What is the recommended treatment for chronic colonization with Methicillin-resistant Staphylococcus aureus (MRSA)?

Treatment of Chronic MRSA Colonization

For chronic MRSA colonization, the recommended treatment is a combination of intranasal mupirocin 2% ointment applied twice daily for 5 days with chlorhexidine gluconate body washes or dilute bleach baths. 1

Decolonization Protocol

First-Line Approach

1. Nasal Decolonization:

   • Mupirocin 2% ointment applied to anterior nares twice daily for 5 days 2, 1
   • Complete the full 10-dose regimen (89.5% effectiveness rate) 1

2. Body Decolonization (choose one):

   • Chlorhexidine gluconate 2-4% body washes daily for 5-14 days 1
   • Dilute bleach baths (1 teaspoon per gallon of water or ¼ cup per ¼ tub) for 15 minutes twice weekly for up to 3 months 2, 1

Special Considerations

• Pre-operative decolonization: Strongly recommended before cardiac and orthopedic surgery (complete 1-2 weeks before surgery) 2
• Household members: Consider evaluating and decolonizing household contacts to prevent recolonization 2, 1
• Site-specific colonization:
  • Throat: Chlorhexidine mouth rinse 3
  • Intestinal: Consider oral vancomycin (if persistent colonization) 3
  • Urinary tract: Consider cotrimoxazole (if persistent colonization) 3

Monitoring and Follow-up

1. Duration of follow-up: Monitor for at least 270 days after decolonization, as 88% of recurrences occur within this timeframe 4

2. Effectiveness assessment:

   • Success rates of 65-87% can be achieved with proper decolonization protocols 3, 4
   • The standardized regimen can reduce post-discharge MRSA infection risk by 30% 5

3. Risk factors for decolonization failure:

   • Respiratory tract colonization (OR 9.1) 4
   • Certain MRSA strains (e.g., spa-type 002) 4
   • Poor adherence to decolonization protocol 5

Management of Persistent Colonization

If initial decolonization fails despite good adherence:

1. Repeat decolonization cycle: Consider up to 2-3 cycles before changing approach 3

2. Consider oral antibiotics (only after topical measures have failed):

   • Rifampin-based combinations (with TMP-SMX or doxycycline) for 5-10 days 2, 1
   • Oral clindamycin 150 mg daily for 3 months for susceptible strains 1

3. Maintenance therapy for recurrent infections:

   • Monthly 5-day courses of mupirocin (can reduce recurrent infections by ~50%) 1

Environmental and Hygiene Measures

1. Personal hygiene:

   • Regular bathing with soap and water 2, 1
   • Hand hygiene with soap or alcohol-based sanitizers 2, 1
   • Keep wounds covered with clean, dry bandages 2

2. Environmental cleaning:

   • Focus on high-touch surfaces (doorknobs, counters, bathroom fixtures) 1
   • Use commercially available cleaners according to instructions 1

3. Personal items:

   • Avoid sharing personal items like towels, razors, and linens 2, 1
   • Wash linens and clothes in hot water when possible 1

Pitfalls and Caveats

1. Mupirocin resistance: Increasing rates of resistance have been reported; consider susceptibility testing if available 1

2. Oral antibiotics: Not routinely recommended for decolonization due to risk of developing resistance and adverse effects 2, 1

3. Chlorhexidine sensitivity: Monitor for skin irritation or allergic reactions 1

4. Bleach baths: Provide clear dilution instructions to prevent skin irritation 2

5. Incomplete decolonization: Failure to address all colonized sites may lead to persistent colonization 3

6. Household transmission: Failure to address household contacts may result in recolonization 6

The evidence strongly supports a structured approach to MRSA decolonization, with the highest quality evidence supporting the combination of intranasal mupirocin and topical antiseptics. This approach has demonstrated significant reductions in MRSA colonization and subsequent infection risk, particularly in high-risk populations such as pre-surgical patients.