ORIGINAL RESEARCH article
Front. Antibiot.
Sec. Antibiotic Resistance
Volume 4 - 2025 | doi: 10.3389/frabi.2025.1612886
Temporal dynamics of antimicrobial resistance genes abundances in chicken manure and anaerobic digestate
Provisionally accepted
- 1Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Potsdam, Germany
- 2Institute for Animal Hygiene and Environmental Health, Department of Veterinary Medicine, Free University of Berlin, Berlin, Berlin, Germany
- 3Institute for Veterinary Epidemiology and Biostatistics, Department of Veterinary Medicine, Free University of Berlin, Berlin, Baden-Württemberg, Germany
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Introduction: 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 for AMR spread.Methods: 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 (tetA, tetX, sul1, sul2, lnuF, emrD, aadA, and tnpA) by qPCR in chicken manure of different flocks and animal ages; as well as in digestate from different AD time points. Results: Chicken manure showed higher amounts of ARGs compared to digestate, which was characterized by a higher ARG diversity. We observed that an 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.Conclusion: 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, anaerobic digestion (AD) was more effective in reducing antimicrobial-resistant (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 processing already resulted in a lower ARG load compared to untreated chicken manure.
Keywords: antibiotics, anaerobic digestionfermentation, antimicrobial resistance geneARG, Poultry, broiler, litter, high throughput qPCRHT-qPCR
Received: 16 Apr 2025; Accepted: 09 Jun 2025.
Copyright: © 2025 Atanasova, Amon, Roesler, Friese, Merle and Kabelitz. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Aleksandra Atanasova, Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Potsdam, Germany
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