Plasmid-encoded resistance to tetracycline in Staphylococcus haemolyticus

A small 4.35 kb plasmid, designated pSTS4, was isolated from a multiresistant Staphylococcus haemolyticus culture. It conferred resistance to tetracycline as shown by protoplast transformation. pSTS4 was further characterized by restriction endonuclease analyses and a preliminary restriction map constructed. It shared some structural similarities with previously described small TcR plasmids from other staphylococcal species of human and animal origin. pSTS4 encoded two proteins of approximately 37 kDa and 52 kDa as revealed by combined in vitro transcription/translation assays.