Microbial-influenced pesticide removal co-occurs with antibiotic resistance gene variation in soil-earthworm-maize system

The effects of combined herbicide and antibiotic pollution on microbial communities and antibiotic-resistance genes in soil are not well understood. Therefore, in this study, we investigated the effects of polymyxin E and topramezone co-contamination using bacterial-16S rRNA sequencing and high-throughput quantitative polymerase chain reaction of ARGs in a soil-earthworm-maize system. After incubating soil for 28 days with PME and TPZ, we found that earthworm growth and survival rates and plant heights and weights differed slightly among all treated groups. PME significantly increased the TPZ degradation efficiency in the soil. TPZ accumulates significantly in earthworm tissues, which may pose potential risks to predators in the food chain. Combined pollution altered the microbial community structure and increased the abundance of functional microorganisms involved in herbicide degradation. Furthermore, TPZ exposure enhanced the abundance of ARGs, whereas PME or co-contamination increased the number of bulk-soil samples. Co-contamination with herbicides and antibiotics can potentially increase the risk of antibiotic resistance.