Comparative proteomics of an extended spectrum β-lactamase producing Escherichia coli strain from the Iberian wolf

• Comparative proteomics of an ESBL-producing Escherichia coli strain from the endangered Iberian wolf
• Report of bacterial subcellular proteome changes induced by cefotaxime exposure
• The abundance of 40 proteins from different subcellular compartments was affected including chaperone, porin and export proteins.
• Advantages of model organism bioinformatics databases for identification and characterization of proteins

The Iberian wolf (Canis lupus signatus) is an endangered species native to the Iberian Peninsula. Due to their predatory and wild nature, these wolves serve as important indicators of environmental contamination by antimicrobial-resistant bacteria. β-Lactam antibiotics like cefotaxime are the most commonly used antibacterial agents. Bacterial resistance to these antibiotics occurs predominantly through enzymatic inactivation by extended-spectrum beta-lactamases. Escherichia coli strain WA57, isolated from Iberian wolf feces, is a cefotaxime-resistant strain that produces extended-spectrum beta-lactamases. In this study, using 2D-GE combined with MS and bioinformatics, we report significant differences in the abundance of 40 protein spots (p < 0.01) from the extracellular, periplasmic, cytoplasmic, and membrane sub-proteomes and the whole-cell proteome of WA57 exposed and non-exposed to cefotaxime. A total of 315 protein spots were collected for protein identification. The comparative proteomics presented gives an overview of the complex changes in expression and metabolism that occur when WA57 is stressed with cefotaxime. Abundance of chaperone, porin and export proteins is particularly affected showing that the stress response and transport functions might directly influence the antibiotic resistance of this strain.Biological significanceThis study highlights the importance of proteomics in detecting protein expression changes in bacterial strains exposed to stress such as that caused by cefotaxime. This approach might help us understand which pathways form barriers for antibiotics. This article is part of a Special Issue entitled: Environmental and structural proteomics.

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