Researchers from the University of Warwick led a team that found that after being immersed in a river for a week, both new and old plastics carried opportunistic "microbial hitchhikers" and different sets of antibiotic resistance genes (ARGs).

Examples of these hitchhikers were organisms such as Pseudomonas aeruginosa and Acinetobacter baumannii.

Plastics operate as a reservoir for pathogenic bacteria, or ARGs, often exacerbated by their persistence in the environment due to their recalcitrance and buoyancy.

The findings raise worries that the "riverine plastisphere" could act as an antibiotic resistance reservoir.

However, the researchers note that it's too early to tell whether plastics can transmit infection-causing, antibiotic-resistant bacteria.