Dominant denitrifying bacteria are important hosts of antibiotic resistance genes in pig farm anoxic-oxic wastewater treatment processes. (October 2020)

• Record Type: Journal Article
• Authors: Yang, Yiwen; Wu, Ruiting; Hu, Jiaxin; Xing, Sicheng; Huang, Chunbo; Mi, Jiandui; Liao, Xindi
• Is Part Of: Environment international. Volume 143(2020)
• Publication Date: 2020-10
• Subjects: Antimicrobial resistance gene -- Dominant bacteria -- Anoxic-oxic process -- Pig farm; Environmental protection -- Periodicals; Environmental health -- Periodicals; Environmental monitoring -- Periodicals; Environmental Monitoring -- Periodicals; Environnement -- Protection -- Périodiques; Hygiène du milieu -- Périodiques; Environnement -- Surveillance -- Périodiques; Environmental health; Environmental monitoring; Environmental protection; Periodicals; 333.705
• DOI: 10.1016/j.envint.2020.105897
• Languages: English
• ISSNs: 0160-4120

Abstract

Highlights: The distribution of ARGs and their hosts in pig farm A/O WWTPs is revealed. Genome bins are used to explore the ARG hosts in pig farm A/O WWTPs. Dominant denitrifying bacteria are important ARG hosts in pig farm A/O WWTPs. Abstract: The anoxic-oxic (A/O) wastewater treatment process that is widely used in pig farms in China is an important repository for antibiotic resistance genes (ARGs). However, the distribution of ARGs and their hosts in the A/O process has not been well characterized. In this study, the wastewaters in the anoxic and oxic tanks for A/O processes were collected from 38 pig farms. The concentrations of 20 subtypes of ARGs, 5 denitrification-related genes, 2 integrons, and bacterial community composition were investigated. Bacterial genome binning was performed using metagenome sequencing. In this study, 20 subtypes of ARGs and integrons were detected in all sampling sites. A total of 16 of the 20 subtypes of ARGs were detected with the highest abundance in anoxic tanks, and sul1 was detected with a maximum average abundance of 19.21 ± 0.24 log10 (copies/mL). Cooccurrence patterns were observed for some genes in the pig farm A/O process, such as sul1 and intl1, sul1 and tetG, and tetO and tetW . There was a significant cooccurrence pattern between the dominant denitrifying bacteria and some ARGs ( blaTEM, ermB, tetC, tetH and tetQ ), so the dominant denitrifying bacteria were considered to be potential ARG hosts. In addition, 170 highly abundant bacterial genome bins were assembled and further confirmed that the denitrifying bacteria Brachymonas, Candidatus Competibacter, Thiobacillus and Steroidobacter were the important ARG hosts in the pig farm A/O process, providing a useful reference for the surveillance and risk management of ARGs in pig farm wastewater.