Location: Agroecosystems Management ResearchTitle: Tylosin-resistant Enterococci, erm genes, and tylosin in drained fields receiving swine manure Author
|Soupir, Michelle - Iowa State University|
|Moorman, Thomas - Tom|
|Garder, Jason - Iowa State University|
Submitted to: American Water Resources Association Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/25/2013
Publication Date: 3/25/2013
Citation: Soupir, M.L., Moorman, T.B., Garder, J.L. 2013. Tylosin-resistant Enterococci, erm genes, and tylosin in drained fields receiving swine manure. American Water Resources Association Conference. Available at: http://www.awra.org/meetings/Spring2013/doc/PP/Sess%204%20abs.pdf.
Technical Abstract: The use of tylosin at subtherapeutic levels by the swine industry provides selective pressure for the development of antibiotic resistance in gastrointestinal bacteria. The land application of swine manure to drained agricultural fields might introduce elevated levels of total and tylosin-resistant enterococci, erm genes and tylosin. We determined the occurrence and transport of total and tylosin-resistant enterococci, erm genes and tylosin in tile-drained chisel plow, and no-till plots that have received alternate year applications of liquid swine manure. Each one-acre plot is drained separately and tile water samples were collected directly from the discharge tile line weekly while the tiles were flowing. Resistance to tylosin in manure, soil and tile drainage water was investigated using phenotypic based (membrane filtration) and genotypic based (qPCR) methods, and compared with samples from control plots treated without manure. Tylosin was quantified using LC-MS/MS. Enterococcus populations in the injection band immediately after manure application were elevated above background, but were well below the abundance of ermB or ermF (> 108 gene copies/g soil). However, over the next 24 months these genes declined in abundance to levels similar to those found in the non-manured soils (103 to 3 x 105 copies/g soil). Concentrations of erm genes in tile drainage water were not different from those in drainage from the control plots. The results suggest that antibiotic use in swine results in elevated levels of antibiotic resistant microorganisms in manure treated soils, but that transport of these organisms (genes) in tile drainage is not increased.