Identifying fungal isolates using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
Green-BJ; Hettick-JM; Schmechel-D; Kashon-ML; Slaven-JE; Blachere-FM; Buskirk-A; Janotka-E; Siegel-PD; Beezhold-DH
J Allergy Clin Immunol 2008 Feb; 121(2)(Suppl 1):S270
RATIONALE: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a powerful tool for phenotyping microorganisms. The purpose of this study was to utilize MALDI-TOF MS to determine whether the mass spectra of individual fungal species produced specific m/z values that could be used to discriminate between species. METHODS: Sixty two different fungal isolates were grown for 14 days on malt extract agar. Conidia and hyphae were extracted in 250 mg of zirconium beads in 1mL 50/50 acetonitrile/4% trifluoroacetic acid by three 1 min bead beating cycles. The resultant extract was centrifuged at 14,500 rpm for 10 minutes and the supernatant analyzed. Samples were mixed 1:1 with 10 mg/mL alpha-cyano-4-hydroxycinnamic acid. A 1 mL aliquot was spotted on a gold target plate and allowed to air dry before MALDI-TOF MS analysis. RESULTS: MALDI-TOF MS mass spectra of fungal isolates contained numerous peaks within the 1,000 - 40,000 mass-to-charge (m/z) range. Statistical discriminative analysis of mass spectra resulted in the ability to unambiguously differentiate fungal species. The mass spectra of closely related species are often similar; however, these may still be distinguished by species-specific m/z values and/or differential relative abundance of shared m/z values. CONCLUSIONS: This work demonstrates the potential utility of MALDI-TOF MS for the objective species identification of both clinically and environmentally relevant fungal isolates.
Immune-system-disorders; Allergic-disorders; Allergic-reactions; Allergens; Fungal-diseases; Fungal-infections; Fungi; Microbiology; Microscopic-analysis; Mass-spectrometry; Sample-preparation; Lasers; Laser-radiation; Ionization; Analytical-processes
Abstract; Conference/Symposia Proceedings
Journal of Allergy and Clinical Immunology