Free-living bacteria and potential bacterial pathogens in sewage treatment plants
To comprehensively understand the profile of free-living bacteria and potential bacterial pathogens in sewage treatment plants (STPs), this study applied high-throughput sequencing-based metagenomics approaches to investigate the effects of activated sludge (AS) treatment process and ultraviolet (UV) disinfection on the community of bacterial pathogens in two full-scale STPs. A total of 23 bacterial genera were identified as free-living bacteria, and 243 species/OTU97% were identified as potential bacterial pathogens, 6 of which were confidently detected in the STPs (with the total abundances ranging from 0.02 to 14.19%). Both diversity and relative abundance of the detected bacterial pathogens decreased obviously after AS treatment process (p < 0.05), and increased slightly after sedimentation (p < 0.05). UV disinfection shows no obvious effects on the total relative abundance of the free-living pathogenic bacteria in sewage. Although large amounts of the particle-bound pathogens were eliminated through the sewage treatment process, the STPs could not effectively remove the free-living bacterial pathogens, and some pathogenic bacteria (e.g., Pseudomonas aeruginosa) present in the effluent had higher relative abundance after UV disinfection. Overall, the results extend our knowledge regarding the community of potential pathogens (especially free-living pathogens) in STPs.
KeywordsPathogenic bacteria Free-living bacteria Sewage treatment plant Metagenomic analysis Network analysis
Dr. Y. Mao wishes to appreciate the financial support of the Natural Science Foundation of Guangdong (2017A030313315), Shenzhen Science & Technology Projects (JCYJ20160520165135743, ZDSYS201606061530079), and the National Science Foundation of Shenzhen University (Grant Nos. 827-000223 and 2016008).
This study was financially supported by National Natural Science Foundation of China (51290282 and 51608329), National Science & Technology Support Program of China (2014BAC08B04), and Hong Kong General Research Fund (172057/15E).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
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