The bacterium Escherichia coli is a major cause of infections in people in hospitals and the community. E. coli can become resistant to commonly used antibiotics through the acquisition of resistance-encoding genes. When people are infected with these strains, their infection can be difficult to treat and they are at a higher risk of death. 

Catherine Ludden's research is based on a One Health approach to investigate the origin and transmission of antimicrobial-resistant E. coli in the UK. She will use genome sequence data of antimicrobial-resistant E. coli from hospitalised haematology patients, the hospital environment, livestock, wastewater and bloodstream infections in the UK to determine the genetic relatedness of isolates and associated mobile genetic elements from these different sources to define shared reservoirs. Mathematical modelling will be used to infer transmission, test hypotheses and to determine the likely impact of interventions to reduce transmission of antimicrobial-resistant E. coli.

She is also involved in the development a National Surveillance programme for Carbapenem resistant Enterobacteriaceae in Ireland and integrating whole genome sequencing into health services. This will provide evidence on antimicrobial resistance reservoirs, routes of transmission between them and detection of novel mechanisms of resistance in emerging strains.