Antibiotic resistance in bacteria is a worldwide health issue with an increasing number of human pathogens acquiring resistance to nearly all available antibiotics. Pre-eminent among these is Staphylococcus aureus, one of the major causes of bacterial infection, particularly in hospitalised patients. Most epidemic strains of multi-resistant S. aureus express resistance to a range of cationic compounds including quaternary ammonium compounds (QACs). In addition to providing many pathogenic bacteria with protection against antiseptics and disinfectants, this resistance may also encode resistance to antimicrobial cationic peptides that form part of the body’s defence mechanism. This study will focus on characterising the genetic determinants of cationic resistance in staphylococci with a view to understanding the roles they may play in the survival and spread of staphylococci within hospitals as well as the virulence and pathogenicity of the staphylococci.