Identifying new virulence genes

Identifying bacterial virulence genes is often challenging, as standard approaches rely on comparing gene expression across different growth conditions, typically a virulence-inducing condition versus an avirulent one. Such comparisons frequently capture many condition-specific changes that are unrelated to virulence itself.

We overcome this limitation by using Microcolony-seq, which enables direct comparison of bacterial subpopulations grown under identical conditions. Using this strategy in EPEC, and focusing on previously unannotated genomic regions, we identified pilW and demonstrated that it encodes a central virulence protein required for attachment to host cells.

Building on this concept, we aim to systematically uncover additional, previously hidden virulence factors by disentangling true virulence programs from general growth-condition effects.