James Paton has made a major scientific contribution to the field of pathogenesis and prevention of bacterial infectious diseases, with particular reference to the human pathogens Streptococcus pneumoniae and Shiga toxigenic Escherichia Coli. His work has established the important role of certain pneumococcal virulence proteins in pathogenesis, and demonstrated their potential as vaccine antigens for prevention of pneumococcal disease, regardless of capsular serotype. Other achievements include characterisation of genes encoding pneumococcal capsule biosynthesis, development of toxin-binding probiotics for prevention of enteric infections, and characterisation of a novel family of bacterial AB5 cytotoxins.