Characterization of microbial communities in urban subway: connotation for indoor environment quality and public health

Metagenomics is a novel genomic tool employed to accurately study the composition of microbial communities in their ecological environments, including mass transport systems. Despite the potential significance of these sites as sources of exposure, the pathogenic microbiomes in these constructed settings remain unexplored. In this study, high-throughput sequencing was utilized to identify the microbiota obtained from the Metropolitan Transport of Shanghai (MTS) during the spring and summer. A diverse range of microbiota, especially pathogens, and models for mapping diversity and environmental variables were analyzed using the metagenomic techniques. The results indicate that bacteria accounted for 95.26% of the categorized genes in the 108 aerosol samples analyzed during the spring and summer, with the remaining 4.73% attributed to eukaryotes, viruses, and archaea. We successfully identified 86 microorganisms that align with the National Microbiology Data Center's List of Pathogenic Microorganisms, uncovering unique characteristics of various species with potential health implications throughout across seasons. Additionally, the distribution and diversity of the microbiota were significantly influenced by temperature, humidity, season, and time of day. The study's findings establish a framework for investigating and evaluating potential public health risks, offering early warning of biosecurity concerns related to these built environments. They also provide a comprehensive and unbiased perspective on the characteristics of microbial communities and potential pathogens in urban metros. Environmental and public health experts will find this investigation into the pathogenic microbiomes found in aerosol samples compelling.