|Cook, Kimberly - Kim|
|Jechalke, Sven - Julius Kuhn Institute|
|Wolters, B - Julius Kuhn Institute|
|Smalla, Kornelia - Julius Kuhn Institute|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/28/2015
Publication Date: 11/15/2015
Citation: Cook, K.L., Jechalke, S., Wolters, B., Smalla. 2015. Elucidating the potential for transfer of antibiotic resistance genes trhough agro-ecosystems. 2015 ASA-CSSA-SSSA Annual Meeting. November 15-18, 2015. Minneapolis, Minnesota.
Technical Abstract: Increases in the occurrence of antibiotic resistance (AR) in clinical pathogens raises concerns about how resistance is spread within and between human, environmental and agricultural eco-systems. Livestock manure applied to soil may increase AR bacterial concentrations as a result of addition of manure-associated-bacteria containing AR genes and/or through selection and enrichment of AR bacteria that are part of the native soil flora. These AR genes are often associated with class 1 integrons which are found on mobile genetic elements (MGE) that are readily transferred between bacterial populations. The broad host range IncP-1 plasmids are particularly ubiquitous and have been isolated from wastewater, soils and manure. In field studies, concentrations of AR genes for sulfonamide, tetracycline and erythromycin were found to be higher in soils with applied poultry, beef or swine manure than in grass or soils with no applied manure. The concentration of the class one integrase (intI1) gene in the same soils with applied poultry (2.7 ± 1.4 X 107 copies intI1 gene g-1), beef (2.1 ± 0.84 X 1010 copies intI1 gene g-1) or swine (1.9 ± 1.0 X 108 copies intI1 gene g-1) manure was also higher than in grass or soils (0.1 to 4.5 X 106 copies intI1 gene g-1) with no applied manure. Detection of IncP-1 and other plasmids as integrons does not demonstrate mobility, therefore, exogenous plasmid isolation will be necessary to confirm that these elements are transferable. However, these results suggest that there is potential for AR genes in these soil systems to be associated with MGE that can contribute to their spread to other eco-systems. In general, more science-based data are needed to fill gaps in understanding how AR factors are transmitted through agro-ecosystems so better risk assessment tools and mitigation strategies can be developed.