Prevalence of MRSA in canine and feline clinical samples from one-third of veterinary practices in Germany from 2019-2021.

Background: MRSA is a major contributor to AMR-related deaths. The WHO's global action plan emphasizes a One Health approach, acknowledging the connection between humans and their companion animals. It is agreed on that comprehensive AMR surveillance is needed.

Objectives: This study provides a large-scale overview of MRSA occurrence in cats and dogs in Germany, serving as a foundation for continuous surveillance.

Methods: The study analysed all results of canine and feline bacterial diagnostic samples from a large laboratory, encompassing samples received from veterinary practices between January 2019 and December 2021. MRSA prevalence between host species, sample types and geographical distribution were compared. Additionally, data were contrasted with human MRSA surveillance data from Germany.

Results: Samples originated from 3491 German veterinary practices, representing 33.1% of practices and clinics nationally. Bacterial examination results from 175 171 samples were analysed, identifying S. aureus in 5526 of these samples (3.2% isolation rate). S. aureus in clinical samples was more prevalent in cats (5.6%) than dogs (2.0%). Methicillin resistance was found in 17.8% of S. aureus samples and was higher in dogs (20.4%, 95%CI 18.9-22.0) than cats (15.6%, 95%CI 14.3-17.0). The highest MRSA prevalence was found in canine wound samples (32%), compared to skin/soft tissue, respiratory tract and other (<23% respectively).

Conclusion: The study reveals a 17.8% MRSA prevalence, which is higher than the human outpatient MRSA prevalence (5.4%). Restriction and regulation of veterinary antibiotic use should be validated with AMR surveillance. Our study shows that this is feasible in companion animals with significant coverage.