The role of the qacA gene in mediating resistance to quaternary ammonium compounds.

Conditions facilitating resistance to quaternary ammonium compounds (QACs) were investigated in Staphylococcus aureus SK982 exposed to benzalkonium chloride (BAC; a member of QACs) under various circumstances. S. aureus SK982 carrying the qacA gene encoding for resistance to QACs was grown in the presence of stable or gradually increasing concentrations of BAC, or it was exposed to this antiseptic in the exponential phase of growth.