selective enrichment of antibiotic resistance genes and pathogens on biodegradable and non-biodegradable microplastics

Microplastics are ubiquitous in the water environment, biofilms on the surface may become a new concern for human health as a carrier of antibiotic resistance genes. Although the mechanism of biofilm formation on microplastics surface has attracted extensive attention, the impact of different plastic substrates on the structure of biofilm community and the role of antibiotic resistance genes in the substrates is still insufficient. In this study, two biodegradable microplastics (PHA, PLA), three conventional microplastics (PP, PS, PE), and a natural substrate (Grit) were exposed to river water for five weeks to reveal the differences in microbial community structure and antibiotic resistance genes of microplastic biofilms by metagenomic sequencing. Metagenomic analysis showed that the structure of biofilm microbial community on microplastic surface was affected by materials. PLA was similar to PS biofilm, PP was similar to PS biofilm, and PHA was significantly different from other biofilms. In addition, 883 ARG subtypes were detected in the plastisphere, and PHA biofilm ARG hosts were annotated as pathogenic pathogens with significantly higher abundance than other samples. These findings provide important information for fully understanding antibiotic resistance in Plastisphere and assessing public health risks.