Multicentre validation of a EUCAST method for the antifungal susceptibility testing of microconidia-forming dermatophytes

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00098892%3A_____%2F20%3AN0000062" target="_blank" >RIV/00098892:_____/20:N0000062 - isvavai.cz</a>

Result on the web

<a href="https://academic.oup.com/jac/article-abstract/75/7/1807/5821486?redirectedFrom=fulltext" target="_blank" >https://academic.oup.com/jac/article-abstract/75/7/1807/5821486?redirectedFrom=fulltext</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1093/jac/dkaa111" target="_blank" >10.1093/jac/dkaa111</a>

Result language

angličtina

Original language name

Multicentre validation of a EUCAST method for the antifungal susceptibility testing of microconidia-forming dermatophytes

Original language description

Objectives: Terbinafine resistance is increasingly reported in Trichophyton, rendering susceptibility testing particularly important in non-responding cases. We performed a multicentre evaluation of six EUCAST-based methods. Methods: Ten laboratories susceptibility tested terbinafine, itraconazole, voriconazole and amorolfine against a blinded panel of 38 terbinafine WT and target gene mutant isolates. E.Def 9.3.1 modifications included: medium with/without addition of chloramphenicol and cycloheximide (CC), incubation at 25°C to 28°C for 5-7 days and three MIC endpoints [visually and spectrophotometrically (90%/50% inhibition)], generating 7829 MICs. Quality control (QC) strains were Aspergillus flavus ATCC 204304 and CNM-CM1813. Eyeball, ECOFFinder (where ECOFF stands for epidemiological cut-off) and derivatization WT upper limits (WT-ULs), very major errors (VMEs; mutants with MICs ≤WT-ULs) and major errors (MEs; WT isolates with MICs >WT-ULs) were determined. Results: MICs fell within the QC ranges for ATCC 204304/CNM-CM1813 for 100%/96% (voriconazole) and 84%/84% (itraconazole), respectively. Terbinafine MICs fell within 0.25-1 mg/L for 96%/92%, suggesting high reproducibility. Across the six methods, the number of terbinafine MEs varied from 2 to 4 (2.6%-5.2%) for Trichophyton rubrum and from 0 to 2 (0%-2.0%) for Trichophyton interdigitale. Modes for WT and mutant populations were at least seven 2-fold dilutions apart in all cases. Excluding one I121M/V237I T. rubrum mutant and two mixed WT/mutant T. interdigitale specimens, the numbers of VMEs were as follows: T. rubrum: CC visual, 1/67 (1.5%); CC spectrophotometric 90% inhibition, 3/59 (5.1%); and CC spectrophotometric 50% inhibition, 1/67 (1.5%); and T. interdigitale: none. Voriconazole and amorolfine MICs were quite uniform, but trailing growth complicated determination of itraconazole visual and spectrophotometric 90% inhibition MIC. Conclusions: Although none of the laboratories was experienced in dermatophyte testing, error rates were low. We recommend the CC spectrophotometric 50% inhibition method and provide QC ranges and WT-ULs for WT/non-WT classification.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10606 - Microbiology

Project

<a href="/en/project/NV17-31269A" target="_blank" >NV17-31269A: Molecular epidemiology and identification improvement of dermatophytes in the Czech Republic</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2020

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Journal of Antimicrobial Chemotherapy

ISSN

0305-7453

e-ISSN

1460-2091

Volume of the periodical

75

Issue of the periodical within the volume

7

Country of publishing house

GB - UNITED KINGDOM

Number of pages

13

Pages from-to

1807-1819

UT code for WoS article

000562411300021

EID of the result in the Scopus database

2-s2.0-85086747650