Department of Animal, Poultry Hygiene and Environmental Sanitation, Faculty of Veterinary Medicine, Assiut University, 71526, Egypt.
Department of Animal, Poultry Hygiene and Environmental Sanitation, Faculty of Veterinary Medicine, Assiut University, 71526, Egypt.
Environ Pollut. 2019 Dec;255(Pt 1):113039. doi: 10.1016/j.envpol.2019.113039. Epub 2019 Aug 17.
Although the poultry production sector plays a key role in sustaining the majority of animal protein demand in Egypt, the deleterious effects of widespread antibiotic resistance on health and environment are currently not well recognized. Litter and dropping samples from broiler and layer poultry farms as well as, tilapia samples from the Nile River and aquaculture farms were collected from Upper Egypt. Samples were extracted and examined for tetracycline residues [tetracycline (TC), chlortetracycline (CTC), oxytetracycline (OTC) and doxycycline (DC)] using HPLC. In addition, tetracycline resistance genes [tet (M), tet (W), tet (Q) and tet (G)] were screened from pooled intestinal contents collected from twelve broiler farms in Upper Egypt. The antibiotic resistance genes results revealed that tet (W) was confirmed to be expressed in all intestinal samples. In contrast, tet (Q) and tet (M) were detected only in 42% and 17% of the samples, respectively. CTC and OTC were the antimicrobial compounds with the highest concentrations in poultry litter and droppings, with concentrations of 6.05 and 2.47 μg g (CTC) and 5.9 and 1.33 μg g (OTC), respectively. However, the concentrations of DC were significantly higher than those of the other compounds in both aquaculture and Nile River tilapia. The tetracycline residue levels in aquaculture tilapia were significantly higher than those in Nile River tilapia. The hazard quotients (HQs) exceeded 1 for OTC, CTC and DC, which highlights the great risk of using broiler litter to fertilize agricultural land. Moreover, the presence of DC and CTC indicates that consumption of aquaculture tilapia poses a considerable health risk. Therefore, poultry litter or droppings containing tetracycline residues and tet resistance determinants used for aquaculture or as farmland fertilizers could be major sources of antibiotic resistance in fish, humans and environment.
尽管家禽生产部门在维持埃及大部分动物蛋白需求方面发挥着关键作用，但抗生素广泛耐药对健康和环境的有害影响目前还没有得到很好的认识。从埃及上埃及的肉鸡和蛋鸡养殖场的垫料和粪便样本以及尼罗河和水产养殖农场的罗非鱼样本中采集了样本。使用 HPLC 提取并检查了四环素残留[四环素 (TC)、金霉素 (CTC)、土霉素 (OTC) 和强力霉素 (DC)]。此外，还从埃及上埃及的 12 个肉鸡养殖场收集的混合肠道内容物中筛选了四环素耐药基因[tet (M)、tet (W)、tet (Q) 和 tet (G)]。抗生素耐药基因的结果表明，tet (W) 在所有肠道样本中均被证实表达。相比之下，tet (Q) 和 tet (M) 仅在 42%和 17%的样本中被检测到。CTC 和 OTC 是家禽垫料和粪便中浓度最高的抗菌化合物，浓度分别为 6.05 和 2.47μg/g（CTC）和 5.9 和 1.33μg/g（OTC）。然而，在水产养殖和尼罗罗非鱼中，DC 的浓度明显高于其他化合物。水产养殖罗非鱼中的四环素残留水平明显高于尼罗罗非鱼。OTC、CTC 和 DC 的危害系数 (HQ) 均超过 1，这突出表明使用肉鸡垫料施肥农业用地的风险很大。此外，DC 和 CTC 的存在表明食用水产养殖罗非鱼会带来相当大的健康风险。因此，用于水产养殖或作为农田肥料的含有四环素残留和 tet 耐药决定因素的家禽垫料或粪便可能是鱼类、人类和环境中抗生素耐药的主要来源。
