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 109 copies/mL and 106 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.
Keywords: Antibiotic resistance genes (ARGs); Phage; Pig farm; Profiles; Wastewater treatment plants (WWTPs).
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