摘要

    牲畜饲料工业的大规模发展增加了土壤中抗生素和重金属污染的机会。重金属和受污染的土壤中的抗生素抗性基因（ARGs）和微生物群落的命运仍不清楚。在这项研究中，我们调查了在土霉素（OTC）污染的土壤中添加镉（Cd）对ARGs，微生物群落和人类病原菌运输的影响。结果表明，OTC的添加显着增加了土壤和生菜组织中ARGs和intI1的含量。在OTC处理过的土壤中添加Cd进一步增加了ARGs和intI1的丰度和转运。此外，镉还促进了潜在的人类致病菌（HPB）向生菜组织的转移。与O10处理相比，Cd的添加降低了土壤和生菜组织中OTC的浓度，但略微增加了生菜组织的鲜重。冗余分析表明细菌群落演替是ARGs变异的主要因素。网络分析表明，ARGs的主要宿主细菌主要来自Proteobacteria。相关分析表明，intl1与tetG，tetC，sul1，sul2，ermX和ermQ显着相关。同时，潜在的HPB（梭菌和伯克霍尔德氏菌）与intI1和八个ARG（tetG，tetC，tetW，tetX，sul1，sul2，ermX和ermQ。）显着相关。这项研究的结果表明，必须考虑在农田中添加重金属，以减少土壤和农作物中ARGs的转移。

    The large-scale development in livestock feed industry has increased the chances of antibiotics and heavy metals contamination in the soil. The fate of antibiotic resistance genes (ARGs) and microbial community in heavy metals and antibiotic contaminated soil is still unclear. In this study, we investigated the effect of cadmium (Cd) addition on the transport of ARGs, microbial community and human pathogenic bacteria in oxytetracycline (OTC) contaminated soil. Results showed that the addition of OTC significantly increased the abundance of ARGs and intI1 in the soil and lettuce tissues. The addition of Cd to OTC treated soil further increased the abundance and translocation of ARGs and intI1. Moreover, Cd promoted the transfer of potential human pathogenic bacteria (HPB) into lettuce tissues. Compared with O10 treatment, the addition of Cd decreased the concentration of OTC in soil and lettuce tissue, but slightly increased the fresh weight of lettuce tissues. Redundancy analysis indicated that bacterial community succession is a major factor in ARGs variation. Network analysis indicated that the main host bacteria of ARGs were mainly derived from Proteobacteria. Correlation analysis showed that intI1 was significantly correlated with tetG, tetC, sul1, sul2, ermX, and ermQ. Meanwhile, potential HPB (Clostridium, and Burkholderia) was significantly correlated with intI1 and eight ARGs (tetG, tetC, tetW, tetX, sul1, sul2, ermX, and ermQ.). The findings of this study suggest that the addition of heavy metals to agricultural fields must be considered in order to reduce the transfer of ARGs in the soil and crops.

    https://www.sciencedirect.com/science/article/abs/pii/S100107422030156X