Insights into the mobility and bacterial hosts of antibiotic resistance genes under dinotefuran selection pressure in aerobic granular sludge based on metagenomic binning and functional modules

Xin Zhang; Wei Guo; Zuyuan Zhang; Peng Gao; Peng Tang; Tingting Liu; Xingrong Yao; Jun Li

doi:10.1016/j.envres.2025.120807

Insights into the mobility and bacterial hosts of antibiotic resistance genes under dinotefuran selection pressure in aerobic granular sludge based on metagenomic binning and functional modules

Environ Res. 2025 Jan 9:120807. doi: 10.1016/j.envres.2025.120807. Online ahead of print.

Authors

Xin Zhang¹, Wei Guo², Zuyuan Zhang¹, Peng Gao¹, Peng Tang¹, Tingting Liu¹, Xingrong Yao¹, Jun Li³

Affiliations

¹ National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China.
² National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China. Electronic address: gwfybj@bjut.edu.cn.
³ National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China. Electronic address: bjutlijun@126.com.

PMID: 39798650
DOI: 10.1016/j.envres.2025.120807

Abstract

Dinotefuran (DIN) is toxic to non-target organisms and accelerates the evolution of antibiotic resistance, which poses a problem for the stable operation of the activated sludge process in wastewater treatment plants (WWTPs). However, the emergence and the transfer mechanism of antibiotic resistance genes (ARGs) in activated sludge systems under DIN stress remains unclear. Thus, in the study, the potential impact of DIN on ARGs and virulence factor genes (VFGs) in aerobic granular sludge (AGS) was investigated in depth using metagenomic binning and functional modules. It was found that DIN stress increased the total abundance of ARGs, mobile genetic elements (MGEs), and VFGs in the AGS system, with the highest abundance of fabG (4.6%), tnpA (55.6%) and LPS (39.0%), respectively. The proliferation of the enteric pathogens Salmonella enterica and Escherichia coli in the system indicates that DIN induces exposure of harmless bacteria to the infected environment. The genera Nitrospira (1169 ARG subtypes) and Dechloromonas (663 ARG subtypes) were identified as the potentially antibiotic-resistant bacteria carrying the most ARGs and MGEs in the metagenome-assembled genomes. Co-localization patterns of some ARGs, MGEs, and the SOS response-related gene lexA were observed on metagenome-assembled contigs under high levels of DIN exposure, suggesting DIN stimulated ROS production (101.8% increase over control), altered cell membrane permeability, and increased the potential for horizontal gene transfer (HGT). Furthermore, the DNA damage caused by DIN in AGS led to the activation of the antioxidant system and the SOS repair response, which in turn promoted the expression of the type IV secretion system and HGT through the flagellar channel. This study extends the previously unappreciated DIN understanding of the spread and associated risks of ARGs and VFGs in the AGS system of WWTPs. It elucidates how DIN facilitates HGT, offering a scientific basis for controlling emerging contaminant-induced resistance.

Keywords: Antibiotic-resistant bacteria; Dinotefuran; Mobile genetic elements; Reactive oxygen species; Virulence factor genes.