Skip to main content
InfectiousICD-10: A49.02Causes over 80,000 invasive infections and 11,000 deaths annually in the U.S.

MRSA (Methicillin-Resistant Staphylococcus Aureus)

Also known as: MRSA, Staph Infection, Superbug, Antibiotic-Resistant Staph

MRSA is a type of Staphylococcus aureus bacteria that has developed resistance to methicillin and many other commonly used antibiotics, making infections more difficult to treat than standard staph infections. MRSA infections range from minor skin infections presenting as boils or abscesses to life-threatening bloodstream infections, pneumonia, and surgical site infections. MRSA can be classified as healthcare-associated (HA-MRSA), typically occurring in hospitals and long-term care facilities, or community-associated (CA-MRSA), which affects otherwise healthy individuals in community settings.

Symptoms

Red, swollen, and painful skin bumps resembling pimples or spider bites
Warm, pus-filled abscesses that may need drainage
Fever accompanying skin infection
Wound infections that do not respond to standard antibiotics
Cellulitis with rapidly spreading redness
Pneumonia symptoms in healthcare-associated MRSA (cough, shortness of breath, fever)
Signs of sepsis in severe cases: high fever, rapid heart rate, low blood pressure

Causes

  • Staphylococcus aureus bacteria that have acquired the mecA gene for antibiotic resistance
  • Overuse and misuse of antibiotics driving resistance selection
  • Direct contact with an infected wound or contaminated surfaces
  • Colonization of MRSA on the skin or in the nasal passages without active infection

Risk Factors

  • Hospitalization, surgery, or residence in a long-term care facility
  • Invasive devices such as IV lines, urinary catheters, or ventilators
  • Weakened immune system from HIV, cancer treatment, or organ transplant
  • Close contact sports with skin-to-skin contact (wrestling, football)
  • Crowded living conditions (military barracks, dormitories, prisons)
  • Open wounds, cuts, or skin abrasions

Diagnosis

  • Wound culture and sensitivity testing to identify MRSA and determine effective antibiotics
  • Nasal swab screening for MRSA colonization in hospital settings
  • Blood cultures for suspected bloodstream infections
  • PCR-based rapid diagnostic testing for fast MRSA identification

Treatment

  • Incision and drainage of abscesses (may be sufficient for small skin infections)
  • Antibiotics effective against MRSA: trimethoprim-sulfamethoxazole, doxycycline, or clindamycin for skin infections
  • Intravenous vancomycin, daptomycin, or linezolid for serious systemic infections
  • Wound care and monitoring for treatment response
  • Decolonization protocols (mupirocin nasal ointment, chlorhexidine body wash) for recurrent MRSA
  • Surgical debridement for deep tissue or bone infections

Prevention

  • Wash hands frequently with soap and water or use alcohol-based hand sanitizer
  • Keep cuts, scrapes, and wounds clean, covered, and bandaged
  • Avoid sharing personal items such as towels, razors, and athletic equipment
  • Clean and disinfect surfaces and equipment that may be contaminated
  • Complete the full course of prescribed antibiotics to prevent resistance
  • Shower after contact sports and athletic activities

When to See a Doctor

  • A skin infection does not improve or worsens despite antibiotic treatment
  • You develop a painful, red, swollen, and warm area of skin with pus
  • You have a fever along with skin infection or wound that is not healing
  • You have been in a hospital or care facility and develop signs of infection

Frequently Asked Questions

Related Conditions

Have questions about MRSA (Methicillin-Resistant Staphylococcus Aureus)?

Ask Mother Nature AI for personalized, evidence-based guidance.

Ask about MRSA (Methicillin-Resistant Staphylococcus Aureus)

Medical Disclaimer: This content is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider.

Content reviewed against peer-reviewed medical literature and clinical guidelines. Read our editorial standards.