Does everyone have Methicillin-resistant Staphylococcus aureus (MRSA) on their skin?

MRSA Skin Colonization: Not Universal but Common in Specific Populations

No, not everyone has MRSA on their skin, but certain populations have significantly higher colonization rates and risk factors for carrying MRSA. 1

MRSA Colonization Patterns

MRSA is not a universal skin colonizer but is found more commonly in specific high-risk populations:

• General population has variable colonization rates, but not universal
• High-risk groups show colonization rates of 4-23% among athletes, with wrestlers having particularly high rates 2
• Colonization is significantly more common in healthcare settings and specific community groups

High-Risk Populations for MRSA Colonization

The following groups have higher rates of MRSA colonization:

• Children < 2 years old
• Athletes, especially contact-sport participants like wrestlers
• Injection drug users
• Military personnel
• Inmates of correctional facilities, residential homes, or shelters
• Veterinarians, pet owners, and pig farmers
• Patients with recent antibiotic use (particularly quinolones or macrolides)
• Individuals with history of previous MRSA infection 1

Community vs. Healthcare-Associated MRSA

Two distinct epidemiological patterns exist:

• Community-acquired MRSA (CA-MRSA):

  • Generally susceptible to multiple antibiotics (often resistant only to beta-lactams)
  • Typically carries SCCmec type IV genetic element
  • Often produces Panton-Valentine leucocidin toxin (PVL)
  • Predominantly causes skin and soft tissue infections 1, 3

• Healthcare-associated MRSA (HA-MRSA):

  • More likely to be multi-drug resistant
  • Typically carries SCCmec types I, II, III, VI, and VIII
  • Different genetic background than CA-MRSA 1

Transmission Dynamics

MRSA transmission occurs primarily through:

• Direct skin-to-skin contact with infected individuals
• Contact with contaminated surfaces and shared items
• Entry through breaks in the skin barrier
• Poor hygiene practices 2, 4

Prevention Strategies

For high-risk populations, especially athletes:

• Immediate showering after physical activities
• Regular laundering of clothing
• Proper hand washing techniques
• Avoiding sharing personal items
• Regular cleaning of equipment and facilities
• Routine skin checks before practices and competitions 2

Clinical Implications

When evaluating skin and soft tissue infections:

• Consider MRSA as a potential pathogen, especially in high-risk populations
• Obtain cultures of purulent lesions to guide therapy
• Incision and drainage is the primary treatment for abscesses
• For severe infections requiring antibiotics, consider agents effective against MRSA (linezolid, trimethoprim-sulfamethoxazole, tetracyclines, or vancomycin) 1

Understanding that MRSA is not universally present on everyone's skin but is more common in specific populations helps guide appropriate prevention strategies and treatment approaches for those at higher risk of infection.