What is the recommended approach for Methicillin-resistant Staphylococcus aureus (MRSA) and/or Methicillin-susceptible Staphylococcus aureus (MSSA) colonization screening in pediatric patients undergoing cardiothoracic surgery?

MRSA/MSSA Screening in Pediatric Cardiothoracic Surgery

Pediatric patients undergoing cardiothoracic surgery should undergo preoperative screening for both MRSA and MSSA colonization, followed by targeted decolonization and prophylaxis based on screening results. 1

Screening Recommendation

Screen all pediatric patients before elective cardiothoracic surgery for S. aureus (both MRSA and MSSA) using nasal swabs. 1 This recommendation is based on the 2024 European Society of Clinical Microbiology and Infectious Diseases guidelines, which specifically designate cardiothoracic surgery as a high-risk operation requiring preoperative S. aureus screening. 1

Screening Methodology

• Utilize rapid PCR-based screening methods to obtain same-day or next-day results, allowing timely implementation of decolonization protocols before surgery. 2, 3
• Nasal swabs are the primary screening site, though approximately 5% of carriers may have negative nasal cultures but positive cultures at other sites (groin, perianal areas). 4
• Screening should be performed within 30 days of the planned operation to ensure results guide perioperative management. 5

Rationale for Screening in Pediatric Cardiothoracic Surgery

The evidence strongly supports screening in this population for several critical reasons:

• Cardiothoracic surgery carries high risk for surgical site infections (SSIs), which are associated with considerable morbidity, extended hospital stays, increased costs, and mortality. 1
• S. aureus colonization is a known risk factor for SSIs, with colonized patients at increased risk of developing infections caused by their colonizing strain. 1
• MRSA-SSIs in cardiothoracic surgery can lead to long-term disability, hospital readmission, and reoperation. 1
• In pediatric cardiac surgery populations, S. aureus colonization prevalence ranges from 23.5-26.5% for MSSA and 2.9% for MRSA. 6

Post-Screening Management Algorithm

For MSSA-Positive Patients:

Implement decolonization with intranasal mupirocin 2% ointment twice daily PLUS chlorhexidine gluconate 4% body wash daily for 5-10 days. 1, 2

• Complete decolonization 1-2 weeks before surgery for optimal efficacy. 2, 4
• Mupirocin should be applied to anterior nares twice daily. 2, 7
• Chlorhexidine body wash should be used for full-body bathing during the treatment period. 2, 7

For MRSA-Positive Patients:

Implement combined interventions including decolonization PLUS targeted antibiotic prophylaxis. 1

• Decolonization protocol: Same as MSSA (intranasal mupirocin + chlorhexidine baths for 5-10 days). 1, 2
• Targeted prophylaxis: Add vancomycin (15 mg/kg, started 1-2 hours before incision) to standard surgical prophylaxis. 1, 4
• Infection control: Implement contact isolation precautions perioperatively. 5

Evidence Supporting This Approach

The recommendation is based on high-quality guideline evidence showing:

• Screening combined with decolonization reduces MRSA colonization by 47% (odds ratio 0.53,95% CI: 0.37-0.76) in cardiac surgery patients. 5
• MRSA transmission rates decrease by 71% (incidence rate ratio 0.29,95% CI: 0.13-0.65) with screening and decolonization programs. 5
• Surgical site infections decrease by 42% (odds ratio 0.58,95% CI: 0.40-0.86) with comprehensive screening and intervention protocols. 5
• MRSA wound infections decreased by 93% in cardiac surgery patients after implementation of screening and intervention programs. 8
• Overall SSI rates fell from 3.30% to 2.22% with PCR screening combined with targeted interventions. 3

Important Caveats and Implementation Considerations

Universal decolonization without screening should be avoided as it may lead to mupirocin resistance. 1, 2 This is particularly important in pediatric populations where antibiotic stewardship is critical.

Longer duration of preoperative decolonization therapy correlates with better outcomes, with each additional day of therapy associated with decreased postoperative MRSA colonization (odds ratio 0.73,95% CI: 0.53-1.00). 5

Screening implementation requires coordination with antimicrobial stewardship and infection control teams, consideration of laboratory workload, and adequate personnel and economic resources. 1

In pediatric populations specifically, colonization rates vary by age, with younger infants potentially having different colonization patterns. 6 However, this does not change the recommendation to screen all pediatric cardiothoracic surgery patients.

Pediatric-Specific Considerations

While most evidence derives from adult populations, the available pediatric data supports screening:

• One pediatric cohort study found 26.5% S. aureus colonization prevalence in children under 1 year undergoing cardiac surgery. 6
• Though this pilot study did not show significant association between colonization and SSI rates (likely due to small sample size), it demonstrated that ventilator-associated pneumonia rates were significantly higher among S. aureus carriers (22.2% vs 2%, p < 0.05). 6
• The high colonization rate and association with other nosocomial infections supports the screening approach in pediatric populations. 6