Effects of temperature and nutrient load on the interaction of Vibrio parahaemolyticus and plastic pollution in the marine environment

Plastic pollution in the marine environment harbors a diverse community of microorganisms called the plastisphere. The plastisphere has been found to contain potential pathogenic species of concern to both marine organisms and human health. This study examines the ability of plastic to harbor Vibrio parahaemolyticus, the leading cause of seafood-borne illness around the globe, in varying environmental conditions. A modified crystal violet assay was utilized to measure biofilm growth over 24 h at 18 °C and 25 °C and at five nutrient conditions. Biofilm growth was compared to free-living cell growth, and results show that free-living cell growth significantly increases with both increased temperature and increased nutrient load, yet biofilm formation was minimally responsive to changing conditions. Thus, pathogen-laden biofilms have the ability to form on plastics throughout much of the year, making plastic pollution both a vector for the transport of pathogens and a reservoir of pathogens in adverse environmental conditions.