An Overview of MRSA

Simple moves like hand-washing can lower your risk

Microbiologist examining an MRSA bacteria on plate
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The bacteria "staph" (Staphylococcus aureus) normally lives on the skin and sometimes in nasal passages. If an opening in the skin occurs, the bacteria may enter a person's body and cause an infection.

While there are many strains of Staphylococcus aureus, one strain called Methicillin-resistant Staphylococcus aureus (MRSA), is particularly notable because it may cause serious infections due to its resistance to many standard antibiotics.

The upside is that once properly diagnosed, there are antibiotics that can eliminate MRSA. Moreover, MRSA infections can be prevented through frequent hand washing, as well as other personal hygiene habits like keeping skin wounds covered and not sharing personal items.

Types and Symptoms

There are two ways a person can have MRSA—either as a carrier or as an active infection.

  • A carrier means that a person has no symptoms, but the MRSA bacteria are living in their nose or on their skin. This is also called "colonization."
  • An active infection means that the MRSA bacteria has entered a person's body through an opening, (usually, a cut, scrape, or wound), and that person now has symptoms.

There are also two types of MRSA infections, depending on where the MRSA was acquired. These two types are:

  • Community-acquired MRSA (CA-MRSA) infections
  • Hospital-acquired MRSA (HA-MRSA) infections

Community-acquired MRSA Infections

Community-acquired MRSA infections occur in healthy individuals, in the absence of exposure to a healthcare setting, like a hospital, dialysis center, or long-term care facility. Usually, CA-MRSA infections are skin infections, such as folliculitisfurunclescarbuncles, and cellulitis.

Symptoms of a MRSA skin infection are sometimes mistaken for a "spider bite," and include one or more of the following symptoms—swelling, warmth, redness, and tenderness within or surrounding the infected area.

In addition, some people may notice thick, yellowish drainage (called pus) from the center of the infected area, especially if a large, red lump is present. A fever may also be present.

Hospital-acquired MRSA Infections

Hospital-acquired MRSA infections refer to either an infection that occurs more than 48 hours following hospitalization or an infection that occurs outside of the hospital within 12 months of being exposed to a health care facility.

Hospital-acquired MRSA infections are generally more serious and invasive than CA-MRSA infections and often result from surgical wound openings. A HA-MRSA skin or wound infection often appears red and swollen and is painful. It may also drain pus and take on the appearance of an abscess or boil. Fever, chills, muscle aches, and fatigue may also be present.

Hospital-acquired MRSA infections may also occur in the bloodstream and cause sepsis. Sepsis is a phenomenon in which the body launches an extreme inflammatory response to an infection, triggering numerous symptoms and signs, such as:

  • Fever
  • Sweating
  • Rapid heart and breathing rate
  • Confusion
  • Organ failure due to impaired blood flow (called septic shock)

Once in a person's bloodstream, MRSA can land on and infect various tissues or organs, like a heart valve (called endocarditis), a bone (called osteomyelitis), a joint (called a septic joint) or the lungs (called pneumonia).

Once infected, symptoms unique to that tissue or organ will develop. For instance, in the case of MRSA pneumonia, a person may experience fever, chills, muscle aches, shortness of breath, chest pain, and a cough.

Cause and Risk Factors

MRSA is a bacteria that over time, with exposure to antibiotics, has mutated (changed its gene sequencing) to become a strong, super resistant bug. That said, while many people are colonized with Staphylococcus aureus (about 33 percent of the population), only about one percent are colonized with MRSA.

The truth is that anyone can become a carrier of MRSA and then get infected; although your risk increases if you spend a lot of time within places that are crowded and/or entail shared equipment or supplies.

Some of these places include:

  • Daycare centers
  • Prisons
  • Military barracks
  • Athletic facilities

Moreover, if one person within a household has MSRA, it commonly spreads to other household members.

