title: Temporal changes of antibiotic-resistance genes and bacterial communities in two contrasting soils treated with cattle manure.
abstract: The emerging environmental spread of antibiotic-resistance genes (ARGs) and their subsequent acquisition by clinically relevant microorganisms is a major threat to public health. Animal manure has been recognized as an important reservoir of ARGs; however, the dissemination of manure-derived ARGs and the impacts of manure application on the soil resistome remain obscure. Here, we conducted a microcosm study to assess the temporal succession of total bacteria and a broad spectrum of ARGs in two contrasting soils following manure application from cattle that had not been treated with antibiotics. High-capacity quantitative PCR detected 52 unique ARGs across all the samples, with β-lactamase as the most dominant ARG type. Several genes of soil indigenous bacteria conferring resistance to β-lactam, which could not be detected in manure, were found to be highly enriched in manure-treated soils, and the level of enrichment was maintained over the entire course of 140 days. The enriched β-lactam resistance genes had significantly positive relationships with the relative abundance of the integrase intI1 gene, suggesting an increasing mobility potential in manure-treated soils. The changes in ARG patterns were accompanied by a significant effect of cattle manure on the total bacterial community compositions. Our study indicates that even in the absence of selective pressure imposed by agricultural use of antibiotics, manure application could still strongly impact the abundance, diversity and mobility potential of a broad spectrum of soil ARGs. Our findings are important for reliable prediction of ARG behaviors in soil environment and development of appropriate strategies to minimize their dissemination.
authors.affiliation: Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3010, Australia.
authors.forename: Hang-Wei
authors.initials: HW
authors.lastname: Hu
authors.affiliation: Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3010, Australia.
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Han
authors.affiliation: Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3010, Australia.
authors.forename: Xiu-Zhen
authors.initials: XZ
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Jun-Tao
authors.initials: JT
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Han
authors.affiliation: Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3010, Australia.
authors.forename: Deli
authors.initials: D
authors.lastname: Chen
authors.affiliation: Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3010, Australia State Key Laboratory of Urban and Regional Ecology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China jzhe@rcees.ac.cn.
authors.forename: Ji-Zheng
authors.initials: JZ
authors.lastname: He
mesh_terms: D000383:Agriculture; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects* / Q000235:genetics*; D002417:Cattle; D004352:Drug Resistance, Microbial / Q000235:genetics*; D004777:Environment; D005798:Genes, Bacterial / Q000235:genetics; D019426:Integrases / Q000235:genetics; D008372:Manure / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012987:Soil; D012988:Soil Microbiology; D001618:beta-Lactamases / Q000235:genetics*; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D008372:Manure; D012336:RNA, Ribosomal, 16S; D012987:Soil; D047090:beta-Lactams; D019426:Integrases; C115006:integron integrase IntI1; D001618:beta-Lactamases
keywords: Antibiotic resistance gene; cattle manure; class 1 integron; soil resistome; β-lactamase