Simultaneous elimination of antibiotic resistance gene and viruses in liquid manure by plasma/peracetic acid combination system

Abstract

The widespread use of antibiotics in livestock farming has led to the accumulation of antibiotic resistance genes (ARGs) in farms and surrounding environments, with manure discharge accelerating their spread. However, effective techniques and mechanisms for removing ARGs from livestock liquid manure remain underexplored. This study examined the efficiency and mechanisms of combined plasma and peracetic acid (plasma+PAA) treatment for ARGs removal from liquid manure. Results show that plasma+PAA treatment significantly enhances ARGs removal efficiency, especially for the aac(3)-II gene, with removal rates increasing by 2.80-log and 1.55-log compared to plasma or PAA alone, with reaction rates improving by 116.6 % and 47.1 %, respectively. Singlet oxygen (¹O₂) was identified as the main reactive species driving the efficient removal of ARGs. The treatment also altered the microbial community, significantly reducing Escherichia, the primary ARGs host. Metagenomic analysis revealed that plasma+PAA suppressed genes related to bacterial physiology, including metabolic pathways and protein synthesis. This resulted in large-scale bacterial inactivation, making ARGs more vulnerable to removal by reactive species. Additionally, plasma+PAA treatment downregulated genes related to antimicrobial resistance, metal resistance, and virulence factors. The treatment also reduced the length and abundance of viral gene fragments. This study offers an effective strategy for controlling ARGs and viruses in livestock manure.