Table 1 Strains and plasmids used in this study

E. coli strains

XL1Blue

recA1 lac endA1 gyrA96 thi hsdR17 supE44 relA1 (F’ proAB lacI ^q lacZ ΔM15 Tn10)

Stratagene

DH5α

F⁻ Φ80lacZΔM15 Δ(lacZYA-argF) U169 recA1 endA1 hsdR17(r_k ⁻ m_k ⁻) phoA supE44 λ⁻ thi- gyrA96 relA1

Gibco BRL

HB101

F⁻ mcrB mrr hsdS20(r_B ⁻ m_B ⁻) recA13 leuB6 ara-14 proA2 lacY1 galK2 xyl-5 mtl-1 rpsL20(Sm^R) glnV44 λ⁻

ATCC 33694

S17(λpir)

Tp^r Sm^r recA thi pro hsdR hsdM ⁺RP4::2-Tc::Mu::Km Tn7 λ

Biomedal

Nissle 1917 (EcN)

Non-pathogenic probiotic isolate (O6:K5:H1)

Ardeypharm

EcNsat::cat

Nissle 1917 sat::cat; Cm^r

This study

E2348/69

Wild type EPEC O127:H6 Sm^r

B.B. Finlay

ECOR collection strains

Human stool isolates

[43]

Plasmids

pBR322

Vector for cloning, Ap^r Tc^r

Biolabs

pSat

Gene sat from EcN cloned in pBR322, Ap^r

This study

pSat-S256I

Gene sat from EcN encoding the mutated Sat-S256I cloned in pBR322, Ap^r

This study

pCAT19

Source of cat gene, Ap^r Cm^r

[26]

pUT mini-Tn5 Tc

tnp* gene of Tn5-IS50R inserted in SalI site of pGP704; mini-Tn5 Tc transposable element, Ap^r Tc^r

Biomedal

pFU34

Plasmid for transcriptional fusions to the reporter gene gfp _mut3.1 , Ap^r

[28]

pFU34-sat

Promoter fusion Φ(sat-gfp _mut3.1 ) in PFU34, Ap^r

This study