Genomic Evidence for Direct Transmission of mecC-MRSA between a Horse and Its Veterinarian

Abstract

Methicillin-resistant Staphylococcus aureus bearing the mecC gene (mecC-MRSA) has been reported from animals and humans in recent years. This study describes the first mecC-MRSA isolates of human and equine origin in Hungary (two isolates from horses and one from a veterinarian, who treated one of the infected horses, but was asymptomatic). MRSA isolates were identified by cultivation and PCR detection of the species-specific spa gene and mecA/mecC methicillin resistance genes. The isolates were characterized by antibiotic susceptibility testing, MLST, spa, SCCmec typing, PFGE and whole genome sequencing (WGS). All three isolates belonged to the ST130-t843-SCCmec XI genotype, and carried the mecC and blaZ genes. Apart from beta-lactam drugs, they were sensitive to all tested antibiotics. The isolates of the infected horse and its veterinarian had the same PFGE pulsotype and showed only slight differences with WGS. Hence, this is the first description of direct transmission of a mecC-carrying MRSA between a horse and its veterinarian. The emergence of mecC in the country highlights the importance of the appropriate diagnostics in MRSA identification.

Clinical Aspects of Bacterial Distribution and Antibiotic Resistance in the Reproductive System of Equids

“…One may suggest that continuing problems are the consequences of inappropriate treatment regimes applied in the animals. The expansion of antibiotic resistance among equids, additionally to the clinical implications for the animals, is also important within the broad concept of One Health as resistant isolates can be transmitted to other animal species and people [ 144 , 145 ]. A diagram of suggested actions in the face of possible antibiotic resistance is shown in Figure 1 .…”

“…Among these, regulatory and voluntary initiatives aim to decrease the dissemination of antibiotic-resistant bacteria to animals, as well as to people, given that recent studies have linked horses as a potential reservoir of a variety of pathogens, which may be transmitted to people [ 187 ]. For example, methicillin-resistant S. aureus from infections of horses have been found to disseminate often to veterinarians in Germany [ 147 ]; moreover, Albert et al [ 145 ] have recently described the first direct transmission of a mecC -carrying methicillin-resistant S. aureus between a horse and the attending veterinarian. Examples of regulatory interventions taken to control antimicrobial resistance may include strict regulations for licencing, prescribing and marketing of antibiotics [ 188 ].…”

MRSA infections in horses

“…Zoonotic transmission is a genuine and significant concern, with clear evidence that these bacteria can be spread from horses to humans, and from humans to horses (Albert et al, 2023;van Duijkeren et al, 2010;Weese et al, 2005;Weese, Caldwell, et al, 2006). Key considerations for our clinical practice include the prevention, containment and successful management of MRSA infections.…”

“…It refers to broad resistance to β‐lactam antimicrobials, confirmed either by in vitro resistance to cefoxitin/oxacillin, by a positive mecA PCR, or by confirmation of penicillin binding protein 2a by latex agglutination. Recently strains of MRSA that test negative by mecA PCR and instead carry the mecC gene have been reported in horses (Albert et al, 2023).…”

“…Zoonotic transmission is a genuine and significant concern, with clear evidence that these bacteria can be spread from horses to humans, and from humans to horses (Albert et al, 2023; van Duijkeren et al, 2010; Weese et al, 2005; Weese, Caldwell, et al, 2006).…”