOI: 10.1007/s12275-015-5014-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 01/13/2015] [Indexed: 10/24/2022]
Abstract
The growing use of immunosuppressive therapies has resulted in a dramatic increased incidence of invasive fungal infections (IFIs) caused by Aspergillus fumigatus, a common pathogen, and is also associated with a high mortality rate. Azoles are the primary guideline-recommended therapy agents for first-line treatment and prevention of IFIs. However, increased azole usage in medicinal and agricultural settings has caused azole-resistant isolates to repeatedly emerge in the environment, resulting in a significant threat to human health. In this review, we present and summarize current research on the resistance mechanisms of azoles in A. fumigatus as well as efficient susceptibility testing methods. Moreover, we analyze and discuss the putative clinical (bedside) indication of these findings from bench work.
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Gupta P, Khare V, Kumar D, Ahmad A, Banerjee G, Singh M. Comparative Evaluation of Disc Diffusion and E-test with Broth Micro-dilution in Susceptibility testing of Amphotericin B, Voriconazole and Caspofungin against Clinical Aspergillus isolates. J Clin Diagn Res 2015; 9:DC04-7. [PMID: 25737984 DOI: 10.7860/jcdr/2015/10467.5395] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 10/31/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND Clinical importance of Aspergillus has increased over the past few decades because of rise in immunosuppressive drugs and immune-modulating diseases. Antifungal susceptibility of Aspergillus is rarely performed by clinical laboratories because of lack of easier method. This study has investigated and compared susceptibility pattern of Aspergillus isolates by disc diffusion, E-test and broth micro-dilution for amphotericin B, voriconazole and caspofungin. MATERIALS AND METHODS Disk diffusion (DD) method of antifungal susceptibility (AFS) was evaluated for three different classes of antifungals: amphotericin B (AMB), voriconazole (VCZ) and caspofungin (CAS). Forty four clinical isolates of Aspergillus were selected; these included 34 A.fumigatus, 8 A.flavus and 2 A. terreus. AFS by DD and E-test was done on non-supplemented Mueller Hinton Agar (MHA) and was compared to Clinical Laboratory Standard Institute(CLSI) broth micro-dilution (BMD) method of AFS. RESULTS Disk diffusion method for amphotericin B showed 87.5% agreement while E-test showed 93.8% agreement with broth micro-dilution. The agreement with broth micro-dilution was similar for both disk diffusion and E-test in case of voriconazole (93.8%) and caspofungin (100%). 31.8% and 9.1% Aspergillus isolates were found to have amphotericin B and voriconazole MIC values above epidemiological cut off value (ECV) respectively. All isolates were within ECV for caspofungin. CONCLUSION CLSI method of DD promises to be easier, reproducible and cost effective method of susceptibility testing, but this method must be interpreted with caution in case of amphotericin B susceptibility testing. E-test correlates better than DD with BMD.
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Affiliation(s)
- Prashant Gupta
- Assistant Professor, Department of Microbiology, King George's Medical University , Lucknow, U.P, India
| | - Vineeta Khare
- Associate Professor, Department of Microbiology, Era's Lucknow Medical College , Sarfarajganj, Hardoi Road, U.P, India
| | - Deepak Kumar
- Resident Doctor, Department of Microbiology, King George's Medical University , Lucknow, U.P, India
| | - Abrar Ahmad
- Junior Research Fellow, Department of Microbiology, King George's Medical University , Lucknow, U.P, India
| | - Gopa Banerjee
- Professor, Department of Microbiology, King George's Medical University , Lucknow, U.P, India
| | - Mastan Singh
- Head of the Department, Department of Microbiology, King George's Medical University , Lucknow, U.P, India
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In vitro amphotericin B susceptibility of Malassezia pachydermatis determined by the CLSI broth microdilution method and Etest using lipid-enriched media. Antimicrob Agents Chemother 2014; 58:4203-6. [PMID: 24752258 DOI: 10.1128/aac.00091-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We determined the in vitro amphotericin B susceptibility of 60 Malassezia pachydermatis isolates by the CLSI broth microdilution method and the Etest using lipid-enriched media. All isolates were susceptible at MICs of ≤ 1 μg/ml, confirming the high activity of amphotericin B against this yeast species. Overall, the essential agreement between the tested methods was high (80% and 96.7% after 48 h and 72 h, respectively), and all discrepancies were regarded as nonsubstantial.
