Impact of an experimental PRRSV and Streptococcus suis coinfection on the pharmacokinetics of ceftiofur hydrochloride after intramuscular injection in pigs

摘要

This study determined the impact of porcine reproductive and respiratory syndrome virus (PRRSV) and Streptococcus suis coinfection on the pharmacokinetic (PK) profile of ceftiofur hydrochloride in pigs after intramuscular (i.m.) injection. Eighteen clinically normal crossbred gilts were assigned by weight into a challenge group (10 pigs) and control group (eight pigs). Pigs in both groups received a single i.m. injection of ceftiofur hydrochloride (Excenel RTU Sterile Suspension; Zoetis) at a 5mg/kg BW dose. Serial blood samples were collected to characterize the plasma concentration curve. After a 10days drug washout period, the challenge group was inoculated with 2mL of PRRSV isolate VR-2385 (10(5.75) 50% tissue culture infective doses per mL) intranasally and 8days later inoculated S.suis. When clinical disease was evident, the second PK assessment began in both challenge and control groups. Coinfected pigs demonstrated lower values of AUC and C-MAX, but higher values of Cl/F and Vz/F indicating drug kinetics were altered by infection. The data from this study have implications on ceftiofur treatment regimens in diseased pigs.