Funding Agency: U.S. Department of Agriculture, National Institute of Food and Agriculture
Collaborators: Adina Howe (Iowa State University); Michelle Soupir (Iowa State University); Daniel Anderson (Iowa State University)
Over 15.6 million kilograms of veterinary antimicrobials are sold yearly in the US alone for disease control and growth promotion of livestock. With about 50-100% of administered antimicrobials passing through the animal unchanged, antimicrobial residues can be introduced into the environment during manure fertilization and can persist in soil due to insufficient degradation. This can promote the development and proliferation of antimicrobial resistance genes (ARGs) in the soil microbiome. Additionally, metals have been previously shown to correlate to the presence of ARGs in soil and manure samples. An increase in occurrence of antimicrobial resistant bacteria (ARB) and ARGs in the environment can impact human health from exposure to contaminated food or water. We propose to combat antimicrobial resistance (AMR) in these systems by: developing improved tools to better indicate AMR risk in agroecosystems, identifying the best practices for mitigating AMR during manure storage and treatment, and providing a better understanding of how AMR develops during swine manure management. Results will be provided to producers and stakeholders through manure management extension programs. Specifically, we propose to achieve the following research objectives:
1. Characterize AMR response to manures and under varying antibiotic usage and pressures;
2. Identify and compare the underlying mechanisms of action of emerging antimicrobial resistance in organisms under varying antibiotic and metabolite pressures;
3. Characterize AMR mitigation effectiveness in manure treatment alternatives;
4. Assess indicators of AMR in diverse manures.
The UB Team will focus on (1) The quantification of the amounts of antimicrobials and metals in various manure treatments; (2) The identification of unknown antimicrobial transformation products. The proposed research will uniquely bring together both traditional and novel AMR indicators to fill important knowledge gaps associated with their linkages to AMR emergence and persistence. The development of these tools are framed through experiments that address open questions about the most effective strategies to decrease AMR during manure management. The outputs of this work will help to inform how we manage the selection, emergence, and spread of AMR in animal production.
Recent Related Publications:
1. Hurst, J. J. et al. Trends in Antimicrobial Resistance Genes in Manure Blend Pits and Long-Term Storage Across Dairy Farms with Comparisons to Antimicrobial Usage and Residual Concentrations. Environ. Sci. Technol. 53, 2405–2415 (2019).
2. Wallace, J. S. & Aga, D. S. Enhancing Extraction and Detection of Veterinary Antibiotics in Solid and Liquid Fractions of Manure. J. Environ. Qual. 45, 471–479 (2016).
3. Wallace, J. S., Garner, E., Pruden, A. & Aga, D. S. Occurrence and transformation of veterinary antibiotics and antibiotic resistance genes in dairy manure treated by advanced anaerobic digestion and conventional treatment methods. Environ. Pollut. 236, 764–772 (2018).
4. Hurst, J. J., Wallace, J. S. & Aga, D. S. Method development for the analysis of ionophore antimicrobials in dairy manure to assess removal within a membrane-based treatment system. Chemosphere 197, 271–279 (2018).
5. Aga, D. S. et al. Challenges in the Measurement of Antibiotics and in Evaluating Their Impacts in Agroecosystems: A Critical Review. J. Environ. Qual. 45, 407–419 (2016).
6. Wallace, J. S., Garner, E., Pruden, A. & Aga, D. S. Occurrence and transformation of veterinary antibiotics and antibiotic resistance genes in dairy manure treated by advanced anaerobic digestion and conventional treatment methods. Environ. Pollut. 236, 764–772 (2018).