Biotic Pathways of Reciprocal Responses between Antibiotic Resistance Genes and Inorganic Nitrogen Cycling Genes in Amoxicillin-Stressed Compost Ecosystems.

This study explores the transformation of inorganic nitrogen under different levels of amoxicillin (AMX) stress, the expression levels of antibiotic resistance genes (ARGs), and the regulatory mechanisms of key species on ARGs and inorganic nitrogen cycling genes (INCGs). High level of AMX inhibited the accumulation of NH4+-N, which increased by only 531 % relative to the initial. Additionally, AMX to some extent increased the levels of nirS and nirK, potentially leading to nitrogen loss and the accumulation of NO2-. Actinobacteria may serve as potential hosts for ARGs during sludge composting. This stress made the response between INCGs and ARGs more complex due to key species. Under high-level AMX pressure, most ARGs-related species likely originate from nitrogen cycling functional species. In conclusion, high levels of AMX stress may lead to nitrogen cycling imbalance and the dissemination of antibiotic resistance genes in composting systems.