Antibiotic resistance genes (ARGs) are emerging contaminants in the environment and have been highlighted as a worldwide environmental and health concern. As an important water source, the Danjiangkou Reservoir's ecological safety is a great public health concern. Therefore, it is necessary to dissect the distribution of ARGs in different media (vertical) and locations (horizontal) of Danjiangkou Reservoir.   

In order to dissect the occurrence of ARGs in Danjiangkou Reservoir, JIANG Chunxia, co-advised by Prof. YANG Yuyi from the Wuhan Botanical Garden of the Chinese Academy of Sciences (CAS), together with Prof. Hans-Peter Grossarti from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries, investigated the vertical and horizontal distribution of ARGs in Danjiangkou Reservoir.    

The researchers investigated seven clinical ARGs and bacterial communities in the Danjiangkou Reservoir using quantitative polymerase chain reaction (qPCR) and next-generation sequencing, respectively.   

According to them, differences in ARG composition were observed in the vertical profile, which related to different environmental media (i.e. water column vs. sediment). Meanwhile, no significant differences in the horizontal profile were observed. Proteobacteria and actinobacteria were the dominant phyla in the Danjiangkou Reservoir. 

Network analysis was used to elucidate the host relationships of ARGs in various environmental media. The results showed that ARGs had high correlation coefficients with Proteobacteria and Chloroflexi in the sediment samples, indicating potential anthropogenic pollution in the Danjiangkou Reservoir.  

Although there was no significant correlation between the occurrence of ARGs and 11 opportunistic pathogens in this area, potential risks still existed for the development of multi-resistant pathogens due to the co-existence of ARGs and opportunistic pathogens. 

These results provide insights into the vertical distribution of ARGs and bacterial communities in the reservoir ecosystem. 

The study entitled "Vertical and horizontal distributions of clinical antibiotic resistance genes and bacterial communities in Danjiangkou Reservoir, China" was recently published in the journal Environmental Science and Pollution Research.  

The research was funded by the National Natural Science Foundation of China, the Starting Research Fund from Key Laboratory of Aquatic Botany and Watershed Ecology of CAS, and the Funding Project of Sino-Africa Joint Research Center of CAS. 

The distribution of ARGs in different media (vertical) and location (horizontal) of Danjiangkou Reservoir. (Image by JIANG Chunxia)