STX2 and hemolytic-uremic syndrome: For this purpose, transcriptional analysis of the Stx2a subunit genes, stxA2a and stxB2a, was performed by quantitative real-time PCR in one foodborne O113:H21 STEC isolate (strain TS18/08) and five HUS-associated EHEC strains with the serotypes O157:H7/H− (HUSEC003, HUSEC004), O103:H− (HUSEC008), O26:H11 (HUSEC018), and O104:H4 (LB226692).