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Validation of a modified algorithm for the identification of yeast isolates using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS)

  • B. H. Van HerendaelEmail author
  • P. Bruynseels
  • M. Bensaid
  • T. Boekhout
  • T. De Baere
  • I. Surmont
  • A. H. Mertens
Article

Abstract

Optimising antifungal treatment requires the fast and species-specific identification of yeast isolates. We evaluated a modified protocol for the rapid identification of clinical yeast isolates using matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) technology. First, we evaluated a simplified extraction procedure using 54 clinical yeast isolates. Second, we validated a new protocol with this simplified extraction procedure and lower identification threshold by analysing 167 isolates with either MALDI-TOF or conventional identification techniques. MALDI-TOF analysis with both the standard and short extraction procedure yielded identical identification results, although the log-scores were lower with the latter. With the modified protocol, 163/167 (97.6%) isolates showed a correct identification as compared to conventional identification techniques. A total of 135 out of the 163 (82.8%) correct identifications showed log-scores above 1.7, which we considered as the minimum log-score for secure species identification. The rapid identification of clinical yeast isolates is crucial in patient management. The MALDI-TOF technique using a short extraction procedure can be an alternative for the labourious standard procedure, although the log-scores will be lower. The identification of clinical yeast isolates with the modified protocol is a practical and accurate alternative for conventional identification techniques. If the isolate shows a log-score below 1.7, the standard extraction procedure should be used.

Keywords

Candida Species Yeast Isolate Identification Threshold Yeast Identification Simplify Extraction Procedure 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgments

We thank all laboratory technicians at the clinical microbiology laboratory of ZNA Middelheim Hospital for their hard work with the sample analysis. Further we thank Dr. Van Esbroeck at the Institute of Tropical Medicine Antwerp, the staff at the ZNA Stuivenberg Hospital and the staff at the clinical microbiology laboratory of GZA St.Vincentius for their help in sample collection.

