How does agriculture fit into the human anitibiotic resistance cycle?

New research explores this global, One Health problem

A new paper explores the relationship between land use and antibiotic resistance genes in the soil

In a recent paper (Distinct Assembly Patterns of Soil Antibiotic Resistome Revealed by Land-Use Changes over 30 Years ), Dr James Tiedje (PSM Emeritus) and a group of scientists from the Chinese Academy of Science, the University of Bonn, and the University of Helsinki published their long term and broad scale study of soil resistome selection and evolution.

As a significant microbial habitat, soil is increasingly recognized as a crucial reservoir of antibiotic resistance. Interaction with the soil through food systems has increased antibiotic resistance spread to humans.

Antibiotic resistance genes (ARGs) are found in plants and animals that come in contact with antibiotic-contaminated manure/biosolids which are spread on soils that grow crops for animal and human consumption.

The biosolid fertilizers contain antibiotics, which enhances ARG growth in bacteria the soils –as well as the plants that grow in the soil. 

“There seems to be a lot of difference in where ARGs are found in abundance- across different land uses,” Tiedje said. Variations in microbial groups, particularly bacteria, can significantly contribute to the dissemination of ARGs.

When approaching this study, the group found that insight into the driving factors modulating the soil antibiotic resistome with limited anthropogenic activities was scarce. “So we looked closely at baseline levels of ARGs in soils with little anthropogenic influence (grassland), and compared that with the same soil cropped 30 years amended with inorganic and organic (manure) fertilizer, and with bare (fallow) soil,” Tiedje said.

The group also quantified the profiles of soil antibiotic resistome under these long-term contrasting land use patterns which (1) revealed the distribution of shared and unique resistome across the change of land uses, and (2) showed that shifts in microbial populations, soil properties and mobile genetic elements (whhch moves genes conferring antibiotic resistances) among microbes including into pathogens, were responsible for the resistome change.

“Antibiotic resistance is listed as one of the most emerging and pressing One Health issues,” Tiedje said, rivaling climate change as serious global challenges. The One Health framework recognizes that antibiotic resistance is an interdisciplinary problem in which human health, animal agriculture, and the environment are the core and interrelated components. 

“We need to continue to enrich our understanding of the natural evolution of antibiotic resistomes under different land use types and related potential influencing factors and, ultimately, guide our mitigation strategies.”

The organizer of the study, Prof Fang Wang of the Chinese Academy of Sciences, was a Visiting Scholar in the Department 7- 8 years ago which laid the foundation for this work on the soil resistome. Dr. Jim Tiedje was elected to the Chinese Academy of Sciences in 2021. Read more about that here.

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