Extracellular protein biomarkers for the characterization of enterohemorrhagic and enteroaggregative Escherichia coli strains.

The extracellular proteins (ECPs) of enterohemorrhagic Escherichia coli (EHEC) can cause hemorrhagic colitis which may cause life threatening hemolytic-uremic syndrome, while that of enteroaggregative E. coli (EAEC) can clump to intestinal membranes. Liquid chromatography-electrospray ionization-tandem mass spectrometry based proteomics is used to evaluate a preliminary study on the extracellular and whole cell protein extracts associated with E. coli strain pathogenicity. Proteomics analysis, which is independent of genomic sequencing, of EAEC O104:H4 (unsequenced genome) identified a number of proteins. Proteomics of EHEC O104:H4, causative agent of the Germany outbreak, showed a closest match with E. coli E55989, in agreement with genomic studies. Dendrogram analysis separated EHEC O157:H7 and EHEC/EAEC O104:H4. ECP analysis compared to that of whole cell processing entails few steps and convenient experimental extraction procedures. Bacterial characterization results are promising in exploring the impact of environmental conditions on E. coli ECP biomarkers with a few relatively straightforward protein extraction steps.