Table 1.

E. coli strains and plasmids used in this study

E. coli strain or plasmidGenotype or characteristic(s)Reference or source
 RS218O18:K1:H7 21
 E44Rifr derivative of RS218
 DH5αF recA1 hsdR17 thi-1 gyrA96 supE44 endA1 relA1 recA1 deoR Δ(lacZYA-argF)U169 (φ80lacZM15)Gibco/BRL
 SM10λpir thi thr leu tonA lacY supE recA::RP4-2-Tc::Mu (λpir)pro endA hsdA hsdR supF 3
 7A-33E44 ibeB::TnphoA This study
 IB7D5ΔibeB derivative of E44 via allelic exchangeThis study
 HB101K-12 supE44 ara-14 galK12 rpsL20 (Strr) 18
 pRT733oriR6K mobRP4 TnphoA 7
 pCVD433pACYC184 modified by insertion of an MluI linker 3
 pCVD442Ampr SacB oriR6K mobRP4 4
 pCD7DpCVD442 carrying a 2.3-kb DNA fragment with an in-frame ibeB deletionThis study
 pCRIIAmpr Kanr oriCol E1 oriF1Invitrogen
 pCD7ApCVD433 carrying the ibeBlocus with a TnphoA insertionThis study
 pCIB7B ibeB (0.67 kb) pCRIIThis study
 pCR7CpCRII carrying the ibeB gene (1.6 kb)This study
 pKS7-13KpBluescript KS carrying a 13.0-kbibeB locus (13K)This study
 pKS7-7BpBluescript KS carrying a 7.0-kb ibeB locus (7B)This study
 pKS7-6NpBluescript KS carrying a 6.1-kb DNA fragment with anibeB deletionThis study
 pKS7-5HpBluescript KS carrying a 5.7-kb DNA fragment with ibeB deleted (5H)This study
 pFN476Ampr low copy, T7 promoter 20
 pFN7CpFN476 carrying theibeB gene (1.6 kb)This study
 pGP1-2Kanr, low copy, T7 RNA polymerase gene 20