Garmyn A, Martel A, Froyman R, Nauwynck H, Duchateau L, Haesebrouck F, Pasmans F
Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B9820 Merelbeke, Belgium.
Poult Sci. 2009 Oct;88(10):2093-100. doi: 10.3382/ps.2009-00200.
Escherichia coli infections are a common cause of respiratory disease in turkeys. To control these respiratory infections in turkeys, drinking water treatment with enrofloxacin is widely used. The current treatment schedule advises a 5-d treatment at 10 mg/kg of BW. Because enrofloxacin exerts a concentration-dependent activity, it might be useful to provide this 50 mg/kg total dose in a single-day treatment regimen. Therefore, we assessed whether a single-day treatment schedule with 50 mg/kg of BW was clinically equivalent to the advised multiple-day treatment schedule with 10 mg/kg of BW for 5 d. For this purpose, 3 groups of seventeen 22-d-old turkeys were experimentally inoculated with avian metapneumovirus and 3 d later with E. coli. One group received 10 mg of enrofloxacin/kg of BW in the drinking water for 5 successive days. The second group received 50 mg of enrofloxacin/kg of BW for 20 h in the drinking water. The third group was enclosed as an untreated positive control group. Both the multiple- and the single-day enrofloxacin treatment regimens reduced E. coli multiplication in the respiratory tract tissues (turbinates, trachea and lung), but the 5-d treatment with 10 mg of enrofloxacin/kg in turkeys provided the best results by shortening the course of clinical disease, by eliminating E. coli from the respiratory tract without remultiplication, and by reducing macroscopic lesions. The efficacy of the single-day treatment did not equal that of the 5-d treatment, possibly by not eliminating E. coli from the respiratory organs, which made it possible for the remaining bacteria to reemerge in those organs. None of the used treatment regimens promoted the selection of bacterial clones with reduced susceptibility or resistance.
大肠杆菌感染是火鸡呼吸道疾病的常见病因。为控制火鸡的这些呼吸道感染，广泛采用恩诺沙星进行饮水处理。目前的治疗方案建议以10毫克/千克体重进行为期5天的治疗。由于恩诺沙星具有浓度依赖性活性，在单日治疗方案中提供这一50毫克/千克的总剂量可能会有效果。因此，我们评估了以50毫克/千克体重进行单日治疗方案在临床上是否等同于建议的以10毫克/千克体重进行为期5天的多日治疗方案。为此，将3组每组17只22日龄的火鸡进行实验性接种禽偏肺病毒，3天后再接种大肠杆菌。一组连续5天在饮水中给予10毫克恩诺沙星/千克体重。第二组在饮水中给予50毫克恩诺沙星/千克体重，持续20小时。第三组作为未治疗的阳性对照组。恩诺沙星的多日和单日治疗方案均减少了呼吸道组织（鼻甲、气管和肺）中的大肠杆菌增殖，但在火鸡中以10毫克恩诺沙星/千克进行5天治疗通过缩短临床疾病病程、从呼吸道清除大肠杆菌且不再增殖以及减少宏观病变提供了最佳结果。单日治疗的疗效不及5天治疗，可能是因为未从呼吸器官清除大肠杆菌，使得剩余细菌有可能在这些器官中再次出现。所采用的治疗方案均未促进对敏感性降低或耐药的细菌克隆的选择。