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Keratitis caused by Aspergillus pseudotamarii. Med Mycol Case Rep 2013; 2:91-4. [PMID: 24432226 DOI: 10.1016/j.mmcr.2013.04.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 04/05/2013] [Accepted: 04/05/2013] [Indexed: 11/22/2022] Open
Abstract
A male patient presented with complaints of redness, pain and defective vision in the left eye. The infiltrate healed completely after two weeks of topical natamycin administration. A polyphasic approach was used to identify the isolate as Aspergillus pseudotamarii, which produced aflatoxins in inducing medium.
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Al-Wathiqi F, Ahmad S, Khan Z. Molecular identification and antifungal susceptibility profile of Aspergillus flavus isolates recovered from clinical specimens in Kuwait. BMC Infect Dis 2013; 13:126. [PMID: 23496810 PMCID: PMC3599693 DOI: 10.1186/1471-2334-13-126] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 02/26/2013] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Within the genus Aspergillus, A. flavus is the second most important species of clinical significance. It is predominantly associated with infections involving sinuses, eye and skin, mostly in geographic regions with hot and arid climate, including the Middle East. Recent reports on emergence of resistance to triazoles among Aspergillus spp. is a cause of concern for treatment of patients with invasive aspergillosis. In this study we present data on genetic characterization and antifungal susceptibility profile of clinical and environmental isolates of A. flavus. METHODS Ninety-nine Aspergillus section Flavi isolates, originating from clinical (n=92) and environmental (n=7) sources, initially identified by morphological characteristics, were analyzed by partial sequencing of β-tubulin and calmodulin gene fragments and their susceptibilities to six antifungal agents was determined by Etest on RPMI1640 and Muller-Hinton agar media. Etest minimum inhibitory concentrations (MICs) of amphotericin B and voriconazole were also compared with zone of inhibition diameters obtained by disc diffusion test on RPMI agar medium. RESULTS The identity of all clinical and environmental isolates was confirmed as A. flavus species by combined analysis of β-tubulin and calmodulin genes. The mean MIC90 (μg/ml) values on RPMI medium for amphotericin B, voriconazole, posaconazole, anidulafungin, micafungin and caspofungin were 3, 0.25, 0.25, 0.002, 0.002 and 0.032, respectively. No environmental isolate exhibited MIC value of >2 μg/ml for amphotericin B. For clinical isolates, the zone of inhibition diameters for amphotericin B and voriconazole ranged from 7-16 mm and 24-34 mm, respectively. Linear regression analysis between Etest MIC values and disk diffusion diameters revealed a significant inverse correlation with amphotericin B (p <0.001) and voriconazole (p<0.003). CONCLUSIONS The β-tubulin and calmodulin gene sequences confirmed that all 92 clinical isolates identified phenotypically belonged to A. flavus taxon, thus suggesting that the other species within Aspergillus section Flavi are of little clinical significance. Triazoles and echinocandins showed very good in vitro activity against the A. flavus, however, 10% clinical isolates showed MICs of >2 μg/ml for amphotericin B.
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Affiliation(s)
- Faten Al-Wathiqi
- Department of Microbiology, Faculty of Medicine, Kuwait University, P. O. Box 24923, 13110, Safat, Kuwait
| | - Suhail Ahmad
- Department of Microbiology, Faculty of Medicine, Kuwait University, P. O. Box 24923, 13110, Safat, Kuwait
| | - Ziauddin Khan
- Department of Microbiology, Faculty of Medicine, Kuwait University, P. O. Box 24923, 13110, Safat, Kuwait
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Hoenigl M, Aspeck E, Valentin T, Heiling B, Seeber K, Krause R, Stammberger H, Beham A, Buzina W. Sinusitis and frontal brain abscess in a diabetic patient caused by the basidiomycete Schizophyllum commune: case report and review of the literature. Mycoses 2013; 56:389-93. [PMID: 23331262 DOI: 10.1111/myc.12040] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Martin Hoenigl
- Section of Infectious Diseases, Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