Besides places, there are also factors that increase your risk of getting a MRSA infection. Some of these factors include:

  • Sharing needles or razors
  • History of injection drug use
  • Prior antibiotic use
  • Having a weak immune system

Within the hospital, there are additional risk factors for becoming infected with hospital-acquired MRSA, such as:

  • Having an open wound, catheter, or breathing tube
  • Being in the hospital for a long period of time
  • Residence in a long-term care facility
  • Recent surgery
  • Receiving dialysis

Diagnosis

The definitive way to diagnose a MRSA skin or wound infection is to perform a bacterial culture on pus from the infected site. Culture results are usually available within 24 to 72 hours.

Blood cultures are used to diagnose MRSA bloodstream infections. For suspected infections of the lung, bone, joint, or heart valve, imaging studies will be ordered. For instance, a chest x-ray or a computed tomography (CT) scan can diagnose pneumonia, while an echocardiogram may diagnose endocarditis.

Finally, to diagnose potential carriers of MRSA (this is mainly only done within hospitals or other healthcare facilities), swabs of each patient's nostrils may be performed and sent to a lab for analysis.

Treatment

The mainstay treatment for a MRSA infection is to take an antibiotic, except for minor MRSA skin infections, which may only require drainage of the pus by a healthcare professional, called an I & D, or incision and drainage. Drainage is also used for more serious infections, along with one or more antibiotics that are used to kill the bacteria.

Keep in Mind

If you have a skin infection, it's important to not squeeze, pop, or try to drain any boil or "pimple" on your own, as this can worsen the infection.

Below are the antibiotics typically used to treat MRSA infections:

  • Septra or Bactrim (trimethoprim-sulfamethoxazole)
  • Cleocin HCl (clindamycin)
  • Zyvox (linezolid)
  • Sumycin (tetracycline)
  • Dynacin or Minocin (minocycline)
  • Vibramycin or Doryx (doxycycline)
  • Vancocin (vancomycin)

The antibiotic your doctor chooses will depend on the severity of your illness, as well as any local resistance patterns and available culture data.

Important Note

It's important to take your antibiotic as instructed by your doctor. Be sure to contact your doctor right away if you are experiencing any adverse effects from the medication, or if your infection is not improving or worsening.

If your illness is severe, you may require hospitalization and an intravenous (IV) antibiotic, such as vancomycin. You may also require other treatments in the hospital, such as:

  • Intravenous fluid administration
  • Dialysis (if your kidneys are failing as a result of the infection)
  • Ventilator placement (to help with breathing, if your lungs are failing as a result of the infection)

Decolonization

For patients in the hospital who are found to be carriers of MRSA, a decolonization treatment plan may be initiated at hospital discharge. The main goals of decolonization are to prevent MRSA transmission and future infection.

This treatment plan may be given for five days twice per month for six months and consist of the following three therapies:

  • 4 percent rinse-off chlorhexidine for daily bathing or showering
  • 0.12 percent chlorhexidine mouthwash twice daily
  • 2 percent nasal mupirocin twice daily

For people within the community, decolonization may be recommended for those who keep getting MRSA infections, despite optimizing their hygiene practices, and/or if there is ongoing MRSA transmission to household members.

Keep in Mind

Decolonization, especially within the community, is still an evolving practice with no set guidelines.

Prevention

Personal hygiene measures are key to preventing MRSA infections.

Specific guidelines to follow include:

  • Cover cuts scrapes and wounds with a bandage until healed
  • Don't touch another person's cuts, scrapes, or wounds
  • Don't share personal items like towels, razors, washcloths, clothing, deodorant, or makeup
  • Clean hands often and for at least twenty seconds using soap and water (if not available, use an alcohol-based hand sanitizer)
  • Clean your body regularly, especially after exercise
  • Ensure your doctor washes his or her hands with soap and water before examining you
  • Wipe down exercise equipment before and after use with an alcohol-based solution

A Word From Verywell

MRSA is a bacteria that healthcare providers continue to worry about, considering the serious infections it may cause, and its resistance to numerous traditional antibiotics.

To protect yourself from MRSA, remain proactive in your hand and body hygiene and be sure to see your doctor right away if you think you have a MRSA infection—prompt attention is key to eliminating this superbug.

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