Resilience of agricultural soils to antibiotic resistance genes introduced by agricultural management practices

• Published in: The Science of the total environment 2021-02, Vol.756, p.143699-143699, Article 143699
• Main Authors: Radu, Elena, Woegerbauer, Markus, Rab, Gerhard, Oismüller, Matthias, Strauss, Peter, Hufnagl, Peter, Gottsberger, Richard A., Krampe, Jörg, Weyermair, Karin, Kreuzinger, Norbert
• Format: Article
• Language: English
• Subjects: Agricultural soils; Animals; Anti-Bacterial Agents - pharmacology; ARG concentrations; Background ARG abundances; Drug Resistance, Microbial - genetics; Genes, Bacterial; Manure; Manure application; Manure maturation; RNA, Ribosomal, 16S; Soil; Soil Microbiology; Soil natural resilience; Swine
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2020.143699

Antimicrobial resistance (AR) represents a global threat in human and veterinary medicine. In that regard, AR proliferation and dissemination in agricultural soils after manure application raises concerns on the enrichment of endogenous soil bacterial population with allochthonous antibiotic resistance genes (ARGs). Natural resilience of agricultural soils and background concentrations of ARGs play key roles in the mitigation of AR propagation in natural environments. In the present study, we carried out a longitudinal sampling campaign for two crop vegetation periods to monitor spatial and temporal changes in the abundance of seven clinically relevant ARGs (sul1, ermB, vanA, aph(3')-IIa, aph(3′)-IIIa, blaTEM-1 and tet(W)) and ribosomal 16S RNA. The absolute and relative abundances of the selected ARGs were quantified in total community DNA extracted from agricultural (manured and non-manured) and forest soils, fresh pig faeces and manure slurry. We observed that ARG concentrations return to background levels after manure-induced exposure within a crop growing season, highlighting the resilience capacity of soil. Naturally occurring high background concentrations of ARGs can be found in forest soil in due distance under low anthropogenic influences. It was observed that pesticide application increases the concentrations of three out of seven ARGs tested (ermB, aph(3′)-IIIa and tet(W)). Moreover, we noticed that the absolute abundances of sul1, vanA, ermB and blaTEM-1 resistance genes show an increase by 100- to 10,000- fold, from maturation of fresh pig faeces to manure. Outcomes of our study suggest that agricultural soil environments show a strong capacity to alleviate externally induced disturbances in endogenous ARG concentrations. Naturally occurring high concentrations of ARGs are present also in low human impacted environments represented by the indigenous resistome. [Display omitted] •Pig manure application increases the abundance of sul1, ermB, tet(W), blaTEM-1 and aph(3')-IIIa in agricultural soil•Agricultural soil shows a high resilience capacity: ARG concentrations reach baseline levels within a crop season•Pesticide application raised the absolute and relative abundances of ermB, tet(W) and aph(3')-IIIa in non-manured soil•VanA concentration remains stable for two vegetation crop seasons in agricultural and forest soils•Concentrations of aph(3')-IIIa and tet(W) remain rather stable before (fresh pig faeces) and after (pig manure) maturation