Bacterial resistance to antimicrobial agents and its impact on veterinary and human medicine

This chapter focuses on acquired resistance mechanisms in bacterial pathogens of human and animal origin, including examples of transfer of resistant pathogens between hosts and of resistance genes between bacteria. Antimicrobial resistance has become a major challenge in veterinary medicine, particularly in the context of bacterial pathogens that play a role in both humans and animals. Antimicrobial agents are used extensively in aquaculture, horticulture, and to treat bacterial infections in humans and animals. Acquired resistance is based on resistance-mediating mutations or on mobile resistance genes. Bacteria, including zoonotic pathogens, can be exchanged between animals and humans mainly via direct contact, but also via dust, aerosols or foods. When resistant bacteria are transferred between humans or between animals, they can also exchange their resistance genes with bacteria already resident in or on the new host. The wide variety in resistance and resistance transfer mechanisms will continue to ensure the success of bacterial pathogens in the future.