Involved in resistance to several unrelated toxic compounds, such as dyes, detergents and antibiotics. Probably part of a tripartite efflux pump, which is composed of an outer membrane efflux protein, an inner membrane protein and a protein that expands the periplasmic space. Could form a tripartite pump with BepC and BepE. Repressed by BepR. Belongs to the membrane fusion protein (MFP) (TC 8.A.1) family.