ABSTRACT BY SPONSOR: Microbiome assessment of water including sewage plant influent/effluent

Methods used to monitor the microbial content of potable and recreational waters, as well as treated wastewater are limited to dated culture-based methods that utilize indicator organisms as surrogates for pathogenic species. Studies utilizing Next-Generation sequencing (NGS) to profile the microbial composition of water samples are now becoming more routine. However, it is well known that results are prone to bias and errors at every step of the workflow, including sample collection, DNA/RNA extraction, library preparation, sequencing and bioinformatics analysis. Therefore, care must be taken at each step in the workflow to minimize the effects of bias to obtain an accurate microbial profile for each sample. In addition, many studies utilizing 16S rRNA targeted sequencing are phylum or genus-level resolution, thus limiting the ability to distinguish between innocuous and pathogenic species.

The purpose of the present study was to profile microbiomes of various environmental and commercial water sources using an unbiased, standardized workflow for accurate analysis. In order to determine the precise differences among various samples, water was collected from several sources. With the inclusion of validated mock microbial communities to ensure unbiased library preparation and sequencing, the microbial profiles of each sample were determined via 16S rRNA targeted sequencing and bioinformatics analysis. Surprisingly, in addition to the expected microbial differences between dissimilar water sources, strikingly different profiles were found among similar sample types collected from different locations. The findings reinforce the need for expanded sampling and the potential of NGS-based Microbiomics methods for water monitoring in the future.