National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, South China Agricultural University, Guangzhou 510642, China; Laboratory of Veterinary Pharmacology, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China; Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, Guangzhou 510642, China.
National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, South China Agricultural University, Guangzhou 510642, China.
Sci Total Environ. 2021 Mar 1;758:143654. doi: 10.1016/j.scitotenv.2020.143654. Epub 2020 Nov 21.
Vast reservoirs of antibiotic resistance genes (ARG) are discharged into the environment via pig manure. We used metagenomic analysis to follow the distribution and shifts of ARGs and their bacterial hosts along wastewater treatment in three large pig farms. The predominating ARGs potentially encoded resistance to tetracycline (28.13%), aminoglycosides (23.64%), macrolide-lincosamide-streptogramin (MLS) (12.17%), sulfonamides (11.53%), multidrug (8.74%) and chloramphenicol (6.18%). The total relative ARG abundance increased along the treatment pathway prior to anaerobic digestion that had a similar degradative capacity for different ARGs and these ARGs were reduced by about 25% after digestion, but ARGs enriched erratically in manured soils. Distinctive ARG distribution patterns were found according to the three sample locations; feces, soil and wastewater and the differences were primarily due to the tetracycline ARGs (feces > wastewater > soil), sulfonamide ARGs (soil > wastewater > feces) and MLS ARGs (feces > wastewater > soil). Metagenomic assembly-based host analyses indicated the Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes were primary ARG carriers. The Streptococcaceae increased the abundance of multidrug, MLS and aminoglycoside ARGs in feces; Moraxellaceae were the primary contributors to the high abundance of multidrug ARGs in wastewater; the Comamonadaceae led to the higher abundance of bacA in wastewater and soil than feces. We found a high level of heterogeneity for both ARGs and ARG-hosts in the wastewater treatment system and in the agricultural soils for these pig farms.
大量的抗生素耐药基因（ARG）通过猪粪排放到环境中。我们使用宏基因组分析来跟踪 ARG 及其细菌宿主在三个大型养猪场的污水处理过程中的分布和变化。主要的 ARG 可能编码对四环素（28.13%）、氨基糖苷类（23.64%）、大环内酯-林可酰胺-链阳菌素（MLS）（12.17%）、磺胺类（11.53%）、多药（8.74%）和氯霉素（6.18%）的耐药性。在厌氧消化之前，随着处理途径的增加，总相对 ARG 丰度增加，而不同的 ARG 具有相似的降解能力，消化后这些 ARG 减少了约 25%，但 ARG 在施肥土壤中不规则地富集。根据三个采样地点（粪便、土壤和废水），发现了独特的 ARG 分布模式；粪便、土壤和废水中的 ARG 丰度存在差异，主要是由于四环素 ARG（粪便>废水>土壤）、磺胺类 ARG（土壤>废水>粪便）和 MLS ARG（粪便>废水>土壤）。基于宏基因组组装的宿主分析表明，变形菌门、厚壁菌门、放线菌门和拟杆菌门是主要的 ARG 载体。链球菌科增加了粪便中多药、MLS 和氨基糖苷类 ARG 的丰度；莫拉氏菌科是废水中多药 ARG 丰度高的主要贡献者；粪水中的 Comamonadaceae 导致 bacA 的丰度高于粪便和土壤。我们发现，在这些养猪场的污水处理系统和农业土壤中，ARG 和 ARG 宿主都存在高度的异质性。
