Coastal urbanization influences human pathogens and microdebris contamination in seafood

Seafood is one of the leading imported products implicated in foodborne outbreaks worldwide. Coastal marine environments are being increasingly subjected to reduced water quality from urbanization and leading to contamination of important fishery species. Given the importance of seafood exchanged as a global protein source, it is imperative to maintain seafood safety worldwide. To illustrate the potential health risks associated with urbanization in a coastal environment, we use next-generation high-throughput amplicon sequencing of the 16S ribosomal RNA gene combined with infrared spectroscopy to characterize and quantify a vast range of potential human bacterial pathogens and microdebris contaminants in seawater, sediment and an important oyster fishery along the Mergui Archipelago in Myanmar. Through the quantification of >1.25 million high-quality bacterial operational taxonomic unit (OTU) reads, we detected 5459 potential human bacterial pathogens belonging to 87 species that are commonly associated with gut microbiota and an indication of terrestrial runoff of human and agricultural waste. Oyster tissues contained 51% of all sequenced bacterial pathogens that are considered to be both detrimental and of emerging concern to human health. Using infrared spectroscopy, we examined a total of 1225 individual microdebris particles, from which we detected 78 different types of contaminant materials. The predominant microdebris contaminants recovered from oyster tissues included polymers (48%), followed by non-native minerals (20%), oils (14%) and milk supplement powders (14%). Emerging technologies provide novel insights into the impacts of coastal development on food security and risks to human and environmental health.