QMRA of beach water by Nanopore sequencing-based viability-metagenomics absolute quantification

Overall, this study aims to achieve absolute quantification for live microbial cells in beach water. To achieve this, propidium monoazide (PMA) dye was used at the sample pre-treatment stage to remove relic DNAs. A cellular bacterial internal standard of known abundances (spike-in) was used for calibration in the absolute quantification of live microbial cells. Applying this method, we conducted a quantitative microbial risk assessment (QMRA) for swimming in 4 marine beach waters in Hong Kong and assessed the microbial risks, in the respect of resistome risks, associated with swimming in these beach waters.