Comparison of the distribution and diversity of antimicrobial resistance genes between wild and commercially available Atlantic Mackerel

Abstract

The global uncontrolled rise of antimicrobial resistance (AMR) is a major societal threat and it is well documented that AMR is already negatively affecting healthcare and intensive livestock farming systems. Nonetheless, capture fisheries are still essential to the global food supply providing over 50% of the world’s aquatic organism production. To facilitate improved management, it is therefore imperative that we better understand reservoirs of AMR and how gene transmission occurs in the aquatic environment. In order to discern which AMR bacteria and genes are present in the marine environment, sediment and seawater samples were collected and Atlantic Mackerel were captured at the beginning of summer and autumn in the Solent Strait (Portsmouth, U.K). In addition, commercially available Atlantic mackerel were purchased at a local fish market. Using culture-dependent techniques we obtained more than 700 bacterial and 20 fungal isolates from skin, intestinal lining, and intestinal content. Ten different cefotaxime-resistant Pseudomonas spp. were isolated from the seawater and market fish skin samples, and one cefotaxime-resistant Rhanella sp. was isolated from wild fish digesta. Results from ongoing whole-genome shotgun metagenomics analysis will be discussed, as well as the connection between AMR bacteria and AMR gene presence within the marine coastal environment and the local fish markets, which are the last link between capture fisheries and consumers.