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Susceptibility testing of Aspergillus niger strains isolated from poultry to antifungal drugs--a comparative study of the disk diffusion, broth microdilution (M 38-A) and Etest methods. Pol J Vet Sci 2012; 15:125-33. [PMID: 22708367 DOI: 10.2478/v10181-011-0123-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The aim of this study was to determine the sensitivity of Aspergillus niger strains isolated from birds to available antifungal drugs using different in vitro assays--classical disk diffusion, Etest and broth microdilution NCCLS/CLSI M 38-A. The study material consisted of about 2.000 swabs and samples from different species of birds. A. niger (n=10) was accounted for 6.81% of the total pool of strains isolated. Determinations were made for 13 antifungal drugs using the disk diffusion method. The A. niger exhibited high susceptibility to enilconazole, terbinafine, voriconazole, tioconazole and ketoconazole, low susceptibility to clotrimazole, miconazole and nystatin, and resistance to amphotericin B, itraconazole, pimaricin, fluconazole and 5-fluorocytosine. Minimum inhibitory concentration (MIC) was determined for 9 antifungal drugs using the micromethod of duplicate serial dilutions in a liquid medium. A. niger strains were most susceptible to enilconazole and voriconazole. MIC ranged from 0.0625 to 0.5 microg/ml for enilconazole, with MIC90-0.5 microg/ml and MIC50-0.125 microg/ml. The corresponding values for voriconazole were 0.25-1 microg/ml, 1 microg/ml and 0.5 microg/ml. MIC for amphotericin B and terbinafine ranged from 0.5 to 4 microg/ml, while the values for the remaining drugs were highly varied. MIC was measured by the gradient diffusion method using Etest for 5 antifungal drugs: amphotericin B, fluconazole, itraconazole, ketoconazole and voriconazole. By far the highest susceptibility was obtained in the case of voriconazole, with MIC ranging from 0.0625 to 1 microg/ml. MIC for amphotericin B ranged from 0.25 to 4 microg/ml, for itraconazole and ketoconazole ranging from 0.5 to 16 microg/ml. Methods available for this purpose are not always applicable in field conditions. The present results indicate that the Etest technique, due to its high percentage of agreement with the M 38-A microdilution method, should find application in medical and veterinary practice.
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Resistance to voriconazole due to a G448S substitution in Aspergillus fumigatus in a patient with cerebral aspergillosis. J Clin Microbiol 2012; 50:2531-4. [PMID: 22573589 DOI: 10.1128/jcm.00329-12] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A voriconazole-resistant isolate of Aspergillus fumigatus was recovered from an immunocompetent patient receiving long-term antifungal therapy for cerebral aspergillosis. A G448S amino acid substitution in the azole target (Cyp51A) was identified as the cause of the resistance phenotype. This article describes the first isolation of a voriconazole-resistant A. fumigatus isolate from an immunocompetent patient in Spain.
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Colosi IA, Faure O, Dessaigne B, Bourdon C, Lebeau B, Colosi HA, Pelloux H. Susceptibility of 100 filamentous fungi: comparison of two diffusion methods, Neo-Sensitabs and E-test, for amphotericin B, caspofungin, itraconazole, voriconazole and posaconazole. Med Mycol 2011; 50:378-85. [PMID: 21981028 DOI: 10.3109/13693786.2011.616543] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We compared the E-test method to that of the Neo-Sensitabs tablet diffusion assay for evaluating the in vitro susceptibility of 100 clinical isolates of filamentous fungi (Aspergillus spp., Fusarium spp., Scedosporium spp., zygomycetes and other molds) to amphotericin B, itraconazole, voriconazole, caspofungin, and posaconazole. We determined the categorical agreement level between E-test minimum inhibitory concentrations (MIC) and tablet end-points, as opposed to the following disagreement parameters: very major error - resistant parameter (R) in E-test and susceptible (S) in tablet; major error - S by E-test and R by tablet; minor error - shifts between S and susceptible dose-dependent (S-DD) or S-DD and R. We also performed linear regression analyses and computed Pearson's correlation coefficients (R values) between the log transforms of MICs and the inhibition zone diameters of the five studied antifungal agents. For itraconazole we obtained 97% categorical agreement and R = -0.727. Categorical agreement for caspofungin and voriconazole was 96% and R =-0.821 and R = -0.789, respectively. For posaconazole the categorical agreement was 94% and R =-0.743. Amphotericin B exhibited a lower degree of agreement (76%, R = -0.672), especially in studies of Aspergillus spp. Our results suggest a potential value of the Neo-Sensitabs assay for in vitro susceptibility testing of molds to itraconazole, voriconazole, caspofungin and posaconazole, while amphotericin B exhibited an overall lower degree of agreement.
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Affiliation(s)
- Ioana A Colosi
- Iuliu Haţieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania.
