Journal de protéomique et d'enzymologie

Tandem Mass Spectrometry Analysis as an Approach to Delineate Genetically Related Taxa, with Specific Implication for Differentiating Escherichia coli from amongst the Complex Enterobacteriaceae Family

Raju V Misra , Tom Gaulton , Min Fang , Renata Culak , Martin Hornshaw , Jenny Ho , Saheer E Gharbia and Haroun N Shah

Aims: This work aims to evaluate the potential of GeLC-MS/MS to delineate taxa which are beyond the resolution of 16S rRNA and MALDI-TOF-MS identification, simultaneously discerning biomarkers of pathogenicity.

Methods and Results: 16S rRNA sequence analysis and MALDITOF- MS was performed to differentiate genetically closely related species from the family Enterobacteriaceae. In parallel GeLC-MS/ MS, using E. coli and related enteric bacteria as a model, was performed. Species specific peptides were identified and used to create an optimised identification database, against which a panel of test strains were analysed to determine the resolution of GeLCMS/ MS for bacterial identification and strain characterisation. The panel included amongst others pathogenic E. coli strains, of differing pathotype, including E. coli O104:H4. The test strains could be resolved to the species and pathotype (subspecies) in addition, specific features could be identified.

Conclusions: Using an optimised genome database and proteome profiling, we identified biomarkers that were specific for the test species and characterised strain-specific virulence factors. Significance and Impact of the

Study: This proof of concept study demonstrates that whole genome sequences and GeLC-MS/ MS have the potential to both identify and characterise pathogenic bacteria in a single assay, ushering in a new proteogenomic trend for microbial clinical diagnostics