Catalyzes the addition of a phosphoethanolamine moiety to the lipid A. The phosphoethanolamine modification is required for resistance to polymyxin. Has been isolated as a 91 kDa complex containing ZipA-EptA and an unidentified 24 kDa protein. The eptA-basRS operon is positively autoregulated by BasR under high iron or aluminum concentration conditions. Belongs to the phosphoethanolamine transferase family. EptA subfamily. Extended N-terminus.