A case of bla(VIM-1) producing E. cloacae disseminated infection in a patient submitted to orthotopic liver transplantation is described. Synergism between colistin, rifampin and imipenem was studied in vitro and this combination of three drugs was used to treat E. cloacae infection. The synergistic activity of this combination was demonstrated showing an increased activity of the serum bactericidal activity in comparison with the bactericidal activity of the serum taken during the previous therapy.