TABLE 1.

Bacterial strains and plasmids used

Strain or plasmidDescriptionSource or reference
Strains
    Sakai 813Isogenic stx1 and stx2-negative nontoxigenic derivative of the Sakai strain; contains insertion of kanamycin resistance gene into stxA2 gene and has deletion of 624-bp BsiWI fragment encompassing the start of the stxA1 gene and the 5′ flanking regionChihiro Sasakawa
    LZ1ygeH deletion mutant of Sakai 813This study
    LZ2etrA deletion mutant of Sakai 813This study
    LZ3eivF deletion mutant of Sakai 813This study
    193 NalrSpontaneous nalidixic acid-resistant mutant of recent bovine EHEC O26:H- isolate from the United KingdomThis study
Plasmids
    pKD46For deletion mutagenesis; encodes lambda Red genes11
    pKD3For deletion mutagenesis; template plasmid11
    pCP20For deletion mutagenesis; encodes FLP recombinase11
    pBAD30Low-copy-number expression vector with arabinose-inducible promoter20
    pBADetrAetrA cloned into pBAD30This study
    pBADeivFeivF cloned into pBAD30This study
    pAJR71 to pAJR75GFP fusion plasmids with promoters from LEE-1 to LEE-5 operons cloned in frame 5′ to the gene amplified from enhanced half-life GFP vector peGFP (Clontech, Ltd., Basingstoke, United Kingdom)48