Zoonotic potential of methicillin-resistant Staphylococcus aureus isolated from pets and their owners in Bangladesh

This study investigated the prevalence of methicillin-resistant Staphylococcus aureus (MRSA), their antimicrobial resistance, virulence determinants, and potential zoonotic potential between pets, owners, and veterinary professionals. From July 2022 to June 2024, 213 human and 191 animal samples (nasal, pus, and wound swabs) were collected from two veterinary hospitals. Staphylococcus aureus was isolated using conventional cultural method and subsequently confirmed through Gram staining, biochemical tests, and PCR targeting the nuc gene. Methicillin resistance was confirmed using the cefoxitin disk diffusion method and PCR for the mecA gene. Antimicrobial susceptibility testing was performed using the disc diffusion method against 15 antibiotics. Additionally, whole genome sequencing (WGS) was conducted on selected MRSA isolates from pets and their owners to study clonal transmission and virulence factors. The prevalence of MRSA in humans was 15.0%, in cats was 5.8% and in dogs was 13.5%. The MRSA isolates exhibited resistance to penicillin (94.9%), azithromycin (82%), and ciprofloxacin (53.9%), in addition to their intrinsic resistance to cefoxitin. Multidrug resistance was observed in 94.9% of MRSA isolates, though all were sensitive to amikacin, clindamycin, linezolid, and vancomycin. Notably, six dogs and cats, along with their respective owners, tested positive for MRSA. WGS analysis of these six pairs (12 isolates) showed four sequence types (ST), with ST6 being the most common (66.7%). There were also four spa types identified, with t304 being the predominant (58.3%). Within four pairs, identical ST-spa patterns were observed, except for the pair C52-P52 and D88-P88. Two pairs of isolates, C134-P134 and C185-P185, showed clonality based on whole genome and core genome SNP analysis, and other genetic parameters, suggesting clonal transmission between the pets and their respective owners. Virulence profiling revealed the presence of hemolysins, Panton-Valentine Leukocidin, and toxic shock syndrome toxin genes in selected isolates. The detection of diverse MRSA lineages, including human lineages ST80, ST88 and ST6-t304 in pets, indicates their zoonotic potential, and emphasizes the necessity for targeted MRSA surveillance and effective infection control measures. A collaborative One Health approach is therefore imperative to address the spread of MRSA between pets and their owners, thereby mitigating associated risks. The detection of diverse MRSA lineages, including human lineages ST80, ST88, and ST6-t304 in pets, underscores their zoonotic potential and emphasizes the necessity for targeted MRSA surveillance and effective infection control measures. A collaborative One Health approach is therefore imperative to address the spread of MRSA between pets and their owners, thereby mitigating associated risks.