Pharmacokinetical aspects of flumequine and therapeutic efficacy in Escherichia coli infection in poultry

This report describes in vitro and in vivo studies with flumequine, a new antibacterial drug for poultry. In the Netherlands, all 223 Gram-negative bacteria tested (E. coli, salmonella and P. multocida), among them many multiresistant strains, were susceptible in vitro to the bactericidal activity of this drug. The in vitro induced bacterial resistance was of a multistep type. No cross-resistance with tetracycline, chloramphenicol, neomycin, ampicillin, sulphonamides, trimethoprim or furazolidone was found. An elimination half time of 1 hour and a rapid absorption from the gastrointestinal tract (peak plasma concentration of 2.6-3.0 μg/ml, 1½ hours after a single oral application of the daily dose: 12 mg/kg body weight) were observed in broilers and White Leghorn layers. During medication via the drinking water or feed with 1 x, 1½ x and 2 x the recommended therapeutic dose, blood plasma concentrations of 0.5 to 0.8, 0.8 to 1.3 and 1.2 to 1.9 μg/ml were demonstrated respectively. No adverse effect on growth rate and performance of broilers was observed. Treatment with these doses resulted in significant therapeutic effects in in vivo experiments with E. coli-infected broilers.