Background/Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudintermedius (MRSP) represent important antimicrobial resistance threats related to companion animals, which can directly or indirectly lead to adverse health effects in humans and animals living in close contact. Characterizing the phenotypic resistance of MRSA and MRSP to a panel of antimicrobials relevant to both veterinary and human medicine is crucial within a “One Health” framework. Methods: In this study, a total of 79 presumptive MRSA isolates (34 from cats, 45 from dogs) and 110 presumptive MRSP isolates (105 from dogs, 5 from cats) from clinical cases were analysed. Real-time PCR was used to detect the presence of mecA and mecC genes, and susceptibility testing was performed using the Sensititre EUST2 panel. Results: Most of the isolates (88.9%, 168/189) were positive for the mecA gene, while a minority (1.1%, 2/189) were mecC-positive (2 MRSA, 1 dog, 1 cat). MRSP isolates exhibited acquired resistance to a broader range of antibiotics compared to MRSA strains. Furthermore, several isolates demonstrated acquired resistance to antibiotics considered critically important for human medicine. Resistance to vancomycin was found in an MRSP isolate from a dog, and resistance to linezolid in an MRSP isolate from a cat. This study reveals that 83.3% (30/36) of MRSA isolates from dogs and 89.3% (25/28) from cats were multidrug-resistant organisms, while MRSP isolates exhibited multidrug resistance in 99% (101/102) of cases for dogs and 100% (4/4) for cats. Conclusions: The extremely high level of multidrug resistance, with some isolates resistant to critically important antibiotics used in human medicine, highlight the importance of monitoring antimicrobial susceptibility in MRSA and MRSP isolates collected from cats and dogs in a One Health perspective.

Background: Raw-meat-based diets (RMBDs) for companion animals have gained popularity but may serve as vehicles for antimicrobial-resistant (AMR) bacteria, posing risks to animal and public health. This study investigated the occurrence and risk factors of AMR in indicator bacteria (Escherichia coli, Enterococcus faecalis, Enterococcus faecium) and Campylobacter spp. from commercial RMBD products. Methods: In 2023, 50 RMBD samples were collected in Belgium, representing 21 brands from five countries. After both selective and non-selective isolation and MALDI-TOF identification, antimicrobial susceptibility testing of the isolates was performed using broth microdilution. Results: From non-selective media, E. coli was found in 45 samples (90.0%), E. faecalis in 31 samples (62.0%), E. faecium in 23 samples (46.0%), and Campylobacter spp. in 3 samples (6.0%). Among these, one E. faecalis strain with acquired resistance to vancomycin and daptomycin was isolated. Multidrug resistance (MDR) was identified in 17 isolates from 15 samples (30.0%), including 14 MDR E. coli, 1 MDR E. faecalis, and 2 MDR E. faecium. From selective media, presumptive ESBL/AmpC-producing E. coli were detected in 17 samples (34.0%), and 5 E. faecium from linezolid-supplemented media were confirmed by the broth microdilution method. Samples from Belgian origin showed significantly higher E. faecium prevalence (76.5%) compared to Dutch samples (21.4%) (OR = 11.9, p < 0.001). Minor livestock sources were associated with increased MDR risk (OR = 5.52, p = 0.016). Conclusions: Commercial RMBDs in Belgium exhibit widespread bacterial contamination with concerning AMR patterns. These findings highlight the need for improved production standards in the RMBD industry and the need to raise awareness in pet owners.