Antimicrobial Resistance and One Health: Companion Animals as Reservoirs of Bacteria and Resistance Genes in Brazil

Objective: This study investigates the role of companion animals, such as dogs and cats, in the spread of antimicrobial resistance (AMR) in Brazil, aiming to understand the interaction between humans, animals, and the environment in the dissemination of resistant bacteria within the "One Health" approach. Theoretical Framework: The "One Health" approach underpins the investigation of AMR, emphasizing the interdependence between human, animal, and environmental health. Notably, resistance in zoonotic pathogens such as Escherichia coli producing ESBL (extended-spectrum β-lactamase) and methicillin-resistant Staphylococcus aureus (MRSA) is a consequence of the excessive use of antimicrobials in humans and animals. Method: This is an integrative literature review, searching for articles published in the last five years (2020 to 2025) in the PubMed and ScienceDirect databases. The search strategy used the Health Sciences Descriptors (DeCS): "cats", "dogs", "antimicrobial resistance", "MRSA", "ESBL", and "Brazil", combined with the boolean operator "AND". Article selection followed relevance and methodological quality criteria. Results and Discussion: The results demonstrated that antimicrobial resistance in companion animals is significant, despite being underestimated. The main bacteria identified were E. coli and MRSA, whose spread is associated with the interaction between pet owners and their animals. The discussion contextualizes these findings within the "One Health" approach, highlighting the need for preventive measures and the rational use of antimicrobials in both human and veterinary sectors. Research Implications: The results reinforce the importance of infection control protocols in human and veterinary hospital environments, as well as guidelines for the responsible use of antimicrobials. The research also contributes to the formulation of public policies aimed at mitigating AMR from an integrated human and animal health perspective. Originality/Value: This study contributes to the literature by highlighting AMR in companion animals, a topic still underexplored in Brazil. Its relevance lies in integrating scientific evidence within the "One Health" concept, promoting strategies to minimize the impacts of antimicrobial resistance on public and veterinary health.