MALDI-TOF Mass Spectrometry for Microorganism Identification

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Key points

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    MALDI-TOF MS is faster and more accurate than conventional identification methods for the identification of most bacterial and fungal clinical isolates.

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    The identification of organisms by MALDI-TOF MS significantly decreases the turnaround time for the provision of definitive identification results to physicians.

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    Some organisms currently cannot be reliably identified by this method, such as Shigella spp and Streptococcus pneumoniae.

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    Direct-from-specimen organism identification, detection of

Principles of MALDI-TOF MS for microbial identification

The basic principle of intact cell MALDI-TOF MS is illustrated in Fig. 1. Briefly, microbial samples deposited on a target plate are overlaid with matrix solution, which cocrystalizes with the sample and lyses vegetative organisms.15, 16 More difficult to lyse microbes, such as certain Gram-positive bacteria, mycobacteria, yeast, and molds, often require an additional pretreatment with a strong organic acid or mechanical lysis (eg, bead-beating).17, 18, 19 Once placed in the instrument, the

Bacteria

Several studies have been published comparing MALDI-TOF MS with conventional microbiologic techniques for the identification of routine clinical isolates of bacteria (Table 1). In most of these studies, identification by MALDI-TOF MS has out-performed conventional methods. For example, in one study where 980 routine clinical isolates were prospectively analyzed by MALDI-TOF MS, 92% of isolates were correctly identified to the species-level compared with 83.1% of isolates identified using

Advantages and limitations of MALDI-TOF MS for microbial identification

The major advantages and limitations associated with MALDI-TOF MS for organism identification are summarized in Table 3. Not only does MALDI-TOF MS outperform conventional methods for organism identification in terms of accuracy, it dramatically outperforms these methods with regards to speed. Thus, the primary advantage associated with MALDI-TOF MS is arguably the dramatically reduced turnaround time for result reporting to physicians (Fig. 3). Multiple studies have demonstrated improved

Potential future applications of MALDI-TOF MS in the clinical microbiology laboratory

The application of MALDI-TOF MS to additional aspects of clinical microbiology is an exciting and increasingly realistic prospect. In particular, the identification of organisms directly from positive blood cultures and clinical specimens has been the subject of numerous studies. Even though eliminating the need to isolate organisms in culture would reduce the time to pathogen identification by at least 12 to 48 hours, recovery of the organism in vitro will continue to be required in most cases

Summary

MALDI-TOF MS is a rapid and reliable method for microbial identification that has been incorporated into the work flow of many clinical microbiology laboratories. Implementation of this method enables laboratories to provide definitive organism identifications to physicians on a time scale that was previously unimaginable. However, the ability of MALDI-TOF MS to more accurately identify microorganisms poses unique opportunities and challenges for physicians and laboratorians. Because of the

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References (89)

  • R. Fournier et al.

    Chemical extraction versus direct smear for MALDI-TOF mass spectrometry identification of anaerobic bacteria

    Anaerobe

    (2012)
  • O. Bader et al.

    Improved clinical laboratory identification of human pathogenic yeasts by matrix-assisted laser desorption ionization time-of-flight mass spectrometry

    Clin Microbiol Infect

    (2011)
  • A. Alanio et al.

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry for fast and accurate identification of clinically relevant Aspergillus species

    Clin Microbiol Infect

    (2011)
  • E. De Carolis et al.

    Species identification of Aspergillus, Fusarium and Mucorales with direct surface analysis by matrix-assisted laser desorption ionization time-of-flight mass spectrometry

    Clin Microbiol Infect

    (2012)
  • P.R. Murray

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry: usefulness for taxonomy and epidemiology

    Clin Microbiol Infect

    (2010)
  • M. Wolters et al.

    MALDI-TOF MS fingerprinting allows for discrimination of major methicillin-resistant Staphylococcus aureus lineages

    Int J Med Microbiol

    (2011)
  • K.A. Jackson et al.

    Optimisation of intact cell MALDI method for fingerprinting of methicillin Staphylococcus aureus

    J Microbiol Methods

    (2005)
  • J. Walker et al.

    Intact cell mass spectrometry (ICMS) used to type methicillin-resistant Staphylococcus aureus: media effects and inter-laboratory reproducibility

    J Microbiol Methods

    (2002)
  • R. Stephan et al.

    Rapid species specific identification and subtyping of Yersinia enterocolitica by MALDI-TOF mass spectrometry

    J Microbiol Methods

    (2011)
  • D.F. Gaieski et al.

