Metagenome study of microbial community

The present study provides the first detailed insight into the composition and spatial and seasonal changes of planktonic and epilithic bacterial communities in the midstream and the littoral zone of the Danube. Year-round sampling was carried out upstream and downstream from a large urban area, in the catchment of bank filtration drinking water abstraction sites. Using high throughput 16S rRNA gene-based amplicon sequencing, significant differences were found between microbial communities of water and pebble epilithic samples, with higher variance in the latter. - In drinking water supply, riverbank filtration (RBF) is an efficient and cost-effective way of eliminating pathogens and micropollutants using a combination of biotic and abiotic processes. Microbial communities in the hyporheic zone contribute to and are shaped by these processes. The source water microbiome, water treatment and distribution system influences microbial water quality at the point of consumption. Understanding microbial community shifts from source to tap and the factors behind them are instrumental in maintaining safe drinking water delivery. To this end, microbial communities of an RBF-based drinking water supply system were investigated by metabarcoding in a one-year sampling campaign. Samples were collected from the river, RBF wells, treated water, and a consumer. Metabarcoding data were analysed in the context of physicochemical and hydrological parameters. Bacterial community diversity and determinants of community structure were investigated in two buildings using a purpose-designed in situ device containing stainless steel and polypropylene coupons and an online biofilm sensor. Next-generation sequencing and scanning electron microscopy revealed increasing diversity and complexity over time. Initial biofilms were dominated by Proteobacteria primarily Burkholderiales and Sphingomonadales), with an increasing ratio of Actinbacteriota and Bacteroidota. Important nosocomial pathogens (Mycobacterium, Legionella, Methylobacterium, Bosea) were detected in the biofilm samples that were absent in bulk water, implying that water monitoring alone is not sufficient for estimating the risk of water-related pathogens.