My research aims at understanding adaptive evolution in bacterial pathogens. I am interested in how and why bacteria evolve to cause disease, colonise and infect new host species, evade vaccines, and resist antibiotic treatments. To address these questions, I develop phylogenetic methodology and population genetic theory, and apply these to genomic and phenotypic data from wild populations and laboratory experiments. My research is inherently collaborative and I work closely with wet-lab microbiologists, epidemiologists, vets and clinicians. 

A common theme in my research is the need to understand bacterial pathogens in their broader evolutionary and ecological context. Advances in sequencing technologies have led to an increasing appreciation of the genetic and ecological diversity within pathogens and more broadly across the microbiome. Studying the drivers of this diversity and the relationship between pathogens and other members of the microbiome could lead to a deeper understanding of the ecology and evolution of pathogens that could inform control and treatment strategies.

Current areas of research:

• The evolution and ecology of bacterial pathogens: how and why bacterial ecologies change over time and how these changes influence broader evolutionary dynamics.
• The role of commensal populations in pathogen evolution, particularly the evolution of antibiotic resistance.
• The impact of purifying selection on bacterial evolution: how changes in mutation rate, genome size or recombination rate influence the burden imposed by deleterious mutations, how this translates to changes in the shape and depth of bacterial phylogenies, and how it influences the emergence and persistence of pathogens.