Microbial diversity and potential pathogens associated with the plastisphere on beaches of Rio de Janeiro, Brazil

Marine pollution caused by plastic waste is a global issue. Improperly discarded plastics often end up in seas and oceans, where they become colonized by a microbial biofilm known as the Plastisphere. In this environment, especially in places where sewage is discharged untreated into water bodies, pathogenic microorganisms and those carrying antimicrobial resistance genes (ARGs) can settle and spread over long distances. To assess the presence of these microorganisms and examine the impact of substrate type on the formation of these communities, plastic waste samples were collected from three beaches in Rio de Janeiro, Brazil. The plastics were identified as polypropylene (PP) and polyethylene (PE) using FTIR analysis, and the microbial biofilm attached to them was studied through 16 S rRNA gene sequencing. The results revealed the presence of bacteria potentially pathogenic to humans and marine life, as well as plastic-degrading species in the biofilms of the analyzed samples. Although the communities present in the different polymers in this study clustered separately, our results did not show specific associations between polymer types and the observed microbial communities. The spread of these plastics in the ocean poses risks to human health and marine biodiversity.