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Pemán J, Salavert M, Cantón E, Jarque I, Romá E, Zaragoza R, Viudes Á, Gobernado M. Voriconazole in the management of nosocomial invasive fungal infections. Ther Clin Risk Manag 2011; 2:129-58. [PMID: 18360588 PMCID: PMC1661660 DOI: 10.2147/tcrm.2006.2.2.129] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Voriconazole is a new triazole developed for the treatment of life-threatening fungal infections. The drug is available for both oral and intravenous administration; the oral formulation has excellent bioavailability. The side-effect profile of voriconazole presents an acceptable safety and tolerability spectrum: transient visual disturbances, liver enzyme abnormalities, and skin rashes are the most frequently reported side effects but rarely lead to discontinuation. The potential for drug–drug interactions is high, because of its extensive hepatic metabolism. Careful attention to dosage is required, and serum levels and the effects of interacting drugs should be monitored. Review of 25 470 isolates of yeasts and 3216 isolates of filamentous fungi showed voriconazole to have broad-spectrum activity against pathogenic yeasts including intrinsically fluconazole-resistant isolates such as Candida krusei, dimorphic fungi, and opportunistic moulds like Aspergillus spp, amphotericin-B-resistant Aspergillus terreus, Fusarium spp, and Scedosporium apiospermum. It displays excellent clinical efficacy in patients with fluconazole-resistant and -susceptible Candida infections, invasive bone and central nervous system aspergillosis, and various refractory fungal infections. Voriconazole has been approved by the US Food and Drug Administration and by the European Medicines Agency for the treatment of invasive aspergillosis, serious infections caused by Fusarium and S. apiospermum, fluconazole-resistant invasive Candida infections, and candidemia in nonneutropenic patients.
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Affiliation(s)
- Javier Pemán
- Microbiology Department, Hospital Universitario La FeValencia, Spain
| | - Miguel Salavert
- Infectious Diseases Unit, Hospital Universitario La FeValencia, Spain
| | - Emilia Cantón
- Experimental Microbiology Unit, Hospital Universitario La FeValencia, Spain
| | - Isidro Jarque
- Hematology Department, Hospital Universitario La FeValencia, Spain
| | - Eva Romá
- Pharmacy Department, Hospital Universitario La FeValencia, Spain
| | - Rafael Zaragoza
- Intensive Care Unit, Hospital Universitario Dr. PesetValencia, Spain
| | | | - Miguel Gobernado
- Microbiology Department, Hospital Universitario La FeValencia, Spain
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Molecular typing and in-vitro activity of azoles against clinical isolates of Aspergillus fumigatus and A. niger in Japan. J Infect Chemother 2011; 17:483-6. [DOI: 10.1007/s10156-010-0202-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 12/07/2010] [Indexed: 10/18/2022]
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Chavez J, Rivas P, Cortés J, Cuervo S, Sánchez R, Parra C. Sensibilidad in vitro de hongos miceliales de aislamientos clínicos en pacientes con cáncer en el Instituto Nacional de Cancerología ESE. INFECTIO 2010. [DOI: 10.1016/s0123-9392(10)70129-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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van de Sande WWJ, Tavakol M, van Vianen W, Bakker-Woudenberg IAJM. The effects of antifungal agents to conidial and hyphal forms of Aspergillus fumigatus. Med Mycol 2010; 48:48-55. [PMID: 20055743 DOI: 10.3109/13693780802713497] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Susceptibility testing for Aspergillus fumigatus is usually performed using a fungal conidial suspension. However, assessment of the susceptibility of fungal hyphae may be more relevant in attempting to mimic the fungal status in infected tissues. In the present study of 12 A. fumigatus clinical isolates and 1 ATCC strain, the antifungal susceptibilities of conidial suspensions, suspensions of hyphal fragments and of hyphal clumps were determined by the XTT-based broth susceptibility assay measuring decrease in fungal metabolic activity. Amphotericin B inhibited A. fumigatus conidia and hyphal fragments in a sharp concentration-dependent manner, with inhibitory concentrations (ICs) of 1 microg/ml for both fungal structures, whereas, hyphal clumps were inhibited at 8 microg/ml. Conidia and hyphal fragments were inhibited by the azoles itraconazole and voriconazole in a more gradual concentration-dependent manner, with ICs of 0.5 microg/ml for both structures with both agents. Hyphal clumps were not inhibited by the azoles at all. Caspofungin inhibited A. fumigatus in a moderate, neither sharp nor gradual, concentration-dependent manner. ICs for conidia were 128 microg/ml and inhibition in metabolic activity was not obtained for both hyphal growth forms. Antifungal susceptibility of conidia was also determined using the E-test in which it was found that the XTT assaygave comparable ICs for amphotericin B, itraconazole and voriconazole but not for caspofungin.
