Methicillin-Resistant Staphylococcus aureus

New MRSA deisolation protocol

In an effort to get patients with a history of MRSA out of contact isolation precautions, OHSU and ICP have developed a new algorithm for de-isolating these patients:

Procedure for de-isolation of a patient with MRSA history

About the organism

Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterial infection that is highly resistant to certain antibiotics called beta-lactams. These antibiotics include methicillin and other more common antibiotics such as oxacillin, penicillin, and amoxicillin. Methicillin resistance is gained by the production of a unique, low-affinity penicillin binding protein (PBP 2a) encoded by a chromosomal mec-A gene. MRSA is different from Methicillin-susceptible Staphylococcus aureus (MSSA) in that neither the protein nor the mec-A gene is present in MSSA.

Staphylococcus aureus (S. aureus) bacteria are anaerobic, coagulase-positive organisms that stain as positive clusters on a gram stain. S. aureus is a common type of bacteria that normally lives on the skin and sometimes in the nasal passages of healthy people (colonization).  MRSA colonization occurs when a person who carries the organism but shows no clinical signs or symptoms of infection.

S. aureus can cause infection when entered thorough the body via a cut, sore, catheter, or breathing tube. The infection can be minor and local (i.e. a pimple), or more serious (involving the heart, lung, blood, or bone). Serious staph infections are more common in people with weak immune systems. This includes patients in hospitals and long-term care facilities and those receiving kidney dialysis.

Common factors associated with acquiring MRSA in any acute care setting include prolonged hospital stay, use of broad spectrum antibiotics, greater number and longer duration of antibiotic use, stay in an ICU or burn unit, surgical wounds, poor functional status, and proximity to other patients with MRSA.

Populations that are more susceptible to MRSA colonization, include intravenous drug users, persons with dermatological diseases, or diabetes, and persons on renal dialysis.

Infection prevention and control 

If you see the Epic MRSA FYI alert screen in a patient's chart, please make sure the patient is on contact precautions. Clinicians should notify the Department of Infection Prevention and Control if a patient with MRSA or a history of MRSA is identified but no FYI alert appears in EPIC. 


Healthcare workers' hands and the environment are the most common means of spreading MRSA. To combat this, be sure to wash your hands and place all inpatients that have a history of MRSA (or a positive MRSA culture) in contact precautions.  contact precautions for MRSA means:

  • Placing patient in a private room (or in a room with another MRSA patient)
  • Following hand hygiene
  • Maintaining clean patient environment/ equipment,
  • Wearing personal protective equipment (PPE) when entering room (gowns and gloves)
  • Only transporting patient out of room for essential tests/ services
  • See the contact precautions policy for more information.

For patients in the ambulatory setting, staff need to follow standard precautions when caring for patients with MRSA. Standard precautions for outpatients with MRSA means:

  • Following hand hygiene at all times
  • Wearing PPE  if there is risk/ potential for exposure to infectious substances
  • Provide covering or dressing for the patient in order to cover and contain draining lesions
  • Prioritize the placement of these patients into the examination/ procedure room so as to minimize the risk of transmission in shared areas
  • See the standard precautions policy for more information.

Additional information can be found in the following policies and procedures:

Transmission based isolation precautions policy

Patient isolation grid

MRSA deisolation procedure

Multi-drug resistant organisms policy

If you have questions regarding a patient's MRSA status call the Infection Prevention and Control Department's mainline at 503 494-6694.