Companion Dogs and Cats as Key Reservoirs of Antimicrobial Resistance: Evidence and One Health Implications

Antimicrobial resistance (AMR) in companion animals is an escalating concern at the interface of veterinary medicine and public health. Dogs and cats, the most commonly treated companion species, are frequently prescribed antimicrobials for dermatological, otic, urinary, and respiratory infections—often involving drug classes that are critically important in human medicine. This overlap underscores the need for judicious use and integrated stewardship within a One Health framework. This narrative review synthesizes current evidence on AMR in companion animals and its implications for One Health. Studies were included if they reported AMR in dogs and cats and addressed zoonotic aspects. Staphylococcus pseudintermedius, S. aureus, Escherichia coli, Pseudomonas aeruginosa, and Enterococcus sp. are examples of clinically significant organisms that are becoming more resistant to several antibiotic classes, which can result in treatment failures and extended illness. Horizontal gene transfer facilitates the spread of resistance determinants across bacterial populations. Improved surveillance systems, prudent antibiotic use, regular culture and susceptibility testing, and enhanced antimicrobial stewardship in veterinary practice are just a few of the many strategies needed to address AMR in companion animals. The integration of companion animals into AMR surveillance, stewardship programs, and infection control strategies is essential. Coordinated One Health interventions are urgently required to mitigate the spread of AMR.