FIG. 3.

Streptomycin pretreatment increases Salmonella infection of the ileum. Real-time PCR was used to compare the numbers of Salmonella bacteria in the ilea of individual mice without additional treatment to those in mice pretreated with oral streptomycin. The number of copies of the Salmonella 16S rRNA gene amplified using Salmonella-specific primers was determined and is shown relative to the mass of the ileal sample. The limit of detection for Salmonella was one copy/100 ng total DNA. Represented adjacent to the circles are the numbers of Salmonella 16S rRNA gene sequences identified over the total size of the clone library analyzed from this same animal. Circles with “nd” (not determined) show animals in which clone libraries could not be produced, primarily due to low bacterial DNA yields. Horizontal lines represent the medians for each group.