摘要
      厌氧消化被建议作为一种干预措施，以减弱牲畜粪便中的抗生素抗性基因（ARGs），但支持数据通常是在实验室规模上收集的。很少有研究量化了牲畜粪便全面消化过程中ARG的命运。我们从七个全尺寸的中温奶牛粪便消化器中取样了未经处理的粪便和消化物，以评估每个系统中ARG的命运。从12月到8月（即冬季、春季和夏季；总共n=235），每两周采集一次样本，并通过定量聚合酶链式反应分析intI1、erm（B）、sul1、tet（A）和tet（W）。在厌氧消化过程中，intI1、sul1和tet（A）的浓度降低，但它们的去除范围不如先前实验室研究预期的那么广泛。厌氧消化过程中intI1的去除率为0.28±0.03 log10单位（平均值±SE），仅相当于48%的去除率，考虑到intI1在水平基因转移和多重抗性中的作用，这一点值得注意。此外，在厌氧消化过程中，tet（W）浓度没有变化（p>0.05），erm（B）浓度增加了0.52±0.03 log10单位（3.3倍），这一点很重要，因为红霉素是人类医学中至关重要的抗生素。intI1、sul1和tet（A）浓度的季节性log10变化≥厌氧消化相应log10去除量的50%，消化器之间ARG和intI1浓度的变化在数量上与厌氧消化效果相当。这些结果表明，中温厌氧消化作为牲畜粪便中ARGs的干预措施可能受到限制，并强调需要多种农场层面的干预措施来减弱抗生素耐药性。
Abstract
Anaerobic digestion has been suggested as an intervention to attenuate antibiotic resistance genes (ARGs) in livestock manure but supporting data have typically been collected at laboratory scale. Few studies have quantified ARG fate during full-scale digestion of livestock manure. We sampled untreated manure and digestate from seven full-scale mesophilic dairy manure digesters to assess ARG fate through each system. Samples were collected biweekly from December through August (i.e., winter, spring, and summer; n = 235 total) and analyzed by quantitative polymerase chain reaction for intI1, erm(B), sul1, tet(A), and tet(W). Concentrations of intI1, sul1, and tet(A) decreased during anaerobic digestion, but their removal was less extensive than expected based on previous laboratory studies. Removal for intI1 during anaerobic digestion equaled 0.28 ± 0.03 log10 units (mean ± SE), equivalent to only 48% removal and notable given intI1’s role in horizontal gene transfer and multiple resistance. Furthermore, tet(W) concentrations were unchanged during anaerobic digestion (p > 0.05), and erm(B) concentrations increased by 0.52 ± 0.03 log10 units (3.3-fold), which is important given erythromycin's status as a critically important antibiotic for human medicine. Seasonal log10 changes in intI1, sul1, and tet(A) concentrations were ≥50% of corresponding log10 removals by anaerobic digestion, and variation in ARG and intI1 concentrations among digesters was quantitatively comparable to anaerobic digestion effects. These results suggest that mesophilic anaerobic digestion may be limited as an intervention for ARGs in livestock manure and emphasize the need for multiple farm-level interventions to attenuate antibiotic resistance.

https://acsess.onlinelibrary.wiley.com/doi/full/10.1002/jeq2.20350