TABLE 1

Bacterial strains

E. coli strainCharacteristicDesignationReference
MG1655 StrrSpontaneous streptomycin-resistant mutant of MG1655MG16559
Nissle 1917 Strr NalrSpontaneous nalidixic acid-resistant mutant of Nissle 1917 StrrNissle 191750
EDL933 Strr RifrSpontaneous streptomycin-resistant mutant of EDL933EDL93332
EDL933 Strr ΔppsA ΔpckA::camDouble deletion mutant of EDL933 Strr carrying cat in the pckA deletion and retaining the pO157 virulence plasmidEDL933 ppsA pckA mutant9