Staphylococcus pseudintermedius is one of the most common causes of infection in dogs. However, these infections are typically endogenous stemming from the dog’s own skin microbiome. Despite this, antimicrobial resistance (AMR) in this pathogen is booming. Our clinical laboratory has observed multi-drug resistance (MDR) in 75.7% of S. pseudintermedius isolates. In fact, pan-resistant isolates have begun to emerge. This skyrocketing resistance is alarming and new antimicrobials are desperately needed to combat this threat to canine medicine. In this proposal, researchers are turning to the dog’s own microbiome as a source of antimicrobial discovery. They plan to discover canine skin commensals with the ability to inhibit S. pseudintermedius. A strong, diverse microbiome has the innate ability to inhibit pathogenic bacteria and one of the main contributors of this are bacteriocins, produced mainly by coagulase-negative Staphylococci (CoNS) and lactic-acid bacteria (LAB). In order to identify potential isolates that can inhibit S. pseudintermedius, they will use culture-based methods and selective media to evaluate isolates in high abundance on the skin of dogs without S. pseudintermedius colonization. Once these isolates are identified, the team will perform competition assays to discover commensals capable of inhibiting S. pseudintermedius growth. Those isolates capable of inhibition will be evaluated for bacteriocin production by chromatography and mass spectrometry. Finally, they will also evaluate the synergism between these bacteriocins from different isolates. The investigators hypothesize that the canine microbiome will provide a robust source of bacteriocins that can be developed into novel therapeutics to combat the rising S. pseudintermedius AMR threat.