QacA Multidrug Efflux Pump from Staphylococcus aureus: Comparative Analysis of Resistance to Diamidines, Biguanidines, and Guanylhydrazones

The staphylococcal multidrug efflux pump QacA mediates resistance to a broad spectrum of monovalent and divalent antimicrobial cations. Resistance toward various classes of these compounds identified features of the substrate that may be important for interaction with QacA. Analysis of combinations of two substrates suggested that the same mechanism is used for the extrusion of different classes of compounds.