Fate of antibiotic and metal resistance genes during two-phase anaerobic digestion of residue sludge revealed by metagenomic approach

• Published in: Environmental science and pollution research international Vol. 25; no. 14; pp. 13956 - 13963
• Main Authors: Wu, Ying, Cui, Erping, Zuo, Yiru, Cheng, Weixiao, Chen, Hong
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.05.2018; Springer Nature B.V
• Subjects: Abundance; Anaerobic digestion; Anaerobic treatment; Anaerobiosis; Anti-Bacterial Agents - pharmacology; Antibiotic resistance; antibiotic resistance genes; Antibiotics; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Drug resistance; Drug Resistance, Microbial - genetics; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Genes; Genes, Bacterial - drug effects; genetic databases; Heavy metals; interspersed repetitive sequences; Metagenomics; metal tolerance; Metals, Heavy - adverse effects; methanogens; Microbial activity; microbial communities; Microorganisms; Research Article; Sewage - chemistry; Sewage - microbiology; Sludge; Sludge digestion; Sludge treatment; Waste Disposal, Fluid; Waste Water Technology; Wastewater treatment; Wastewater treatment plants; Water Management; Water Pollution Control; Metagenomic analysis; Metal resistance genes; Two-phase anaerobic digestion; Antibiotic resistance genes
• ISSN: 0944-1344; 1614-7499; 1614-7499
• DOI: 10.1007/s11356-018-1598-x

The prevalence and persistence of antibiotic resistance genes in wastewater treatment plants (WWTPs) is of growing interest, and residual sludge is among the main sources for the release of antibiotic resistance genes (ARGs). Moreover, heavy metals concentrated in dense microbial communities of sludge could potentially favor co-selection of ARGs and metal resistance genes (MRGs). Residual sludge treatment is needed to limit the spread of resistance from WWTPs into the environment. This study aimed to explore the fate of ARGs and MRGs during thermophilic two-phase (acidogenic/methanogenic phase) anaerobic digestion by metagenomic analysis. The occurrence and abundance of mobile genetic elements were also determined based on the SEED database. Among the 27 major ARG subtypes detected in feed sludge, large reductions (> 50%) in 6 ARG subtypes were achieved by acidogenic phase (AP), while 63.0% of the ARG subtypes proliferated in the following methanogenic phase (MP). In contrast, a 2.8-fold increase in total MRG abundance was found in AP, while the total abundance during MP decreased to the same order of magnitude as in feed sludge. The distinct dynamics of ARGs and MRGs during the two-phase anaerobic digestion are noteworthy, and more specific treatments are required to limit their proliferation in the environment.