In this PhD project, you will combine classical microbiology, microbial genetics and single cell microscopy to determine how bacterial defences evolve, and how they shape the spread of antimicrobial resistance (AMR). You will identify primary defence barriers for mobile genetic elements and trade-offs between genome protection and AMR acquisition. This project will advance our understanding of the importance of defences for the spread of AMR, a slow-moving pandemic, identified by the WHO as a top 10 threat facing humanity. Results from this work will pave the way for personalised medicine based on pathogen genotypes and phenotypes, leveraging incomplete defences of multidrug resistant pathogens for phage therapy. This work can also help to predict and manipulate the risks of AMR spread in natural, medical or industrial contexts.