Methicillin-Resistant Staphylococcus (MRSA)

What is MRSA?

Methicillin-resistant Staphylococcus aureus (MRSA) is a type of bacteria that causes serious infections that are resistant to many of the strongest antibiotics, including methicillin and other more commonly used antibiotics (including penicillin and amoxicillin). (1)

MRSA occurs most frequently among patients who undergo invasive medical procedures or who have weakened immune systems and are being treated in hospitals and healthcare facilities. (2) These healthcare-associated infections (HAIs) include surgical wound infections, urinary tract infections, bloodstream infections and pneumonia. (3) People who have been hospitalized or had surgery within the past year or who are receiving treatments like dialysis are at increased risk for infections with MRSA. (4)

MRSA infections have risen sharply in recent years. In 1972, MRSA accounted for only two percent of all Staphylococcus aureus HAIs reported to the Centers for Disease Control and Prevention (CDC) in the U.S. (5) Recent data show that MRSA now accounts for 50 to 70 percent of Staphylococcus aureus infections. (6)

Staphylococcus aureus (“staph”) organisms are common bacteria that can live on the skin and are one of the most common causes of skin infections in the U.S. (7) The bacteria also live harmlessly in the nasal passages of roughly 30 percent of the U.S. population. These people are sometimes called “staph carriers” or persons who are “colonized” with staph organisms. Staph organisms can cause infection when they enter the skin through a cut or sore. Infection can also occur when the bacteria move inside the body through a catheter or breathing tube. The infection can be minor and local (for example, a pimple) or more serious. (8)

Though MRSA is generally associated with healthcare institutions, it can also occur in persons who have had no contact with a healthcare facility. These types of MRSA infections are classified as community-acquired MRSA (CA-MRSA) and are presenting to hospital emergency departments and outpatient clinics in increasing numbers. In addition, patients with CA-MRSA who are admitted to a healthcare facility can be the source for organisms that can be spread to other hospitalized patients, and such spread has been well documented. Many such infections have also occurred among athletes who share equipment or personal items (such as towels or razors) and among children in daycare facilities who are in very close contact with one another throughout the day. (9) By some estimates, more than half of all skin infections now treated in emergency rooms are caused by MRSA. (10)

How does someone contract MRSA?
MRSA is most often contracted while a patient is in the hospital. Transmission of MRSA organisms can occur from skin-to-skin contact with someone who has MRSA on their skin, by hands of healthcare personnel who pick up organisms on their hands from a colonized patient and then care for another patient without washing their hands between the tasks, by contact with items such as computer keyboards or surfaces such as bedrails that have the
organisms on them, and through insertion of devices such as catheters or breathing tubes that bypass the body’s natural defenses.

The risk for the spread of CA-MRSA is highest where people with poor hygiene are associating in close quarters such as prisons, homeless shelters, locker rooms and daycare centers.

How do we clean rooms used by MRSA infected patients?
Using a EPA registered disinfectant with a MRSA rating clean thoroughly using friction, all surfaces in the patient room, paying particular attention to high touch  surfaces. Be sure to follow contact precautions in addition to universal precautions, and wash hands thoroughly, when you finish cleaning.


6 Siegel JD, Rhineheart E, Jackson M, Linda C; Healthcare Infection Control Practices Advisory Committee.
“Management of Multidrug-Resistant Organisms in Healthcare Settings, 2006.” Available at
10 Moran GJ, Krishnadasan A, Gorwitz RJ, Fosheim GE, McDougal LK, Carey RB, Talan DA; Emergency ID Net Study Group. (2006). Methicillin-Resistant S. aureus Infections among Patients in the Emergency Department, New England Journal of Medicine, 355,666-674.

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