The definition of antibiotic resistance in bacteria differs if it is seen from the viewpoint of the bacteriologist and the epidemiologist, or of the clinician and the pharmacologist. The standardization by the European Union Committee on antimicrobial susceptibility testing (EUCAST) led to more accurate definitions. This committee defined critical concentrations based on pharmacological approaches and clinical outcomes, and on the variability of exposure of the treated subjects. In France, the values used for veterinary antibiograms are based on epidemiological data. New funding is necessary to move to the next stage and use all available data to define clinical resistance in veterinary medicine.