Increased species-assignment of filamentous fungi using MALDI-TOF MS coupled with a simplified sample processing and an in-house library
Identifiers
URI: http://hdl.handle.net/20.500.12020/1190ISSN: 1369-3786
DOI: https://doi.org/10.1093/mmy/myx154
Author/s
Zvezdanova, Margarita Estreya; Escribano, Pilar; Ruiz, Adrián; Martínez-Jiménez, María del Carmen; Pelaez, Teresa; [et al.]Date
2019Document type
articleÁrea/s de conocimiento
Ciencias BiomédicasMateria/s Unesco
2414 MicrobiologíaAbstract
In this study we evaluated the capacity of MALDI-TOF MS (Bruker Daltonics, Bremen,
Germany) to identify clinical mould isolates. We focused on two aspects of MALDI-TOF
MS identification: the sample processing and the database. Direct smearing of the sample
was compared with a simplified processing consisting of mechanical lysis of the
moulds followed by a protein extraction step. Both methods were applied to all isolates
and the Filamentous Fungi Library 1.0 (Bruker Daltonics) was used for their identification.
This approach allowed the correct species-level identification of 25/34 Fusarium
spp. and 10/10 Mucor circinelloides isolates using the simplified sample processing. In
addition, 7/34 Fusarium spp. and 1/21 Pseudallescheria/Scedosporium spp. isolates were
correctly identified at the genus level. The remaining isolates–60–could not be identified
using the commercial database, mainly because of the low number of references for
some species and the absence of others. Thus, an in-house library was built with 63
local isolates previously characterized using DNA sequence analysis. Its implementation
allowed the accurate identification at the species level of 94 isolates (91.3%) and the
remaining nine isolates (8.7%) were correctly identified at the genus level. No misidentifications
at genus level were detected. In conclusion, with improvements of both the
sample preparation and the feeding of the database, MALDI-TOF MS is a reliable, ready
to usemethod to identify moulds of clinical origin in an accurate, rapid, and cost-effective
manner.