Association of antimicrobial resistant Vibrio and species pathogenic to humans with aquacultured seafood

Vibrio is a genus of bacteria commonly found on seafood products and includes many important human pathogens. Most seafood is produced using aquaculture systems, which frequently use antimicrobial agents. Here we aimed to determine if method of seafood production was associated with Vibrio pathogenic to humans and/or antimicrobial resistant (AMR) Vibrio. Retail prawn and salmon samples that were produced using aquaculture or were wild-caught were cultured for Vibrio spp. Isolates were sequenced to identify the species and AMR genes (ARGs) present, followed by long-read sequencing of a subset of genomes to identify mobile genetic elements (MGEs). Vibrio was cultured from 136/279 of prawn and 4/157 of salmon samples, and ARG-containing Vibrio and Vibrio pathogenic to humans were associated with aquacultured prawn samples. A quarter of ARGs were found on plasmids, mostly in close vicinity to the insertion sequence type IS6/IS26. Most intrinsic chromosomal ARGs were not associated with an MGE, but most acquired chromosome ARGs were associated with a MGE, most commonly IS91. Vibrio isolates belonging to different species contained ARGs associated with similar MGEs. Vibrio has an arsenal of MGEs that can facilitate the spread of ARGs. Aquaculture practices may need to be adjusted in order to prevent the spread of AMR Vibrio and Vibrio pathogenic to humans.