Bacterial Strains and Culturing Conditions

Salmonella enterica serovar Typhimurium strain SL1344, E. coli strain K12 were obtained from the American Type Culture Collection (ATCC) (Manassas, VA, USA), E. coli DH5α was obtained from ThermoFischer Scientific, E. coli strain Nissle 1917 was obtained from Ardeypharm, and the SL1344 sifA mutant strain was obtained from Dr Olivia Steele-Mortimer.^{36 (link),45 (link)} All bacteria were maintained as described previously.^{9 (link),46 (link)} Briefly, a single colony was inoculated into LB broth and grown for 8 h under aerobic conditions and then under oxygen-limiting conditions. For the SL1344 sifA mutant, streptomycin with a final conc of 100 μg/mL was added to LB broth. Cells were infected with a multiplicity of infection (moi) of 10.