Multidrug resistance efflux protein involved in transporting several clinically relevant monovalent and divalent biocides and the fluoroquinolone antimicrobial agents norfloxacin and ciprofloxacin. Required for transcription of agr and RNAIII and involved in the production of protein A (spa) and toxins alpha, beta and delta. Repressed by MepR. Belongs to the multi antimicrobial extrusion (MATE) (TC 2.A.66.1) family. MepA subfamily.