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Analysis of Microorganisms Using MALDI-TOF-MS
A New Tool for Research Applications
AXIMA-iDPlus
SARAMIS Software
Identification
„„Rapid microbial identification for research use
„„Identifies and classifies strains based on phenotype
characteristics
„„Open system allows addition of new species to the
database, or the creation of new databases
„„High performance MS and MS/MS options allow the
study of microorganism proteins and peptides
„„SuperSpectra™ reduce the incidence of false positives
and ensure robustness and reproducibility
„„Clustering allows tracking of change and evolution.
AXIMA-iDPlus utilises SARAMIS: the easy to use microbial
identification software which has revolutionized daily
routine in analytical and diagnostic-research laboratories.
The sample mass spectrum is automatically processed
and condensed to a fingerprint peak list containing the
mass/intensity data. This is then searched against the
SuperSpectra in the SARAMIS database. AXIMA-iDPlus
typically identifies 95% of clinical samples unambiguously
within one minute.
MALDI-TOF mass spectra of bacteria and fungi are highly
taxon-specific and can be used for specimen identification.
As reference spectra, AXIMA-iDPlus uses SuperSpectra which
are based on mass spectra of isolates identified by widely
accepted methods such as biochemical phenotyping,
16sRNA analysis or MLST (Multi-Locus Sequence Typing).
Matrix Assisted Laser Desorption/Ionization-Time-of-Flight
Mass Spectrometry.
The biomolecules embedded in the matrix crystals are
desorbed and ionized by a laser pulse and accelerated in a
high voltage field. Different ions are detected after a timeof-flight proportional to their mass, generating a high
resolution mass spectrum of the sample; the ‘fingerprint’.
Depending on the choice of mass spectrometer, both
intact proteins (linear mode) and structural determination
of fragments (reflectron mode) can be investigated.
AXIMA Performance offers the same advantages as the
Confidence, but with the addition of high-energy Collision
Induced Dissociation (CID) to give greater fragmentation
and thus better structural elucidation and sequencing for
research into the proteome of microorganisms.
Complementary
Methods
AXIMA-iDPlus is the perfect addition
to the research laboratory. It meets
the demands for fast and reliable
screening of the broadest range of
microorganisms and is complemented
by biochemical methods for antibiotic
susceptibility testing, by PCR
diagnostic and by sequencing for
unknown species using traditional MS
and MS/MS methods.
In addition, investigations into
the lipids, glycopeptides and
glycoproteins of microorganisms can
be undertaken.
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Clustering
A006528-1:
Klebsiella
oxytoca
AXIMA Confidence is a combination linear and reflectron
mode MALDI-TOF system. In addition to microbial
identification, the reflectron provides higher resolution
and greater mass accuracy. The ability to perform Post
Source Decay (PSD) provides the possibility to carry out
MS/MS experiments, for improved structural elucidation
and sequencing of peptides and proteins.
3,000
Mass (Da)
Patented identification procedures are designed to
definitely avoid false identifications by setting stringent
thresholds for significant database matches.
The analysis can be performed fully automatically or in
manual acquisition mode for greater control.
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AXIMA Assurance is a linear mode MALDI-TOF system
with a high performance-to-price ratio. It is a robust, high
sensitivity system for research use microbial identification
and investigations into the proteins of microorganisms.
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MALDI-TOF
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It comprises one of the AXIMA MALDI-TOF mass
spectrometers and the SARAMIS database (Spectral
ARchive And Microbial Identification System).
SuperSpectrum:
Klebsiella oxytoca
Type 9
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AXIMA-iDPlus is a platform for carrying out microbial
identification for research purposes and for identifying
and studying the proteins of microorganisms.
In uncertain cases, when the identification confidence
is below 90 %, a sample’s fingerprint is re-searched
against all available reference spectra in the database
collected since 1998 – a significant improvement for the
identification of atypical specimens.
The SARAMIS software is able to carry out heirarchical
clustering of samples, the results being represented by
dendrograms. This technique can be used to identify
changes in the microbial population over time, or to create
new SuperSpectra which are representative of a particular
environment.
