摘要

       动物集中饲养操作中残留抗生素和抗生素抗性基因（ARGs）造成的环境污染越来越受到关注。本研究通过一系列模拟猪粪堆肥试验，研究了土霉素 (OTC) 和磺胺二甲嘧啶 (SMN) 的去除及其相应 ARG 的行为。结果表明，当高温阶段在 55°C 下保持 3.5 天时，堆肥堆在 32 天后完全成熟。在 50 (SMN) 和 32 mg kg-1 (OTC) 的初始加标浓度下，它们的去除效率可分别达到 89.8% 和 100%。非生物过程主要负责 SMN 的降解，而非生物和生物过程都负责 OTC 的降解。在所有研究的 ARGs 中，只有编码核糖体保护蛋白的四环素抗性基因 (TRGs) 在整个堆肥过程中保持相对稳定，而编码外排泵 (EFP) 和酶失活 (EI) 蛋白和磺胺抗性基因 (SRGs) 的那些基因明显增加当堆肥完成时。抗生素的添加在堆肥早期抑制了微生物活性，但促进了 ARGs 的增殖，尤其是在嗜温阶段。整合子介导的水平基因转移在研究的大多数 ARG 类型（即 EFP TRG、EI TRG 和 SRG）的增殖中发挥了重要作用。综上所述，猪粪高温堆肥可以有效去除所研究的抗生素，但未能阻止其相应ARGs的增殖。

       Environmental contamination caused by residual antibiotics and antibiotic resistance genes (ARGs) in concentrated animal feeding operations has drawn increasing attention. This study investigated the removal of oxytetracycline (OTC) and sulfamethazine (SMN) as well as the behavior of their corresponding ARGs through a series of simulated composting tests with swine manure. The results indicate that the composting piles became fully mature after 32 days when the thermophilic stage was maintained at 55 °C for 3.5 days. At an initial spiked concentration of 50 (SMN) and 32 mg kg−1 (OTC), their removal efficiency could reach 89.8% and 100%, respectively. An abiotic process was mainly responsible for the degradation of SMN, whereas both abiotic and biotic processes were responsible for the degradation of OTC. Among all the studied ARGs, only the tetracycline resistance genes (TRGs) encoding ribosomal protection proteins remained relatively stable throughout the composting process, while those encoding efflux pump (EFP) and enzymatic inactivation (EI) proteins and sulfonamide resistance genes (SRGs) obviously increased when the composting was complete. The addition of antibiotics inhibited the microbial activity in the early stage of composting but promoted the proliferation of ARGs particularly in the mesophilic stage. Integron-mediated horizontal gene transfers played an important role in the proliferation of most ARG types studied (i.e., EFP TRGs, EI TRG and SRGs). In summary, thermophilic composting of swine manure could remove the studied antibiotics effectively, but failed to prevent the proliferation of their corresponding ARGs.

https://pubs.rsc.org/en/content/articlelanding/2015/em/c5em00132c/unauth#!divAbstract