Rafal Mostowy: Diversity and evolution of polysaccharide antigens in Enterobacteriaceae
May 25, 2018
15:00 - 16:00
Rafal Mostowy from the Imperial College London, UK
More information on the speaker: https://www.imperial.ac.uk/people/r.mostowy
Polysaccharide antigens (PAs), like capsules and LPS, coat many bacteria. Their enormous diversity suggests that they might dynamically evolve via recombination, which would present a big challenge for capsule-targeting treatments like vaccines or phage therapy. To investigate this, I have analysed >27,000 genomes from all publicly available isolates of Enterobacteriaceae at NCBI, and searched for the presence of two major PA biosynthesis loci. I then used a combination of sequence-similarity graphs and phylogenetics to analyse what PA diversity tells us about the evolution of these loci. These results emphasise a large evolutionary plasticity of PAs, and their potential to rapidly adapt to clinical treatments; they also point to different ecological mechanisms shaping antigen-directed diversifying selection in different species.