15,000
SuperSpectrum of Klebsiella oxytoca and a fingerprint of a
clinical isolate. Dotted lines indicate matching masses in the
fingerprint spectrum when compared to the reference spectrum.
Each SuperSpectrum is derived from multiple reference
spectra of at least 15 individual isolates of a species,
acquired after varying growth times and from different
growth media to ensure robustness and reproducibility.
SARAMIS offers a comprehensive database of species
(supported by internationally recognized strain collections
and clinical laboratories) and the flexibility for the user to
create new entries and databases.
Cultured microorganisms can be directly applied to
the MALDI sample target and introduced into one of
the AXIMA series mass spectrometers. Analysis and
identification can be completed in 1-2 minutes.
The software identifies gram-positive and gramnegative bacteria, yeasts, fungi and spores based on
their characteristic MALDI-TOF-MS fingerprints down to
sub-species level. No preselection of analytical methods
is required; hands-on time is reduced and costs are cut
dramatically.
Example of a clustering of clinical samples based on MALDI-TOF
mass spectra. An explicit separation is given for all species and a
SuperSpectrum could be generated from all spectra of one species
which could be seen as representative for the environment.
Workflow
Step 1: Typical Sample
Preparation
AXIMA-iDPlus identifies a
sample grown overnight
on a culture plate. A small
number of cells is transferred
to a FlexiMass-DS™ disposable
polymeric target, followed
by the addition of a matrix
solution. The sample is then
air-dried.
1 Minute
Sample Transfer
Applications
AXIMA-iDPlus covers a wide range of applications. Various
industries benefit from this new analytical approach,
such as diagnostics research, pharmaceutical industry,
healthcare and food industry.
In the drug discovery process, AXIMA-iDPlus recognizes new
isolates generated by microorganisms and classifies the
unknown into a taxonomic tree.
For use in culture collections, AXIMA-iDPlus identifies and
classifies strains based on phenotype characteristics.
AXIMA-iDPlus can also be used to develop manufacturing
processes for the food and beverage industry; to maintain
quality and to recognize upcoming toxic microorganisms
at an early stage.
References
“Tapping the potential of intact cell mass spectrometry with
a combined data analytical approach applied to Yersinia spp.:
Detection, differentiation and identification of Y. pestis.”
Wittwer et al. Syst Appl Microbiol. 34(1):12-9. 2011
“Species identification of staphylococci by amplification and sequencing
of the tuf gene compared to the gap gene and by matrix-assisted
laser desorption ionization time-of-flight mass spectrometry.”
Bergeron et al. Eur J Clin Microbiol Infect Dis. (3):343-54. 2011
“The use in routine of mass spectrometry in a hospital microbiology
laboratory.” Gravet et al. Pathol Biol (Paris). 59(1):19-25. 2011
Step 2: Identification
The FlexiMass-DS target is loaded into
the AXIMA where the mass spectral
‘fingerprints’ of the samples are
acquired.
These fingerprints are matched
against the SARAMIS database
of SuperSpectra for immediate
identification. Results are displayed
within 1-2 minutes.
“Rapid genus- and species-specific identification of Cronobacter spp.
by matrix-assisted laser desorption ionization-time of flight mass
spectrometry.” Stephan et al. J Clin Microbiol. 48(8):2846-51. 2010.
“Identification of dermatophyte species causing onychomycosis
and tinea pedis by MALDI-TOF mass spectrometry.”
Erhard et al. Exp Dermatol. 17(4):356-61. 2008
FOR RESEARCH USE ONLY
SARAMIS is covered by European Patent numbers EP1437673 and
EP1253622
SARAMIS is a trademark of bioMérieux. No attempt is made to
supercede this or any other trademarks
1-2 Minute
Identification
Kratos Analytical Ltd.
Wharfside, Trafford Wharf Road
Manchester M17 1GP, UK
Phone:+44 161 888 4400,
Fax: +44 161 888 4402
www.SSI.shimadzu.com
MO347 V1 ©Shimadzu June 2011