Insights into antibiotic resistance gene abundances and regulatory mechanisms induced by ionic liquids during composting.

This study investigated the regulatory mechanism of the evolution of antibiotic resistance genes (ARGs) during the composting process with sawdust and cow manure as raw materials using ionic liquids (ILs) pretreatment. The results showed that genes of MLS, chloramphenicol, tetracycline, beta - lactam as composting gradually decreased. From day0 to day3, MLS in control group (CK) and experimental group (T) decreased by 25.62% and 26.66%, respectively. Tetracycline decreased by 7.21% in CK and by 7.86% in T. Chloramphenicol decreased by 2.85% in CK and 3.34% in T. Beta-lactam decreased by 1.95% in Ck and by 3.69% in T. Mechanism studies have shown that ILs can effectively decompose extracellular polymeric substances (EPS) and enhance lactose dehydrogenase (LDH) release, resulting in ARGs release and elimination. Meanwhile, ILs pretreatment can inhibit growth of some ARGs hosts, especially Firmicutes, resulting in decreased ARGs. Moreover, metabolic pathways and related genes take part in ARGs transmission were down regulated, leading to decreased ARGs.