Summary of variants in the ancestral wild-type S.

Typhimurium strain or S.Tm* strains used in this study. Non-synonymous mutations in SB300 (SL1344 WT; S.Tm) and M2730 (SL1344 ΔssaV; S.Tm*) used to infected mice in this study are compared to the wild-type S. Typhimurium SL1344 reference genome NCBI accession FQ312003.1. The SipC phenotype in our colony protein blot assay (as a proxy for TTSS-1 expression) is shown; + and blue color code indicates that SipC is detected in the colony protein blot assay. In order to generate S.Tm* (termed M2730 in the laboratory strain collection), we have used P22 transduction followed by removal of the resistance cassette (e.g., ssaV). The deletion is indicated by the “Δ” symbol in S6 Table. (XLSX)