Exploring microbial ecology in public swimming pools: a metagenomic investigation of community structure and environmental correlates

Epidemiological studies have identified correlations between swimming and outbreaks of various infectious diseases. However, a comprehensive understanding of the pathogens present in public swimming pool water has yet to be systematically established. Swimming pool water samples were collected from 20 indoor public swimming pools in Shanghai, China during the summer of 2023. After quality inspection of the extracted nucleic acid, the qualified samples were subjected to metagenomic sequencing to profile the microbial communities of swimming pool water. A total of 24,035 microbial species were identified with the abundance of bacteria (99.46%), followed by archaea (0.29%), viruses (0.20%), and fungi (0.05%), including 441 pathogenic species, 23 of which were classified as biosafety level 3 (BSL-3) microorganisms. Environmental sources constituted the dominant origin (86.00%) of the pool water microbiome. Additionally, suburban pools demonstrated greater microbial diversity than urban pools (P < 0.05). The abundance of viruses exhibited a positive correlation with the concentration of urea in pool water (r = 0.31, P < 0.05). This study demonstrated that swimming pool water serves as a potent reservoir and mixing vessel for various highly pathogenic microorganisms. Effective water quality management strategies are essential to mitigating the potential public health threats of public swimming pools.