Co-effect of cadmium and iron oxide nanoparticles on plasmid-mediated conjugative transfer of antibiotic resistance genes. (July 2021)

• Record Type: Journal Article
• Authors: Pu, Qiang; Fan, Xiao-Ting; Sun, An-Qi; Pan, Ting; Li, Hu; Bo Lassen, Simon; An, Xin-Li; Su, Jian-Qiang
• Is Part Of: Environment international. Volume 152(2021)
• Publication Date: 2021-07
• Subjects: Nanomaterials -- Conjugative transfer -- Horizontal gene transfer -- Microbial community -- Plasmid; Environmental protection -- Periodicals; Environmental health -- Periodicals; Environmental monitoring -- Periodicals; Environmental Monitoring -- Periodicals; Environnement -- Protection -- Périodiques; Hygiène du milieu -- Périodiques; Environnement -- Surveillance -- Périodiques; Environmental health; Environmental monitoring; Environmental protection; Periodicals; 333.705
• DOI: 10.1016/j.envint.2021.106453
• Languages: English
• ISSNs: 0160-4120

Abstract

Highlights: Co-exposure of nano Fe2 O3 and Cd 2+ significantly promotes transfer of RP4 plasmid. Antioxidant enzyme activities were enhanced by Cd 2+ -nano Fe2 O3 treatment. Bacterial cell permeability and conjugation genes expression were accelerated. The majority of transconjugants were identified to be human pathogens. Abstract: Conjunctive transfer of antibiotic resistance genes (ARGs) among bacteria driven by plasmids facilitated the evolution and spread of antibiotic resistance. Heavy metal exposure accelerated the plasmid-mediated conjunctive transfer of ARGs. Nanomaterials are well-known adsorbents for heavy metals removal, with the capability of combatting resistant bacteria/facilitating conjunctive transfer of ARGs. However, co-effect of heavy metals and nanomaterials on plasmid-mediated conjunctive transfer of ARGs was still unknown. In this study, we investigated the effect of the simultaneous exposure of Cd 2+ and nano Fe2 O3 on conjugative transfer of plasmid RP4 from Pseudomonas putida KT2442 to water microbial community. The permeability of bacterial cell membranes, antioxidant enzyme activities and conjugation gene expression were also investigated. The results suggested that the combination of Cd 2+ and high concentration nano Fe2 O3 (10 mg/L and 100 mg/L) significantly increased conjugative transfer frequencies of RP4 plasmid ( p < 0.05). The most transconjugants were detected in the treatment of co-exposure to Cd 2+ and nano Fe2 O3, the majority of which were identified to be human pathogens. The mechanisms of the exacerbated conjugative transfer of ARGs were involved in the enhancement of cell membrane permeability, antioxidant enzyme activities, and mRNA expression levels of the conjugation genes by the co-effect of Cd 2+ and nano Fe2 O3 . This study confirmed that the simultaneous exposure to Cd 2+ and nano Fe2 O3 exerted a synergetic co-effect on plasmid-mediated conjunctive transfer of ARGs, emphasizing that the co-effect of nanomaterials and heavy metals should be prudently evaluated when combating antibiotic resistance.