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ARS Home » Midwest Area » Urbana, Illinois » Global Change and Photosynthesis Research » Research » Publications at this Location » Publication #257646
Title: Antibiotic resistance in swine manure-impacted environments

Author
item Chee Sanford, Joanne
item MAXWELL, S - University Of Illinois
item TSAU, K - University Of Illinois
item MERRICK, M - University Of Illinois
item AMINOV, R - Rowett Research Institute

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 1/1/2011
Publication Date: 12/7/2011
Citation: Chee Sanford, J.C., Maxwell, S., Tsau, K., Merrick, M., Aminov, R. 2011. Antibiotic resistance in swine manure-impacted environments. In: Keen, Patricia L., Montforts, Mark H.M.M., editors. Antimicrobial Resistance in the Environment. Hoboken, NJ: Wiley-Blackwell. p. 203-223.

Interpretive Summary: The addition of high nutrient and bacterial loads via land application of animal waste to crop fields has consequent effects on natural soil microbial communities present in soil. In addition to the concerns over the potential expansion of antibiotic resistances among bacterial species as a result of manure addition, there are rising concerns over whether these drug resistance genes can circulate back to human and animal environments again. Newly emerging information on native soil species that are also opportunistic human pathogens, along with the findings from this study that many of these species carry drug resistances, suggest that the reservoir and mechanisms of genetic transfer are probably higher in soil environments than previously thought. In this study, we demonstrated a high diversity of species carrying multiple drug resistance genes, and these populations are common to agricultural soils. Genes encoding other physiological functions may be associated with the mechanisms of gene exchange present in the soils, and these may be significant drivers that coincidentally carry with them the additional drug resistance genes. The signficance of these findings are some of the first to suggest a much broader range of bacterial species harboring genes that are thought to reside only in clinical species, and the circulation of these genes may not always link to the practice of manure addition to soil. Further, rhizosphere communities are underinvestigated for their role in maintenance and dissemination of drug resistances, and may pose as reservoirs for later re-entry into human and animal systems.

Technical Abstract: The impact of land-applied manure resulting from common practices of waste disposal in animal agriculture has been associated with emergent concerns over the potential persistence and distribution of antibiotic resistant genes in natural environments. Here we investigated how the application of manure from antibiotic-fed swine to soil affects the antibiotic resistance profile of soil microbiota. Collectively, the findings within the assemblage of bacterial isolates obtained in this study present a high complexity regarding the molecular ecology of antibiotic resistance genes in differing environments. The diversity of bacterial genera harboring antibiotic resistance genes appears quite extensive, likely beyond many hypothesized occurrences from the flow of genes originating from animal systems. Attention to rhizospheres where multiple mechanisms of natural gene exchange are common among some species, resulting in not only acquisition of new capabilities, but may also be linked to the circulation of both exogenous and natural reservoirs of antibiotic resistances in commensal soil microbial communities.