Location: Livestock Bio-SystemsTitle: Comparison of stockpiling and composting on reducing antibiotic resistant bacteria and resistance genes in beef cattle manure
|STALEY, ZACHERY - University Of Nebraska|
|STROMER, BOBBI - Us Army Corp Of Engineers (USACE)|
|SCHMIDT, AMY - University Of Nebraska|
|SNOW, DANIEL - University Of Nebraska|
|BARTET-HUNT, SHANNON - University Of Nebraska|
|WANG, BING - University Of Nebraska|
|LI, XU - University Of Nebraska|
Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/28/2021
Publication Date: N/A
Interpretive Summary: Manure accumulates on pen surfaces during the production of beef. This manure is periodically collected from the pen surface and temporally stockpiled until it can be applied to crop land as a fertilizer. There has been concern that medications administered to the animals during production will accumulate in the manure and cause an increase stains of bacteria that are resistant to the medication. A study was conducted to determine how this management practice impacts the potential for increasing bacteria resistant to human medications. Results from this study suggest that (1) bulking agent can be an important source of genetic material associate with resistance when adding for composting; (2) during cold months the variability of the temperature profile in composting piles could result in poor reduction in the genetic material associate with resistance; (3) during warm months both stockpiling and composting can be effective in reducing the abundance of this genetic material.
Technical Abstract: Manure storage methods can affect the concentration and prevalence of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in cattle manure prior to land application. The objective of this study was to compare stockpiling and composting with respect to their effectiveness in reducing ARB and ARGs in beef cattle manure using full-scale setup in the field. Two rounds of experiments were conducted in different seasons with different bulking agents for composting. In both the winter-spring round and the summer-fall round, while ARB concentrations declined below the limit of quantification rapidly in all manure piles, ARB prevalence was significantly greater in composting piles than in stockpiling piles. This was likely due to the introduction of ARB from bulking agents. There was no significant change in ARG concentrations between initial and final concentrations in either manure storage treatment in the winter-spring round, but a significant reduction of ARGs erm(B) and tet(O) and (Q) over time in both the composting and stockpiling pile during the summer-fall round. Results from this study suggest that (1) bulking agent can be an important source of ARGs for composting; (2) during cold months the heterogeneity of the temperature profile in composting piles could result in poor ARG reduction; (3) during warm months both stockpiling and composting can be effective in reducing ARG abundance.