1 research outputs found
Typing <i>Pseudomonas aeruginosa</i> Isolates with Ultrahigh Resolution MALDI-FTICR Mass Spectrometry
The introduction of standardized
matrix-assisted laser desorption/ionization
time-of-flight mass spectrometry (MALDI-TOF MS) platforms in the medical
microbiological practice has revolutionized the way microbial species
identification is performed on a daily basis. To a large extent, this
is due to the ease of operation. Acquired spectra are compared to
profiles obtained from cultured colonies present in a reference spectra
database. It is fast and reliable, and costs are low compared to previous
diagnostic approaches. However, the low resolution and dynamic range
of the MALDI-TOF profiles have shown limited applicability for the
discrimination of different bacterial strains, as achieved with typing
based on genetic markers. This is pivotal in cases where certain strains
are associated with, e.g., virulence or antibiotic resistance. Ultrahigh
resolution MALDI-FTICR MS allows the measurement of small proteins
at isotopic resolution and can be used to analyze complex mixtures
with increased dynamic range and higher precision than MALDI-TOF MS,
while still generating results in a similar time frame. Here, we propose
to use ultrahigh resolution 15T MALDI-Fourier transform ion cyclotron
resonance (FTICR) MS to discriminate clinically relevant bacterial
strains after species identification performed by MALDI-TOF MS. We
used a collection of well characterized <i>Pseudomonas aeruginosa</i> strains, featuring distinct antibiotic resistance profiles, and
isolates obtained during hospital outbreaks. Following cluster analysis
based on amplification fragment length polymorphism (AFLP), these
strains were grouped into three different clusters. The same clusters
were obtained using protein profiles generated by MALDI-FTICR MS.
Subsequent intact protein analysis by electrospray ionization (ESI)-collision-induced
dissociation (CID)-FTICR MS was applied to identify protein isoforms
that contribute to the separation of the different clusters, illustrating
the additional advantage of this analytical platform