Profiles of bacteria/phage-comediated ARGs in pig farm wastewater treatment plants in China: Association with mobile genetic elements, bacterial communities and environmental factors

In this study, the profiles of bacteria/phage-comediated antibiotic resistance genes (b/pARGs) were monitored in water samples collected from 45 pig farm wastewater treatment plants (WWTPs) in seven different regions of China. We found that 8 major types and 112 subtypes of b/pARGs were detected in all the water samples, and the detected number ranged from 53 to 92. The absolute abundances of bARGs and pARGs in the influent were as high as 10(9) copies/mL and 10(6) copies/mL, respectively. Anaerobic anoxic/oxic (AAO) and anaerobic short-cut nitrification/denitrification (ASND) treatment plants can effectively reduce the absolute abundance and amount of b/pARGs. Anaerobic treatment plants cannot reduce the absolute abundance of pARGs, and even increase the amount of pARGs. Mobile genetic elements (MGEs), bacterial communities and environmental factors were important factors impacting the b/pARG profile. Among these factors, the bacterial community was the major driver that impacted the bARG profile, while bacterial community and MGEs were the major codrivers impacting the pARG profile. This study was the first to investigate the profiles of b/pARGs in pig farm WWTPs in China on such a large scale, providing a reference for the prevention and control of ARG pollution in agricultural environments.

Automated summary

This study analyzed the profiles of bacteria/phage-comediated antibiotic resistance genes in water samples collected from pig farm wastewater treatment plants in different regions of China. The research found multiple types and subtypes of these genes, as well as identified factors such as treatment methods and microbial communities that impact their abundance. This large-scale study provides valuable insights for the prevention and control of antibiotic resistance gene pollution in agricultural environments.