1564. Examining the In Vitro Volatile Metabolite Profile of Pathogenic Scedosporium and Lomentospora Species
Session: Poster Abstract Session: Mycology: Diagnostic
Friday, October 28, 2016
Room: Poster Hall

Background: Scedosporium apiospermum, Scedosporium boydii, and Lomentospora (formerly Scedosporium) prolificans are ubiquitous molds that can cause severe, life-threatening fungal disease. Identification of scedosporiosis is important due to the resistance of these molds to many antifungal agents, but challenging due to the lack of specific diagnostic methods.

Methods: We examined the volatile organic metabolite profile of pathogenic Scedosporium species and L. prolificans in vitro, identifying key volatile organic metabolites using thermal desorption-gas chromatography (GC)/tandem mass spectrometry (MS), in parallel with GC-differential mobility spectrometry (DMS). DMS provides a rapid, portable method of identifying particular volatile metabolites in complex gas mixtures based on atmospheric pressure ionization followed by differential trajectories of these ion species across an asymmetric waveform electrical field.

Results: We identified a unique pattern of secondary sesquiterpene metabolites for each Scedosporium species and L. prolificans by GC-MS, with corresponding identification of these species-specific metabolite signatures by GC-DMS. S. prolificans (N = 6) emitted a signature of farnesene, alloaromadendrene, bisabolene, and germacrene (Fig 1: left panel: representative GC-MS total ion chromatogram segment of relative abundance vs. retention time), right panel: representative GC-DMS plot of metabolite intensity vs. VC (compensation voltage) vs. retention time). S. apiospermum produced cedrene, aromadendrene, selinene, and isogermacrene (Fig 2), and S. boydii produced cedrene, guaiene, gurjunene, sesquisabinene hydrate and cadinene (Fig 3).

Conclusion: Pathogenic Scedosporium and Lomentospora emit unique, species-specific secondary metabolite volatile metabolite signatures, distinct from the volatile metabolite signatures of Aspergillus and Fusarium species, and pathogenic Mucorales. These distinctive fungal metabolite signatures may be used as targets for rapid, species-specific, breath-based identification of Scedosporium/Lomentospora infections and allow differentiation from other invasive mold infections.

Figure 1. L. prolificans.

Figure 2. S. apiospermum.

Figure 3. S. boydii.

Xinwei Yu, PhD1, Seena Koshy, PhD1, Obadah Aloum, MBBCh1, Lindsey R. Baden, MD1, Francisco M. Marty, MD, FIDSA2, Nathan Wiederhold, PharmD3 and Sophia Koo, MD1, (1)Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, (2)Division of Infectious Diseases, Brigham and Women's Hospital, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, (3)Univ. TX, San Antonio, TX

Disclosures:

X. Yu, None

S. Koshy, None

O. Aloum, None

L. R. Baden, None

F. M. Marty, Alexion: Scientific Advisor , Consulting fee
Ansun: Investigator , Research support
Astellas: Consultant and Investigator , Consulting fee and Research support
Basilea: Conference speaker , Speaker honorarium
Chimerix: Consultant and Investigator , Consulting fee and Research support
Gilead: Consultant and Investigator , Consulting fee and Research support
GlaxoSmithKline: Consultant and Investigator , Consulting fee and Research grant
LFB, S.A.: Consultant , Consulting fee
Merck: Consultant and Investigator , Consulting fee and Research support
Shire: Consultant and Investigator , Consulting fee and Research support
WHISCON: Investigator , Research support
Pfizer: Course speaker , Speaker honorarium
Fate Therapeutics: Scientific Advisor , Consulting fee

N. Wiederhold, BioMerieux: Grant Investigator , Research support

S. Koo, Wako Diagnostics: Grant Investigator , Research support

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