National Laboratory for Veterinary Drug Safety Evaluation, Huazhong Agriculture University, Wuhan 430070, China; MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Hubei 430070, China; College of Veterinary Medicine, Huazhong Agriculture University, Wuhan 430070, China.
National Reference Laboratory of Veterinary Drug Residues (HZAU), Huazhong Agriculture University, Wuhan 430070, China; MOA Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei 430070, China; College of Veterinary Medicine, Huazhong Agriculture University, Wuhan 430070, China.
Sci Total Environ. 2022 Sep 15;839:156243. doi: 10.1016/j.scitotenv.2022.156243. Epub 2022 May 25.
Livestock manure is an important source of antibiotic resistance genes (ARGs) spreading to the environment, posing a potential threat to human health. Here, we investigated the dissipation of florfenicol (FF) and thiamphenicol (TAP), and their effects on the bacterial community, mobile genetic elements (MGEs), and ARGs during composting. The results indicated that FF and TAP dissipated rapidly in compost, with half-life values of 5.1 and 1.6 d, respectively. However, FF could not be completely removed during composting. The FF and TAP residues in manure could reduce the elimination of ARGs and MGEs during composting, and had a negative effect on the physicochemical factors of the compost. Significant correlations were found between floR and intI1, indicating that floR in manure may more easily diffuse to the soil environment. Meanwhile, the presence of FF in manure could increase the abundance of floR. Network analysis showed that Proteobacteria and Firmicutes were the dominant bacterial communities and important potential pathogen hosts carrying ARGs. The predicted environmental concentration of FF in the soil was over 100 μg kg, which indicates that FF poses a potential risk to the natural environment, and we verified this result through field experiments. The results showed that FF dissipated in the soil after it migrated from manure to soil. In contrast, TAP in manure posed lower environmental risk. This study highlights that changed in composting conditions may control the rate of removal of ARGs. Further studies are needed to investigate the best environmental conditions to achieve a faster degradation of FF and a more comprehensive elimination of ARGs during composting.
家畜粪便是抗生素耐药基因（ARGs）传播到环境中的一个重要来源，对人类健康构成潜在威胁。在这里，我们研究了氟苯尼考（FF）和噻苯隆（TAP）在堆肥过程中的消解及其对细菌群落、移动遗传元件（MGEs）和 ARGs 的影响。结果表明，FF 和 TAP 在堆肥中迅速消解，半衰期值分别为 5.1 和 1.6 d。然而，FF 在堆肥过程中不能完全去除。粪肥中的 FF 和 TAP 残留会降低堆肥过程中 ARGs 和 MGEs 的消除率，并对堆肥的理化因素产生负面影响。floR 和 intI1 之间存在显著相关性，表明粪肥中的 floR 可能更容易扩散到土壤环境中。同时，粪肥中 FF 的存在会增加 floR 的丰度。网络分析表明，变形菌门和厚壁菌门是主要的细菌群落，也是携带 ARGs 的重要潜在病原菌宿主。FF 在土壤中的预测环境浓度超过 100 μg kg，表明 FF 对自然环境构成潜在风险，我们通过田间实验验证了这一结果。结果表明，FF 从粪肥迁移到土壤后在土壤中消解。相比之下，粪肥中的 TAP 对环境的风险较低。本研究强调，堆肥条件的变化可能会控制 ARGs 去除率。需要进一步研究以寻找最佳的环境条件，以实现 FF 在堆肥过程中的快速降解和 ARGs 的更全面消除。
