The overuse of antibiotics has led to the development of bacterial resistance and the emergence of antibiotic resistance genes (ARGs) in the environment. Coastal waters are major gathering places for land-based pollutants and potential hubs for ARG transmission through food chains.
Traditional methods have relied heavily on qPCR or high-throughput qPCR, however, these approaches are limited by specific primers and known genes, making it difficult to comprehensively characterize the composition and complex sources of ARGs.
Recently, the research team led by Associate Prof. SHAO Zhanru from the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS) utilized metagenomics to provide a more comprehensive analysis of ARGs in the Yellow Sea and Yangtze River Delta.
This study was published in Environmental Pollution on Feb. 24.
The researchers noted that elucidating the diversity, spatial distribution characteristics, and primary sources of ARGs and their hosts is crucial for providing scientific evidence to control antibiotic resistance pollution in coastal ecosystems.
"Based on metagenomics, we can not only detect ARGs and their hosts more comprehensively but also investigate ARG transmission mechanisms mediated by horizontal gene transfer (HGT) through mobile genetic elements (MGEs)," said WANG Xin, first author of the study. "Our results showed that transposons and insertion_element_IS91 played significant roles in HGT."
According to bacterial community structure and ARG composition and distribution, agriculture, animal husbandry, and wastewater treatment plants were identified as potential major sources of ARGs.
Temperature, dissolved oxygen, pH, and depth influenced the distribution of ARGs in seawater, however, compared to environmental factors and MGEs, bacterial communities had the greatest impact on ARG variation.
"To further interpret differences between our study area and global marine systems, we compared our results with Tara Oceans datasets," said Associate Prof. SHAO, the corresponding author. "Our findings revealed that dominant ARG types and bacterial genera in coastal waters were consistent with global characteristics, but ARG subtypes exhibited regional differences."
This study expands understanding of the distribution patterns of ARGs at an offshore scale and provides a scientific basis for managing antibiotic resistance risks in coastal ecosystems.
Sampling stations and potential pollution sources of ARGs. (Image by IOCAS)
(Text by WANG Xin)
Media Contact:
ZHANG Yiyi
Institute of Oceanology
E-mail: zhangyiyi@qdio.ac.cn
(Editor: ZHANG Yiyi)