Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Jun 15;67(6):e0171622.
doi: 10.1128/aac.01716-22. Epub 2023 May 10.

Evaluation of Gradient Concentration Strips for Detection of Terbinafine Resistance in Trichophyton spp

Anne-Laure Bidaud  1   2 , Alicia Moreno-Sabater  3   4 , Anne-Cécile Normand  5 , Geneviève Cremer  6 , Françoise Foulet  7   8 , Sophie Brun  9   10 , Aymen Ayachi  11 , Sébastien Imbert  12 , Anuradha Chowdhary  13   14 , Eric Dannaoui  1   2   8
Affiliations

Evaluation of Gradient Concentration Strips for Detection of Terbinafine Resistance in Trichophyton spp

Anne-Laure Bidaud et al. Antimicrob Agents Chemother. .

Abstract

The number of dermatophytosis cases resistant to terbinafine is increasing all over the world. Therefore, there is a need for antifungal susceptibility testing of dermatophytes for better management of the patients. In the present study, we have evaluated a gradient test (GT) method for testing the susceptibility of dermatophytes to terbinafine. MIC values to terbinafine determined by the EUCAST reference technique and by gradient test were compared for 79 Trichophyton spp. isolates. Overall, MICs were lower with gradient test (MIC50 of 0.002 μg/mL) than with EUCAST (MIC50 of 0.016 μg/mL). Good categorical agreement (>90%) between the 2 techniques was obtained but the essential agreement was variable depending on the batch of gradient test.

Keywords: EUCAST; Etest; Trichophyton; antifungal susceptibility testing; antifungals; terbinafine.

PubMed Disclaimer

Conflict of interest statement

The authors declare a conflict of interest. During the past 5 years, Eric Dannaoui has received research grants from MSD and Gilead; travel grants from Gilead, MSD, Pfizer, and Astellas; and speaker's fees from Gilead, MSD, and Astellas.

Figures

FIG 1
FIG 1
Examples of inhibition patterns obtained with gradient test (left panels) and EUCAST (right panels) for terbinafine-susceptible isolates BCL 173 (A) and PSL 42 (B) and for terbinafine-resistant isolates VPCI 1983/P/16 (C) and BOD 1 (D). Inhibition curves were obtained by non-linear curve fitting. Dots represent experimental values.
FIG 2
FIG 2
Comparison of MICs obtained with batch A and batch B of the gradient test for susceptible and resistant isolates.
See this image and copyright information in PMC

References

    1. Bongomin F, Gago S, Oladele RO, Denning DW. 2017. Global and multi-national prevalence of fungal diseases-estimate precision. JoF 3:57. doi: 10.3390/jof3040057. - DOI - PMC - PubMed
    1. Krishnan-Natesan S. 2009. Terbinafine: a pharmacological and clinical review. Expert Opin Pharmacother 10:2723–2733. doi: 10.1517/14656560903307462. - DOI - PubMed
    1. Ebert A, Monod M, Salamin K, Burmester A, Uhrlaß S, Wiegand C, Hipler U-C, Krüger C, Koch D, Wittig F, Verma SB, Singal A, Gupta S, Vasani R, Saraswat A, Madhu R, Panda S, Das A, Kura MM, Kumar A, Poojary S, Schirm S, Gräser Y, Paasch U, Nenoff P. 2020. Alarming India-wide phenomenon of antifungal resistance in dermatophytes: a multicentre study. Mycoses 63:717–728. doi: 10.1111/myc.13091. - DOI - PubMed
    1. Singh A, Masih A, Khurana A, Singh PK, Gupta M, Hagen F, Meis JF, Chowdhary A. 2018. High terbinafine resistance in Trichophyton interdigitale isolates in Delhi, India harbouring mutations in the squalene epoxidase gene. Mycoses 61:477–484. doi: 10.1111/myc.12772. - DOI - PubMed
    1. Singh S, Chandra U, Anchan VN, Verma P, Tilak R. 2020. Limited effectiveness of four oral antifungal drugs (fluconazole, griseofulvin, itraconazole and terbinafine) in the current epidemic of altered dermatophytosis in India: results of a randomized pragmatic trial. Br J Dermatol 183:840–846. doi: 10.1111/bjd.19146. - DOI - PubMed