Revisiting PK-PD Integration of Ciprofloxacin against Escherichia coli in Broiler Chickens

Ciprofloxacin, a second-generation fluoroquinolone, is a broad-spectrum antimicrobial drug used to treat many bacterial infections including colibacillosis in poultry, caused by Escherichia coli. Failure of antimicrobial therapy of colibacillosis due to increasing resistance problem needs re-evaluation of pharmacokinetic-pharmacodynamic (PK-PD) integration of the ciprofloxacin in broiler chickens. Blood sampling in eight broiler chickens was done following single dose intravenous and oral administration of ciprofloxacin at the dose rate of 10 mg/kg body weight to obtain plasma drug concentrations at various time-points. Drug concentrations were measured by Ultra High Performance Liquid Chromatography (UHPLC) method and pharmacokinetic parameters were calculated with non-compartmental approach. For pharmacodynamic study, field isolates of E. coli recovered from natural outbreaks at broiler chicken farms were used and minimum inhibitory concentration (MIC) data were worked out for ciprofloxacin against recovered isolates using HiComb™ method. A MIC₉₀ breakpoint of 0.10 µg/ml was estimated to cover most of field E. coli infections. The pharmacokinetic pharmacodynamic (PK-PD) indices like AUC_0-24/MIC and C_max/MIC were found favourable (>96 and >18, respectively) for ciprofloxacin at the dose rate of 10 mg/kg body weight, once a day, in poultry to treat susceptible E. coli infection.