The multidrug effluxtransporterNorM from V. parahaemolyticus which mediatesresistance to multiple antimicrobial agents and its homologue from E. coli were identified in 1998. NorM seems to function as drug/sodium antiporter which is the first example of Na+-coupled multidrug efflux transporter discovered. NorM is a prototype of a new transporter family and Brownet al. named it the multidrug and toxic compound extrusion family. NorM is nicknamed "Last of the multidrug transporters" because it is the last multidrug transporter discovered functionally as well as structurally.