Table 1

E. coli strains and plasmids

Strain or plasmid	Genotype and phenotype	Source
Strains
χ289	E. coli K-12 W1485 λ⁻, F⁻glnV44	Ref. 11
χ7122	Avian pathogenic, O78:K80:H9, gyrA, Nal^R	Ref. 23
χ7273	tsh∷tetAR(B), Tc^R (Tsh⁻)	χ7122; ref. 18
χ7301	ΔiucABCD iutA∷xylE tsh∷tetAR(B) Tc^R (Aerobactin⁻, Tsh⁻)	χ7273
χ7303	ΔiroBCDEN∷nptII, Km^R (Iro⁻)	χ7122
χ7306	ΔiroBCDEN∷nptII tsh∷tetAR(B) ΔiucABCDiutA∷xylE Tc^R, Km^R (Tsh⁻, Iro⁻, Aerobactin⁻)	χ7301
Plasmids
pACYC184	p15A replicon, Tc^R, Cm^R	Ref. 24
pBSL86	nptII cassette vector. Km^R, Ap^R	Ref. 25
pC6	E. coli rrnB in pBR322, Ap^R	C. Squires
pMEG-375	sacRB mobRP4 oriR6K. Cm^R, Ap^R	Megan Health (St. Louis, MO)
pMEG-685	xylE cassette vector, Ap^R	Megan Health
pYA3661	pACYC184∷iroBCDEN, Cm^R	This work
pYA3662	pMEG-375∷ΔiucABCDiutA∷xylE. Cm^R, Ap^R	This work
pYA3663	pMEG-375∷ΔiroBCDEN∷nptII. Cm^R, Ap^R, Km^R	This work

Ap, ampicillin; Cm, chloramphenicol; Km, kanamycin; Nal, nalidixic acid; Tc, tetracycline.