Proteomic comparison of three clinical diarrhoeagenic drug-resistant Escherichia coli isolates grown on CHROMagar™STEC media

• Published in: Journal of proteomics Vol. 180; pp. 25 - 35
• Main Authors: Kalule, John Bosco, Fortuin, Suereta, Calder, Bridget, Robberts, Lourens, Keddy, Karen H., Nel, Andrew J.M., Garnett, Shaun, Nicol, Mark, Warner, Digby F., Soares, Nelson C., Blackburn, Jonathan M.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 30-05-2018
• Subjects: Antimicrobial resistance; Drug Resistance, Bacterial; Electron microscopy; Enteropathogenic Escherichia coli - growth & development; Enteropathogenic Escherichia coli - isolation & purification; Escherichia coli Proteins - metabolism; Proteomics; Shiga-Toxigenic Escherichia coli - growth & development; Shiga-Toxigenic Escherichia coli - isolation & purification; Shiga-toxin-producing E. coli; Virulence; Virulence Factors - metabolism; Shiga-toxin-producing E. coli; Antimicrobial resistance; Electron microscopy; Virulence; Proteomics
• ISSN: 1874-3919; 1876-7737
• DOI: 10.1016/j.jprot.2017.09.003

Shiga-toxin-producing Escherichia coli (STEC) and enteropathogenic Escherichia coli (EPEC) are key diarrhoea-causing foodborne pathogens. We used proteomics to characterize the virulence and antimicrobial resistance protein profiles of three clinical pathogenic E. coli isolates (two EPEC [one resistant to ciprofloxacin] and one STEC) cultured on CHROMagar™STEC solid media after minimal laboratory passage. We identified 4767 unique peptides from 1630 protein group across all three clinical E. coli strains. Label-free proteomic analysis allowed the identification of virulence and drug resistance proteins that were unique to each of the clinical isolates compared in this study. The B subunit of Shiga toxin, ToxB, was uniquely detected in the STEC strain while several other virulence factors including SheA, OmpF, OmpC and OmpX were significantly more abundant in the STEC strain. The ciprofloxacin resistant EPEC isolate possessed reduced levels of key virulence proteins compared to the ciprofloxacin susceptible EPEC and STEC strains. Parallel reaction monitoring assays validated the presence of biologically relevant proteins across biologically-replicated cultures. Propagation of clinical isolates on a relevant solid medium followed by mass spectrometry analysis represents a convenient means to quantify virulence factors and drug resistance determinants that might otherwise be lost through extensive in vitro passage in enteropathogenic bacteria.
Through the use of quantitative proteomics, we have characterized the virulence and antimicrobial resistance attributes of three clinically isolated, pathogenic E. coli strains cultured on solid media. Our results provide new, quantitative data on the expressed proteomes of these tellurite-resistant, diarrhoeagenic E. coli strains and reveal a subset of antimicrobial resistance and virulence proteins that are differentially abundant between these clinical strains. Our quantitative proteomics-based approach should thus have applicability in microbiological diagnostic labs for the identification of pathogenic/drug resistant E. coli in the future.
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•Virulence and antimicrobial resistance attributes of three clinically isolated pathogenic E. coli strains.•Link between cell envelope thickness and levels of key cell envelope proteins.•Utility of tellurite containing screening agar for the detection of EPEC and STEC.•Proteomic analysis enable identification of virulence factors and antimicrobial resistance mechanisms.•Verification of key differentially abundant proteins by PRM assays.