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Affiliation(s)
- Wendy W J van de Sande
- Department of Medical Microbiology & Infectious Diseases, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
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Caspofungin Etest endpoint for Aspergillus isolates shows poor agreement with the reference minimum effective concentration. J Clin Microbiol 2009; 48:479-82. [PMID: 20007389 DOI: 10.1128/jcm.01677-09] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Clinical and Laboratory Standards Institute (CLSI) M38-A2 reference broth microdilution (BMD) method for the antifungal susceptibility testing of filamentous fungi now includes guidelines for testing echinocandin activity using the minimum effective concentration (MEC) as the endpoint measurement. In this study, we compared the caspofungin Etest MIC on RPMI agar and Mueller-Hinton agar (supplemented with glucose and methylene blue [MGM]) to the BMD MEC for 345 clinical Aspergillus isolates, including A. flavus, A. fumigatus, A. nidulans, A. niger, and A. terreus. The essential agreement (+/-1 log(2) dilution) of the Etest on MGM and RPMI agar with the reference BMD MEC was 18 and 26%, respectively. The geometric mean values for BMD MEC and MGM Etest were 0.137 and 0.024 microg/ml, respectively, and the geometric mean values for BMD and RPMI agar were 0.128 and 0.031 microg/ml, respectively. Comparatively, 91% of paired MGM and RPMI Etest results were within 2 log(2) dilutions of each other and consistently produced clearly defined endpoints. In conclusion, the caspofungin Etest MIC, like the BMD MEC, is a reproducible endpoint but is markedly lower than the reference BMD. In anticipation of susceptibility breakpoint assignments, optimization studies will be required to improve the concordance of these two assays so that the potential for underreporting echinocandin resistance in Aspergillus is mitigated.
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Comparison of assessment of oxygen consumption, Etest, and CLSI M38-A2 broth microdilution methods for evaluation of the susceptibility of Aspergillus fumigatus to posaconazole. Antimicrob Agents Chemother 2009; 53:4921-3. [PMID: 19704132 DOI: 10.1128/aac.00862-09] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Posaconazole MICs for 50 Aspergillus fumigatus isolates with distinct genotypes were determined by three methods. MICs were > or = 0.5 microg/ml for 5, 11, and 15 strains by the CLSI reference M38-A2, Etest (48-h), and oxygen consumption methods, respectively. The levels of categorical agreement between the results obtained by the CLSI method and those obtained by the oxygen consumption and Etest methods were 80 and 84%, respectively.
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Aktas E, Yigit N. Determination of antifungal susceptibility of Aspergillus spp. responsible for otomycosis by E-test method. J Mycol Med 2009. [DOI: 10.1016/j.mycmed.2009.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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In vitro activities of fluconazole, itraconazole and voriconazole against otomycotic fungal pathogens. J Laryngol Otol 2009; 123:978-81. [PMID: 19454132 DOI: 10.1017/s0022215109005489] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE To determine the causative pathogens of otomycosis, and to evaluate the in vitro activity of antifungal agents against these pathogens. MATERIALS AND METHODS A total of 96 fungal isolate were taken from 92 patients suspected of otomycosis. The in vitro activity of fluconazole, itraconazole and voriconazole against otomycotic pathogens was tested using the E-test method. RESULTS The most common pathogen was Aspergillus fumigatus (40.6 per cent), followed by A niger (35.4 per cent), A flavus (12.5 per cent) and Candida albicans (11.5 per cent). All Aspergillus species were found to be resistant to fluconazole (minimum inhibitory concentration > or =256 microg/ml). The mean minimum inhibitory concentrations of voriconazole for A fumigatus, A niger, A flavus and C albicans were significantly lower than those of itraconazole for the same pathogens. CONCLUSION This study found that the most common otomycotic fungal pathogen was A fumigatus, and that voriconazole had more potent in vitro activity than itraconazole against all Aspergillus species as well as against C albicans.
