Atanasova Aleksandra, Amon Thomas, Roesler Uwe, Friese Anika, Merle Roswitha, Kabelitz Tina
Department Sensors and Modelling, Leibniz Institute for Agricultural Engineering and Bioeconomy e. V. (ATB), Potsdam, Germany.
Institute for Animal Hygiene and Environmental Health, Veterinary Centre for Resistance Research, Freie Universität Berlin (FU), Berlin, Germany.
Front Antibiot. 2025 Jun 27;4:1612886. doi: 10.3389/frabi.2025.1612886. eCollection 2025.
Antimicrobial resistance (AMR) can spread in microorganisms through the transfer of antimicrobial resistance genes (ARGs). Livestock husbandry is one of the pathways for AMR emergence and transmission. Chicken manure contains valuable nutrients for agricultural field fertilization and can be used as input material for biogas production by anaerobic digestion (AD). However, usually, chicken manure also contains quite high levels of ARGs. In this study, we investigated the presence and temporal dynamics of ARGs against different antibiotic classes in chicken manure and anaerobic digestate as a source of AMR spread.
To get an overview of the ARG profiles, we quantified the abundances of 374 ARGs by high-throughput (HT)-PCR. We studied eight selected ARGs (, , , , , , , and ) using qPCR in chicken manure from different flocks and animal ages and in digestate from different AD time points.
Chicken manure showed higher amounts of ARGs compared to digestate, which was characterized by a higher ARG diversity. We observed that the effect of chicken age differed between the flocks. ARG abundances in digestate from different time points and different treatment conditions did not exhibit major changes.
The flocks' variability had no relevant effect on ARG abundances in chicken manure, likely due to similar growth conditions. However, manure ARG content increased with the age of the chickens. In our experimental batch setup, AD was more effective in reducing AMR microorganisms than reducing ARGs. Further investigations on process optimization or the application of pre-treatment methods could enhance ARG reduction. Notably, pre-mixing chicken manure with material from a biogas plant prior to processing resulted in a lower ARG load compared to untreated chicken manure.
抗菌药物耐药性（AMR）可通过抗菌药物耐药基因（ARGs）的转移在微生物中传播。畜牧业是AMR出现和传播的途径之一。鸡粪含有用于农田施肥的宝贵养分，可作为厌氧消化（AD）生产沼气的原料。然而，通常鸡粪中也含有相当高水平的ARGs。在本研究中，我们调查了鸡粪和厌氧消化产物中针对不同抗生素类别的ARGs的存在情况及其时间动态，它们是AMR传播的来源。
为了全面了解ARG谱，我们通过高通量（HT）-PCR对374种ARGs的丰度进行了定量。我们使用qPCR研究了来自不同鸡群和不同动物年龄的鸡粪以及来自不同AD时间点的消化产物中的8种选定ARGs（、、、、、、和）。
与消化产物相比，鸡粪显示出更高的ARGs含量，消化产物的特点是ARG多样性更高。我们观察到鸡龄的影响在不同鸡群之间存在差异。来自不同时间点和不同处理条件的消化产物中的ARG丰度没有表现出重大变化。
鸡群的变异性对鸡粪中ARG丰度没有相关影响，可能是由于生长条件相似。然而，粪便中ARG含量随着鸡龄的增加而增加。在我们的实验批次设置中，AD在减少AMR微生物方面比减少ARGs更有效。对工艺优化或预处理方法应用的进一步研究可以增强ARGs的减少。值得注意的是，与未处理的鸡粪相比，在处理前将鸡粪与沼气厂的物料预混合会导致更低的ARG负荷。
