Comparison of the Efficacies of Three Fluoroquinolone Antimicrobial Agents, Given as Continuous or Pulsed-Water Medication, againstEscherichia coliInfection in Chickens

Abstract

This study compared the efficacy of continuous or pulsed-water medication with enrofloxacin, danofloxacin, and sarafloxacin in eight groups of 90 chicks each by using an infectious bronchitis virus-Escherichia coli model of colisepticemia. The model produced lesions of typical those occurring in birds with severe colisepticemia; for the infected, nonmedicated birds the mortality was 43.5% and the morbidity was 89%, 17.8% of birds had severe lesions, and the birds had a mean air sac lesion score of 2.58. This experiment showed that continuous dosing and pulsed dosing are clinically equivalent. However, for all fluoroquinolones studied, there was a trend for the continuously mediated birds to have lower mortality and less severe disease than birds receiving pulsed doses. Compared with infected, nonmedicated controls, only birds continuously medicated with enrofloxacin had a significantly lower morbidity (32%), and only birds medicated with enrofloxacin and danofloxacin (continuous and pulsed treatments) had significantly lower mortality (6.7 and 11.0% and 16.8 and 19.2% for continuous and pulsed treatments with enrofloxacin and danofloxacin, respectively). A significantly lower proportion of birds only in the groups medicated with enrofloxacin had severe lesions (for birds receiving continuous and pulsed treatments, 2.2 and 6.7%, respectively). Birds medicated with any of the three fluoroquinolones (continuous and pulsed treatments) except pulsed-water treatment with sarafloxacin had significantly reduced mean air sac lesion scores compared with the scores for nonmedicated birds (air sac lesion scores, 0.60 and 0.83, 1.38 and 1.63, and 1.80 and 2.05 for birds receiving continuous and pulsed treatments with enrofloxacin, danofloxacin, and sarafloxacin, respectively). The performance of the birds that survived the challenge or that recovered after receiving medication was not compromised compared to the performance of noninfected birds. Enrofloxacin was more efficacious than either danofloxacin or sarafloxacin for the treatment of colisepticemia in chickens by medication in drinking water. Similarly, danofloxacin appeared to be more effective than sarafloxacin in treating colisepticemia.

Comparison ofIn VitroActivities and Pharmacokinetics/Pharmacodynamics Estimations of Veterinary Fluoroquinolones Against Avian PathogenicEscherichia coliIsolates

“…23 A previous study involving experimentally infected chickens reported that the clinical usefulness of ERFX was superior to DNFX. 2 The AUC:MIC and C max :MIC ratios have been shown to have a particular ability in determining the optimal activity of fluoroquinolones. 13 Our calculated AUC:MIC and C max :MIC ratios support the observation that ERFX is more suitable for the treatment of avian colibacillosis than DNFX.…”

“…Although fluoroquinolones are classified as concentration-dependent drugs, Charleston et al reported similar efficacies of continuous and pulsed regimens and suggested that the duration of exposure (time above MIC) is also important for antimicrobial effect in the treatment of avian colibacillosis. 2 Thus, the requirement of PK/PD analysis has not been fully established, and further investigation is required to predict the efficacy of veterinary fluoroquinolones for the selection of the appropriate drug.…”

Pharmacokinetic-Pharmacodynamic Modelling of Danofloxacin in Turkeys

“…The efficacy of fluoroquinolones against E. coli infections administered via drinking water has been reported for enrofloxacin in chickens (Bauditz, 1987) and turkeys (Behr et al, 1988;Hafez et al, 1990), for danofloxacin in chickens (Ter Hune et al, 1991), and for sarafloxacin in chickens and turkeys (Chansiripornchai and Sasipreeyajan, 2002). Under field conditions these fluoroquinolones can be applied to poultry with the drinking water in a flexible manner without compromising efficacy (Charleston et al, 1998).…”

Comparative studies on the effects of lincomycin and bacitracin on hematobiochemical and immunological parameters in broiler chickens

“…Healthy broiler chickens received bacitracin and lincomycin either alone or together showed non-significant elevation on bodyweight and weight gain but improved feed conversion rate throughout the experimental period when compared with the control group. The growth promoting the effect of antimicrobials may be due to suppression to the microorganisms that invade the host and retard its metabolic activity (Charleston et al 1998). Another explanation for improved body performance after using lincomycin and bacitracin is the antimicrobial effect of them which consequently improves the metabolic activity of bird by inhibiting pathogenic organisms that damage gut epithelium and impairing food absorption, inhibiting non pathogenic organisms which compete for growth factors in gut and inhibiting organisms producing toxic substances affecting growth (Abdelaziz 2002).…”