Evaluation of the chemotherapeutic effect of a drug based on levofloxacin in experimental colibacteriosis of chickens

Abstract

The aim of the present study was to assess chemotherapeutic action of a levofloxacin-based drug, administered singly parenterally at doses 5 mg/kg and 10 mg/kg, for treatment of experimental colibacillosis of chicks. We conducted two experiments with day-old Hisex Brown chicks (body weight ranging from 39 g to 42 g). We challenged the chicks by injecting each of them with 0.5 mL of one-day old E. coli culture in suspension intraperitoneally, having adjusted its McFarland standard to ensure cell density of 1.5 х 10^8 CFUs (1 McFarland standard). For the first experiment we made 16 groups of chicks (n=10). The drug was injected intraperitoneally singly at doses 5 mg/kg and 10 mg/kg at 24h, 8h, 6h, 4h, 2h and 1h prior to the challenge and simultaneously with the challenge. In the second experiment we endeavoured to assess therapeutic effectiveness of levofloxacin and we made 20 groups of chicks (n=10). The drug was injected intraperitoneally singly at doses 5 mg/kg and 10 mg/kg at 0.5h, 1h, 2h, 3h, 4h, 5h, 6h and 7h following the challenge and simultaneously with the challenge. The experiments we conducted show that the total lifespan of the chicks was 92% when the drug was administered at a dose 5 mg/kg at 2h prior to the challenge. That dose 5 mg/kg therefore can be considered a highly active dose. When we increased the dose to 10 mg/kg the prophylactic effectiveness of the drug rose significantly. At all time intervals below 4 hours the dose of the drug was highly active.When levofloxacin was administered for prophylaxis at a dose 5 mg/kg that dose was proven as highly active for all time intervals below 5 hours, and at a dose 10 mg/kg – 7 hours.