Assessment of Fecal Pollution Sources in a Small Northern-Plains Watershed Using PCR and Phylogenetic Analyses of Bacteroidetes 16s rRNA Gene


We evaluated the efficacy, sensitivity, host-specificity, and spatial/temporal dynamics of human- and ruminant-specific 16S rRNA gene Bacteroidetes markers used to assess the sources of fecal pollution in a fecally impacted watershed. Phylogenetic analyses of 1271 fecal and environmental 16S rRNA gene clones were also performed to study the diversity of Bacteroidetes in this watershed. The host-specific assays indicated that ruminant feces were present in 28-54% of the water samples and in all sampling seasons, with increasing frequency in downstream sites. The human-targeted assays indicated that only 3-5% of the water samples were positive for human fecal signals, although a higher percentage of human-associated signals (19-24%) were detected in sediment samples. Phylogenetic analysis indicated that 57% of all water clones clustered with yet-to-be-cultured Bacteroidetes species associated with sequences obtained from ruminant feces, further supporting the prevalence of ruminant contamination in this watershed. However, since several clusters contained sequences from multiple sources, future studies need to consider the potential cosmopolitan nature of these bacterial populations when assessing fecal pollution sources using Bacteroidetes markers. Moreover, additional data is needed in order to understand the distribution of Bacteroidetes host-specific markers and their relationship to water quality regulatory standards.


Civil, Architectural and Environmental Engineering

Keywords and Phrases

bacterial RNA; assessment method; bacterium; bioassay; feces; microbial community; phylogenetics; pollutant source; polymerase chain reaction; RNA; ruminant; spatiotemporal analysis; water pollution; water quality; watershed; Bacteroides; biodiversity; environment; evaluation; feces analysis; gene cluster; gene sequence; molecular cloning; nonhuman; nucleotide sequence; phylogeny; priority journal; sediment; signal transduction; water sampling; Animals; Bacteroidetes; Fresh Water; Genes; Bacterial; Humans; Molecular Sequence Data; Nebraska; Quality Control; Ribosomal; 16S; Ruminants; Sensitivity and Specificity; Species Specificity; Water Microbiology; Bacteria (microorganisms); 16S rRNA gene; Fecal pollution; Microbial source tracking

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Article - Journal

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