Figure 1. Distribution of S. Typhimurium 14028 s and SPI-6 T6SS mutants in the gastrointestinal tract and internal organs of orally infected chickens.

Four-day-old White Leghorn chicks were infected by gavage with 10⁹ CFU of either the wild-type S. Typhimurium 14028s, the ΔT6SS_SPI-6 mutant or the ΔclpV mutant strains. After 1, 3 and 9 days post-infection, the chicks were humanely euthanized and the ileum, cecum, liver and spleen were aseptically removed. Tissues were homogenized and viable bacterial counts were determined. Data are mean values of log₁₀ CFU/g of tissue, from five animals at each time point.