Heavy metals driven co-selection of antibiotic resistance in soil and water bodies has been widely concerned, but the response of antibiotic resistance to co-existence of antibiotics and heavy metals in composting system is still unknown. Commonly used sulfamethoxazole and copper were individually and jointly added into four reactors to explore their effects on antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), heavy metal resistance genes (MRGs) and bacterial community structure. The abundance of total ARGs and MGEs were notably decreased by 68.64%–84.95% and 91.27–97.38%, respectively, after the composting. Individual addition of sulfamethoxazole, individual addition of copper, simultaneously addition of sulfamethoxazole and copper increased the abundance of ARGs and MGEs throughout the composting period. Co-exposure of sulfamethoxazole and copper elevated the total abundance of ARGs by 1.17–1.51 times by the end of the composting compared to individual addition of sulfamethoxazole or copper. Network analysis indicated that the shifts in potential host bacteria determined the ARGs variation. Additionally, MGEs and MRGs had significant effects on ARGs, revealing that horizontal gene transfer and heavy metals induced co-resistance could promote ARGs dissemination.

重金属驱动的土壤和水体抗生素抗性的共同选择已被广泛关注，但抗生素抗性对堆肥系统中抗生素和重金属共存的反应仍然未知。将常用的磺胺甲恶唑和铜分别加入到四个反应器中，探索它们对抗生素抗性基因（ARGs）、移动遗传元件（MGEs）、重金属抗性基因（MRGs）和细菌群落结构的影响。堆肥后总 ARGs 和 MGEs 的丰度分别显着降低了 68.64%–84.95% 和 91.27–97.38%。单独添加磺胺甲恶唑、单独添加铜、同时添加磺胺甲恶唑和铜增加了整个堆肥期间 ARG 和 MGE 的丰度。与单独添加磺胺甲恶唑或铜相比，磺胺甲恶唑和铜的共同暴露在堆肥结束时将 ARGs 的总丰度提高了 1.17-1.51 倍。网络分析表明，潜在宿主细菌的变化决定了 ARG 的变异。此外，MGEs和MRGs对ARGs有显着影响，表明水平基因转移和重金属诱导的共抗可以促进ARGs的传播。