Agriculture and Agri-Food Canada, London, ON N5V 4T3, Canada.
Graduate School at Shenzhen, Tsinghua University, China.
Sci Total Environ. 2017 Mar 1;581-582:32-39. doi: 10.1016/j.scitotenv.2016.12.138. Epub 2017 Jan 8.
Manuring ground used for crop production is an important agricultural practice. Should antibiotic-resistant enteric bacteria carried in the manure be transferred to crops that are consumed raw, their consumption by humans or animals will represent a route of exposure to antibiotic resistance genes. Treatment of manures prior to land application is a potential management option to reduce the abundance of antibiotic resistance genes entrained with manure application. In this study, dairy manure that was untreated, anaerobically digested, mechanically dewatered or composted was applied to field plots that were then cropped to lettuce, carrots and radishes. The impact of treatment on manure composition, persistence of antibiotic resistance gene targets in soil following application, and distribution of antibiotic resistance genes and bacteria on vegetables at harvest was determined. Composted manure had the lowest abundance of antibiotic resistance gene targets compared to the other manures. There was no significant difference in the persistence characteristics of antibiotic resistance genes following land application of the various manures. Compared to unmanured soil, antibiotic resistance genes were detected more frequently in soil receiving raw or digested manure, whereas they were not in soil receiving composted manure. The present study suggests that vegetables grown in ground receiving raw or digested manure are at risk of contamination with manure-borne antibiotic resistant bacteria, whereas vegetables grown in ground receiving composted manure are less so.
用于作物生产的施肥地是一种重要的农业实践。如果粪便中携带的抗药性肠道细菌转移到生吃的作物上，人类或动物食用这些作物将代表接触抗生素耐药基因的途径。在土地应用前处理粪便，是减少随粪便应用而夹带的抗生素耐药基因丰度的一种潜在管理选择。在这项研究中，未处理、厌氧消化、机械脱水或堆肥的奶牛粪便被应用于田间试验，然后种植生菜、胡萝卜和萝卜。处理对粪便成分的影响、施用后土壤中抗生素耐药基因靶标的持久性，以及收获时蔬菜上抗生素耐药基因和细菌的分布，都得到了确定。与其他粪便相比，堆肥粪便中的抗生素耐药基因靶标丰度最低。各种粪便土地应用后，抗生素耐药基因的持久性特征没有显著差异。与未施肥土壤相比，在接收生肥或消化肥的土壤中更频繁地检测到抗生素耐药基因，而在接收堆肥的土壤中则没有。本研究表明，在接收生肥或消化肥的土地上种植的蔬菜有被粪便携带的抗药性细菌污染的风险，而在接收堆肥的土地上种植的蔬菜则风险较小。
