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A Pragmatic Approach to Susceptibility Classification of Yeasts without EUCAST Clinical Breakpoints

EUCAST has established clinical breakpoints for the six most common Candida species and Cryptococcus neoformans but not for less common yeasts because sufficient evidence is lacking. Consequently, the question “How to interpret the MIC?” for other yeasts often arises. We propose a pragmatic classifi...

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Autores principales: Astvad, Karen Marie Thyssen, Arikan-Akdagli, Sevtap, Arendrup, Maiken Cavling
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8877802/
https://www.ncbi.nlm.nih.gov/pubmed/35205895
http://dx.doi.org/10.3390/jof8020141
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author Astvad, Karen Marie Thyssen
Arikan-Akdagli, Sevtap
Arendrup, Maiken Cavling
author_facet Astvad, Karen Marie Thyssen
Arikan-Akdagli, Sevtap
Arendrup, Maiken Cavling
author_sort Astvad, Karen Marie Thyssen
collection PubMed
description EUCAST has established clinical breakpoints for the six most common Candida species and Cryptococcus neoformans but not for less common yeasts because sufficient evidence is lacking. Consequently, the question “How to interpret the MIC?” for other yeasts often arises. We propose a pragmatic classification for amphotericin B, anidulafungin, fluconazole, and voriconazole MICs against 30 different rare yeasts. This classification takes advantage of MIC data for more than 4000 isolates generated in the EUCAST Development Laboratory for Fungi validated by alignment to published EUCAST MIC data. The classification relies on the following two important assumptions: first, that when isolates are genetically related, pathogenicity and intrinsic susceptibility patterns may be similar; and second, that even if species are not phylogenetically related, the rare yeasts will likely respond to therapy, provided the MIC is comparable to that against wild-type isolates of more prevalent susceptible species because rare yeasts are most likely “rare” due to a lower pathogenicity. In addition, the treatment recommendations available in the current guidelines based on the in vivo efficacy data and clinical experience are taken into consideration. Needless to say, it is of utmost importance (a) to ascertain that the species identification is correct (using MALDI-TOF or sequencing), and (b) to re-test the isolate once or twice to confirm that the MIC is representative for the isolate (because of the inherent variability in MIC determinations). We hope this pragmatic guidance is helpful until evidence-based EUCAST breakpoints can be formally established.
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spelling pubmed-88778022022-02-26 A Pragmatic Approach to Susceptibility Classification of Yeasts without EUCAST Clinical Breakpoints Astvad, Karen Marie Thyssen Arikan-Akdagli, Sevtap Arendrup, Maiken Cavling J Fungi (Basel) Review EUCAST has established clinical breakpoints for the six most common Candida species and Cryptococcus neoformans but not for less common yeasts because sufficient evidence is lacking. Consequently, the question “How to interpret the MIC?” for other yeasts often arises. We propose a pragmatic classification for amphotericin B, anidulafungin, fluconazole, and voriconazole MICs against 30 different rare yeasts. This classification takes advantage of MIC data for more than 4000 isolates generated in the EUCAST Development Laboratory for Fungi validated by alignment to published EUCAST MIC data. The classification relies on the following two important assumptions: first, that when isolates are genetically related, pathogenicity and intrinsic susceptibility patterns may be similar; and second, that even if species are not phylogenetically related, the rare yeasts will likely respond to therapy, provided the MIC is comparable to that against wild-type isolates of more prevalent susceptible species because rare yeasts are most likely “rare” due to a lower pathogenicity. In addition, the treatment recommendations available in the current guidelines based on the in vivo efficacy data and clinical experience are taken into consideration. Needless to say, it is of utmost importance (a) to ascertain that the species identification is correct (using MALDI-TOF or sequencing), and (b) to re-test the isolate once or twice to confirm that the MIC is representative for the isolate (because of the inherent variability in MIC determinations). We hope this pragmatic guidance is helpful until evidence-based EUCAST breakpoints can be formally established. MDPI 2022-01-30 /pmc/articles/PMC8877802/ /pubmed/35205895 http://dx.doi.org/10.3390/jof8020141 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Review
Astvad, Karen Marie Thyssen
Arikan-Akdagli, Sevtap
Arendrup, Maiken Cavling
A Pragmatic Approach to Susceptibility Classification of Yeasts without EUCAST Clinical Breakpoints
title A Pragmatic Approach to Susceptibility Classification of Yeasts without EUCAST Clinical Breakpoints
title_full A Pragmatic Approach to Susceptibility Classification of Yeasts without EUCAST Clinical Breakpoints
title_fullStr A Pragmatic Approach to Susceptibility Classification of Yeasts without EUCAST Clinical Breakpoints
title_full_unstemmed A Pragmatic Approach to Susceptibility Classification of Yeasts without EUCAST Clinical Breakpoints
title_short A Pragmatic Approach to Susceptibility Classification of Yeasts without EUCAST Clinical Breakpoints
title_sort pragmatic approach to susceptibility classification of yeasts without eucast clinical breakpoints
topic Review
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8877802/
https://www.ncbi.nlm.nih.gov/pubmed/35205895
http://dx.doi.org/10.3390/jof8020141
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