Metagenomic screening of global microbiomes identifies pathogen-enriched environments

BackgroundHuman pathogens are widespread in the environment, and examination of pathogen-enriched environments in a rapid and high-throughput fashion is important for development of pathogen-risk precautionary measures.\n\nMethodsIn this study, a Local BLASTP procedure for metagenomic screening of pathogens in the environment was developed using a toxin-centered database. A total of 27 microbiomes derived from ocean water, freshwater, soil, feces, and wastewater were screened using the Local BLASTP procedure. Bioinformatic analysis and Canonical Correspondence Analysis were conducted to examine whether the toxins included in the database were taxonomically associated.\n\nResultsThe specificity of the Local BLASTP method was tested with known and unknown toxin sequences. Bioinformatic analysis indicated that most toxins were phylum-specific but not genus-specific. Canonical Correspondence Analysis implied that almost all of the toxins were associated with the phyla of Proteobacteria, Nitrospirae and Firmicutes. Local BLASTP screening of the global microbiomes showed that pore-forming RTX toxin and adenylate cyclase Cya were most prevalent globally in terms of relative abundance, while polluted water and feces samples were the most pathogen-enriched.\n\nConclusionsA Local BLASTP procedure was established for rapid detection of toxins in environmental samples. Screening of global microbiomes in this study provided a quantitative estimate of the most prevalent toxins and most pathogen-enriched environment.