Journal Article

Complexities associated with the molecular and proteomic identification of Paecilomyces species in the clinical mycology laboratory

Adam P. Barker, Jennifer L. Horan, E. Susan Slechta, Barbara D. Alexander and Kimberly E. Hanson

in Medical Mycology

Published on behalf of International Society for Human and Animal Mycology

Volume 52, issue 5, pages 537-545
Published in print July 2014 | ISSN: 1369-3786
Published online March 2014 | e-ISSN: 1460-2709 | DOI: https://dx.doi.org/10.1093/mmy/myu001
Complexities associated with the molecular and proteomic identification of Paecilomyces species in the clinical mycology laboratory

More Like This

Show all results sharing these subjects:

  • Mycology and Fungi
  • Infectious Diseases
  • Medical Toxicology
  • Veterinary Medicine
  • Environmental Science

GO

Show Summary Details

Preview

Paecilomyces species are emerging fungal pathogens. Morphological identifications are complicated by similarities among the members of the P. variotii complex as well as to some Rasamsonia and Hamigera species. The purpose of this study was to compare matrix-assisted laser desorption ionization–time-of-flight mass spectrometry (MALDI–TOF MS) with molecular diagnostic standards (i.e., multilocus DNA sequencing of the internal transcribed spacer regions 1 and 2, D1/D2 regions, and part of the β-tubulin gene) for the identification of Paecilomyces spp. encountered in two clinical mycology laboratories. A total of 77 clinical isolates identified morphologically as P. variotii (n = 21), P. lilacinus (n = 52), and Paecilomyces spp. not otherwise specified (n = 4) were included. In accord with the most recent taxonomy, all P. lilacinus isolates were confirmed as Purpureocillium lilacinum by both sequencing and MALDI–TOF MS. Fungi phenotypically resembling P. variotii or Paecilomyces spp. were identified by molecular techniques as P. variotii sensu stricto (n = 12), P. formosus (n = 3), P. dactylethromorphus (n = 3), Rasamsonia argillacea (n = 4), or R. piperina (n = 1) and at the genus level as an isolate of a Hamigera sp. and a Paecilomyces sp. There was 92.2% (71/77) agreement between the molecular and proteomic methods only after supplementation of the MALDI–TOF MS database with type strains. Paecilomyces variotii–like organisms required multilocus DNA interrogations for differentiation and account for all of the fungi whose identification was missed by MALDI–TOF MS. Overall, MALDI–TOF MS was a rapid and reliable alternative to multilocus sequencing. However, significant augmentation of the commercially available database was required to reproducibly identify this group of important human pathogens.

Keywords: fungal infections; Paecilomyces variotii; Purpureocillium lilacinum; filamentous fungi; matrix-assisted laser desorption–ionization time-of-flight mass spectrometry

Journal Article.  3783 words.  Illustrated.

Subjects: Mycology and Fungi ; Infectious Diseases ; Medical Toxicology ; Veterinary Medicine ; Environmental Science

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content. subscribe or login to access all content.