His personal research interests focus on severe bacterial infections, including meningitis and Staphylococcus aureus bloodstream infection, and tuberculosis. He has a longstanding research interest in the diagnosis, treatment and pathophysiology of tuberculous meningitis. Much of his research has been centred on large, pragmatic, randomized controlled trials which have addressed questions of key clinical importance, but have also provided the framework for providing unique insights into disease pathogenesis, antimicrobial pharmacology, and host and bacterial genetics.