Is there a correlation between Methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization and the development of Ear, Nose, and Throat (ENT) infections?

MRSA Nasal Colonization and ENT Infections: The Connection

MRSA nasal colonization significantly increases the risk of subsequent ENT infections, with colonized individuals having approximately 4 times higher risk of developing invasive MRSA infections compared to non-colonized individuals. 1

Relationship Between MRSA Nasal Colonization and ENT Infections

Pathophysiology and Risk

• Nasal colonization with MRSA serves as an important reservoir for subsequent infections
• The nose is a primary site for Staphylococcus aureus colonization, with approximately 22-37% of the general population carrying S. aureus nasally 2, 1
• MRSA colonization rates vary by population:
  • 7.8% in emergency department patients
  • 6.1% in healthcare workers 2
  • Higher rates in patients with specific risk factors

Risk Factors for MRSA Colonization and Subsequent Infection

• Prior history of MRSA infection
• Recent hospitalization (within preceding year)
• Antibiotic exposure within 3 months before admission
• Comorbidities such as:
  • Immunosuppression
  • Diabetes
  • Chronic obstructive pulmonary disease
  • Congestive heart failure
  • Hemodialysis 2
• Specific high-risk populations:
  • ICU patients (39.1% infection rate in colonized vs. 14.7% in non-colonized) 3
  • Patients undergoing high-risk surgeries (cardiothoracic, orthopedic) 2

Clinical Implications

Screening Recommendations

• Screening for S. aureus/MRSA is recommended before high-risk operations:
  • Cardiothoracic surgery
  • Orthopedic surgery 2
• Screening should be considered for patients with:
  • Recurrent skin and soft tissue infections
  • Ongoing transmission among household members 4

Decolonization Strategies

• Recommended decolonization protocol:
  • Intranasal mupirocin 2% ointment twice daily for 5-10 days
  • Combined with chlorhexidine gluconate 2-4% body washes or dilute bleach baths 4
• Decolonization effectiveness:
  • 89.5% of patients remain decolonized for at least four weeks after proper treatment 4
  • Resistance to mupirocin is a growing concern, requiring monitoring 4

Surgical Prophylaxis for MRSA Carriers

• For MRSA carriers undergoing surgery:
  • Complete decolonization 1-2 weeks before surgery
  • Consider adding vancomycin to standard prophylaxis for MRSA carriers undergoing:
    • Cardiothoracic surgery
    • Orthopedic surgery
    • Neurosurgery 2, 4

Infection Control Considerations

Healthcare Settings

• Implementation of MRSA monitoring programs
• Contact precautions for MRSA-colonized patients
• Proper cleaning and disinfection of equipment and environment
• Education of healthcare workers and patients 2

Community Settings

• Avoid sharing personal items (razors, towels, linens)
• Keep draining wounds covered with clean, dry bandages
• Regular hand hygiene with soap and water or alcohol-based sanitizers
• Focus cleaning on high-touch surfaces 4

Special Populations

Pediatric Considerations

• Children in day-care centers show high colonization rates with S. aureus (29.6%)
• MRSA colonization rates may vary by geographic location 5

Immunocompromised Patients

• Higher risk of progression from colonization to infection
• May require more aggressive screening and decolonization protocols 2

Conclusion

The correlation between MRSA nasal colonization and ENT infections is well-established, with colonization significantly increasing the risk of subsequent infections. Screening and decolonization strategies are particularly important for high-risk populations, including those undergoing surgery or with recurrent infections. The molecular identity between nasal and clinical isolates (up to 75% shared identity) further confirms the direct relationship between colonization and subsequent infection 3.