Figure 5

Evolution of plasma CS concentrations over time in pigs challenged with an ETEC: F4 strain and receiving colistin sulfate (CS) orally (mean ± standard deviation [SD]). Colistin sulfate concentrations were obtained by HPLC–MS/MS after 0.5, 12, 24 and 48 h of CS treatment discontinuation at a therapy regimen of 100 000 IU/kg (trial 1) or 50 000 IU/kg (trial 2). In trial 1, at 0.5, 12 and 24 h, CS concentrations were statistically higher in the challenged treated group compared to the unchallenged treated group with p < 0.001, p < 0.0001 and p < 0.001 respectively. In trial 2, at 0.5 and 12 h, CS concentration was statistically higher in the challenged treated group compared to the unchallenged treated group with p < 0.001 and p = 0.04 respectively (n = 8 per group).