In January 2025, Santé publique France detected several cases of hemolytic uremic syndrome (HUS) in adults caused by a rare serotype of Shiga toxin-producing Escherichia coli, STEC O77g:H18. Epidemiological and traceability investigations linked the consumption of raw-milk cheese to these cases. The outbreak strain belonged to sequence type 69 (ST69) and harbored a Shiga toxin (stx) subtype stx2d located on a unique prophage. Putative virulence genes cdt-VABC, hlyE, <