Plastic Leachate Exposure Drives Antibiotic Resistance and Virulence in Marine Bacterial Communities

Abstract

Plastic pollution is a serious global problem, with more than 12 million tonnes of plastic waste entering the oceans every year. Plastic debris can have considerable impacts on microbial community structure and functions in marine environments, and has been associated with an enrichment in pathogenic bacteria and antimicrobial resistance (AMR) genes. However, our understanding of these impacts is largely restricted to microbial assemblages on plastic surfaces. It is therefore unclear whether these effects are driven by the surface properties of plastics, providing an additional niche for certain microbes residing in biofilms, and/or chemicals leached from plastics, the effects of which could extend to surrounding planktonic bacteria. Here, we examine the effects of polyvinyl chloride (PVC) plastic leachate exposure on the relative abundance of genes associated with bacterial pathogenicity and AMR within a seawater microcosm community. We show that PVC leachate, in the absence of plastic surfaces, drives an enrichment in AMR and virulence genes. In particular, leachate exposure significantly enriches AMR genes that confer multidrug, aminoglycoside and peptide antibiotic resistance. Additionally, enrichment of genes involved in the extracellular secretion of virulence proteins was observed among pathogens of marine organisms. This study provides the first evidence that chemicals leached from plastic particles alone can enrich genes related to microbial pathogenesis within a bacterial community, expanding our knowledge of the environmental impacts of plastic pollution with potential consequences for human and ecosystem health.

Diversity of marine bacteria growing on leachates from virgin and weathered plastic: Insights into potential degraders

“…For example, leachates from high-density polyethylene (HDPE) and polyinyl chloride (PVC) have been found to inhibit the growth and photosynthetic capacity of the cyanobacteria Prochlorococcus (Tetu et al, 2019). Likewise, leachates from PVC have been reported to increase antibiotic resistance and virulence in marine bacterial communities (Vlaanderen et al, 2023). The sea urchin Paracentrotus lividus exposed to leachates from PVC and beach-collected pellets showed abnormalities including developmental delay, malformation of skeletal structures and nervous and immune systems, as well as abnormal axis formation (Rendell-Bhatti et al, 2021).…”