Cloning and characterization of a novel chromosomal drug efflux gene in Staphylococcus aureus

A novel drug efflux gene (named sepA, staphylococcal efflux pump-gene) is cloned from antiseptic-resistant mutants of Staphylococcus aureus into Escherichia coli. The sepA gene conferred the reduction of susceptibility to acriflavine and the acceleration of ethidium bromide efflux from the E. coli cells. The sepA (474 bp) encoded the protein that has four predicted transmembrane segments. These results indicate that sepA gene is a multidrug-resistant gene and encodes a drug efflux protein.