Consistent with a role for O-Ag in S. sonnei virulence, dual-RNAseq profiling identified wzzB/SSON53G_RS12230 (a protein involved in the extension of O-Ag oligosaccharide chains) as significantly upregulated (Log2(FC) = 1.31, padj = 3.31·10−25) during zebrafish infection (S3L Fig). This evidence concerns the gene RENBP and infection.