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Castro Méndez C, Carmen Serrano M, Valverde A, Pemán J, Almeida C, Martín-Mazuelos E. Comparison of E-Test®, disk diffusion and a modified CLSI broth microdilution (M 38-A) method forin vitrotesting of itraconazole, fluconazole and voriconazole against dermatophytes. Med Mycol 2008; 46:119-23. [DOI: 10.1080/13693780701670491] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Diekema DJ, Messer SA, Hollis RJ, Boyken LB, Tendolkar S, Kroeger J, Pfaller MA. Evaluation of Etest and disk diffusion methods compared with broth microdilution antifungal susceptibility testing of clinical isolates of Candida spp. against posaconazole. J Clin Microbiol 2007; 45:1974-7. [PMID: 17301284 PMCID: PMC1933029 DOI: 10.1128/jcm.02087-06] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We performed Etest, disk diffusion, and broth microdilution susceptibility testing of 2,171 clinical isolates of Candida spp. against posaconazole. By using provisional breakpoints for comparison purposes only, the categorical agreement between the agar-based methods and broth microdilution results ranged from 93 to 98%, with <1% very major errors. The essential agreement (within 2 well dilutions) between the Etest and broth microdilution methods was 94%. These agar-based methods hold promise as simple and reliable methods for determination of the posaconzole susceptibilities of Candida spp.
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Affiliation(s)
- Daniel J Diekema
- Department of Pathology, Roy J. and Lucille A. Carver College of Medicine and College of Public Health, University of Iowa, Iowa City, IA 52242, USA.
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Messer SA, Diekema DJ, Hollis RJ, Boyken LB, Tendolkar S, Kroeger J, Pfaller MA. Evaluation of disk diffusion and Etest compared to broth microdilution for antifungal susceptibility testing of posaconazole against clinical isolates of filamentous fungi. J Clin Microbiol 2007; 45:1322-4. [PMID: 17267623 PMCID: PMC1865846 DOI: 10.1128/jcm.02450-06] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We performed Etest, disk diffusion, and broth microdilution susceptibility testing of posaconazole against 146 clinical isolates of filamentous fungi. By using provisional breakpoints for comparison purposes only, categorical agreement between the results of the agar-based methods and those of broth microdilution were 96 to 98%, with no very major errors. These agar-based methods hold promise as simple and reliable methods for determining the posaconazole susceptibilities of filamentous fungi.
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Affiliation(s)
- Shawn A Messer
- University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242, USA
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Maschmeyer G, Haas A. Voriconazole: a broad spectrum triazole for the treatment of serious and invasive fungal infections. Future Microbiol 2006; 1:365-85. [PMID: 17661629 DOI: 10.2217/17460913.1.4.365] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
For many years, serious systemic fungal infections have been treated with amphotericin B or narrow-spectrum azole antifungals. These treatments have been effective in many patients, but are associated with tolerability or pharmacokinetic concerns, or suboptimal antifungal activity in some patient groups. Voriconazole is a second-generation triazole with an extended spectrum of activity offering the potential to treat life-threatening fungal infections. The drug is available for intravenous or oral administration and has been shown to be effective in invasive aspergillosis, fluconazole-susceptible and -resistant candidiasis, and infections caused by various other fungal pathogens, including some formerly refractory organisms. Voriconazole is generally well tolerated with transient visual disturbances, liver enzyme abnormalities and skin rashes being the most common adverse events reported, but these rarely lead to treatment discontinuation.
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Affiliation(s)
- Georg Maschmeyer
- Klinikum Ernst von Bergmann, Department of Hematology & Oncology, Potsdam, Germany.
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Salgado-Parreño FJ, Alcoba-Flórez J, Arias A, Moragues MD, Quindós G, Pontón J, Arévalo MP. In VitroActivities of Voriconazole and Five Licensed Antifungal Agents AgainstCandida dubliniensis:Comparison of CLSI M27-A2, Sensititre YeastOne, Disk Diffusion, and Etest Methods. Microb Drug Resist 2006; 12:246-51. [PMID: 17227209 DOI: 10.1089/mdr.2006.12.246] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We compared the in vitro activity of six antifungal agents against 62 isolates of Candida dubliniensis by the Clinical Laboratory Standards Institute (CLSI [formerly National Committee for the Clinical Laboratory Standards]) M27-A2, Sensititre YeastOne, disk diffusion, and Etest methods and we studied the effect of the time of reading. For the azoles, voriconazole was the most potent in vitro followed by fluconazole, ketoconazole, and itraconazole. All the isolates were susceptible to amphotericin B and flucytosine. The highest rate of resistance was obtained against itraconazole with a high number of isolates defined as susceptible dose-dependent. At 24 hr, 100% of the isolates were susceptible to ketoconazole, amphotericin B, and flucytosine, 98% susceptible to voriconazole and fluconazole, and 95% for itraconazole. At 48 hr, 100% of the isolates remained susceptible for flucytosine and amphotericin B, 95% for voriconazole, 93% for fluconazole, 90% for ketoconazole, and 82% for itraconazole. The agreement between the CLSI and the other methods was better at 24 than 48 hr.
