Figure 4.

This panel represents E. coli isolates grown over time with no antibiotic (A), ampicillin (32 μg/mL) (B), ceftiofur (8 μg/mL) (C), or tetracycline (16 μg/mL) (D). The dark circle presents the intramuscular dosing group and the open circle represents the subcutaneous dosing group over a 912 h time period. Panel (A) demonstrates the log₁₀ CFU/g of E. coli. Panels (B–D) show the proportion of E. coli demonstrating phenotypic resistance based on human breakpoints. Bars represent the standard error of the mean. There were no significant differences noted for each dosing group per plain and antibiotic infused plates at the predetermined time points.