title: Discrimination of Aspergillus lentulus from Aspergillus fumigatus by Raman spectroscopy and MALDI-TOF MS.
abstract: In 2005, a new sibling species of Aspergillus fumigatus was discovered: Aspergillus lentulus. Both species can cause invasive fungal disease in immune-compromised patients. The species are morphologically very similar. Current techniques for identification are PCR-based or morphology-based. These techniques are labour-intense and not sufficiently discriminatory. Since A. lentulus is less susceptible to several antifungal agents, it is important to correctly identify the causative infectious agent in order to optimize antifungal therapy. In this study we determined whether Raman spectroscopy and/or MALDI-TOF MS were able to differentiate between A. lentulus and A. fumigatus. For 16 isolates of A. lentulus and 16 isolates of A. fumigatus, Raman spectra and peptide profiles were obtained using the Spectracell and MALDI-TOF MS (VITEK MS RUO, bioMérieux) respectively. In order to obtain reliable Raman spectra for A. fumigatus and A. lentulus, the culture medium needed to be adjusted to obtain colourless conidia. Only Raman spectra obtained from colourless conidia were reproducible and correctly identified 25 out of 32 (78 %) of the Aspergillus strains. For VITEK MS RUO, no medium adjustments were necessary. Pigmented conidia resulted in reproducible peptide profiles as well in this case. VITEK MS RUO correctly identified 100 % of the Aspergillus isolates, within a timeframe of approximately 54 h including culture. Of the two techniques studied here, VITEK MS RUO was superior to Raman spectroscopy in the discrimination of A. lentulus from A. fumigatus. VITEK MS RUO seems to be a successful technique in the daily identification of Aspergillus spp. within a limited timeframe.
authors.affiliation: Department of Medical Microbiology and Infectious Diseases, Erasmus MC, University Medical Centre Rotterdam, 's Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands, p.verwer@erasmusmc.nl.
authors.forename: P E B
authors.initials: PE
authors.lastname: Verwer
authors.forename: W B
authors.initials: WB
authors.lastname: van Leeuwen
authors.forename: V
authors.initials: V
authors.lastname: Girard
authors.forename: V
authors.initials: V
authors.lastname: Monnin
authors.forename: A
authors.initials: A
authors.lastname: van Belkum
authors.forename: J F
authors.initials: JF
authors.lastname: Staab
authors.forename: H A
authors.initials: HA
authors.lastname: Verbrugh
authors.forename: I A J M
authors.initials: IA
authors.lastname: Bakker-Woudenberg
authors.forename: W W J
authors.initials: WW
authors.lastname: van de Sande
mesh_terms: D001230:Aspergillus / Q000737:chemistry* / Q000145:classification*; D001431:Bacteriological Techniques / Q000379:methods*; D003470:Culture Media / Q000737:chemistry; D006801:Humans; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013997:Time Factors
chemical_list: D003470:Culture Media
references.citation: J Clin Microbiol. 2009 Apr;47(4):1096-100
references.pmid: 19244469
references.citation: Proteomics. 2002 Jun;2(6):747-53
references.pmid: 12112858
references.citation: J Proteomics. 2012 Jun 18;75(11):3314-30
references.pmid: 22504628
references.citation: Antimicrob Agents Chemother. 2008 Apr;52(4):1244-51
references.pmid: 18212093
references.citation: Semin Respir Crit Care Med. 2010 Feb;31(1):79-86
references.pmid: 20101550
references.citation: J Clin Microbiol. 2009 Oct;47(10):3138-41
references.pmid: 19675215
references.citation: Clin Dermatol. 2010 Mar 4;28(2):197-201
references.pmid: 20347663
references.citation: Antimicrob Agents Chemother. 2011 Dec;55(12):5459-68
references.pmid: 21947395
references.citation: J Clin Microbiol. 2008 Mar;46(3):961-5
references.pmid: 18174303
references.citation: BMC Infect Dis. 2012 Oct 02;12:237
references.pmid: 23031334
references.citation: Antimicrob Agents Chemother. 2004 Apr;48(4):1197-203
references.pmid: 15047520
references.citation: Expert Rev Anti Infect Ther. 2009 Oct;7(8):981-98
references.pmid: 19803707
references.citation: Crit Rev Microbiol. 2010;36(1):1-53
references.pmid: 20088682
references.citation: Anal Biochem. 2008 Sep 15;380(2):276-81
references.pmid: 18577370
references.citation: Anal Chem. 1999 May 15;71(10):1990-6
references.pmid: 10361498
references.citation: Eukaryot Cell. 2005 Mar;4(3):625-32
references.pmid: 15755924
references.citation: Clin Microbiol Infect. 2011 May;17(5):750-5
references.pmid: 20673266
references.citation: J Clin Microbiol. 2009 Mar;47(3):652-9
references.pmid: 19109462
references.citation: Eukaryot Cell. 2006 Oct;5(10):1705-12
references.pmid: 17030996
references.citation: Antimicrob Agents Chemother. 2009 May;53(5):2005-13
references.pmid: 19237647
references.citation: BMC Microbiol. 2011 Jul 28;11:172
references.pmid: 21798007
references.citation: BMC Microbiol. 2011 Apr 21;11:82
references.pmid: 21510879
references.citation: Clin Microbiol Infect. 2012 Nov;18(11):1117-25
references.pmid: 22044600
references.citation: BMC Microbiol. 2012 Jul 28;12:154
references.pmid: 22838495
references.citation: Appl Microbiol. 1975 Dec;30(6):909-15
references.pmid: 1211936
references.citation: Anal Biochem. 2011 Apr 1;411(1):122-8
references.pmid: 21094115