Occurrence and Antimicrobial Resistance of Staphylococcus aureus Isolated from Healthy Pet Rabbits

Staphylococcus aureus is a ubiquitous microorganism and an opportunistic pathogen responsible for numerous diseases in humans and animals, characterized by different clinical pictures with acute or subacute course. S. aureus, due to its great adaptability and versatility in terms of infections and hosts, can be considered a relevant pathogen because of the harmful effects on animal health and its potential for transmission from animals to humans and vice versa. In recent years, a marked increase in multidrug-resistant S. aureus has been reported, posing a serious threat for disease management, food safety, and animal and human health as they limit available therapeutic options. In light of a growing interest of the scientific community for this micro- organism and considering the limited data availability on the prevalence of this pathogen in pet rabbits, the purpose of this research was to evaluate the presence of S. aureus in pet rabbits. From November 2021 to December 2022, nasal swabs were collected from 50 pet rabbits from private households in the Campania Region, southern Italy, and underwent analysis for S. aureus detection. Samples were enriched in broth, then inoculated onto nutrient and selective media, including Blood agar base supplemented with 7% sheep blood and Baird-Parker Agar Base, following standard laboratory protocols. Incubations in aerobic conditions at 37°C were performed for 24/48h for colony identification. Antimicrobial susceptibility testing for all S. aureus isolates was conducted using the disc diffusion method. Our results reported the presence of S. aureus in 16/50 (32%) rabbits examined, showing high levels of phenotypic resistance to different antibiotics, in particular penicillin 10U (81.2%) and erythromycin 15 μg (62.5%). The study demonstrated that pet rabbits represent a significant reservoir of S. aureus and contributes to the knowledge on the phenotypic antimicrobial resistance of these bacteria in rabbits raised in a domestic environment.