Antibiotic use in animal husbandry is a potential entryway for antibiotics and antibiotic resistance genes (ARGs) to enter the environment through manure fertilizer application. The potential of anaerobic digestion (AD) to remove antibiotics and ARGs was investigated through tetracycline (TC) and sulfadimethoxine (SDM) additions into dairy manure digested for 44 d. This was the first study to evaluate antibiotics at concentrations quantified on-farm and relevant to field applications of manure. Triplicate treatments included a 1 mg L^–1 TC spike, a 10 mg L^–1 TC spike, a 1 mg L^–1 SDM spike (SDM 1), a 10 mg L^–1 SDM spike, a mixture of TC and SDM at 1 mg L^–1 each (TC+SDM 1), and a manure-only treatment. The SDM spikes were reduced by >99% reduction during the AD processing, but TC additions had variable reductions (0–96%). Molecular analyses showed that decreases in tetM gene copies correlated with declines in TC; however, reductions in SDM concentration did not correlate with decreases in sul1 gene copy concentrations. The AD reactors containing 10 mg L^–1 of TC and 10 mg L^–1 of SDM both had CH₄ production reductions of 7.8%, whereas no CH₄ reduction was observed in other treatments (1 mg L^–1 treatments). The study results were the first to confirm that AD can remove SDM when adding at concentrations observed in on-farm manure (<1 mg L^–1) without compromising energy production. Because TC adsorbs to the solid particles and transforms into isomers, the decreases in TC concentrations were more variable and should be closely monitored.

中文翻译：

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牛粪厌氧消化过程中四环素、磺胺二甲氧嘧啶和抗生素抗性基因动态

在畜牧业中使用抗生素是抗生素和抗生素抗性基因 (ARG) 通过施肥进入环境的潜在入口。通过将四环素 (TC) 和磺胺二甲氧嘧啶 (SDM) 添加到消化 44 天的奶牛粪中，研究了厌氧消化 (AD) 去除抗生素和 ARG 的潜力。这是第一项评估农场中量化浓度且与粪便田间施用有关的抗生素的研究。一式三份处理包括 1 mg L ^–1 TC 加标、10 mg L ^–1 TC 加标、1 mg L ^–1 SDM 加标 (SDM 1)、10 mg L ^–1 SDM 加标、TC 和 SDM 的混合物在1 毫克升^–1每个（TC + SDM 1），以及仅粪便处理。在 AD 处理期间，SDM 尖峰减少了 > 99%，但 TC 添加有可变的减少（0-96%）。分子分析表明，tetM基因拷贝的减少与 TC 的减少相关；然而，SDM 浓度的降低与sul1基因拷贝浓度的降低无关。含有 10 mg L ^–1 TC 和 10 mg L ^–1 SDM的 AD 反应器的CH ₄产量减少了 7.8%，而在其他处理中没有观察到CH ₄减少（1 mg L ^–1治疗）。该研究结果首次证实，当添加农场粪便中观察到的浓度 (<1 mg L ^–1 )时，AD 可以去除 SDM，而不会影响能源生产。由于 TC 吸附在固体颗粒上并转化为异构体，因此 TC 浓度的降低变化更大，应密切监测。