Metagenomic analysis of the microbial community and antibiotic resistance genes in an urban recreational lake, Jiushan Lake

Abstract:

[Background] Urban water is facing excessive antibiotic resistance genes (ARGs) contamination. However, few studies have studied the occurrence of ARGs in urban recreational waters. [Objective] To analyze the microbial community and resistance gene composition in urban recreational waters between summer and winter, for the understanding of aquatic ecosystem in recreational waters. [Methods] We determined the summer and winter microbial and ARGs composition of Jiushan Lake, an urban recreational lake, using high-throughput sequencing technology. [Results] The study revealed the existence of 148 and 152 phyla in summer and winter samples, respectively. Proteobacteria and Actinobacteria were the two predominant phyla in both seasons. The dominant genus in summer was Synechococcus, while the dominant genus in winter was Liminohabitans. A total of 449 ARGs were identified (304 shared by both seasons, 66 summer-exclusive, and 79 winter-exclusive). In contrast to the number of ARGs, their abundance was higher in summer samples. MCR-1.2 and BcI were the predominant ARGs in summer and winter water samples, respectively. The resistance mechanisms of the detected ARGs were mainly antibiotic efflux, antibiotic inactivation, or antibiotic target alteration. The results of redundancy analysis and canonical correspondence analysis showed that environmental factors were significantly correlated with the distribution of microbial community and resistance genes. [Conclusion] The microbial community structure and resistance gene composition are significantly different between winter and summer in Jiushan Lake. The results provide useful information toward a more comprehensive understanding of the structure of urban recreational aquatic ecosystems and also highlight the potential health hazards resulting from their ARGs contamination.