Assessment and prediction of spatio-temporal dynamics of Vibrio vulnificus in the coastal Baltic Sea

With rising infection rates in recent years Vibrio vulnificus pose an increasing threat to public safety in the coastal brackish Baltic Sea. V. vulnificus, associated with high mortality, can thrive in the Baltic Sea during summer months due to optimal conditions and can cause severe infections to humans through open-wound infections. Pinpointing a timeframe of increased risk of infection is the next step in curbing the increasing numbers of infections and also has wide-ranging ecological and economic effects. Routine monitoring of this bacterium in the Baltic Sea is critical to provide a warning system for the public when the risk of infection is potentially high. As part of an extensive twice weekly sampling campaign that included 14 locations in the coastal Baltic Sea across a one-year period between 2022-2023, we investigated the abundance of V. vulnificus using a multi-method approach, including droplet digital PCR (ddPCR) results targeting the vvhA gene region, agar cultivation, and species level classification of 16S rRNA gene sequencing. Physico-, biological- and hydrochemical parameters were measured concurrently and variables explaining V. vulnificus occurrence were identified by machine learning. In addition, numerous machine learning techniques were applied in order to predict V. vulnificus gene concentrations using ddPCR, with the objective of establishing models that accurately predict when V. vulnificus is most abundant in the coastal Baltic Sea. Time-series analysis was performed using variables from previous timepoints as predictors, with the goal of pinpointing the most important markers for creating an early warning system and highlighting the importance of improved coastal monitoring. First results will be presented at the conference.