References

  1. 1.
    Trick WE, Fridkin SK, Edwards JR, Hajjeh RA, Gaynes RP; National Nosocomial Infections Surveillance System Hospitals (2002) Secular trend of hospital-acquired candidemia among intensive care unit patients in the United States during 1989–1999. Clin Infect Dis 35:627–630PubMedCrossRefGoogle Scholar
  2. 2.
    Poikonen E, Lyytikäinen O, Anttila VJ, Ruutu P (2003) Candidemia in Finland, 1995–1999. Emerg Infect Dis 9:985–990PubMedGoogle Scholar
  3. 3.
    Harbarth S, Ferrière K, Hugonnet S, Ricou B, Suter P, Pittet D (2002) Epidemiology and prognostic determinants of bloodstream infections in surgical intensive care. Arch Surg 137:1353–1359PubMedCrossRefGoogle Scholar
  4. 4.
    Gudlaugsson O, Gillespie S, Lee K, Vande Berg J, Hu J, Messer S, Herwaldt L, Pfaller M, Diekema D (2003) Attributable mortality of nosocomial candidemia, revisited. Clin Infect Dis 37(9):1172–1177PubMedCrossRefGoogle Scholar
  5. 5.
    Morrell M, Fraser VJ, Kollef MH (2005) Delaying the empiric treatment of Candida bloodstream infection until positive blood culture results are obtained: a potential risk factor for hospital mortality. Antimicrob Agents Chemother 49:3640–3645PubMedCrossRefGoogle Scholar
  6. 6.
    Garey KW, Rege M, Pai MP, Mingo DE, Suda KJ, Turpin RS, Bearden DT (2006) Time to initiation of fluconazole therapy impacts mortality in patients with candidemia: a multi-institutional study. Clin Infect Dis 43(1):25–31PubMedCrossRefGoogle Scholar
  7. 7.
    Taur Y, Cohen N, Dubnow S, Paskovaty A, Seo SK (2010) Effect of antifungal therapy timing on mortality in cancer patients with candidemia. Antimicrob Agents Chemother 54:184–190PubMedCrossRefGoogle Scholar
  8. 8.
    Parkins MD, Sabuda DM, Elsayed S, Laupland KB (2007) Adequacy of empirical antifungal therapy and effect on outcome among patients with invasive Candida species infections. J Antimicrob Chemother 60:613–618PubMedCrossRefGoogle Scholar
  9. 9.
    Playford EG, Nimmo GR, Tilse M, Sorrell TC (2010) Increasing incidence of candidaemia: long-term epidemiological trends, Queensland, Australia, 1999–2008. J Hosp Infect 76(1):46–51PubMedCrossRefGoogle Scholar
  10. 10.
    Verweij PE, Breuker IM, Rijs AJ, Meis JF (1999) Comparative study of seven commercial yeast identification systems. J Clin Pathol 52(4):271–273PubMedCrossRefGoogle Scholar
  11. 11.
    Putignani L, Paglia MG, Bordi E, Nebuloso E, Pucillo LP, Visca P (2008) Identification of clinically relevant yeast species by DNA sequence analysis of the D2 variable region of the 25-28S rRNA gene. Mycoses 51(3):209–227PubMedCrossRefGoogle Scholar
  12. 12.
    Seng P, Drancourt M, Gouriet F, La Scola B, Fournier PE, Rolain JM, Raoult D (2009) Ongoing revolution in bacteriology: routine identification of bacteria by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Clin Infect Dis 49(4):543–551PubMedCrossRefGoogle Scholar
  13. 13.
    van Veen SQ, Claas EC, Kuijper EJ (2010) High-throughput identification of bacteria and yeast by matrix-assisted laser desorption ionization-time of flight mass spectrometry in conventional medical microbiology laboratories. J Clin Microbiol 48(3):900–907PubMedCrossRefGoogle Scholar
  14. 14.
    Marklein G, Josten M, Klanke U, Müller E, Horré R, Maier T, Wenzel T, Kostrzewa M, Bierbaum G, Hoerauf A, Sahl HG (2009) Matrix-assisted laser desorption ionization-time of flight mass spectrometry for fast and reliable identification of clinical yeast isolates. J Clin Microbiol 47(9):2912–2917PubMedCrossRefGoogle Scholar
  15. 15.
    Bader O, Weig M, Taverne-Ghadwal L, Lugert R, Groß U, Kuhns M (2010) Improved clinical laboratory identification of human pathogenic yeasts by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Clin Microbiol Infect. doi: 10.1111/j.1469-0691.2010.03398.x
  16. 16.
    Stevenson LG, Drake SK, Shea YR, Zelazny AM, Murray PR (2010) Evaluation of matrix-assisted laser desorption ionization-time of flight mass spectrometry for identification of clinically important yeast species. J Clin Microbiol 48(10):3482–3486PubMedCrossRefGoogle Scholar
  17. 17.
    Dhiman N, Hall L, Wohlfiel SL, Buckwalter SP, Wengenack NL (2011) Performance and cost analysis of matrix-assisted laser desorption ionization-time of flight mass spectrometry for routine identification of yeast. J Clin Microbiol 49(4):1614–6PubMedCrossRefGoogle Scholar
  18. 18.
    White TJ, Bruns T, Lee S, Taylor J (1990) Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: Innis MA, Gelfand DH, Shinsky JJ, White TJ (eds) PCR protocols: a guide to methods and applications. Academic Press, San Diego, pp 315–322Google Scholar
  19. 19.
    Kurtzman CP, Robnett CJ, Basehoar-Powers E (2008) Phylogenetic relationships among species of Pichia, Issatchenkia and Williopsis determined from multigene sequence analysis, and the proposal of Barnettozyma gen. nov., Lindnera gen. nov. and Wickerhamomyces gen. nov. FEMS Yeast Res 8:939–954PubMedCrossRefGoogle Scholar
  20. 20.
    Kurtzman CP, Robnett CJ (1998) Identification and phylogeny of ascomycetous yeasts from analysis of nuclear large subunit (26S) ribosomal DNA partial sequences. Antonie Van Leeuwenhoek 73(4):331–371PubMedCrossRefGoogle Scholar
  21. 21.
    Villa-Carvajal M, Querol A, Belloch C (2006) Identification of species in the genus Pichia by restriction of the internal transcribed spacers (ITS1 and ITS2) and the 5.8S ribosomal DNA gene: Identification of Pichia species by 5.8S-ITS rDNA RFLP. Antonie Van Leeuwenhoek 90:171–181PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • B. H. Van Herendael
    • 1
    Email author
  • P. Bruynseels
    • 1
  • M. Bensaid
    • 1
  • T. Boekhout
    • 2
  • T. De Baere
    • 3
  • I. Surmont
    • 4
  • A. H. Mertens
    • 1
  1. 1.Department of MicrobiologyZNA MiddelheimAntwerpBelgium
  2. 2.CBS Fungal Diversity CentreUtrechtThe Netherlands
  3. 3.Department of Molecular DiagnosticsHeilig-Hart ZiekenhuisRoeselareBelgium
  4. 4.Department of MicrobiologyHeilig-Hart ZiekenhuisRoeselareBelgium

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