What treatment is recommended for a patient with a pre-operative nasal swab positive for Methicillin-Sensitive Staphylococcus Aureus (MSSA)?

Treatment for Pre-operative Nasal Swab Positive for MSSA

For patients with pre-operative nasal swabs positive for Methicillin-Sensitive Staphylococcus Aureus (MSSA), a 5-day decolonization regimen with intranasal mupirocin and chlorhexidine body washes is recommended, followed by appropriate surgical antibiotic prophylaxis based on the type of surgery.

Decolonization Protocol for MSSA Carriers

Recommended Regimen

• Intranasal mupirocin: Apply to both nares 2-3 times daily for 5 days pre-operatively 1
• Chlorhexidine body washes: Daily for 5 days pre-operatively 1

Rationale

• Multiple studies demonstrate that this decolonization protocol significantly reduces surgical site infections (SSIs) in MSSA carriers 1
• The European Society of Clinical Microbiology and Infectious Diseases guidelines support this approach for reducing MSSA-related surgical site infections 1

Surgical Antibiotic Prophylaxis for MSSA Carriers

For Most Surgical Procedures

• First-line prophylaxis: Cefazolin 2g IV 30-60 minutes before incision 1, 2
  • Re-dose if surgery exceeds 4 hours (1g IV) 2
  • For prolonged procedures, continue for 24 hours maximum post-operatively 1

For Specific Surgeries

• Orthopedic surgery with implants/prosthetics: Cefazolin 2g IV pre-op 1
• Cardiac surgery: Cefazolin 2g IV pre-op 1
• Neurosurgery: Cefazolin 2g IV pre-op 3

For Patients with Penicillin/Cephalosporin Allergy

• Non-anaphylactic allergy: Consider cefazolin (if appropriate) 4
• Severe/anaphylactic allergy: Vancomycin 15mg/kg (maximum 1g) IV over 1-2 hours, completed before surgical incision 1, 2
• Alternative: Clindamycin 900mg IV 1

Important Clinical Considerations

Benefits of Targeted Approach

• Studies show significant reduction in SSIs with this protocol:
  • Overall SSI reduction of up to 60% 1
  • MSSA-specific SSI reduction of up to 56% 1

Common Pitfalls to Avoid

1. Don't use vancomycin for MSSA prophylaxis unless truly allergic to beta-lactams

   • Beta-lactams (cefazolin) are superior to vancomycin for MSSA infections 4, 5
   • Vancomycin results in lower cure rates (67.3% vs 84.5%) and higher recurrence rates (14.8% vs 8.9%) compared to cefazolin for MSSA infections 6

2. Don't extend prophylaxis unnecessarily

   • Limit to 24 hours post-operatively in most cases 1
   • Exception: high-risk procedures (e.g., prosthetic joints, cardiac surgery) may warrant 3-5 days 2

3. Don't skip decolonization for MSSA-positive patients

   • Decolonization plus appropriate prophylaxis is more effective than prophylaxis alone 1

Special Populations

• Patients with implantable devices: Consider extended prophylaxis (up to 3-5 days) 2
• Patients with recurrent MSSA infections: May require longer decolonization protocols 1

Monitoring and Follow-up

• Monitor for signs of surgical site infection
• If infection occurs despite prophylaxis, obtain cultures to assess for resistance development
• For MSSA bacteremia treatment (if infection occurs), antistaphylococcal beta-lactams remain first-line therapy 4, 7

This evidence-based approach combining pre-operative decolonization with appropriate surgical prophylaxis provides optimal protection against MSSA surgical site infections while minimizing unnecessary antibiotic exposure.