Identification of molecularly defined Staphylococcus aureus strains using matrix-assisted laser desorption/ionization time of flight mass spectrometry and the Biotyper 2.0 database

Abstract

Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) has recently been introduced for bacterial identification. To our knowledge, this is the first study where the Biotyper 2.0 database (Bruker Daltonics) has been applied for bacterial identification in a local strain collection of molecularly defined Staphylococcus aureus. We showed that the accuracy of the Biotyper 2.0-based identification for 602 molecularly defined strains of S. aureus, irrespective of meticillin resistance, was equivalent to that of the molecularly defined reference even at a score cutoff value of 2. Also, 412 isolates of 20 different species of non-S. aureus staphylococci were all correctly identified to species level compared to the molecularly defined reference. Moreover, the MALDI-TOF MS-based S. aureus identification approach was clearly faster than more time-consuming methods such as a molecular identification approach.

Evaluation of species-specific score cut-off values for various Staphylococcus species using a MALDI Biotyper-based identification

“…This database contains .3000 well-characterized microbial species, including 124 spectra representing 36 different staphylococcal species and subspecies. Although the accuracy of the MALDI Biotyper 2.0 database has been described in a variety of studies (Seng et al, 2009;Bizzini et al, 2010;Harris et al, 2010;Risch et al, 2010;Szabados et al, 2010;Neville et al, 2011), these experiments also varied in many details. A divergent number of tested strains, number of spectra to generate a sum spectrum and number of replicates tested and the use of different mass spectrometry instruments and target types make it difficult to compare the published data.…”

“…A variety of studies declared this method to be cost-effective and rapid for bacterial identification (Eigner et al, 2009;Marklein et al, 2009;Seng et al, 2009;Szabados et al, 2010;Carpaij et al, 2011), which is a proven benefit for patient care (Barenfanger et al, 1999;Neville et al, 2011). MALDI-TOF MS is based on soft laser ionization on intact bacteria or bacterial extracts.…”

Characterization of a Staphylococcus aureus USA300 protein signature using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

“…In the case of S. aureus, two recent studies (Szabados et al, 2010(Szabados et al, , 2011 have validated the superiority of MALDI-TOF identification over traditional biochemical techniques and other identification systems. We hypothesized that MALDI-TOF could also be used to rapidly discriminate bacteria at the subspecies or strain level, and specifically to identify USA300 family organisms.…”

Rapid Identification of <i>Mycoplasma pulmonis</i> Isolated from Laboratory Mice and Rats Using Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry

“…More recently, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been applied to analyze the protein composition and used for direct identification of pathogens in the culture agar and/ or broth [8,14,15]. However, there has been limited work thus far on the use of MALDI-TOF MS for the identification of pathogens in laboratory animals.…”

“…The culture method is one of the most common and specific methods to detect bacteria; however, a laborious step is needed to identify the colonies [4], such as morphological studies, reversion studies, or the sterol requirement and metabolism inhibition test. Recently, sequence analysis of the 16S rRNA gene has also been used as a simple method for identification of the bacteria [16].More recently, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been applied to analyze the protein composition and used for direct identification of pathogens in the culture agar and/ or broth [8,14,15]. However, there has been limited work thus far on the use of MALDI-TOF MS for the identification of pathogens in laboratory animals.…”