FIG. 5.
Localization of Salmonella in the terminal ileum. The mouse terminal ileum was removed from mice at 7 days post-peroral inoculation with 108 CFU S. enterica serovar Typhimurium and fixed in Carnoy's fixative. Three-micrometer sections were cut and analyzed by FISH to localize bacteria within the tissue section. Sections of small intestinal tissue were cohybridized with a combination of FAM-Sal and TR-Bact338 probes, which enabled visualization of the distribution of both Salmonella (a) and the total indigenous microbiota (b) within the small intestinal lumen. FAM-Sal specifically hybridizes to Salmonella (a), while TR-Bact338 shows total bacteria (b). Arrows show examples of Salmonella in each field. Circles illustrate examples of non-Salmonella indigenous bacteria. (c) qPCR was used to quantify total bacteria and Salmonella from the DSI, ceca, and LI of infected mice. The black section of each pie chart represents the percentage of the total microbiota comprised by Salmonella.