Maria Arias-Andres, Uli Klümper, Keilor Rojas-Jimenez, Hans-Peter Grossart,
Microplastic pollution increases gene exchange in aquatic ecosystems,
Environmental Pollution, Volume 237, 2018, Pages 253-261, ISSN 0269-7491,
Pollution by microplastics in aquatic ecosystems is accumulating at an unprecedented scale, emerging as a new surface for biofilm formation and gene exchange. In this study, we determined the permissiveness of aquatic bacteria towards a model antibiotic resistance plasmid, comparing communities that form biofilms on microplastics vs.
those that are free-living. We used an exogenous and red-fluorescent E. coli donor strain to introduce the green-fluorescent broad-host-range plasmid pKJK5 which encodes for trimethoprim resistance.
We demonstrate an increased frequency of plasmid transfer in bacteria associated with
microplastics compared to bacteria that are free-living or in natural aggregates. Moreover, comparison of communities grown on polycarbonate filters showed that increased gene exchange occurs in a broad range of phylogenetically-diverse bacteria. Our results indicate horizontal gene transfer in this habitat could distinctly affect the ecology of aquatic microbial communities on a global scale. The spread of antibiotic
resistance through microplastics could also have profound consequences for the evolution of aquatic bacteria and poses a neglected hazard for human health.