The PET-AMR project will investigate the “One Health” implications of the use of antibacterial agents in pet animals in Belgium. Five different research questions will be investigated through 5 corresponding work packages. The first question is “which antibiotics are used in dogs and cats, for which indications and in which quantity”. To answer this, up to 200 veterinary practices will be contacted to collect data to quantify the antimicrobial use (AMU) in dogs and cats, to gain insight into the indications, and to participate in a survey aiming to understand the possible reasons for deviating from the national guidelines and use of critically important antimicrobials. Secondly, the prevalence of resistance in commensal organisms (E. coli and Enterococcus faecium/faecalis) and in the pathogenic zoonotic bacteria methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP) in dogs and cats will be determined. For this purpose, 150 healthy dogs and 150 healthy cats will be swabbed in the rectum to search for E. coli and Enterococci and in the nares (dogs) or oropharynx (cats) to search for MRSA and MRSP. A questionnaire will be filled by the owner to collect data for risk assessment of the presence of resistant bacteria/resistance genes in dogs and cats. Clinical isolates of MRSA and MRSP from dogs and cats will also be collected to study the level of AMR in these isolates. The resistance profiles of all the isolated bacteria will be determined through micro-dilution methods with a panel of antimicrobials selected either for their relevance in human medicine and/or frequent use in veterinary medicine. Genetic characterization of the resistance will be performed with micro-arrays and by whole-genome sequencing. The third question is the identification of the risk factors for both the presence of resistant germs/resistance genes in dogs and cats and their transfer to and from humans. This will be investigated through a literature review and the analysis of the questionnaires filled previously by the owners during the collection of the isolates. Samples from raw pet food will also be collected to evaluate the presence of resistant bacteria in such products. The fourth work package will be dedicated to the identification of risk factors for the circulation of resistant bacteria within companion animal practices. To this aim, surfaces of different locations (waiting room, consultation room, hospitalization, surgical tables,…) will be swabbed before and after cleaning and disinfection procedures to assess the presence of E. coli and Enterococci and their AMR in several practices. Questionnaires about the cleaning and disinfection procedures will be distributed and the analysis of these questionnaires will be compiled with the analysis of AMR in the isolated bacteria. Finally, a global risk assessment will be conducted to describe and quantify the critical factors for the presence and transfer of resistance germs between pets, their owners, and the general population.