To further analyze the influence of the SPI-1 encoded TTSS-1 on colonization of the murine and chick intestine over time, we represented our data from competitive infections of wild type serotype Typhimurium ATCC14028 and our ΔinvA mutant as the normalized log (wild type CFU/ΔinvA mutant CFU) for each cecal compartment we analyzed in these experiments over 15 days of infection. The gene discussed is SPI1; the disease is infection.