title: Ionic Liquid Facilitates the Conjugative Transfer of Antibiotic Resistance Genes Mediated by Plasmid RP4.
abstract: The dissemination and propagation of antibiotic resistance genes (ARGs) is an emerging global health concern. In our previous study, the ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]) had been proven to facilitate the dissemination of ARGs via horizontal gene transfer. In this study, we further confirm that this compound facilitates the horizontal transfer of plasmid RP4 through a conjugation mechanism and not by natural transformation. The mechanisms for [BMIm][PF6] promoting conjugative transfer are attributable to enhancing the mRNA expression levels of conjugative and global regulatory genes, as well as by inhibiting the genes that are responsible for the vertical transfer of cell growth. [BMIm][PF6] significantly enhanced the expression of the outer membrane porin proteins (OMPs) OmpC and OmpA and the corresponding mRNA expression levels of ompC and ompA genes in recipient bacteria, which contributed to pore formation and increased cell membrane permeability. The increased expression of pilin and pili allowed the donor pilus to attach to and access the recipient cells, thereby assisting cell-to-cell contact to facilitate the conjugative transfer of plasmid RP4. To the best of our knowledge, this is the first insightful exploration of [BMIm][PF6] facilitating the conjugative transfer of ARGs mediated by plasmid RP4 and of several other ILs with different cations or anions that are capable of promoting plasmid transfer. It is therefore suggested that the application of some ILs in industrial processes should be carefully evaluated before their bulk emission into the environment.
authors.affiliation: ‡College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.affiliation: †School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
authors.forename: Daqing
authors.initials: D
authors.lastname: Mao
authors.affiliation: ‡College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects; D003227:Conjugation, Genetic / Q000187:drug effects; D004352:Drug Resistance, Microbial / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D036781:Fimbriae Proteins / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D022761:Gene Transfer, Horizontal / Q000187:drug effects*; D005798:Genes, Bacterial; D007093:Imidazoles / Q000494:pharmacology; D052578:Ionic Liquids / Q000494:pharmacology*; D010957:Plasmids / Q000378:metabolism*; D018272:Porins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019779:Salmonella enterica / Q000187:drug effects / Q000235:genetics
chemical_list: C412621:1-butyl-3-methylimidazolium hexafluorophosphate; D000900:Anti-Bacterial Agents; D007093:Imidazoles; D052578:Ionic Liquids; D018272:Porins; D012333:RNA, Messenger; D036781:Fimbriae Proteins