MRSA

MRSA is the abbreviation for methicillin-resistant Staphylococcus aureus. Staphylococcus aureus is a type of bacteria primarily found in people and may also be called Staph aureus, S. aureus, or a staph infection. Methicillin is a type of antibiotic that was created in the late 1950s to combat Staphylococcus aureus bacteria that had become resistant to penicillin. For bacteria that are resistant to an antibiotic, that means the antibiotic, which should normally be able to kill the bacteria, is not strong enough to kill it. In other words, those antibiotics no longer work. In the early 1960s it was discovered that some S. aureus bacteria had also become resistant to methicillin. Thus, MRSA became the new name for this type of bacteria.

Even though methicillin is no longer used today, the name remains because MRSA, and its veterinary counterpart MRSP, remain resistant to many types of antibiotics (referred to as a multi-drug resistant bacteria), making it extremely hard to kill. Even more concerning is that MRSA is quick to adapt, or change, to its current environment, so it is able to become resistant to new drugs and treatments and avoid being removed by the immune system. This limits the options of what can be used to treat infections caused by MRSA.

MRSP

MRSP stands for methicillin-resistant Staphylococcus pseudointermedius (S. pseudointermedius). Unlike S. aureus, S. pseudointermedius is more commonly found on dogs, and less commonly cats, than people. It too is resistant to numerous drugs and adapts quickly to the immune system, so it is a big concern for veterinary patients.

Where Do MRSA and MRSP Come from?

MRSA can be contracted by people from their environment, such as the community where they live and work, or in a hospital or nursing home setting. Any person can get MRSA. Risk for infection is increased with crowded areas, skin to skin contact with an infected person, and sharing equipment or supplies (e.g. medical equipment, towels, shaving razors). Open wounds, such as a scratch, are a common site for infection. One study found that 5% of people hospitalized in the United States carry MRSA in their nose or on their skin, even if they do not show symptoms. MRSP can be contracted from the environment as well, but may