Evaluation of the new Id-Fungi plates medium from Conidia for MALDI-TOF MS identification of filamentous fungi and comparison with conventional methods as identification tool for dermatophytes from nails, hair and skin samples.

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Evaluation of the new Id-Fungi plates medium from Conidia for MALDI-TOF MS identification of filamentous fungi and comparison with conventional methods as identification tool for dermatophytes from nails, hair and skin samples.

Mycoses. 2020 Aug 05;:

Authors: Rosalie S, Anne-Sophie H, Laurence S, Marie E, Rajae D, Caroline A, Marjorie S, Ludwig M, C├ęcile M, Jorge A, Marie-Pierre H

Abstract
OBJECTIVES: We first compare the efficiency of mould/dermatophytes identification by MALDI-TOF MS using a new medium called Id-Fungi plates (IDFP) from Conidia® and two different databases. For the second purpose, we evaluated a new version of the medium supplemented with cycloheximide, Id-Fungi plates Plus (IDFPC) for the direct inoculation of nails, hair and skin samples and compared the efficiency of MALDI-TOF MS identification of dermatophytes to classical methods based on culture and microscopy.
METHODS: A total of 71 strains have been cultured IDFP and Sabouraud gentamicin plates (SGC2) and were identified by MALDI-TOF MS. For the evaluation of the combination IDFPC/ MALDI-TOF MS as a method of identification for dermatophytes, 428 samples of hair nails and skin were cultivated in parallel on IDFPC and Sabouraud + cycloheximide medium (SAB-ACTI ).
RESULTS: For Aspergillus sp. and non-Aspergillus moulds, the best performances were obtained on IDFP after maximum 48h growth, following protein extraction. For dermatophytes, the best condition was using the IDFP at 72h, after extended direct deposit. Regarding the direct inoculation of nails, hair skin on IDFPC, 129/428 (30.1%) showed a positive culture against 150/428 (35%) on SAB-ACTI medium. Among the 129 positive strains the identification by MALDI-TOF MS was correct for 92/129 (71.4%).
CONCLUSION: The IDFP allows the generation of better spectra by MALDI-TOF MS compared to SGC2. It facilitates sampling and deposit. Regarding the use of IDFPC, this medium seems less sensitive than SAB-ACTI but among positive strains, the rate of correct identification, by MALDI-TOF MS is satisfactory.

PMID: 32757444 [PubMed – as supplied by publisher]

Source: Industry