Rapid Identification of Bacillus Spores by MALDImini™-1 Compact MALDI Digital Ion Trap (DIT) Mass Spectrometer

Introduction

Identification of bacterial species is necessary for the determination of the appropriate antibacterial drugs for pathogenic strains and for identifying the type of bacteria responsible for food spoilage. In recent years, microbial analysis by MALDI-TOF MS has become the technique of choice in microbiology laboratories, as this method enables simple and quick identification of a wide variety of microorganisms. Although powerful, this technique is limited in its ability to identify mixed cultures and spore-based bacteria. Quick identification of powdered anthrax spores as a bio terrorism countermeasure is a prime example. One way to overcome this limitation is to target peptides generated by proteolysis of bacterial proteins. Protein identification using an MS/MS search against available databases enables the determination of the species from which the proteins originated. This workflow can be readily applied to protein extracted from a mixture of microorganisms. Thanks to the precursor selection, specific peaks can be selected from multiple peaks which suggests that microbial identification is possible using a different approach from conventional microbial identification by MALDI. Based on an early approach published by Warscheid, et al. (1), we attempted quick identification of Bacillus spores by using a combination of rapid tryptic digestion of proteins on trypsin beads followed by MS/MS fragmentation using the compact MALDI digital ion trap (MALDImini-1) mass spectrometer.

July 27, 2020 GMT