Role of multiple antibiotic efflux pumps in the removal of cellular metabolites

Bacteria resistant to multiple antibiotics are one of the major challenges to public health worldwide. Bacterial pumps capable of effluxing multiple antibiotics out of cells are major contributors to this problem, and are also involved in virulence. These pumps are present in all bacteria, and are well conserved in many cases. AcrAB>TolC is the main multidrug efflux in Escherichia)coli and many other important pathogenic bacteria. This pump effluxes multiple classes of antibiotics, as well as bile salts and other exogenous toxic compounds. However, the physiological roles and substrates of this pump, beyond the efflux of exogenous compounds, are still poorly understood. Finding such substrates could lead to development of novel efflux pump inhibitors. Such inhibitors could have a tremendous impact in the therapy of infectious diseases by restoring antibiotic efficacy and decreasing virulence. The aims of this project are: 1) To identify the cellular metabolites that are substrates of the AcrAB>TolC multidrug efflux in Escherichia)coli by untargeted metabolomicsF and 2) To test whether those metabolites can be used as competitive inhibitors of this pump to lock antibiotic efflux in Escherichia)coli and related pathogens such as Salmonella or Klebsiella.