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Affiliation(s)
- F J Salgado-Parreño
- Departamento de Medicina Preventiva y Salud Pública, Facultad de Medicina, Universidad de La Laguna, Tenerife, Spain
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Guinea J, Peláez T, Alcalá L, Bouza E. Correlation between the E test and the CLSI M-38 A microdilution method to determine the activity of amphotericin B, voriconazole, and itraconazole against clinical isolates of Aspergillus fumigatus. Diagn Microbiol Infect Dis 2006; 57:273-6. [PMID: 17141455 DOI: 10.1016/j.diagmicrobio.2006.09.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Revised: 09/04/2006] [Accepted: 09/07/2006] [Indexed: 11/23/2022]
Abstract
The in vitro activities of amphotericin B, itraconazole, and voriconazole against 283 clinical isolates of Aspergillus fumigatus were studied by comparing the E test method with the reference procedure NCCLS (CLSI) M-38A. The methods were considered to agree when the results of the MICs by E test were within +/-2 dilutions of the MICs obtained by CLSI M-38 A. Agreement of readings at 24, 48, and 72 h of incubation was as follows: amphotericin B: 4.2%, 98%, and 40.6%; itraconazole: 92.5%, 100%, and 89.9%; and voriconazole: 98.9%, 100%, and 99.7%. The correlation between methods to classify the strains as "susceptible" or "resistant" was very good for itraconazole and voriconazole after 48 h of incubation, but 23% of the strains were incorrectly classified by E test for amphotericin B. The E test is an efficacious method for antifungal susceptibility testing in A. fumigatus for itraconazole and voriconazole when the plates are read after 48 h of incubation. The use of the E test to study the activity of amphotericin B should be avoided.
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Affiliation(s)
- Jesús Guinea
- Clinical Microbiology and Infectious Diseases Department, Hospital General Universitario Gregorio Marañón, Universidad Complutense, Madrid, Spain.
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Gangwar M, Cole R, Ramani R, Sheehan DJ, Chaturvedi V. Application of fluorescent probes to study structural changes in Aspergillus fumigatus exposed to amphotericin B, itraconazole, and voriconazole. Mycopathologia 2006; 162:103-9. [PMID: 16897588 DOI: 10.1007/s11046-006-0040-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Accepted: 06/20/2006] [Indexed: 10/24/2022]
Abstract
The broad objective of this study was to document patterns of structural changes following antifungal treatment, and to determine any relationship with minimum inhibitory concentration (MIC) of an antifungal. Three clinical isolates of Aspergillus fumigatus, with high, intermediate, and low amphotericin B (AB), itraconazole (IZ), and voriconazole (VZ) MICs were studied in 24-well plates with cover slips. The fluorescent probes used were Calcofluor White (cell wall), propidium iodide (nucleus), and MitoTracker Green FM (mitochondria). Fluorescent microscopy as early as 3-h after exposure revealed that AB treated hyphae had intact cell wall with deformed mitochondria and nuclei while IZ and VZ treated hyphae revealed no intact cell wall, and deformation of mitochondria and nuclei. At 48 h, AB treated cells revealed rupture of hyphae and disintegration of mitochondria, and nuclei, IZ treated hyphae were swollen with disintegration of mitochondria, and nuclei while VZ treated hyphae showed rupture and disintegration of mitochondria and nuclei. The structural changes for the three strains studied were similar in fluorescent microscopy as long as the incubation time and their respective MICs were used. Thus, AB, IZ, and VZ induced gross organelle defects in A. fumigatus nuclei, mitochondria, and cell wall, which were consistent with respective MICs of antifungals used.
