Proteomics for Drug Resistance on the Food Chain? Multidrug-Resistant Escherichia coli Proteomes from Slaughtered Pigs

Understanding global drug resistance demands an integrated vision, focusing on both human and veterinary medicine. Omics technologies offer new vistas to deciphermechanisms of drug resistance in the food chain. For example, Escherichia coli resistance to major antibiotics is increasing whereas multidrug resistance (MDR) strains are now commonly found in humans and animals. Little is known about the structural and metabolic changes in the cell that trigger resistance to antimicrobial agents. Proteomics is an emerging field that is used to advance our knowledge in global health and drug resistance in the food chain. In the present proteomic analysis, we offer an overview of the global protein expression of differentMDR E. coli strains from fecal samples of pigs slaughtered for human consumption. A full proteomic survey of the drug-resistant strains SU60, SU62, SU76, and SU23, under normal growth conditions, was made by two-dimensional electrophoresis, identifying proteins by MALDI-TOF/MS. The proteomes of these four E. coli strains with different genetic profiles were compared in detail. Identical transport, stress response, or metabolic proteins were discovered in the four strains. Several of the identified proteins are essential in bacterial pathogenesis (GAPDH, LuxS, FKBPs), development of bacterial resistance (Omp's, TolC, GroEL, ClpB, or SOD), and potential antibacterial targets (FBPA, FabB, ACC's, or Fab1). Effective therapies against resistant bacteria are crucial and, to accomplish this, a comprehensive understanding of putative resistance mechanisms is essential. Moving forward, we suggest that multi-omics research will further improve our knowledge about bacterial growth and virulence on the food chain, especially under antibiotic stress.