Determining the Contribution of Micro/Nanoplastics to Antimicrobial Resistance: Challenges and Perspectives

Abstract

Microorganisms colonizing the surfaces of microplastics form a plastisphere in the environment, which captures miscellaneous substances. The plastisphere, owning to its inherently complex nature, may serve as a "Petri dish" for the development and dissemination of antibiotic resistance genes (ARGs), adding a layer of complexity in tackling the global challenge of both microplastics and ARGs. Increasing studies have drawn insights into the extent to which the proliferation of ARGs occurred in the presence of micro/nanoplastics, thereby increasing antimicrobial resistance (AMR). However, a comprehensive review is still lacking in consideration of the current increasingly scattered research focus and results. This review focuses on the spread of ARGs mediated by microplastics, especially on the challenges and perspectives on determining the contribution of microplastics to AMR. The plastisphere accumulates biotic and abiotic materials on the persistent surfaces, which, in turn, offers a preferred environment for gene exchange within and across the boundary of the plastisphere. Microplastics breaking down to smaller sizes, such as nanoscale, can possibly promote the horizontal gene transfer of ARGs as environmental stressors by inducing the overgeneration of reactive oxygen species. Additionally, we also discussed methods, especially quantitatively comparing ARG profiles among different environmental samples in this emerging field and the challenges that multidimensional parameters are in great necessity to systematically determine the antimicrobial dissemination risk in the plastisphere. Finally, based on the biological sequencing data, we offered a framework to assess the AMR risks of micro/nanoplastics and biocolonizable microparticles that leverage multidimensional AMR-associated messages, including the ARGs' abundance, mobility, and potential acquisition by pathogens.

The “Microplastome” – A Holistic Perspective to Capture the Real-World Ecology of Microplastics

“…This could be achieved through ecotoxicological experiments that concentrate on one given dimension while holding the other dimensions constant, ultimately analyzing the collective and independent impact of each dimension on (eco)­toxicity. Notably, the risk ranking or scoring of microplastic features needs to take into account both direct and indirect effects including their interactions with other chemical contaminants , and microorganisms ,,, in their immediate environment. The long-term consequences of plastic degradation and pollution release also need to be considered in the risk scoring. , …”

Freshwater plastisphere: a review on biodiversity, risks, and biodegradation potential with implications for the aquatic ecosystem health

“…ARG enrichment in plastic-associated biofilms is promoted by the proximity and close contact between bacterial cells that facilitate horizontal gene transfer, contributing to long-distance dispersal and long-term persistence of ARGs in the environment ( Di Pippo et al, 2022 ; Du et al, 2022 ; Rubin and Zucker, 2022 ; Luo et al, 2023 ; Chen et al, 2024 ; Li et al, 2024 ; Figure 1 ). Moreover, the presence of plastic-adsorbed xenobiotics and metals might enhance ARG occurrence through co-selection processes ( Abe et al, 2020 ; Junaid et al, 2022 ; Michaelis and Grohmann, 2023 ).…”

“…Once in water, the plastic debris provides hard surfaces for rapid microbial colonization and a new pelagic habitat for benthonic species ( Yang Y. et al, 2020 ; Dąbrowska, 2021 ; Haram et al, 2021 ). Plastics and microplastics (MPs) were reported either as dispersal vehicles for microorganisms of health concern ( Di Pippo et al, 2022 ; Du et al, 2022 ; Rubin and Zucker, 2022 ) or as hotspots for horizontal gene transfer, including antibiotic resistance genes (ARGs) ( Luo et al, 2023 ; Chen et al, 2024 ; Li K. et al, 2024 ). Furthermore, plastisphere microorganisms were also found to be directly involved in polymer biodegradation ( Du et al, 2022 ; Mishra et al, 2022 ; Yuan et al, 2022 ; Li K. et al, 2023 ).…”

Current examining methods and mathematical models of horizontal transfer of antibiotic resistance genes in the environment

“…Current research primarily focuses on conjugation and transformation, with a notable lack of investigation into transduction and vesiduction processes ( Luo et al, 2023 ). Therefore, there is a necessity for a more comprehensive examination of the contributions of phages and OMVs to the dissemination of ARB in the environment, as well as the impacts of exogenous compounds (e.g., non-antibiotic drugs) on the induction of transduction and vesiduction, in order to better understand the contribution of HGT to ARG dissemination in the environment ( Liu et al, 2020 ).…”

“…Hence, there is a need to integrate mathematical models with commonly used risk assessment models such as human exposure assessment model, Sanganyado and Gwenzi, 2019;Morgado-Gamero et al, 2021;Goh et al, 2022). The output of mathematical models will serve as inputs for risk assessment models, facilitating ongoing risk ranking and source tracking, thereby establishing an HGT risk assessment framework (Luo et al, 2023).…”