IREB2 and escherichia coli infection: These include adhesion factors, toxins, iron acquisition genes and genes associated with serum resistance, such as fyuA, iucD, iroN, iss, irp2, hlyF, vat, kpsM and ompT. Although APEC isolates present different combinations of virulence factors, each retains the capability to cause colibacillosis [13, 74].