[Distribution Characteristics of Antibiotic Resistance Genes and Microbial Communities in the Surface Water Environment of Chaohu Lake].

As the fifth largest lake in China， Chaohu Lake plays a pivotal role in bolstering the coastal economy and is instrumental to the livelihood of the substantial population residing around its shores. Moreover， it harbors a multitude of distinctive biological species that are characteristic of the region. The pollution problem of Chaohu Lake has been a concern for many decades， and many scholars have conducted antibiotic research around the lake. However， there remains a lack of in-depth research on the microbial community and antibiotic resistance genes （ARGs） in the water environment of Chaohu Lake. Surface water samples were collected from five sampling points established in Chaohu Lake. Point CH1 is the only outlet of the Yuxi River in Chaohu Lake， CH2 is the center of Donghu Lake， CH3 is the center of Zhonghu Lake， CH4 is the inlet of the Nanfei River with heavy pollution in the surrounding area， and CH5 is the center of Xihu Lake， which can better reflect the overall condition of the surface water environment of Chaohu Lake. The distribution characteristics of microorganisms and ARGs in the surface water of Chaohu Lake were analyzed thoroughly by using high-throughput sequencing technology. The study found that Proteobacteria， Actinobacteria， and Bacteroidetes were the three dominant phyla of the microbial communities in the surface water of Chaohu Lake and that there were spatial differences in the composition of microbial communities at different points. A total of 146 subtypes of 14 classes of ARGs were detected in the surface water of Chaohu Lake， with aminoglycoside， multi-drug， and sulfonamide ARGs being the main ones. Affected by human activities， the degree of antibiotic pollution in Chaohu Lake has intensified， with the pollution level in the western half of the lake being higher than the level in the eastern half. The microbial diversity and abundance of ARGs in Chaohu Lake are higher in the western half of the lake （CH4 and CH5）， and the overall trend of higher in the west and lower in the east in terms of geographical location may be related to this result. Network co-occurrence analysis was conducted on the top 15 ARGs with relative abundance and microbial phyla. The result showed that there was a high degree of connectivity between microbial communities and ARGs， revealing a significant correlation between microbial communities and ARGs in the surface water of Chaohu Lake. Among them， phyla Armatimonadetes， Firmicutes， Bacteroidetes， and Cyanobacteria had the highest connectivity， and may be potential hosts for multidrug resistance of ARGs. The research results of this in-depth analysis of the microorganisms and ARGs in Chaohu Lake provide data support for the prevention and control of new pollutants in the lake. They also emphasize the importance of continuous monitoring and in-depth research on the relationship between microbial communities and ARGs in the water environment of Chaohu Lake， which provide a scientific basis for water environment management and public health safety of the lake， and a commitment to ensuring the ecological security and public health safety of the local water environment.