Abstract：
Commercial Hog Operations (CHOs) produce large amounts of fecal waste, which is often treated in lagoons and sprayed onto fields as fertilizer. The effects of these systems on proximal water quality compared to ambient conditions have not been well-studied, and are particularly important for understanding the dissemination of fecal bacteria and antimicrobial resistance. A longitudinal, case-control watershed study was designed to study effects of CHOs on microbial water quality among watersheds with similar soil, land use, human population, and area. We compared watersheds with (n = 13) and without (n = 9) CHOs over one year measuring fecal indicator bacteria (FIB), microbial source tracking (MST) fecal markers, and antimicrobial resistance in isolated Escherichia coli. E. coli concentrations were higher (p < 0.001) at sites downstream of CHOs (1284 CFU/100 mL, n = 103) compared to background sites (687 CFU/100 mL, n = 74). The human MST marker HF183 was detected at similarly low concentrations (PR = 1.3 (0.91, 1.8), p = 0.30). However, the swine MST marker pig-2-bac was found at more sites downstream of CHOs (PR = 3.5 (0.98, 12), p = 0.035) and at a significantly higher (p = 0.003) mean concentration at sites downstream of CHOs (283 copies/mL) compared to background sites (0.76 copies/mL). The presence of any antimicrobial resistance was observed more often for E. coli isolated downstream from CHOs (19%, n = 556) than background sites (6%, n = 356), with tetracycline resistance observed most often. Nine isolates from four sites downstream of CHOs and one isolate from a background site were confirmed β-lactamase-producing E. coli. Overall, these results show that fecal microbes and antimicrobial resistance from CHOs may be transported off-site, however more research is needed to characterize timing and conditions of off-site transport. Mitigation strategies such as optimizeation of waste treatment, buffers, and antibiotic stewardship could help reduce the contributions of microbial contaminants to surface water.
摘要：
商业养猪业务(CHOs)产生大量粪便废物，通常在泻湖中处理并喷洒在田地上作为肥料。与环境条件相比，这些系统对近端水质的影响尚未得到充分研究，对于了解粪便细菌的传播和抗菌素耐药性尤为重要。纵向，病例对照流域研究旨在研究CHOs对相似土壤流域微生物水质的影响，土地利用,人口,和面积。我们比较了（n=13）和没有（n=9）CHO的流域超过一年测量粪便指示细菌（FIB），微生物源追踪（MST）粪便标记，和分离的大肠杆菌的耐药性。CHOs下游的大肠杆菌浓度较高（p<0.001）（1284CFU/100mL，n=103）与背景位点（687CFU/100mL，n=74）。在类似的低浓度下检测到人MST标志物HF183(PR=1.3(0.91,1.8),p=0.30)。然而,在CHOs下游的更多位置发现了猪MST标记pig-2-bac（PR=3.5（0.98，12），p=0.035），并且与背景位点（0.76拷贝/mL）相比，CHO下游位点的平均浓度（283拷贝/mL）明显更高（p=0.003）。从CHOs下游分离的大肠杆菌更经常观察到任何抗微生物耐药性的存在(19%，n=556)比背景位点(6%，n=356),最常观察到四环素耐药性。来自CHO下游四个位点的9个分离物和来自背景位点的1个分离物被证实为产生β-内酰胺酶的大肠杆菌。总的来说,这些结果表明，粪便微生物和来自CHOs的抗菌素耐药性可能被转移到场外，然而，需要更多的研究来描述异地运输的时间和条件。缓解策略，如优化废物处理，缓冲区,和抗生素管理可以帮助减少微生物污染物对地表水的贡献。
