**2.1 What is MRSA?**

The *Staphylococcus* genus consists of a variety of opportunistic pathogens of variable relevance in veterinary medicine, being the coagulase-positive *S. aureus* and members of the group *Staphylococcus intermedius*, particularly *Staphylococcus pseudointermedius,* the most important clinically [13]. In human medicine, *S. aureus* can cause clinical manifestations ranging from mild skin and soft tissue infections to severe bloodstream infections. A remarkable skill of this genus is its capacity to acquire antibiotic resistance [20], mainly from the irrational increase in the intensity of its use [21]. Methicillin resistant *S. aureus* (MRSA) are resistant to an important range of antibiotics [20]. The resistance to methicillin, conferred by the presence of the *mec*A or *mec*C gene, is of particular relevance. These genes, located in Staphylococcal Chromosomal Cassette (*SCCmec*) confer the methicillin resistance [22] and codify the production of a penicillin-binding protein (PBP) with low affinity to beta-lactams antibiotics, such penicillin, cephalosporins, and carbapenems [20, 23].
