Involved in the efflux of toxic and relatively hydrophobic compounds. Influences survival inside the host. 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 BepD and BepE or with BepF and BepG. Mutation strongly affects resistance to bile salts and toxic chemicals, and significantly decreases the resistance to antibiotics such as erythromycin, ampicillin, tetracycline, and norfloxacin. The mutant also has attenuated effects in the mouse model of infection. Belongs to the outer membrane factor (OMF) (TC 1.B.17) family.