2.2. Shiga Toxin-Producing Escherichia coli (STEC)
STEC were obtained from the USDA-ARS Western Regional
Research Center, USDA-ARS Mid-Western Center, USDA-ARS Clay
Center, the Centers for Disease Control and Prevention (Atlanta,
GA), and the American Type Culture Collection (ATCC, Manassas,
VA, 2012). STEC origins and genotypes including O and H antigen
types, and presence or absence of virulence genes were provided by
those donating the isolates (Table 1)