State Key Laboratory of Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China.
Appl Environ Microbiol. 2023 Jul 26;89(7):e0064523. doi: 10.1128/aem.00645-23. Epub 2023 Jul 6.
Antibiotic resistance is a global threat to public health, with antibiotic resistance genes (ARGs) being one of the emerging contaminants; furthermore, animal manure is an important reservoir of biocide resistance genes (BRGs) and metal resistance genes (MRGs). However, few studies have reported differences in the abundance and diversity of BRGs and MRGs between different types of animal manure and the changes in BRGs and MRGs before and after composting. This study employed a metagenomics-based approach to investigate ARGs, BRGs, MRGs, and mobile genetic elements (MGEs) of yak and cattle manure before and after composting under grazing and intensive feeding patterns. The total abundances of ARGs, clinical ARGs, BRGs, MRGs, and MGEs were lower in the manure of grazing livestock than in the manure of the intensively fed group. After composting, the total abundances of ARGs, clinical ARGs, and MGEs in intensively fed livestock manure decreased, whereas those of ARGs, clinical ARGs, MRGs, and MGEs increased in grazing livestock manure. The synergy between MGEs mediated horizontal gene transfer and vertical gene transmission via host bacteria proliferation, which was the main driver that altered the abundance and diversity of ARGs, BRGs, and MRGs in livestock manure and compost. Additionally, , IS, , and were potential indicators for estimating the total abundance of clinical ARGs, BRGs, MRGs, and MGEs in livestock manure and compost. These findings suggest that grazing livestock manure can be directly discharged into the fields, whereas intensively fed livestock manure should be composted before returning to the field. The recent increase in the prevalence of antibiotic resistance genes (ARGs), biocide resistance genes (BRGs), and metal resistance genes (MRGs) in livestock manure poses risks to human health. Composting is known to be a promising technology for reducing the abundance of resistance genes. This study investigated the differences and changes in the abundances of ARGs, BRGs, and MRGs between yak and cattle manure under grazing and intensive feeding patterns before and after composting. The results indicate that the feeding pattern significantly affected the abundances of resistance genes in livestock manure. Manure in intensive farming should be composted before being discharged into the field, while grazing livestock manure is not suitable for composting due to an increased number of resistance genes.
抗生素耐药性是对公共卫生的全球性威胁，抗生素耐药基因 (ARGs) 是新兴污染物之一；此外，动物粪便是杀生物剂耐药基因 (BRGs) 和金属耐药基因 (MRGs) 的重要储存库。然而，很少有研究报道不同类型动物粪便中 BRGs 和 MRGs 的丰度和多样性的差异，以及堆肥前后 BRGs 和 MRGs 的变化。本研究采用基于宏基因组学的方法，研究了放牧和集约化饲养模式下堆肥前后牦牛和牛粪中 ARGs、BRGs、MRGs 和移动遗传元件 (MGEs) 的情况。放牧牲畜粪便中 ARGs、临床 ARGs、BRGs、MRGs 和 MGEs 的总丰度低于集约化饲养组。堆肥后，集约化饲养牲畜粪便中 ARGs、临床 ARGs 和 MGEs 的总丰度下降，而放牧牲畜粪便中 ARGs、临床 ARGs、MRGs 和 MGEs 的总丰度增加。MGEs 介导的水平基因转移与通过宿主细菌增殖的垂直基因传递之间的协同作用是改变牲畜粪便和堆肥中 ARGs、BRGs 和 MRGs 丰度和多样性的主要驱动因素。此外，IS、Tn 和Tn5401 是估计牲畜粪便和堆肥中临床 ARGs、BRGs、MRGs 和 MGEs 总丰度的潜在指标。这些发现表明，放牧牲畜粪便可以直接排放到田间，而集约化饲养牲畜粪便在返回田间之前应进行堆肥。
最近，抗生素耐药基因 (ARGs)、杀生物剂耐药基因 (BRGs) 和金属耐药基因 (MRGs) 在牲畜粪便中的流行率增加，对人类健康构成威胁。堆肥被认为是减少耐药基因丰度的一种有前途的技术。本研究调查了放牧和集约化饲养模式下堆肥前后牦牛和牛粪中 ARGs、BRGs 和 MRGs 丰度的差异和变化。结果表明，饲养方式显著影响了牲畜粪便中耐药基因的丰度。集约化养殖的粪便在排放到田间之前应进行堆肥，而放牧牲畜的粪便由于耐药基因数量的增加，不适合进行堆肥。
