naa a22 4500 510752802 CHVBK 20180411083110.0 cr unu---uuuuu 180411e20131101xx s 000 0 eng 10.1007/s11270-013-1754-3 doi (NATIONALLICENCE)springer-10.1007/s11270-013-1754-3 Occurrence of Tylosin-Resistant Enterococci in Swine Manure and Tile Drainage Systems under No-Till Management [Elektronische Daten] [Trang Hoang, Michelle Soupir, Ping Liu, Alok Bhandari] The sub-therapeutic use of tylosin in commercial swine operations can produce selective pressure for the development of antibiotic resistant bacteria. When swine manure from such operations is applied on drained agricultural fields, it can lead to transport and dissemination of resistant microorganisms through soils, into tile drainage lines, and ultimately into surface waters. The objective of this study was to investigate the occurrence and transport of tylosin-resistant enterococci from two different tile-drained agricultural fields receiving biennial swine-waste applications during different seasons. Resistance to tylosin in manure, soil, and tile water was investigated by a phenotype-based method and polymerase chain reaction. All enterococci in manure samples obtained from the spring application were resistant to tylosin, whereas 68% of the total enterococci from the fall application were resistant to tylosin. Average concentrations of total and tylosin-resistant enterococci in soil samples over the two sampling periods were 9.8 × 103 and 7.5 × 103cfu/g of soil, respectively. Total and tylosin-resistant enterococci concentrations in tile water collected from the two plots were significantly different (P < 0.05) during the spring and fall experiments. In drainage water, the total enterococci peaked at 2.6 × 103 and 5.0 × 103cfu/100mL for the fall and spring experiments, respectively, while tylosin-resistant enterococci peaked at 1.4 × 103 and 1.2 × 103cfu/100mL for the fall and spring experiments, respectively. Total suspended solid concentrations in tile water were correlated with enterococci concentrations when base flow was present. Seven out of eight macrolide-resistance genes tested were detected (ermA, ermB, ermC, ermF, ermT, ermX, and msrA, but not mefA). Five of these genes (ermB, ermC, ermF, ermT, and msrA) were detected in at least 9% of the samples. On average, most of the phenotypically resistant isolates (97%) harbored msrA, while only 10% contained ermT and 9% contained ermC. Genes containing ermF and ermB were detected in 78% and 69% of resistant isolates, respectively. Only 2% of the total isolates (n = 4) harbored all five genes. Of the isolates collected from manure, soil, and water samples, 12% were confirmed as Enterococcus faecalis with 96% of the confirmed E. faecalis isolates containing multiple resistance genes. The findings from this study are useful to provide baseline information on the export of total and tylosin-resistant enterococci during rainfall events from manured, tile-drained agricultural fields of the Upper Midwestern USA. Springer Science+Business Media Dordrecht, 2013 Tylosin-resistant enterococci nationallicence Microbial transport nationallicence Swine manure nationallicence Antibiotics nationallicence Tile drainage nationallicence Hoang Trang Department of Agricultural and Biosystems Engineering, Iowa State University, 50011-3310, Ames, IA, USA aut Soupir Michelle Department of Agricultural and Biosystems Engineering, Iowa State University, 50011-3310, Ames, IA, USA aut Liu Ping Department of Microbiology, Iowa State University, 50011, Ames, IA, USA aut Bhandari Alok Department of Civil Engineering, Kansas State University, 61506, Manhattan, KS, USA aut Water, Air, & Soil Pollution Springer Netherlands 224/11(2013-11-01), 1-15 0049-6979 224:11<1 2013 224 11270 https://doi.org/10.1007/s11270-013-1754-3 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11270-013-1754-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hoang Trang Department of Agricultural and Biosystems Engineering, Iowa State University, 50011-3310, Ames, IA, USA aut NATIONALLICENCE 700 1- Soupir Michelle Department of Agricultural and Biosystems Engineering, Iowa State University, 50011-3310, Ames, IA, USA aut NATIONALLICENCE 700 1- Liu Ping Department of Microbiology, Iowa State University, 50011, Ames, IA, USA aut NATIONALLICENCE 700 1- Bhandari Alok Department of Civil Engineering, Kansas State University, 61506, Manhattan, KS, USA aut NATIONALLICENCE 773 0- Water, Air, & Soil Pollution Springer Netherlands 224/11(2013-11-01), 1-15 0049-6979 224:11<1 2013 224 11270 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer