Multiwalled Carbon Nanotubes Promote Bacterial Conjugative Plasmid Transfer

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

Abstract

Multiwalled carbon nanotubes (MWCNTs) regularly enter aquatic environments due to their ubiquity in consumer products and engineering applications. However, the effects of MWCNT pollution on the environmental microbiome are poorly understood. Here, we evaluated whether these carbon nanoparticles can elevate the spread of antimicrobial resistance by promoting bacterial plasmid transfer, which has previously been observed for copper nanomaterials with antimicrobial properties as well as for microplastics. Through a combination of experimental liquid mating assays between Pseudomonas putida donor and recipient strains with plasmid pKJK5::gfpmut3b and mathematical modeling, we here demonstrate that the presence of MWCNTs leads to increased plasmid transfer rates in a concentration-dependent manner. The percentage of transconjugants per recipient significantly increased from 0.21 ± 0.04% in absence to 0.41 ± 0.09% at 10 mg L-1 MWCNTs. Similar trends were observed when using an Escherichia coli donor hosting plasmid pB10. The identified mechanism underlying the observed dynamics was the agglomeration of MWCNTs. A significantly increased number of particles with >6 μm diameter was detected in the presence of MWCNTs, which can in turn provide novel surfaces for bacterial interactions between donor and recipient cells after colonization. Fluorescence microscopy confirmed that MWCNT agglomerates were indeed covered in biofilms that contained donor bacteria as well as elevated numbers of green fluorescent transconjugant cells containing the plasmid. Consequently, MWCNTs provide bacteria with novel surfaces for intense cell-to-cell interactions in biofilms and can promote bacterial plasmid transfer, hence potentially elevating the spread of antimicrobial resistance. IMPORTANCE In recent decades, the use of carbon nanoparticles, especially multiwalled carbon nanotubes (MWCNTs), in a variety of products and engineering applications has been growing exponentially. As a result, MWCNT pollution into environmental compartments has been increasing. We here demonstrate that the exposure to MWCNTs can affect bacterial plasmid transfer rates in aquatic environments, an important process connected to the spread of antimicrobial resistance genes in microbial communities. This is mechanistically explained by the ability of MWCNTs to form bigger agglomerates, hence providing novel surfaces for bacterial interactions. Consequently, increasing pollution with MWCNTs has the potential to elevate the ongoing spread of antimicrobial resistance, a major threat to human health in the 21st century.

Details

Original languageEnglish
Pages (from-to)e0041022
JournalMicrobiology spectrum
Volume10
Issue number2
Early online date6 Apr 2022
Publication statusPublished - 6 Apr 2022
Peer-reviewedYes

External IDs

Scopus 85129779658
unpaywall 10.1128/spectrum.00410-22
Mendeley 8bc063c0-4277-396c-b7d7-42d8d47516a5
WOS 000779337300001
ORCID /0000-0002-6048-6984/work/142240083
ORCID /0000-0002-4169-6548/work/142247374
ORCID /0000-0002-9301-1803/work/161409811

Keywords

Sustainable Development Goals

Keywords

  • MWCNT, agglomeration, antimicrobial resistance, emerging pollutants, horizontal gene transfer, nanoparticles, plasmid, MEMBERS, ENGINEERED NANOPARTICLES, TOXICITY, Bacteria/genetics, Humans, Plasmids/genetics, Escherichia coli/genetics, Anti-Bacterial Agents/pharmacology, Plastics/pharmacology, Nanotubes, Carbon

Library keywords