LANZHOU -- Chinese scientists have uncovered the distribution and dissemination mechanisms of soil antibiotic resistance genes (ARGs) in China, according to the Northwest Institute of Eco-environment and Resources (NIEER) under the Chinese Academy of Sciences.

This new study advances the understanding of ARGs in terrestrial ecosystems across China. It provides an important scientific basis for further exploring their distribution, dissemination, and public health risks, according to the institute.

Conducted by NIEER researchers, the study's findings have been published in the journal Ecotoxicology and Environmental Safety.

Antibiotics have been widely and increasingly used in medicine, agriculture, and animal husbandry, ensuring the prevention and treatment of diseases and infections in humans, plants and animals.

Those uncontrolled uses of such medicines are making ARGs become a new type of environmental pollutant, posing a common public health challenge to the global community, according to Li Yuqiang, a researcher from the NIEER who led the study.

Li explained that antibiotic resistance refers to the ARGs carried by microorganisms and their corresponding drug resistance capabilities. These genes enable bacteria to survive and reproduce in the presence of antibiotics. Soil is the largest gene bank of ARGs in the natural environment, and soil ARGs are highly transferable.

"It is of significance to comprehensively understand the distribution and transmission mechanisms of ARGs both in regions with intensive human activities and in near-natural ecosystems," Duan Yulong said, an associate researcher of the NIEER.

Researchers from the NIEER conducted a large-scale, cross-regional soil survey spanning 4,300 km across the country. They collected samples at 42 intervals in six distinct terrestrial ecosystems, including forests, grasslands, deserts and other ecosystems.

They detected high diversity, comprising 18 ARG types and 129 ARG subtypes, as well as the abundance of ARGs in the topsoil across the six terrestrial ecosystems.

Only aac (6′)-I ranked among the highest-risk ARGs, indicating that merely 0.78 percent of detected ARGs pose a severe pathogenic threat. While most ARGs currently present minimal direct public health risks, their high transmission potential warrants attention, the study showed.

"A thorough understanding of the sources and transmission of soil ARGs is of crucial significance for pollution prevention and control works. Moreover, systematic comparison of these differences is of importance to carry out precise source tracing and regional prevention and control of soil ARGs in different terrestrial ecosystems," Li said.

This new study established for the first time the distribution baseline of ARGs in multiple types of natural terrestrial ecosystems in China, providing an important scientific basis for a deeper understanding of the environmental sources, transmission routes, and health risks of antibiotic resistance, according to Li.