Antibiotic resistance in agricultural soils: Source, fate, mechanism and attenuation strategy

Antibiotic resistance in agricultural soils is a significant environmental and health challenge worldwide. To minimize the risk of antibiotic resistance, it is important to understand the fate and spread mechanism of antibiotics and antibiotic resistance genes (ARGs), and develop effective technologies to minimize their negative effects. In this work, we reviewed recent studies on the occurrence of antibiotic resistance in soil by different agricultural practices. The continuous land applications of manures and sewage sludge, and irrigation with wastewater contribute to the elevated antibiotic resistance in soil. The fate of antibiotic resistance from different interfaces are also discussed. In particular, the mechanisms of ARGs dissemination between bacteria are presented. Aerobic composting, and anaerobic and aerobic digestions of manure, sludge, or wastewater are found to be effective treatments to reduce antibiotic resistance into agricultural soils from the sources. Furthermore, strategies to alleviate antibiotic resistance in soil are proposed, and research directions on in-depth mechanisms are outlined to elucidate the antibiotic resistance decay in soil treatment processes. Although much progress has been made in understanding the links of antibiotic resistance between soil and human health, there are still many unknowns on the complex interactions between them.