Updated EUCAST Clinical Breakpoints against Aspergillus, Implications for the Clinical Microbiology Laboratory.

Jesús Guinea

doi:10.3390/jof6040343

Abstract

Azole resistance poses a problem for the management of patients with invasive aspergillosis. Former species are in fact groups of closely related species (or complexes); cryptic species frequently show high antifungal resistance. The European Committee on Antimicrobial Susceptibility Testing (EUCAST) Definitive Document (E.Def) 9.3.2 includes guidelines for antifungal susceptibility testing on Aspergillus spp. and clinical breakpoints for amphotericin B, itraconazole, voriconazole, posaconazole, and isavuconazole against A. flavus, A. fumigatus, A. nidulans, A. niger, and A. terreus. New clinical breakpoints were released in February 2020 and one of the most relevant modifications was the definition of the new “susceptible, increased exposure” (formerly “intermediate”) category. Another relevant change was the adoption of the concept of area of technical uncertainty (ATU) that refers to problematic areas which involve uncertainty of susceptibility categorisation (e.g., when minimum inhibitory concentrations (MICs) for susceptible and resistant organisms overlap). To accommodate both the new “susceptible, increased exposure” category and the concept of ATU, MICs of azoles and amphotericin B that fall in the former “intermediate” category have been automatically categorized as either R (amphotericin B) or ATU (triazoles). Finally, EUCAST-AFST (Antifungal Susceptibility Testing) decided to adopt new breakpoints for less common species provided that the epidemiological cut-off value (ECOFF) is below or comparable to the breakpoint for the type species (A. fumigatus).

Highlights

Aspergillus spp. cause a variety of fungal-related conditions grouped under the term aspergillosis, including allergic manifestations, progressive chronic syndromes such as chronic pulmonary aspergillosis, and the threatening acute invasive infection [1]
Another relevant change was the adoption of the concept of area of technical uncertainty (ATU) that refers to problematic areas which involve uncertainty of susceptibility categorisation (e.g., when minimum inhibitory concentrations (MICs) for susceptible and resistant organisms overlap)
To accommodate both the new “susceptible, increased exposure” category and the concept of ATU, MICs of azoles and amphotericin B that fall in the former “intermediate” category have been automatically categorized as either R or ATU

Summary

Introduction

Aspergillus spp. cause a variety of fungal-related conditions grouped under the term aspergillosis, including allergic manifestations, progressive chronic syndromes such as chronic pulmonary aspergillosis, and the threatening acute invasive infection [1]. Aspergillus spp. and clinical breakpoints for amphotericin B, itraconazole, voriconazole, posaconazole, and isavuconazole against A. flavus, A. fumigatus, A. nidulans, A. niger, and A. terreus.

Results

Conclusion