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Should Etest MICs for Yeasts Be Categorized by Reference (BPs/ECVs) or by Etest (ECVs) Cutoffs as Determinants of Emerging Resistance?

  • Clinical Mycology Lab Issues (S Cordoba, Section Editor)
  • Published:
Current Fungal Infection Reports Aims and scope Submit manuscript

Abstract

Purpose of Review

To summarize the potential clinical usefulness of available Etest echinocandin and amphotericin B ECVs in identifying non-WT-type yeasts.

Recent Findings

In lieu of breakpoints (predictors of clinical response), Etest echinocandin, triazoles, and amphotericin B ECVs have been recently established for certain Candida spp. Reference BPs are only available for echinocandins and triazoles and some Candida spp. The categorical agreement between Etest and reference MICs was mostly evaluated before adjustment of CLSI triazole/echinocandin BPs to current values or using various amphotericin B cutoffs.

Summary

Etest anidulafungin ECVs for C. albicans (0.015 μg/mL), C. glabrata (0.03 μg/ml), C. tropicalis (0.03 μg/mL), and C. krusei (0.06 μg/mL) categorized 65/69 (93%) as non-wild-type isolates (harboring Fks1p/Fks2p mutations). The amphotericin B Etest ECV for C. lusitaniae (0.5 μg/mL) classified 8/9 as non-wild-type and 38/39 (97%) as wild-type isolates, respectively. Similar results were reported for C. glabrata, C. parapsilosis, and Cryptococcus neoformans. Further evaluation is warranted, especially for amphotericin B.

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Acknowledgments

We thank Dr. John Turnidge, University of Adelaide, Adelaide, Australia, for his collaboration on the definition of the amphotericin B Etest ECV for C. lusitaniae.

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Authors and Affiliations

  1. VCU Medical Center, Richmond, VA, USA

    A. Espinel-Ingroff

  2. Faculté de Médecine, APHP, Hôpital Européen Georges Pompidou, Unité de Parasitologie-Mycologie, Service de Microbiologie, Université Paris-Descartes, Paris, France

    E. Dannaoui

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Correspondence to A. Espinel-Ingroff.

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Conflict of Interest

Eric Dannaoui reports grants from Gilead, grants from MSD, personal fees from Pfizer, personal fees from Astellas, travel grant from MSD, and travel grant from Pfizer outside the submitted work. Ana Espinel-Ingroff declares no conflicts of interest relevant to this manuscript.

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Espinel-Ingroff, A., Dannaoui, E. Should Etest MICs for Yeasts Be Categorized by Reference (BPs/ECVs) or by Etest (ECVs) Cutoffs as Determinants of Emerging Resistance?. Curr Fungal Infect Rep 14, 120–129 (2020). https://doi.org/10.1007/s12281-020-00378-3

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