Figure 3.

Fold change in the abundance of antimicrobial resistance genes strA, sul1, cfxA, tetQ, and ermF, and an integrase gene, intI1, (mean + SE) in fecal samples from mice following an inoculation with Salmonella Typhimurium and Salmonella Heidelberg. Mice were pre-treated with either no antibiotic (blue), ampicillin (red), streptomycin (green), or sulfamethazine (purple). Gene abundances were averaged from triplicate technical replicates and were normalized against that of the rrnS1 genes for each mouse. Fold changes from 0 to 21 days post-infection (DPI) were calculated relative to the baseline of −7 DPI. Asterisks (*) indicate a significant difference (p < 0.05) between an antibiotic pre-treatment group and the control group with no antibiotic pre-treatment within each DPI, as determined by Welch’s ANOVA followed by Dunnett’s test.