Pyraclostrobin and polyethylene nanoplastics jointly interfere with the antibiotic resistome in earthworm gut

Abstract

Antibiotic resistance has emerged as a global threat to public health. However, the current information is insufficient to understand how other pollutants, such as fungicides and nanoplastics, affect the spread of antibiotic resistance genes (ARGs) among bacteria in the soil. Here, our findings revealed that polyethylene nanoplastics (PENPs) prolonged the persistence of pyraclostrobin (PYR) in the soil by 13 days, increased PYR bioaccumulation in earthworm (Eisenia fetida) by 8.4%, and reduced its weights by 26.8%. PYR alone or combined with PENPs significantly increased the microbiome diversities of earthworm guts, while PENPs alone decreased those but increased the relative abundances of Proteobacteria and Firmicute. PYR and/or PENPs enhanced the diversity and abundance of ARGs in earthworm guts, the range of ARG hosts, and the complexity of ARGs and antibiotic-resistant bacteria coexistence network. The abundance of plasmid-origin ARG-harboring contigs in PYR, PENP, and PYR + PENP treatments was 1.5-, 3.8-, and 2.4-fold higher than that in the control, respectively. Overall, PYR and/or PENPs specifically disturbed the antibiotic resistome in earthworm guts by altering the bacterial community composition and richness, increasing the abundance of mobile genetic elements (MGEs) and ARGs, and modifying the co-occurrence pattern of ARGs-MGEs, particularly plasmids.