Resistome in urban landscape lakes

Urban landscape lakes provide aesthetics and recreation values for residents. The pollution of antibiotic resistance genes (ARGs) threatens the aquatic ecosystems and public health. However, a comprehensive understanding of the fate and transmission of ARGs in different types of park landscape lakes (i.e., backwater and living water) remains deficient. Here, we profiled the diversity, origin and spread risk of ARGs and opportunistic pathogens in backwater and living water of eight urban parks as well as park soil, tap water, Yellow River water and local human feces using metagenomics and 16S rRNA gene sequencing. Our results showed higher antibiotic resistance risk presented in backwater due to higher ARG diversity, while higher resistance transfer risk occurred in living water due to higher mobile genetic elements (MGEs) diversity. ARG community assembly was dominated by stochastic processes both in backwater and living water, indicating that ARGs in park lakes cannot be regulated through external intervention. Park soil shared the most ARGs with backwater (40.85%) and living water (42.56%), which may be the dominant potential source of ARGs in park lakes. Notably, there were nine high-risk ARGs (such as mdtM and msrA) that exist in park water significantly enriched in human feces, implying possible spread risk from environment to human. Metagenomics binning revealed that metagenome assembled genomes carrying ARGs mainly belong to Actinobacteria. Our study highlights the potential origin and spread risk of resistomes in urban lakes, which is significant for healthy management of urban lakes.