Journal of Fungi (Oct 2022)

MALDI-TOF Mass Spectrometry Online Identification of <i>Trichophyton indotineae</i> Using the MSI-2 Application

  • Anne-Cécile Normand,
  • Alicia Moreno-Sabater,
  • Arnaud Jabet,
  • Samia Hamane,
  • Geneviève Cremer,
  • Françoise Foulet,
  • Marion Blaize,
  • Sarah Dellière,
  • Christine Bonnal,
  • Sébastien Imbert,
  • Sophie Brun,
  • Ann Packeu,
  • Stéphane Bretagne,
  • Renaud Piarroux

DOI
https://doi.org/10.3390/jof8101103
Journal volume & issue
Vol. 8, no. 10
p. 1103

Abstract

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Trichophyton indotineae is an emerging pathogen which recently spread from India to Europe and that is more prone than other species of the Trichophyton mentagrophytes complex to show resistance to terbinafine, resulting in the necessity of rapid identification. Here, we improved the online MSI-2 MALDI-TOF identification tool in order to identify T. indotineae. By multiplying the culture conditions (2 culture media and 6 stages of growth) prior to protein extractions for both test isolates and reference strains, we added 142 references corresponding to 12 strains inside the T. mentagrophytes complex in the online MSI-2 database, of which 3 are T. indotineae strains. The resulting database was tested with 1566 spectra of 67 isolates from the T. mentagrophytes complex, including 16 T. indotineae isolates. Using the newly improved MSI-2 database, we increased the identification rate of T. indotineae from 5% to 96%, with a sensitivity of 99.6%. We also identified specific peaks (6834/6845 daltons and 10,634/10,680 daltons) allowing for the distinction of T. indotineae from the other species of the complex. Our improved version of the MSI-2 application allows for the identification of T. indotineae. This will improve the epidemiological knowledge of the spread of this species throughout the world and will help to improve patient care.

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