Expression of the tetA(C) tetracycline efflux pump in Escherichia coli confers osmotic sensitivity

Expression of tetA(C) in Escherichia coli confers resistance to tetracyclin e as well as sensitivity to nickel and cadmium salts, lipophilic chelating agents, and aminoglycoside antibiotics. In this report we determine that hi gh-level expression of tetA(C) also confers an osmotic sensitivity. The osm otic-sensitive phenotype is distinct from the tetracycline-resistant phenot ype and can be localized to a domain contained within the first 98 amino ac id residues of the TetA(C) polypeptide. (C) 2000 Federation of European Mic robiological Societies. Published by Elsevier Science B.V. All rights reser ved.