previously (Fode-Vaughan et al. 2001). The PCR conditions
for amplification of stx1 and stx2 were those used for pmoA
(Fode-Vaughan et al. 2001). The stx1F/stx1R primer pair
has £2 mismatches to all stx1 sequences deposited in
GenBank by February 2003. The stx2F/stx2R primer pair is
a perfect match for all the E. coli O157:H7 sequences
deposited with one exception that has an insertion within the
stx2 sequence. The stx2 primer pair would also be expected
to amplify stx2 sequences from other STEC, and from
Citrobacter freundii and Enterobacter cloacae.