Free Radicals on Aging Microplastics Regulated the Prevalence of Antibiotic Resistance Genes in the Aquatic Environment: New Insight into the Effect of Microplastics on the Spreading of Biofilm Resistomes
Kaipeng Zhai, Keke Yin, Lin Ying, Shu Chen, Yuzhang Bi, Ruizhi Xing, Chenjia Ren, Ziyu Chen, Ziyu Chen, Zhen Yu, Zhi Chen, Zhi Chen, Shungui Zhou
Abstract
The spread of antibiotic resistance genes (ARGs) by microplastics has received a great concern in coexisting “hotspots”. Despite most microplastics suffering from natural aging, little is known about the effect of aging microplastics (A-MPs) on ARGs dissemination. Here, we demonstrated significant suppression of A-MPs on ARGs dissemination in natural rivers. Although ARGs and mobile genetic elements (MGEs) were effectively enriched on A-MPs, the relative abundance of ARGs and MGEs on A-MPs as well as in receiving water decreased by approximately 21.4% to 42.3% during a period of 30 days of dissemination. Further investigation revealed that • OH was consistently generated on A-MPs with a maximum value of 0.2 μmol/g. Importantly, scavenging of • OH significantly increased the relative abundance of ARGs and MGEs both on A-MPs and in receiving water 1.4–29.1 times, indicating the vital role of • OH in suppressing ARGs dissemination. Microbial analysis revealed that • OH inhibited the potential antibiotic-resistant bacteria in surface biofilms, such as Pseudomonas and Acinetobacter (with a decrease of 68.8% and 89.3%). These results demonstrated that • OH was extensively produced on A-MPs, which greatly reduced both the vertical and horizontal gene transfer of ARGs. This study provided new insights into the dissemination of ARGs through microplastics in natural systems.