Incidence of virulence genes in all O157 and non-O157 STEC isolatesa.

aRepresents isolates saved after screening a larger number of isolates by stx-PCR, O-typing ELISA, MLVA and ompA sequencing. Data from this characterization facilitated selection of isolates to represent those from an individual sample and minimize replication of strains from a sample. STECs isolated by all 3 methods are included.bBoth stx1 and stx2 present in the same strain.cCattle, alpaca, goats.dIsolates from any water sample are included.