Methods for Antifungal Susceptibility Testing of the <i>Cryptococcus neoformans</i>/<i>C. gattii</i> Complex: Strengths and Limitations

When method-dependent categorical endpoints are available, namely either BPs or ECVs, MICs could aid in selecting the best treatment agent(s). BPs can categorize an isolate as either susceptible or resistant while the ECVs/ECOFFs can distinguish the wild type (WT, no known resistance mechanisms) fro...

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Main Authors: Ana Espinel-Ingroff, Emilia Cantón
Format: Article
Language:English
Published: MDPI AG 2023-05-01
Series:Journal of Fungi
Subjects:
Online Access:https://www.mdpi.com/2309-608X/9/5/542
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author Ana Espinel-Ingroff
Emilia Cantón
author_facet Ana Espinel-Ingroff
Emilia Cantón
author_sort Ana Espinel-Ingroff
collection DOAJ
description When method-dependent categorical endpoints are available, namely either BPs or ECVs, MICs could aid in selecting the best treatment agent(s). BPs can categorize an isolate as either susceptible or resistant while the ECVs/ECOFFs can distinguish the wild type (WT, no known resistance mechanisms) from the Non-WT (NWT, harboring resistant mechanisms). Our literature review focused on the <i>Cryptococcus</i> species complex (SC) and the available methods and categorization endpoints. We also covered the incidence of these infections as well as the numerous <i>Cryptococcus neoformans</i> SC and <i>C. gattii</i> SC genotypes. The most important agents to treat cryptococcal infections are fluconazole (widely used), amphotericin B, and flucytosine. We provide data from the collaborative study that defined CLSI fluconazole ECVs for the most common cryptococcal species or genotypes and modes. EUCAST ECVs/ECOFFs are not yet available for fluconazole. We have summarized the incidence of cryptococccal infections (2000–2015) where fluconazole MICs were obtained by reference and commercial antifungal susceptibility tests. This occurrence is documented all over the world and those fluconazole MICs are mostly categorized by available CLSI ECVs/BPs as “resistant” instead of non-susceptible strains, including those by the commercial methods. As expected, the agreement between the CLSI and commercial methods is variable because SYO and Etest data could yield low/variable agreement (<90%) versus the CLSI method. Therefore, since BPs/ECVs are species and method dependent, why not gather sufficient MICs by commercial methods and define the required ECVs for these species?
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spelling doaj.art-f372a45bb8c041d082e2013ac9f23b332023-11-18T02:02:02ZengMDPI AGJournal of Fungi2309-608X2023-05-019554210.3390/jof9050542Methods for Antifungal Susceptibility Testing of the <i>Cryptococcus neoformans</i>/<i>C. gattii</i> Complex: Strengths and LimitationsAna Espinel-Ingroff0Emilia Cantón1VCU Medical Center, Richmond, VA 23298, USASevere Infection Research Group, Health Research Institute Hospital La Fe, 46026 Valencia, SpainWhen method-dependent categorical endpoints are available, namely either BPs or ECVs, MICs could aid in selecting the best treatment agent(s). BPs can categorize an isolate as either susceptible or resistant while the ECVs/ECOFFs can distinguish the wild type (WT, no known resistance mechanisms) from the Non-WT (NWT, harboring resistant mechanisms). Our literature review focused on the <i>Cryptococcus</i> species complex (SC) and the available methods and categorization endpoints. We also covered the incidence of these infections as well as the numerous <i>Cryptococcus neoformans</i> SC and <i>C. gattii</i> SC genotypes. The most important agents to treat cryptococcal infections are fluconazole (widely used), amphotericin B, and flucytosine. We provide data from the collaborative study that defined CLSI fluconazole ECVs for the most common cryptococcal species or genotypes and modes. EUCAST ECVs/ECOFFs are not yet available for fluconazole. We have summarized the incidence of cryptococccal infections (2000–2015) where fluconazole MICs were obtained by reference and commercial antifungal susceptibility tests. This occurrence is documented all over the world and those fluconazole MICs are mostly categorized by available CLSI ECVs/BPs as “resistant” instead of non-susceptible strains, including those by the commercial methods. As expected, the agreement between the CLSI and commercial methods is variable because SYO and Etest data could yield low/variable agreement (<90%) versus the CLSI method. Therefore, since BPs/ECVs are species and method dependent, why not gather sufficient MICs by commercial methods and define the required ECVs for these species?https://www.mdpi.com/2309-608X/9/5/542detection resistancecryptococcal isolatesECVsmutant detection<i>Cryptococcus</i> isolatescryptococcal species/genotypes
spellingShingle Ana Espinel-Ingroff
Emilia Cantón
Methods for Antifungal Susceptibility Testing of the <i>Cryptococcus neoformans</i>/<i>C. gattii</i> Complex: Strengths and Limitations
Journal of Fungi
detection resistance
cryptococcal isolates
ECVs
mutant detection
<i>Cryptococcus</i> isolates
cryptococcal species/genotypes
title Methods for Antifungal Susceptibility Testing of the <i>Cryptococcus neoformans</i>/<i>C. gattii</i> Complex: Strengths and Limitations
title_full Methods for Antifungal Susceptibility Testing of the <i>Cryptococcus neoformans</i>/<i>C. gattii</i> Complex: Strengths and Limitations
title_fullStr Methods for Antifungal Susceptibility Testing of the <i>Cryptococcus neoformans</i>/<i>C. gattii</i> Complex: Strengths and Limitations
title_full_unstemmed Methods for Antifungal Susceptibility Testing of the <i>Cryptococcus neoformans</i>/<i>C. gattii</i> Complex: Strengths and Limitations
title_short Methods for Antifungal Susceptibility Testing of the <i>Cryptococcus neoformans</i>/<i>C. gattii</i> Complex: Strengths and Limitations
title_sort methods for antifungal susceptibility testing of the i cryptococcus neoformans i i c gattii i complex strengths and limitations
topic detection resistance
cryptococcal isolates
ECVs
mutant detection
<i>Cryptococcus</i> isolates
cryptococcal species/genotypes
url https://www.mdpi.com/2309-608X/9/5/542
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