Microplastics enhance the prevalence of antibiotic resistance genes in mariculture sediments by enriching host bacteria and promoting horizontal gene transfer

Summary

This experimental study demonstrates that microplastics significantly enhance antibiotic resistance gene prevalence in mariculture sediments through distinct polymer-specific mechanisms. Polystyrene and polyvinyl chloride MPs increased ARG abundance by 1.41–2.84-fold, with polymer type exerting greater influence than particle size. The findings reveal that PVC shifts microbial assembly from stochastic to deterministic processes whilst recruiting ARG-harbouring pathogens, and that PS facilitates horizontal gene transfer within the plastisphere; PVC's chemical additives synergistically promote conjugative transfer by inducing oxidative stress.

Regional applicability

The findings are relevant to UK mariculture operations, particularly in Scotland and Wales where aquaculture is significant, as they highlight the need for microplastics pollution control to prevent the dissemination of antibiotic resistance in farmed fish production systems. However, the study was conducted in a controlled laboratory setting and may not fully reflect the complex environmental dynamics of UK marine sediments.

Key measures

Relative abundance of antibiotic resistance genes (fold-change relative to control); microbial community composition and assembly processes; rates of conjugative ARG transfer; oxidative stress markers; cell membrane permeability

Outcomes reported

The study measured the relative abundance of antibiotic resistance genes (ARGs) in mariculture sediments exposed to different microplastics (PS and PVC) of varying sizes, and identified mechanisms by which microplastics promote ARG dissemination through shifts in microbial community assembly and enhanced horizontal gene transfer.

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