The existence of the type 1 fimbriae gene (fimC), temperature-sensitive hemagglutinin (tsh), aerobactin gene (iucD), enteroaggregative toxin gene (astA), increased serum survival gene (iss), iron repressible gene (irp2), and iron transport gene (iutA) in the E. coli O2 strain may be a higher potential risk factor for infection in poultry than the existence of those in other E. coli isolates. Here, IREB2 is linked to infection.