MALDI-TOF Microbial ID Service:
The MALDI-TOF microbial identification testing process yields a unique protein spectral fingerprint that is then compared to the Accugenix® validated MALDI database for bacterial and yeast identification. The AccuPRO-ID® solution provides higher accuracy rates than phenotypic methods, produces faster results, and is a less expensive option for routine environmental monitoring programs.
Use this guide for interpreting identification results generated by the AccuPRO-ID® MALDI microbial identification service.
Why Outsource MALDI-TOF Microbial Identification Services Using Accugenix®?
- Higher confidence for species-level identifications when applying MALDI-TOF for microbiology lab applications.
- AccuPRO-ID® MALDI-TOF microbial identification process is cGMP-compliant and ISO 17025-accredited.
- Superior performance over existing phenotypic and other MALDI-TOF systems due to relevant microbial databases.
- Demonstrated improvement in accuracy (30 – 40%) over phenotypic identification systems.
- Proven to increase reproducibility and repeatability.
- Accugenix® proprietary MALDI-TOF microbial database provides more extensive coverage for environmental monitoring isolates than any other commercially available MALDI-TOF system for microbiology labs.
- Backed up by our AccuGENX-ID® DNA sequencing method at no additional cost.
AccuPRO-ID® MALDI-TOF microbial identification requires fresh growth, so samples must be alive and healthy. Live cultures should be shipped overnight at ambient temperature. The total time from sample inoculation to arrival should not exceed 48 hours. Live cultures exceeding 48 hours of age may have to be subcultured.
Frequently Asked Questions (FAQ’s) for MALDI-TOF Microbial Identification
What is mass spectrometry?
Mass spectrometry is an analytical technique where chemical substances are identified by sorting gaseous ions in electric and magnetic fields according to mass-to-charge ratios. The exact molecular weight of the sample can often be calculated based on the mass-to charge-ratio. By determining the weight, the sample can be identified. Accugenix® uses MALDI-TOF mass spectrometry for AccuPRO-ID® microbial identification services.
What does the MALDI-TOF acronym stand for?
MALDI-TOF stands for Matrix-Assisted Laser Desorption/Ionization-Time of Flight.
What is a molecular ion peak in mass spectrometry?
Emission of an electron from an electrically neutral compound leads to production of a molecular ion. This ion provides information on molecular weight because the electron mass is so small compared to the mass of a molecule that the mass of a molecular ion is regarded as the mass of the molecule.
What MALDI-TOF system can be used to identify microbial organisms in a microbiology lab?
Our Axcess® MALDI-TOF solution is an ideal combination of precise instrument and relevant microbial libraries for maximizing in-house identification rates.
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What is the MALDI-TOF microbial identification process?
A small portion of the colony is deposited and smeared on a dedicated spot of a plate to form an even layer of cells. When performing the MALDI-TOF microbial identification process freshly grown colonies containing actively dividing cells with intact proteins should be subjected to testing. A solution of an organic acid referred to ensure good sample integrity for analysis. A solution of an organic acid referred to as "matrix" is then deposited on the spot to cover the sample. Upon drying, the matrix co-crystallizes with biomolecules present in the colony material. These biomolecules include peptides and proteins, the target analytes in the process. The matrix forms a scaffold and provides a source of protons for the ionization and undergoes a UV laser irradiation. The matrix features a maximum of energy absorbance at the same wavelength at which the laser works (337 nm), hence avoiding the destruction of the sample by the laser. The energy of the radiation is transferred to the sample, allowing desorption of the main compounds (transition of the solid state to the gas phase). Additionally, the sample gets ionized by the slightly acidic matrix (proton transfer) upon which the journey of charged peptides and proteins starts. After initial acceleration using an electrostatic field, the proteins drift toward the detector at a speed defined by their mass-to-charge ratio. The end of the journey occurs when the proteins hit the surface of the detector lined with a semi-conductive layer, resulting in electrical impulses produced at times specific for different proteins. A major part of information comes from the fraction of ribosomal proteins in addition to DNA-binding proteins as well as heat shock proteins. Among others, a time of flight (ToF) information is then transformed into mass spectra data depicted as a sequence of mass peaks forming a characteristic microorganisms' profile, also called peptide mass fingerprint (PMF).The integrated software generates a list of closest matching species classified according to their protein fingerprint similarity, accompanied by a score value which indicates secure species or genus level identification.