Background: Pseudomonas aeruginosa is one of the leading causes of healthcare-associated infections in humans. This bacterium is less represented in veterinary medicine, despite causing difficult-to-treat infections due to its capacity to acquire antimicrobial resistance, produce biofilms and persist in the environment. Objectives: Determine the susceptibility profiles of a large panel of P. aeruginosa strains to antipseudomonal antibiotics and didecyldimethylammonium chloride (DDAC), widely used as a disinfectant. Study design: Genomic surveillance. Methods: A phenotypical and genomic characterisation carried out on 180 strains isolated in hospitals and 168 strains from animals, particularly horses. Susceptibility profiles to antipseudomonal antibiotics and DDAC were established using disk diffusion and broth microdilution respectively. A genomic study was performed on 121 strains (77 human and 44 animal) to determine their resistome and putative clonal relatedness. Results: 28 Sequence Types (ST) were found among strains of animal origin and 18 for strains of hospital origin. ST strains considered among the top ten high-risk clones of P. aeruginosa for human health were found in hospitals and animals. While veterinary medicine has a very few therapeutic options to control P. aeruginosa infections, resistance rates to critical antibiotics (carbapenems) in humans were found for both populations. In addition, an important representation of a decreased susceptibility phenotype to DDAC was observed and was more represented in the hospital setting (62.5%) than in patients (28.2%) and animals (11.3%). Biofilm formation did not appear to be directly involved in decreased susceptibility to DDAC but was a persistent structure of the bacteria in the environment. Main limitations: Knowledge of the mechanisms underlying this decreased susceptibility to DDAC is limited: preliminary observations suggest overexpression of the efflux resistance-nodulationdivision pump. Conclusion: All these observations reinforce the need to study the different reservoirs of resistance in P. aeruginosa, using a “One health” approach. Ethical animal research: Not required: analysis of microorganisms Informed consent: Not applicable. Competing interests: None declared. Funding: Conseil Régional de Normandie, Ministère de l'Agriculture et de la Souveraineté Alimentaire