    Impact of time to antibiotics on survival in patients with severe sepsis or septic shock in whom early goal-directed therapy was initiated in the emergency department

    Crit Care Med

    (2010)
  • A. Kumar et al.

    Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock

    Crit Care Med

    (2006)
  • P. Seng et al.

    Ongoing revolution in bacteriology: routine identification of bacteria by matrix-assisted laser desorption ionization time-of-flight mass spectrometry

    Clin Infect Dis

    (2009)
  • J.P. Anhalt et al.

    Identification of bacteria using mass spectrometry

    Anal Chem

    (1975)
  • M. Karas et al.

    Influence of the wavelength in high-irradiance ultraviolet laser desorption mass spectrometry of organic molecules

    Anal Chem

    (1985)
  • M. Karas et al.

    Laser desorption ionization of proteins with molecular masses exceeding 10,000 daltons

    Anal Chem

    (1988)
  • M.A. Claydon et al.

    The rapid identification of intact microorganisms using mass spectrometry

    Nat Biotechnol

    (1996)
  • R.D. Holland et al.

    Rapid identification of intact whole bacteria based on spectral patterns using matrix-assisted laser desorption/ionization with time of flight mass spectrometry

    Rapid Commun Mass Spectrom

    (1996)
  • T. Krishnamurthy et al.

    Rapid identification of bacteria by direct matrix-assisted laser desorption/ionization mass spectrometric analysis of whole cells

    Rapid Commun Mass Spectrom

    (1996)
  • K.J. Welham et al.

    The characterization of micro-organisms by matrix-assisted laser desorption time-of-flight mass spectrometry

    Rapid Commun Mass Spectrom

    (1998)
  • C. Fenselau et al.

    Characterization of intact microorganisms by MALDI mass spectrometry

    Mass Spectrom Rev

    (2001)
  • A. Bizzini et al.

    Performance of matrix-assisted laser desorption ionization-time of flight mass spectrometry for identification of bacterial strains routinely isolated in a clinical microbiology laboratory

    J Clin Microbiol

    (2010)
  • S.Q. van Veen et al.

    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

    (2010)
  • R.D. Holland et al.

    Identification of bacterial proteins observed in MALDI TOF mass spectra from whole cells

    Anal Chem

    (1999)
  • V. Rhyzhov et al.

    Characterization of the protein subset desorbed by MALDI from whole bacterial cells

    Anal Chem

    (2001)
  • L. Sun et al.

    Characterization of ribosomal proteins as biomarkers for matrix-assisted laser desorption/ionization mass spectral identification of Lactobacillus plantarum

    Rapid Commun Mass Spectrom

    (2006)
  • K. Sogawa et al.

    Rapid identification of microorganisms by mass spectrometry: improved performance by incorporation of in-house spectral data into a commercial database

    Anal Bioanal Chem

    (2012)
  • A.J. Saenz et al.

    Reproducibility of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for replicate bacterial culture analysis

    Rapid Commun Mass Spectrom

    (1999)
  • A. Wieser et al.

    MALDI-TOF MS in microbiological diagnostics-identification of microorganisms and beyond (mini-review)

    Appl Microbiol Biotechnol

    (2012)
  • K. Sogawa et al.

    Use of MALDI BioTyper system with MALDI-TOF mass spectrometry for rapid identification of microorganisms

    Anal Bioanal Chem

    (2011)
  • A. Cherkaoui et al.

    Comparison of two matrix-assisted laser desorption ionization-time of flight mass spectrometry methods with conventional phenotypic identification for routine identification of bacteria to the species level

    J Clin Microbiol

    (2010)
  • D. Dubois et al.

    Performances of the VITEK MS matrix-assisted laser desorption ionization-time of flight mass spectrometry system for rapid identification of bacteria in routine clinical microbiology

    J Clin Microbiol

    (2012)
  • E. Farfour et al.

    Evaluation of the Andromas matrix-assisted laser desorption ionization-time of flight mass spectrometry system for identification of aerobically growing gram-positive bacilli

    J Clin Microbiol

    (2012)
  • A. Fernandex-Olmos et al.

    MALDI-TOF MS improves routine identification of non-fermenting gram negative isolates from cystic fibrosis patients

    J Cyst Fibros

    (2012)
  • D.C. Marko et al.

    Evaluation of the Bruker Biotyper and Vitek MS matrix-assisted laser desorption ionization-time of flight mass spectrometry systems for identification of nonfermenting gram-negative bacilli isolated from culture from cystic fibrosis patients

    J Clin Microbiol

    (2012)

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