Reducing antibiotic resistance genes, integrons, and pathogens in dairy manure by continuous thermophilic composting.
This study explored the effects of composting using three temperature regimes, namely, insufficient thermophilic composting (ITC), normal thermophilic composting (NTC), and continuous thermophilic composting (CTC), on antibiotic resistance genes (ARGs), integrons, and human pathogenic bacteria (HPB), as well as the mechanisms involved. The NTC and CTC treatments led to greater decreases in 5/10 ARGs and two integrons than ITC, and the abundances of ARGs (tetC, tetG, and tetQ) and int1 only declined in the NTC and CTC treatments. The abundances of HPB decreased by 82.8%, 76.9%, and 96.9% under ITC, NTC, CTC, respectively. Redundancy analysis showed that both bacterial succession and horizontal gene transfer play important roles in the variation of ARGs, and the changes in different ARGs were due to diverse mechanisms. CTC performed significantly better at reducing ARGs, integrons, and HPB, thus it may be used to manage the public health risks of ARGs in animal manure.
College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
Xun
X
Qian
College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
Wei
W
Sun
College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China; Research Center of Recycle Agricultural Engineering and Technology of Shaanxi Province, Northwest A&F University, Yangling, Shaanxi 712100, China. Electronic address: gujie205@sina.com.
Jie
J
Gu
College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
Xiao-Juan
XJ
Wang
College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
Ya-Jun
YJ
Zhang
College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
Man-Li
ML
Duan
College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
Hai-Chao
HC
Li
College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi 712100, China.
Ran-Ran
RR
Zhang
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001673:Biodegradation, Environmental; D004352:Drug Resistance, Microbial / Q000235:genetics*; D005798:Genes, Bacterial; D032023:Integrons; D008372:Manure / Q000382:microbiology*; D009691:Nucleic Acid Denaturation; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D013696:Temperature
D000900:Anti-Bacterial Agents; D008372:Manure
Antibiotic resistance gene; Bacterial community; Composting; Horizontal gene transfer; Temperature