Pathogens transported by plastic debris: does this vector pose a risk to aquatic organisms?

Abstract

Microplastics are small (<5 mm) plastic particles of varying shapes and polymer types that are now widespread global contaminants of marine and freshwater ecosystems. Various estimates suggest that several trillions of microplastic particles are present in our global oceanic system, and that these are readily ingested by a wide range of marine and freshwater species across feeding modes and ecological niches. Here, we present some of the key and pressing issues associated with these globally important contaminants from a microbiological perspective. We discuss the potential mechanisms of pathogen attachment to plastic surfaces. We then describe the ability of pathogens (both human and animal) to form biofilms on microplastics, as well as dispersal of these bacteria, which might lead to their uptake into aquatic species ingesting microplastic particles. Finally, we discuss the role of a changing oceanic system on the potential of microplastic-associated pathogens to cause various disease outcomes using numerous case studies. We set out some key and imperative research questions regarding this globally important issue and present a methodological framework to study how and why plastic-associated pathogens should be addressed.

Evidence of Interspecific Plasmid Uptake by Pathogenic Strains Of Klebsiella Isolated from Microplastic Pollution on Public Beaches

“…The public health risks of pathogens within the plastisphere are poorly resolved, due to limited evidence of pathogenicity and/or expression of virulence factors [35,75]. The presence of pathogenic-related taxa in the plastisphere does not necessarily correlate with pathogenicity and virulence [12,7]; and there remains uncertainty about whether pathogens attached to microplastics pose a relevant risk to human health [48,9]. To date, studies which have assigned genes encoding virulence mechanisms to specific pathogens in the plastisphere have been unable to confirm whether these genes are expressed in situ [56,59].…”