Bacterial infectious diseases are a serious threat to human health, accounting for over 10 million deaths each year. This multidisciplinary collaborative team is investigating the complex interactions between major disease-causing bacteria and their human hosts, in order to determine how they cause disease. These studies will make a major contribution to fundamental knowledge in this field. This information is also essential for the development of cheaper and more effective vaccins, as well as novel drugs. These are urgently needed to reduce death and illness due to bacterial infectious diseases in the 21st century.