Microbiome of Bacterially Impaired Watersheds: Distribution of Potential Bacterial Pathogens

Abstract

Bacterial impairment of freshwater systems is a commonly studied global problem. However, studies on the relative distribution of bacterial pathogens in different impaired aquatic systems have been limited. Frequently, impaired freshwater systems are classified by the presence of fecal indicator bacteria (FIB) and the identification of sources of fecal contamination through microbial source tracking. In this study, we assessed the relative abundance of DNA sequences related to potential human bacterial pathogens along with human fecal indicator bacteria in three impaired watersheds. These watersheds consistently showed a high abundance of FIB for the past several years. Using Illumina paired-end DNA sequencing of 16S rRNA gene amplicons, we observed variation in the relative distribution of DNA sequences related to Legionellaceae, Enterobacteriaceae and Bacteroidaceae families across different sites. We identified potential hotspots sites in these impaired water systems, which showed a relatively high abundance of pathogen-related DNA sequences. This study demonstrates the significance of Next-Gen DNA sequencing for the initial screening of waterborne pathogens and the identification of high-risk sites for preferential remediation efforts in impaired water systems. Secondly, the frequent temporal monitoring of specifically identified pathogens that are in high abundance in a watershed can help in the accurate prediction and prevention of disease outbreaks.