Professor Riley divides his time in Perth, Western Australia, between PathWest Laboratory Medicine, WA’s public sector pathology service provider where he is a Senior Clinical Scientist, Edith Cowan University where he is a Professorial Research Fellow, and Murdoch University where he is Professor of Public Health. He has had a long standing interest in healthcare-related infections, particularly the diagnosis, pathogenesis and epidemiology of Clostridium difficile infection and the antimicrobial activity of Australian native plants. He is a Fellow of the Royal College of Pathologists, the Australian Society for Microbiology, the American Academy of Microbiology, the Society for Healthcare Epidemiology of America and the Faculty of Science of the Royal College of Pathologists of Australasia, and has published over 400 book chapters and refereed journal articles, including more than 50 related to the antimicrobial properties of tea tree oil, an area of research for which he has been continuously funded by the Rural Industries Research and Development Corporation since 1993, and over 200 on C. difficile.