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Methicillin-Resistant Staphylococcus aureus (MRSA)

MRSA are strains of staphylococcus aureus bacteria that became difficult to treat with commonly used antibiotics. Learn about identifying and treating MRSA, as well as other MRSA facts.

MSSA versus MRSA

Methicillin-sensitive staphylococcus aureus (MSSA) is the common type of staphylococcus aureus that is often found on the skin and in the nose of healthy people. Infections caused by staphylococcus aureus are usually treated with penicillin-type of antibiotics. Methicillin-resistant staphylococcus aureus (MRSA) are strains of staphylococcus aureus bacteria that became difficult to treat with commonly used antibiotics (e.g., penicillin, methicillin, oxacilin, cloxacilin, other antibiotics). These resistant strains have been more often associated with healthcare settings, affecting people with chronic illnesses or those with a weakened immune system. MRSA infections still respond to certain antibiotics as prescribed by your healthcare provider.

Types of MRSA

MRSA was first reported a decade ago and caused infections that were related to healthcare settings (HA-MRSA). Some MRSA strains developed the ability to cause infections in otherwise healthy people and to spread throughout community settings (CA-MRSA).

Healthcare professionals can differentiate between the HA and CA strains. Many characteristics of MRSA are overlapping and some are common to all staphylococcus bacteria.


Symptoms are related to the type of infection and the body site affected by the MRSA infection:

  • Symptoms can range from abscesses (boils) or open wounds to more serious infections affecting the lungs, bones, urinary tract or the bloodstream.
  • CA-MRSA infections are often seen as skin and soft tissue infections, such as folliculitis and abscesses, often thought to be “spider bites” that occur in otherwise healthy people.
  • Bacteria can enter through skin cuts or scrapes into the bloodstream and cause more serious illness.
  • Serious MRSA pneumonia might develop as a complication during an influenza illness.

You might have MRSA and not be affected; however, you can still spread it to others who might become ill.

How MRSA spreads

MRSA is more often spread person to person by direct skin-to-skin contact with a person who already has MRSA. An injury in the skin might allow bacteria that live on the skin to enter inside the body and cause an infection.

All strains of MRSA can also be transmitted indirectly, through unwashed hands or through sharing contaminated clothing, towels, linen, sport-equipment etc. Very rarely, a person with a respiratory infection with MRSA can spread it through the air.

Pets might become infected with MRSA similar to humans, but they do not have a major role in MRSA infection transmission.

People at risk from HA-MRSA

There is an increased risk of acquiring HA-MRSA with:

  • Individuals who have another medical condition (e.g., chronic skin conditions, obesity, diabetes, weaker immune system)
  • Persons with invasive medical devices, including tube feedings
  • Too often or inadequate use of antibiotics

People at risk from CA-MRSA

Risk factors for acquiring CA-MRSA are a bit different from risk factors for HA-MRSA, although there are some overlaps. Higher risk for getting CA-MRSA is related to practices that support transmission of germs from one person to another such as:

  • Close skin-to-skin contact with a person who has MRSA
  • Crowded living conditions
  • Poor hand hygiene
  • Skipping showers before and after using public swimming pools or whirlpools
  • Sharing personal items such as towels, linen, razors or bar soap
  • Improper wound care of skin cuts or open wounds that can allow harmful bacteria throughout the normal skin barrier
  • Touching objects that are contaminated with MRSA such as used bandaids

MRSA on surfaces

MRSA can survive on some surfaces for a long time from hours to days or months, depending on the contaminated surface condition. If surfaces are soiled with organic material, they might allow MRSA to survive for a long period of time. Porous surfaces that cannot be properly cleaned and disinfected will allow MRSA to survive longer than a smooth, easily cleanable surface.

MRSA is not naturally occurring in the environment.


MRSA infections can be treated with antibiotics (other than penicillin type) that are still effective against MRSA. Treatment of skin and soft tissue infections include incision and drainage with or without antibiotics.

Dying from MRSA

On rare occasions, a MRSA infection can result in life-threatening illness or death from complications. Most cases are successfully treated. The effectiveness of treatment is greater if MRSA is detected early.

MRSA numbers

In November 2008, Ontario reported an increase of MRSA cases over a 3-year period. Some of these cases were ill with MRSA infections, and some were MRSA carriers (they only carried the MRSA on their skin or in their nose, without showing symptoms). Starting on December 31, 2008, hospitals are required to publicly report MRSA rates along with other patient safety indicators.

Healthcare professionals are working hard to fight all HA infections.


There is no effective vaccine against MRSA available at this time.

It is important to practice good hygiene step by step:

  1. Wash your hands: Use soap and water or use alcohol-based hand rub for at least 15 seconds. Wash hands after touching any skin lesion, wound drainage (either yours or others) or potentially contaminated environmental surface.
  2. Treat and cover open wounds: Any cut, abrasion or skin lesion might be a point of entry for bacteria, including MRSA. Cleanse wounds, treat with an anti-infective solution or ointment, and cover with a band aid. Keep them clean and covered until they have healed.
  3. Seek healthcare advice: Consult your healthcare provider for any redness or swollen active wound, and for suspicion of a skin infection. Early diagnosis can help you to receive effective treatment.
  4. Shower after each sport activity: Shower with soap and water after sport events and close contact with athletic team to avoid the spread of CA-MRSA.
  5. Never share personal items: Do not share towels, sport uniform, razors, clothing, etc. with others. Exclude athletes from joining your team where there is an open wound or drainage that cannot be contained with a waterproof band aid.
  6. Thoroughly clean gear and equipment: Commonly used surfaces - sport mats, shared equipment, benches - must be washed before and after use. Non-washable items such as head gear must be wiped after each use with a disinfectant.

Protecting others from infection

If you have MRSA, do the following to protect others from infection:

  • Seek medical advice and appropriate treatment for your infection.
  • Keep your wounds clean and covered until they have healed completely.
  • Discard your used band aid and used skin care materials properly, so no other person can accidentally touch them.
  • If your doctor prescribed antibiotic, take it until you have finished the entire prescribed dose. Never share antibiotics with another person.
  • Wash your hands frequently. Use alcohol-based hand rub to disinfect your hands if hands are not visibly soiled.
  • Do not share personal items such as used towels, razors, clothing, bar soap, cosmetics and lotions.
  • If you have wounds that cannot be covered with a waterproof band aid, or if the wound drainage cannot be contained, do not go to swimming pools, public fitness clubs or saunas, and do not participate in team sports.

Family's risk of infection

For casual household contact and if you have good hygiene practices (to protect others), your family is not at great risk of getting MRSA. To protect your family from infection:
  • Maintain a clean environment, and focus cleaning on frequently touched surfaces.
  • Disinfect surfaces after cleaning with a product that destroys microorganisms (e.g., use 1 tablespoon of household bleach in 1 quart of water solution to disinfect washroom surfaces).
  • Wash your dishes and do laundry just like the rest of your household members. You might want to use the hot air cycle for drying.
  • No special cleaning of furniture is needed.
  • Use barriers between your skin and shared equipment - such as sitting on a clean towel if you are using common benches or the same toilet seat.
  • Hand washing is the best prevention that can stop the spread of infection.
  • A member of your family who helps with your personal care, similar to your healthcare provider, must perform good hand hygiene and follow precautions, such as wearing clean and disposable gloves and a long sleeved gown, especially if they can touch your open wound.

Washing your hands

You should wash your hands:

  • After using the washroom
  • After coughing or sneezing
  • Before and after preparing food
  • Before eating and drinking
  • Before and after caring for your wound
  • Whenever your hands become soiled or contaminated