I have worked for over 20 years on the molecular physiology of Staphylococcus aureus (S. aureus), a major cause of death and disease in humans. The spread of antibiotic resistance (MRSA, VRSA) highlights its importance. Research has concentrated on a number of areas including stress responses, vaccine development, essential genes, host-pathogen interaction and cell wall architecture/dynamics. The research spans from fundamental biology to the discovery and development of targets for novel therapy and prophylaxis. Research in my laboratory centres on two main themes associated with bacterial molecular physiology: 1. How S. aureus interacts with its host. In particular we have been determining the role of human innate defences in the control of S. aureus. We have also identified a number of potential novel targets to be exploited as vaccine components. The role and use of these for prophylaxis are the subject of current investigations. 2. Bacterial cell wall structure and function. The cell wall peptidoglycan is essential for the life of most bacteria and its synthesis is the target of important antibiotics such as penicillin and vancomycin. We are using atomic force microscopy and other super-resolution microscopy techniques to determine the architecture and dynamics of peptidoglycan across the bacteria. This has revealed a hitherto unexpected complexity leading to new models of cell wall growth and division.