Mapping total microbial communities and waterborne pathogens in household drinking water in China by citizen science and metabarcoding

This project combined citizen science sampling approach with 16S rRNA gene metabarcoding to profile the drinking water microbiome in China. The approach addresses challenges in monitoring microbial water quality, particularly in resource-constrained settings. Utilizing a low-cost, custom-made water sampling kit, volunteers collected 50 tap waters from 19 provinces in China between December 2020 and August 2021, including after two extreme weather events: the 2021 Henan Floods and Typhoon In-Fa. Using a protocol optimized for low-biomass samples, 22 out of 50 tap water samples were tested positive for microbial DNA. In total 7,635 Amplicon Sequence Variants (ASVs) were identified, indicating a diverse microbiome in household drinking water. Pathogenic bacteria, including Escherichia coli, Mycobacterium spp., and Legionella spp., were detected in all PCR-positive samples. Notably, an increase in potential pathogenic ASVs, such as Salmonella enterica, was observed in flood-impacted regions, drawing attention to the susceptibility of water systems to contamination during extreme weather events.