title: Mechanism and Effect of Temperature on Variations in Antibiotic Resistance Genes during Anaerobic Digestion of Dairy Manure.
abstract: Animal manure comprises an important reservoir for antibiotic resistance genes (ARGs), but the variation in ARGs during anaerobic digestion at various temperatures and its underlying mechanism remain unclear. Thus, we performed anaerobic digestion using dairy manure at three temperature levels (moderate: 20 °C, mesophilic: 35 °C, and thermophilic: 55 °C), to analyze the dynamics of ARGs and bacterial communities by quantitative PCR and 16S rRNA gene sequencing. We found that 8/10 detected ARGs declined and 5/10 decreased more than 1.0 log during thermophilic digestion, whereas only four and five ARGs decreased during moderate and mesophilic digestion, respectively. The changes in ARGs and bacterial communities were similar under the moderate and mesophilic treatments, but distinct from those in the thermophilic system. Potential pathogens such as Bacteroidetes, Proteobacteria, and Corynebacterium were removed by thermophilic digestion but not by moderate and mesophilic digestion. The bacterial community succession was the dominant mechanism that influenced the variation in ARGs and integrons during anaerobic digestion. Thermophilic digestion decreased the amount of mesophilic bacteria (Bacteroidetes and Proteobacteria) carrying ARGs. Anaerobic digestion generally decreased the abundance of integrons by eliminating the aerobic hosts of integrons (Actinomycetales and Bacilli). Thermophilic anaerobic digestion is recommended for the treatment and reuse of animal manure.
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Xun
authors.initials: X
authors.lastname: Qian
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Gu
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Xiao-Juan
authors.initials: XJ
authors.lastname: Wang
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Man-Li
authors.initials: ML
authors.lastname: Duan
mesh_terms: D000693:Anaerobiosis / Q000235:genetics*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000627:therapeutic use; D001419:Bacteria / Q000235:genetics / Q000472:pathogenicity; D018407:Bacterial Physiological Phenomena / Q000235:genetics*; D041963:Bacteroidetes / Q000235:genetics / Q000378:metabolism; D003352:Corynebacterium / Q000235:genetics / Q000378:metabolism; D004063:Digestion / Q000502:physiology; D004352:Drug Resistance, Microbial / Q000235:genetics* / Q000502:physiology; D008372:Manure / Q000382:microbiology*; D020560:Proteobacteria / Q000235:genetics / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013696:Temperature
chemical_list: D000900:Anti-Bacterial Agents; D008372:Manure; D012336:RNA, Ribosomal, 16S