MRSA (Methicillin-Resistant Staphylococcus aureus)
A staph infection resistant to many common antibiotics
Quick Facts
- Type: Bacterial infection
- Cause: Antibiotic-resistant Staphylococcus aureus
- Most common form: Skin and soft tissue infection
- Spreads by: Skin contact, shared items
Overview
MRSA stands for methicillin-resistant Staphylococcus aureus. Staph bacteria normally live harmlessly on the skin and in the nose of many healthy people, but they can cause infection if they enter the body through a cut or scrape. MRSA is a strain of staph that has become resistant to methicillin and several other common antibiotics, which makes these infections harder to treat.
Most MRSA infections involve the skin and appear as a painful red bump, boil, or abscess. Less often, the bacteria reach the bloodstream, lungs, bones, or other organs, causing more serious illness. MRSA is grouped into community-associated infections, which occur in otherwise healthy people, and healthcare-associated infections, which occur in hospitals and care settings.
Symptoms
Skin infections are the most common form. Signs include:
- A red, swollen, painful bump or boil, sometimes mistaken for a spider bite
- An area that is warm to the touch and may drain pus
- Surrounding redness, swelling, or tenderness
- Fever in more serious infections
If MRSA spreads beyond the skin it can cause symptoms such as high fever, chills, chest pain, cough, shortness of breath, severe headache, or a rapidly worsening, very painful area. These signs of a deeper or bloodstream infection need urgent medical care.
Causes
MRSA is caused by staph bacteria that have developed resistance to certain antibiotics. The infection begins when these bacteria get past the skin barrier, usually through:
- Cuts, scrapes, insect bites, or other breaks in the skin
- Surgical wounds or sites where medical devices enter the body
The bacteria spread mainly through direct skin-to-skin contact with an infected person or carrier, or by touching contaminated surfaces and shared items such as towels, razors, or sports equipment. Some healthy people carry MRSA on their skin or in their nose without symptoms and can pass it to others.
Risk Factors
- Recent hospital stay, surgery, or having a medical device such as a catheter
- Living in crowded settings such as dormitories, prisons, or long-term care facilities
- Participation in contact sports with shared equipment and skin contact
- Sharing personal items like towels or razors
- Cuts, scrapes, or skin conditions that break the skin barrier
- A weakened immune system
Diagnosis
Doctors diagnose MRSA by examining the affected area and testing a sample:
- Wound or tissue culture: A swab of pus or fluid is sent to the lab to grow the bacteria and confirm whether it is MRSA.
- Antibiotic susceptibility testing: The lab checks which antibiotics will work, since this guides treatment.
- Blood, urine, or sputum cultures: Used if a deeper infection of the blood, lungs, or other organ is suspected.
Treatment
Treatment depends on where the infection is and how severe it is.
- Drainage: Many skin abscesses are treated by a doctor draining the pus, which is often the most important step.
- Antibiotics that still work: MRSA resists some antibiotics, so doctors choose ones the lab confirms are effective. It is important to finish the full course.
- Hospital care: Severe, bloodstream, or organ infections may need intravenous antibiotics and close monitoring in hospital.
Never squeeze or pop a suspected MRSA boil yourself, as this can spread the infection. Keep the area covered and follow the full treatment plan.
Prevention
- Wash hands often with soap and water or use hand sanitizer
- Keep cuts and scrapes clean and covered until healed
- Do not share towels, razors, clothing, or sports equipment
- Shower after contact sports and wash athletic gear regularly
- Clean and disinfect frequently touched surfaces
- Take antibiotics only as prescribed and finish the full course to limit resistance
When to See a Doctor
See a doctor for any skin bump or wound that is red, swollen, painful, warm, or draining pus, especially if it is getting worse. Seek urgent or emergency care if you develop:
- A high fever, chills, or feeling very unwell
- A rapidly spreading or extremely painful red area
- Chest pain, cough, or shortness of breath
- Confusion, severe headache, or a wound that is worsening quickly
These can be signs of a serious infection spreading beyond the skin.
Frequently Asked Questions
Is MRSA contagious?
Yes. MRSA spreads through direct skin contact with an infected person or carrier and by touching contaminated items such as towels, razors, or sports gear. Good hand hygiene and not sharing personal items help prevent spread.
Why is MRSA harder to treat than other staph?
MRSA has become resistant to methicillin and several other common antibiotics, so the usual drugs may not work. Doctors use cultures to find which antibiotics are still effective and often also drain skin abscesses.
Can MRSA be cured?
Yes. Most skin infections clear up with drainage and the right antibiotics. More serious infections of the blood or organs can also be treated, though they may require hospital care and intravenous antibiotics.
Should I pop a MRSA boil at home?
No. Squeezing or popping it can push bacteria deeper and spread the infection. Keep the area clean and covered and have a doctor drain it if needed.
How can I avoid getting MRSA?
Wash your hands often, keep cuts covered, do not share towels or razors, shower after contact sports, and clean shared surfaces. Using antibiotics only as prescribed also helps limit resistance.
References
- Centers for Disease Control and Prevention (CDC). MRSA (Methicillin-resistant Staphylococcus aureus).
- Mayo Clinic. MRSA infection — Symptoms and causes.
- MedlinePlus, U.S. National Library of Medicine. MRSA.
- World Health Organization (WHO). Antimicrobial resistance.