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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #314911
Title: Fate and transport of tylosin-resistant bacteria and macrolide resistance genes in artificially drained agricultural fields receiving swine manure

Author
item LUBY, ELIZABETH - Iowa State University
item Moorman, Thomas
item SOUPIR, MICHELLE - Iowa State University

Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2016
Publication Date: 3/7/2016
Citation: Luby, E.M., Moorman, T.B., Soupir, M.L. 2016. Fate and transport of tylosin-resistant bacteria and macrolide resistance genes in artificially drained agricultural fields receiving swine manure. Science of the Total Environment. 550:1126-1133.

Interpretive Summary: Midwestern agriculture lands are extensively tile-drained. Application of manure from swine treated with antibiotics introduces antibiotics and antibiotic resistance genes to soil with the potential for further movement in drainage water. We used DNA-based methods to measure four genes which confer resistance to bacteria against macrolide antibiotics. Concentrations of these genes were greatest in swine manure and in manure-treated soil. High concentrations were found immediately following manure injection, but overwinter these concentrations returned to background levels. MsrA was not detected in manure, soil or water.Concentrations of the genes ermB and ermF were significantly higher in drainage water from manured plots compared to non-manured plots. ErmB and ermF were detected in 78% and 44%, respectively, of drainage water samples from plots with manure treatment. Although ermC was detected at the highest concentrations of the three genes in drainage water, concentrations in water from manure treated plots were not significantly greater than concentrations in drainage water from the no-manure plots. This study is the first to report significant increases in resistance gene abundances in agricultural drainage water from soils receiving manure application. There is currently extensive debate of the use of antibiotics in agriculture and the results of this study will inform scientists and others on this issue.

Technical Abstract: Application of manure from swine treated with antibiotics introduces antibiotics and antibiotic resistance genes to soil with the potential for further movement in drainage water. Manure concentrations for ermB, ermC and ermF were all >109 copy g-1. Manure contained 1.76 x 105 CFUg-1 enterococci with 83% resistant to tylosin. Soil where manure was injected obtained median concentrations >200 CFUg-1 soil of enterococci and tylosin resistant enterococci. Gene abundances of ermB, ermC and ermF in manured soil returned to levels identified in non-manured control plots by the spring following manure application. While enterococci and tylosin resistant enterococci concentrations in drainage water samples showed no effects of manure treatments, resistance genes ermB and ermF concentrations were significantly higher (p<0.01) in drainage water from manured plots compared to non-manured plots. ErmB and ermF were detected in 78% and 44%, respectively, of drainage water samples from plots with manure treatment. Although ermC was detected at the highest concentrations of the three genes in drainage water, concentrations in water from manure treated plots were not significantly greater (p>0.10) than concentrations in drainage water from the no-manure plots. No significant differences (p>0.10) were identified due to tillage treatments for any of the genes detected. MsrA was not detected in manure, soil or water. This study is the first to report significant increases in resistance gene abundances in agricultural drainage water from soils receiving manure application.