Rapid differentiation of Enterococcus species by MALDI-TOF mass spectrometry

The controversial nature of Enterococcus genus is due to the great variability among pathogens, spoilage and apparently safe strains. The current research focuses on the study and characterization of Enterococcus strains involved in nosocomial infections. However, little research has been carried out on Enterococcus strains in foodstuffs. In this work, 54 strains of different species of Enterococcus have been characterized by means of MALDI-TOF MS analysis, getting highly specific mass spectral fingerprints. Genus-specific peaks and peaks common to certain bacterial species of Enterococcus have been identified. Thus, three protein peaks at m/z 4426, 4732 and 6401 were marked our as genus specific biomarkers, this is, proteins that are characteristic for each species of Enterococcus. The approach described in this study leads the way toward the rapid and specific identification of different strains and species of Enterococcus in food based on molecular protein markers with aiming the early detection of pathogenic strains and strains implicated in food poisoning and in food spoilage of the Enterococcus genus.