摘要

人们普遍认为农业抗生素耐药性应该降低，但是，从现有文献中还不清楚适当的减排目标是什么。有机农场提供了一个独特的机会，可以解决农业抗生素药物使用问题与土壤中抗生素抗性问题。在这项研究中，从内布拉斯加州的12个经过认证的有机农场收集土壤，评估四环素和磺酰胺抗性基因（n = 15个目标）的存在，并与土壤的物理，化学和生物参数相关联。在所有12个农场的土壤中发现了四环素和磺胺类抗生素抗性基因（ARGs），196个土壤样本中有182个（93％）。最常检测到的基因是tetG（55％的样本），其次是tet（Q）（49％），tet（S）（46％），tet（X）（30％）和tetA（P）（29） ％）。从两个深度收集土壤。根据土壤深度没有观察到ARG的差异。在ARG存在和土壤电导率之间以及Ca，Na和Mehlich-3磷的浓度之间存在正相关。来自该研究的数据指出了所选土壤性质与个体四环素抗性基因之间可能的关系，包括tet（O），其是环境样品的共同目标。我们将有机农场结果与之前公布的草原土壤数据进行了比较，发现12种基因的检测频率存在显着差异，其中8种基因在草原土壤中更常见。有趣的是，当通过基因机制对四环素ARG结果进行分类时，外排基因通常在草原土壤中以较高频率存在，而核糖体保护和酶基因在有机农场土壤中更频繁地被检测到，这表明特定的生态作用。四环素抗性机制。通过比较有机农场的土壤和草原土壤，我们可以开始确定低化学品投入农业生产实践对多种抗性措施的基线影响。

There is widespread agreement that agricultural antibiotic resistance should be reduced, however, it is unclear from the available literature what an appropriate target for reduction would be. Organic farms provide a unique opportunity to disentangle questions of agricultural antibiotic drug use from questions of antibiotic resistance in the soil. In this study, soil was collected from 12 certified organic farms in Nebraska, evaluated for the presence of tetracycline and sulfonamide resistance genes (n = 15 targets), and correlated to soil physical, chemical, and biological parameters. Tetracycline and sulfonamide antibiotic resistance genes (ARGs) were found in soils from all 12 farms, and 182 of the 196 soil samples (93%). The most frequently detected gene was tetG (55% of samples), followed by tet(Q) (49%), tet(S) (46%), tet(X) (30%), and tetA(P) (29%). Soil was collected from two depths. No differences in ARGs were observed based on soil depth. Positive correlations were noted between ARG presence and soil electrical conductivity, and concentrations of Ca, Na, and Mehlich-3 phosphorus. Data from this study point to possible relationships between selected soil properties and individual tetracycline resistance genes, including tet(O) which is a common target for environmental samples. We compared organic farm results to previously published data from prairie soils and found significant differences in detection frequency for 12 genes, eight of which were more commonly detected in prairie soils. Of interest, when tetracycline ARG results were sorted by gene mechanism, the efflux genes were generally present in higher frequency in the prairie soils, while the ribosomal protection and enzymatic genes were more frequently detected in organic farm soils, suggesting a possible ecological role for specific tetracycline resistance mechanisms. By comparing soil from organic farms with prairie soils, we can start to determine baseline effects of low-chemical input agricultural production practices on multiple measures of resistance.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6033193/