A Proteomics Approach to Identify Possible Biomarkers of Early and Late Stages of E. coli-induced Urinary Tract Infections

As one of the most common bacterial infections globally, urinary tract infections (UTI)s affect the bladder and kidneys of many the bladders and kidneys of many. Along with gram-negative bacteria, Escherichia coli (E. coli) causes nearly 40% of nosocomial UTIs, 25% of recurrent infections, and between 80 to 90% of community-acquired infections. Proteomics, commonly used to study changes in protein expression of organisms, can be used to explore candidate biomarkers useful for the diagnosis of pathological conditions. Here, protein profiles of samples from patients diagnosed with E. coli-induced UTI were compared to identify distinctive proteins. Extracted proteins from bacteria from patients’ urine samples were separated into excisable spots using 2D-gel electrophoresis. The gels were then analyzed using Progenesis SameSpot software to select uniquely expressed protein spots, excised, and analyzed by LC/MS. The results were then compared against a database of known proteins. We identified two proteins, outer membrane protein A (OmpA) and RNA polymerase-binding transcription factor (DksA), involved in the survival of E. coli in the harsh environment of the host. We suggest their use as a part of a battery of possible biomarkers proteins for E. coli-induced UTI, and suggest that their overexpression is possibly associated with the stage of infection, early or late.