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Affiliation(s)
- Madhurama Gangwar
- Mycology Laboratory, Wadsworth Center, NYSDOH, 120 New Scotland Ave., Albany, NY 12208 - 2002, USA
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Espinel-Ingroff A. Comparison of three commercial assays and a modified disk diffusion assay with two broth microdilution reference assays for testing zygomycetes, Aspergillus spp., Candida spp., and Cryptococcus neoformans with posaconazole and amphotericin B. J Clin Microbiol 2006; 44:3616-22. [PMID: 16943356 PMCID: PMC1594793 DOI: 10.1128/jcm.01187-06] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We compared posaconazole M27-A2 and M38-A MICs to Etest and YeastOne MICs for 92 zygomycetes, 126 Aspergillus isolates, 110 Candida isolates, and Cryptococcus neoformans. Reference MICs were also correlated with inhibition zone diameters in millimeters (modified M44-A disk and Neo-Sensitabs tablet methods). Etest MICs were obtained on solidified (1.5% agar) RPMI 1640 (2% dextrose), and zone diameters were obtained on supplemented (2% glucose and 0.5 microg/ml methylene blue [for all isolates]) and nonsupplemented Mueller-Hinton (MH; molds only) agar. MICs and zone diameters were obtained between 16 and 72 h. The overall agreement (% MIC pairs within a three-dilution range) between reference posaconazole and YeastOne MICs was 98 to 100% at 16 to 24 h for zygomycetes and yeasts and 99% at 24 to 48 h for Aspergillus. The overall agreement was lower between reference posaconazole and Etest MICs (94 to 97%) and by both methods with amphotericin B for all species (95 to 99.3%). For yeasts, the correlation coefficient was similar between reference posaconazole MICs and either disk (R, 0.810) or tablet (R, 0.769) zone diameter at 24 h and was superior on MH agar for molds at 16 to 48 h (R, 0.804 and 0.799 for disk and tablet, respectively). For amphotericin B, the best correlation between reference MICs and zone diameters was observed at 16 to 48 h for molds on MH agar (R, 0.736 to 0.812 and 0.765 to 0.749 for disk and tablet, respectively) and at 48 h for yeasts (R, 0.681 and 0.503 for disk and tablet, respectively). These data suggest the potential value of these alternative broth dilution and agar diffusion methods for testing posaconazole and amphotericin B in the clinical laboratory against the species evaluated.
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Affiliation(s)
- A Espinel-Ingroff
- Division of Infectious Diseases, VCU Medical Center, 1101 East Marshall St., Sanger Hall Room 7-049, Richmond, VA 23298-0049, USA.
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49
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Alexander BD, Pfaller MA. Contemporary Tools for the Diagnosis and Management of Invasive Mycoses. Clin Infect Dis 2006. [DOI: 10.1086/504491] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Singh J, Rimek D, Kappe R. Intrinsic in vitro susceptibility of primary clinical isolates of Aspergillus fumigatus, Aspergillus terreus, Aspergillus nidulans, Candida albicans and Candida lusitaniae against amphotericin B. Mycoses 2006; 49:96-103. [PMID: 16466441 DOI: 10.1111/j.1439-0507.2006.01197.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A total of 60 clinical fungal isolates from patients without prior amphotericin B treatment and three control strains were evaluated for their intrinsic susceptibility to amphotericin B (AmB) using microdilution, Etest and disc diffusion assays, on three media each, Roswell Park Memorial Institute (RPMI) 1640, Antibiotic Medium 3 (AM3) and High Resolution Medium. The fungal strains included isolates of Aspergillus fumigatus (n = 10), Aspergillus terreus (n = 12), Aspergillus nidulans (n = 9), Candida albicans (n = 6) and Candida lusitaniae (n = 23). The A. terreus strains were significantly less susceptible to AmB than the A. fumigatus strains in all nine experimental settings (P-values ranging from 0.009 to <0.00001). The A. nidulans strains were equally susceptible to AmB as the A. fumigatus strains in seven of nine experimental settings and less susceptible in two (microdilution performed on RPMI and AM3, P = 0.01 and 0.007). The C. lusitaniae strains were equally susceptible to AmB as the C. albicans strains in seven of nine experimental settings and more susceptible in two (microdilution and Etest, both performed on AM3, P = 0.01 and 0.0002). Thus, we confirmed that A. terreus is intrinsically less susceptible to AmB than A. fumigatus. In contrast, nine German clinical isolates of Aspergillus nidulans were found equally susceptible to AmB as 10 isolates of A. fumigatus. Furthermore, we found 23 German clinical isolates of C. lusitaniae from patients without prior treatment with AmB equally susceptible to AmB as C. albicans.
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Affiliation(s)
- Jagpal Singh
- Department of Microbiology and Infectious Diseases, Haema Institute of Laboratory Medicine at the Helios Medical Center, Erfurt, Germany
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