Microbial Identification using MALDI-TOF Mass Spectrometry

In the field of microbiology, ifp has established MALDI-TOF mass spectrometry (Matrix Assisted Laser Desorption Ionization - Time of Flight) as a method for the identification of bacteria, yeasts and moulds.

Microbial identification according to specific ribosomal protein patterns

Identification by means of MALDI-TOF relies on obtaining a unique molecular fingerprint of the respective target organism. This is done by measuring specifically the ribosomal proteins, which are found in large quantities in all microorganisms. The characteristic spectra of these proteins are used to identify a certain microorganism by comparing the respective pattern with those in several databases.

Ionization and detection in a Time-of-flight detector

To do so, the pure-culture microorganism to be identified is placed on a sample carrier either directly or after brief protein extraction, coated with an organic matrix and measured in the MALDI-TOF. Measurement is done based on laser bombardment of the analyte-matrix mixture, leading to ionization. The ions are accelerated and their specific masses are detected in the time-of-flight detector. This results in the specific mass spectrum which is used to identify the microorganism to be determined. The measuring procedure takes only a few minutes.

Advantages of microbial identification using MALDI-TOF

  • rapid and precise
  • little sample material required
  • can be used for bacteria, yeasts and fungi
  • constantly expanding database
  • readily available storage of all spectra and evaluations
  • customized databases
  • contamination traceability
  • identification of facility-specific monitoring isolates