Time-course biofilm formation and presence of antibiotic resistance genes on everyday plastic items deployed in river waters

The plastisphere has been widely studied in the oceans; however, there is little information on how living or-ganisms interact with the plastisphere in freshwater ecosystems, and particularly on how this interaction changes over time. We have characterized, over one year, the evolution of the eukaryotic and bacterial communities colonizing four everyday plastic items deployed in two sites of the same river with different anthropogenic impact. alpha-diversity analyses showed that site had a significant role in bacterial and eukaryotic diversity, with the most impacted site having higher values of the Shannon diversity index. beta-diversity analyses showed that site explained most of the sample variation followed by substrate type (i.e., plastic item) and time since first colo-nization. In this regard, core microbiomes/biomes in each plastic at 1, 3, 6 and 12 months could be identified at genus level, giving a global overview of the evolution of the plastisphere over time. The measured concentration of antibiotics in the river water positively correlated with the abundance of antibiotic resistance genes (ARGs) on the plastics. These results provide relevant information on the temporal dynamics of the plastisphere in freshwater ecosystems and emphasize the potential contribution of plastic items to the global spread of antibiotic resistance.

Automated summary

This study investigated the interaction between the plastisphere and living organisms in freshwater ecosystems over a one-year period. It found that species diversity was influenced by the site, and analyzed the core microbiomes in plastic items at different time points. Additionally, the study revealed a positive correlation between antibiotic concentration in river water and abundance of antibiotic resistance genes on plastics.