Discrimination of Pathogenic Versus Non-Pathogenic Yersinia Pestis and Escherichia Coli Using Proteomics Mass Spectrometry

摘要

Recently, the use of mass spectrometry analysis to characterize and identify biological agents using a proteomic approach has been demonstrated. The present study sought to determine whether proteomics mass spectrometry could be used to distinguish between pathogenic and non-pathogenic strains of the same organism based on outer membrane proteins (OMPs). OMPs are often associated with virulence in gram-negative pathogens and could prove to be excellent model biomarkers for strain differentiation among bacteria. OMPs were isolated from pathogenic and non-pathogenic strains of Yersinia pestis and Escherichia coli using ultracentrifugation and a sarkosyl extraction method followed by protein digestion and analysis using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). The experimental MS/MS spectral data of bacterial peptides were searched using the SEQUEST algorithm against a constructed proteomic database of microorganisms to determine the identity and number of unique peptides. Results showed that pathogenic strains could be distinguished from nonpathogenic strains for both organisms based on differences in OMP profiles. Virulent E. coli and Y. pestis expressed multiple OMPs that were not present in avirulent samples. In conclusion, proteomics MS proved useful in discriminating between pathogenic and non-pathogenic strains, and OMPs unique to pathogenic strains could prove to be useful biomarkers for strain differentiation.