Bacterial DNA was obtained by boiling method. Briefly,
the isolates were cultivated onto Luria-Bertani (LB) Agar
(Difco, USA) overnight at 37 8C. A loopful for each bacterial
growth was resuspended in 300 mL of sterile ultrapure
water, boiled at 100 8C for 10 min and centrifuged to
10,000 g for 5 min. The supernatants were utilized as
templates in mPCR for detection of the Shiga toxin (stx1
and stx2) and intimin (eae) genes, according to Paton and
Paton (1998).