Comparison of the efficacy of difloxacin and orbifloxacin in the treatment of E. coli and S. intermedius infections in dogs

Abstract

The objective of the present study is to evaluate and compare the effect of changes in MIC, efficacy rates of difloxacin and orbifloxacin in the treatment of bacterial infections caused by E. coli or S. intermedius in dogs. The PK / PD modeling was performed to determine the efficacy of oral orbifloxacin 5 mg / kg diclofaxine or 2.5 mg / kg orally every 24 hours from E. coli or S. intermedius infections in dogs. A Monte Carlo simulation of the pharmacokinetic parameters of 10,000 events was performed. PK values were obtained from studies in dogs, where they determined AUC24 values of 9.34 ± 2.09 μg / ml for difloxacin and AUC24 of 12.72 ± 2.29 μg / ml for orbifloxacin. Then, PK / PD modeling was performed to determine the likelihood of reaching corresponding AUC24 / CIM90 indices in the MIC range of 0.062 - 0.5ug / ml. The probability of obtaining bacteriology cure after treatment with either drug decreased significantly for infections caused by E. coli or S. intermedius with MICs greater than 0.125æg / ml. The comparative analysis of the estimated efficacy rates for the two drugs evaluated determined that there are no significant differences for the treatment of infections caused by E. coli or S. intermedius in the MIC range studied. These results indicate that despite the difference in the doses administered the efficacy of both treatments did not present significant differences. However, in cases with higher MICs, dose adjustments should be made.