Compounds that regulate quorum sensing in Staphylococcal bacteria and in particular in Staphylococcus aureus are provided. Compounds are described in formulas I, II, III, IV, V and VI herein. One or more compounds herein can be employed to inhibit QS and to thus inhibit virulence in Staphylococcus bacteria and in particular in Staphylococcus aureus. Compounds herein and pharmaceutical compositions containing one or more of these compounds are useful, for example, in treating infections of Staphylococcus bacteria and in particular of Staphylococcus aureus. Methods for treating such bacterial infections are provided.