Abstract：
Antimicrobial resistance (AMR) stands as an escalating public health crisis fueled by antimicrobial residues in the environment, particularly in soil, which acts as a reservoir for antimicrobial resistance genes (ARGs). Merely quantifying the total extractable concentration of antimicrobials, instead of bioavailable fractions, may substantially underestimate their minimal selection concentration for propagating ARGs. To shed light on the role of bioavailability in ARG abundance within soil, a systematic bioavailability assessment method was established for accurately quantifying the partitioning of multi-class antimicrobials in representative Chinese soils. Microcosm studies unveiled that antimicrobials persisting in the bioavailable fraction could potentially prolong their selection pressure duration to trigger AMR. Notably, the co-occurrence of pesticide or steroid hormone influenced the development trends of ARG subtypes, with fluoroquinolone resistance genes (RGs) being particularly susceptible. Partial least squares path model (PLS-PM) analysis uncovered potentially distinct induction mechanisms of antimicrobials: observable results suggested that extractable residual concentration may exert a direct selection pressure on the development of ARGs, while bioavailable concentration could potentially play a stepwise role in affecting the abundance of mobile genetic elements and initiating ARG dissemination. Such unprecedented scrutinization of the interplay between bioavailable antimicrobials in soils and ARG abundance provides valuable insights into strategizing regulatory policy or guidelines for soil remediation.
摘要：
抗生素耐药性（AMR）是由环境中的抗生素残留引发的不断升级的公共卫生危机。特别是在土壤中，作为抗微生物药物抗性基因(ARGs)的储库。仅量化抗微生物剂的总可提取浓度，而不是生物可利用的部分，可能大大低估了它们传播ARGs的最小选择浓度。为了阐明生物有效性在土壤中ARG丰度中的作用，建立了系统的生物利用度评估方法，以准确地定量中国代表性土壤中多类抗微生物剂的分配。微观世界研究表明，在生物可利用部分中持续存在的抗菌剂可能会延长其选择压力持续时间以触发AMR。值得注意的是,农药或类固醇激素的共同出现影响了ARG亚型的发展趋势，与氟喹诺酮抗性基因（RGs）特别敏感。偏最小二乘路径模型（PLS-PM）分析揭示了抗菌药物的潜在不同诱导机制：可观察到的结果表明，可提取的残留浓度可能对ARGs的发展施加直接选择压力，而生物可利用浓度可能在影响可移动遗传元素的丰度和启动ARG传播方面发挥逐步作用。对土壤中生物可利用的抗微生物剂与ARG丰度之间相互作用的这种前所未有的审查为制定土壤修复的监管政策或指南提供了宝贵的见解。
