| Autor: |
Nesse LL; Department of Food Safety and Animal Health Research, Norwegian Veterinary Institute, N-1431 Ås, Norway., Forfang K; Division of Environment and Natural Resources, Norwegian Institute of Bioeconomy Research (NIBIO), N-1431 Ås, Norway., Slettemeås JS; Department of Food Safety and Animal Health Research, Norwegian Veterinary Institute, N-1431 Ås, Norway., Hagen S; Division of Environment and Natural Resources, Norwegian Institute of Bioeconomy Research (NIBIO), N-1431 Ås, Norway., Sunde M; Department of Microbiology, Norwegian Veterinary Institute, N-1431 Ås, Norway., Elameen A; Division of Biotechnology and Plant Health, Norwegian Institute of Bioeconomy Research (NIBIO), N-1431 Ås, Norway., Johannessen G; Department of Food Safety and Animal Health Research, Norwegian Veterinary Institute, N-1431 Ås, Norway., Stenrød M; Division of Biotechnology and Plant Health, Norwegian Institute of Bioeconomy Research (NIBIO), N-1431 Ås, Norway., Tessema GT; Department of Microbiology, Norwegian Veterinary Institute, N-1431 Ås, Norway., Almvik M; Division of Biotechnology and Plant Health, Norwegian Institute of Bioeconomy Research (NIBIO), N-1431 Ås, Norway., Eiken HG; Division of Environment and Natural Resources, Norwegian Institute of Bioeconomy Research (NIBIO), N-1431 Ås, Norway. |
| Abstrakt: |
The abundance and diversity of antimicrobial-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs) in agricultural landscapes may be important for the spread of antimicrobial resistance (AMR) in the environment. The aim of this study was to apply screening methods for ARB and ARGs to investigate the impact of farming on the prevalence of AMR in a country with low antibiotic usage. We have analyzed samples (n = 644) from soil and wild terrestrial animals and plants (slugs, snails, mice, shrews, earthworms, and red clover) collected over two years in agricultural fields accompanied by nearby control areas with low human activity. All samples were investigated for the occurrence of 35 different ARGs using high-throughput quantitative PCR (HT-qPCR) on a newly developed DNA array. In addition, samples from the first year (n = 415) were investigated with a culture-based approach combined with whole-genome sequencing (WGS) to identify antimicrobial-resistant E. coli (AREC). ARGs were detected in 59.5% of all samples (2019 + 2020). AREC, which was only investigated in the 2019 samples, was identified in 1.9% of these. Samples collected in the autumn showed more ARGs and AREC than spring samples, and this was more pronounced for organic fields than for conventional fields. Control areas with low human activity showed lower levels of ARGs and a lack of AREC. The use of livestock manure was correlated with a higher level of ARG load than other farming practices. None of the soil samples contained antibiotics, and no association was found between AMR and the levels of metals or pesticides. High qualitative similarity between HT-qPCR and WGS, together with the positive controls to the validation of our 35 ARG assays, show that the microfluid DNA array may be an efficient screening tool on environmental samples. In conclusion, even in a country with a very low consumption of antimicrobials by production animals, our results support the hypothesis of these animals being a source of AREC and ARGs in agricultural environments, primarily through the use of manure. |
