In Belgium, aquaculture is mostly semi-intensive and the farms are mainly raising salmonids in ponds fed by a river’s diversion. There are no vaccines for fish available in Belgium, and farmers need to use antimicrobials to treat bacterial diseases, however, there is also no antibiotic available with a market authorization. Antimicrobial resistance (AMR) and antimicrobial use (AMU) monitoring are not yet applied, but AMU rregistration in food producing aquatic animals shall be put in place by 2027. In Belgium, very scarce information are available to date on AMU and AMR in aquaculture.

This project aims to shed light on AMR and AMU in aquaculture in Belgium as well as bringing first elements to assess the risk of AMR in aquatic animals for public health. It will also allow authorities to assess the best way to include AMR and AMU in aquatic animals in the national monitoring program.

To achieve these goals, after a literature review, a sampling will be performed in the field (44 farms) in order to isolate the bacteria Aeromonas spp. that seems to be the best bacteria to monitor based on literature research and experts' consultation. The antimicrobial resistance pattern of the newly isolated Aeromonas will be determined by Sensititre and genomic analysis. Metagenomics will also be assessed as a monitoring tool and will determine what is the best sample and the best bacterium/antimicrobial to use for AMR monitoring. Questionnaires destined to farmers, veterinarians and feed companies will allow us to determine the current Belgian antimicrobial use in aquaculture and, finally, a list of potential risk factors and key drivers of AMR in aquatic environments will be obtained after epidemiological studies.