Hormetic dose-responses for silver antibacterial compounds, quorum sensing inhibitors, and their binary mixtures on bacterial resistance of Escherichia coli

Hongyan Shen; Yingying Liu; Yinan Liu; Zemeng Duan; Pengpeng Wu; Zhifen Lin; Haoyu Sun

doi:10.1016/j.scitotenv.2021.147464

Hormetic dose-responses for silver antibacterial compounds, quorum sensing inhibitors, and their binary mixtures on bacterial resistance of Escherichia coli

Sci Total Environ. 2021 Sep 10:786:147464. doi: 10.1016/j.scitotenv.2021.147464. Epub 2021 May 1.

Authors

Hongyan Shen¹, Yingying Liu², Yinan Liu¹, Zemeng Duan¹, Pengpeng Wu³, Zhifen Lin⁴, Haoyu Sun⁵

Affiliations

¹ School of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China.
² State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China.
³ Huaxin College of Hebei Geo University, Shijiazhuang 050700, China.
⁴ State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Key Lab of Chemical Assessment and Sustainability, Shanghai, China.
⁵ State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Key Lab of Chemical Assessment and Sustainability, Shanghai, China; Post-doctoral Research Station, College of Civil Engineering, Tongji University, Shanghai 200092, China. Electronic address: sunhaoyu2015@tongji.edu.cn.

PMID: 33965827
DOI: 10.1016/j.scitotenv.2021.147464

Abstract

Silver antibacterial compounds (SACs) and quorum sensing inhibitors (QSIs), as the potential antibiotic substitutes, have been recommended to prevent and treat microbial infections for the purpose of controlling the increasingly serious bacterial resistance induced by the abuse of antibiotics. However, there is little information regarding the resistance risk of these compounds, especially their mixtures. In this study, bacterial mutation and RP4 plasmid conjugative transfer among bacteria were used to characterize the bacterial endogenous and exogenous resistance, respectively. The effects of SACs (including silver nitrate (AgNO₃) and silver nanoparticle (AgNP)), QSIs, and their binary mixtures on the bacterial resistance were investigated via setting the frequency of mutation and conjugative transfer in Escherichia coli (E. coli) as the test endpoints. The results indicated that these two endpoints exhibited hormetic dose-responses to each treatment. Furthermore, the joint resistance actions between SACs and QSIs were all judged to be antagonism. Correlation analysis suggested that the promotion of the bacterial resistance in each treatment was closely related to its toxicity. It was speculated that AgNO₃ and AgNP might both release Ag⁺ ions to facilitate the E. coli resistance, while QSIs probably acted on LsrR and SdiA proteins to stimulate the bacterial mutation and accelerate the RP4 plasmid conjugative transfer, respectively. These findings imply that the bacteria may generate targeted stress response to the survival pressure from environmental compounds, displaying hormetic phenomenon in resistance-related test endpoints. This study provides a new insight into the resistance risk induced by SACs and QSIs, benefiting the environmental risk assessment of these compounds from the perspective of bacterial resistance.

Keywords: Bacterial resistance; Escherichia coli; Hormesis; Quorum sensing inhibitors; Silver nanoparticle; Silver nitrate.

MeSH terms

Anti-Bacterial Agents / toxicity
Escherichia coli
Hormesis
Metal Nanoparticles*
Quorum Sensing*
Silver / toxicity
Sulfonamides / pharmacology

Substances

Anti-Bacterial Agents
Sulfonamides
Silver